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### 5.40 libsys

#### 5.40.1 Overview

View lcov test coverage results on http://www.gnu.org/software/liquidwar6/coverage/src/lib/sys/index.html.

#### 5.40.2 API

— Function: int lw6sys_arg_match (char * keyword, char * argv_string)

> keyword: the option to match, without the prefix "-" or "–"

> argv_string: the argv value, for instance argv[1]

> This is an utility function which allow the program to handle options in a uniform manner. Key comparison is insensitive, that is, –option and –OPTION are equivalent. Besides, -option and –OPTION are equivalent too. Liquid War 6 documentation mentions options in lowercase with a double dash (–option) by default, but it's a fact, the program supports variants. This is just for convenience, the philosophy behind this behavior is "be as permissive as possible when interpreting input, and as strict as possible when generating output". In fact, it's even said that Liquid War 6 will accept the argument without any prefix dash as being valid... This is to say running "liquidwar6 –option" is the same as running "liquidwar6 option". But, this is a secret 8-)

> Return value: non zero if it matches, 0 if it doesn't.

— Function: int lw6sys_arg_exists (int argc, char * [] argv, char * keyword)

> argc: the number of arguments, as passed to `main`

> argv: an array of arguments, as passed to `main`

> keyword: the keyword to match

> Parses all command-line arguments, searching for one precise "–key[=...]" entry.

> Return value: 1 if key is present, 0 if not.

— Function: char * lw6sys_arg_get_value (int argc, char * [] argv, char * keyword)

> argc: the number of arguments, as passed to `main`

> argv: an array of arguments, as passed to `main`

> keyword: the keyword to match

> Parses all command-line arguments, searching for one precise "–key=value" pair, and returns the value.

> Return value: a pointer to the value. May be NULL. Must be freed.

— Function: char * lw6sys_arg_get_value_with_env (int argc, char * [] argv, char * keyword)

> argc: the number of arguments, as passed to `main`

> argv: an array of arguments, as passed to `main`

> keyword: the keyword to match

> Parses all command-line arguments, searching for one precise "–key=value" pair, and returns the value. If a corresponding environment variable is available, but no command-line parameter was passed, the environment variable is intepreted. Such environment variables are uppercased, prefixed by "LW6_" and "_" replaces "-". The environment variable will be overriden if the command-line parameter is present.

> Return value: a pointer to the value. May be NULL. Must be freed.

— Function: int lw6sys_arg_test_mode (int argc, char * [] argv)

> argc: argc as passed to main

> argv: argv as passed to main

> Chooses between the two test modes "check" or "test". Check (value 0) is a lighter test which should never fail even if some special hardware or environment is missing. Test (value 1) is a more complete test which does things which *can* require some special conditions. Function will log and be verbose is syntax is not correct.

> Return value: 1 if complete test must be run, 0 is only check

— Function: lw6sys_assoc_t * lw6sys_assoc_new (lw6sys_free_func_t free_func)

> free_func: optional callback used to free memory when stored date is a pointer. Can be NULL when one stores non dynamically allocated data, such as an integer or a static array.

> Creates an empty assoc. There's a difference between NULL and an empty assoc. The empty assoc would (in Scheme) be '() whereas NULL corresponds to undefined "is not a assoc and will generate errors if you ever call assoc functions on it". Such created assoc are not performant hash tables but slowish "strcmp me for each key" associative arrays, the key being a "char *" string and the value a "void *" pointer.

> Return value: a pointer to the newly allocated associative array. Must be freed with `lw6sys_assoc_free`.

— Function: void lw6sys_assoc_free (lw6sys_assoc_t * assoc)

> assoc: the assoc to be freed.

> The function will cascade delete all elements, using (if not NULL...) the callback passed when first creating the assoc.

> Return value: void

— Function: int lw6sys_assoc_has_key (lw6sys_assoc_t * assoc, char * key)

> assoc: the assoc to test

> key: the key to search

> Not a very fast function, since on a "big" assoc, strcmp will be called internally until the key is found.

> Return value: non-zero if there's an entry with the corresponding key.

— Function: void * lw6sys_assoc_get (lw6sys_assoc_t * assoc, char * key)

> assoc: the assoc to query

> key: the key of which we want the value

> Return value: a void pointer to the data contained in the assoc. Note that the pointer on the actual data is returned, that is, if it's static data, you must not try to free it... As long as memory management is concerned, destroying the assoc will actually free the data if needed.

— Function: void lw6sys_assoc_set (lw6sys_assoc_t ** assoc, char * key, void * value)

> assoc: the assoc to modify

> key: the key we want to updated

> value: the new value

> Sets a value in an associative array. The key pointer need not be persistent, it can be freed after affectation. In fact a new string will be created internally. This is not true for the value, it's hard to find way to copy "any object". So if you want an associative array of strings, key can disappear after calling this function, but not value. The function passed as free_func when creating the assoc will be used to free stuff whenever needed (unset or free).

> Return value: void

— Function: void lw6sys_assoc_unset (lw6sys_assoc_t * assoc, char * key)

> assoc: the assoc concerned

> key: the key to unset

> Clears an entry in an associative array. The callback passed when creating the assoc will be called if needed, to free the data automatically.

> Return value: void

— Function: lw6sys_list_t * lw6sys_assoc_keys (lw6sys_assoc_t * assoc)

> assoc: the assoc to work on

> Returns a list containing all the keys of the assoc. The list must be free with lw6sys_list_free by the caller. This list copies all the keys of the assoc, so it is safe to use it once the assoc is deleted. However the keys will of course be of little interest in this case. But the program won't segfault.

> Return value: the list of keys.

— Function: void lw6sys_assoc_map (lw6sys_assoc_t * assoc, lw6sys_assoc_callback_func_t func, void * func_data)

> assoc: the assoc to work on

> func: a callback to call on each entry

> func_data: a pointer on some data which will be passed to the callback

> Executes a function on all assoc items. The func_data parameter allows you to pass extra values to the function, such as a file handler or any variable which can not be inferred from list item values, and you of course do not want to make global...

> Return value: void

— Function: void lw6sys_assoc_sort_and_map (lw6sys_assoc_t * assoc, lw6sys_assoc_callback_func_t func, void * func_data)

> assoc: the assoc to work on

> func: a callback to call on each entry, may be NULL

> func_data: a pointer on some data which will be passed to the callback

> Executes a function on all assoc items, like `lw6sys_assoc_sort_and_map` but befor doing so, sorts all entries in alphabetical order.

> Return value: void

— Function: lw6sys_assoc_t * lw6sys_assoc_dup (lw6sys_assoc_t * assoc, lw6sys_dup_func_t dup_func)

> assoc: the assoc to duplicate, can be NULL

> dup_func: the function which will be called to duplicate data

> Duplicates an assoc. All keys will be copied so that if the first assoc is deleted, the duplicated one is fine. Additionnaly, dup_func will be called with all data fields. If dup_func is NULL, then data values will simply be copied. This is likely to be usefull when data is not dynamically allocated.

> Returned value: a newly allocated assoc.

— Function: char * lw6sys_backtrace (int skip)

> skip: number of calls to skip

> Returns the current backtrace as a comma separated list. This can typically be used for debugging purposes. Not available on some platforms, including mingw32, it requires backtrace_symbols to be defined. Note that this function calls internal string functions so it makes usage of the sys module in many ways, therefore should be used only in other modules, it can't be used for debugging of internal memory functions for instance. To debug those, use backtrace_symbols_fd directly (or maybe just gdb...). The skip parameter allows you to skip caller's stack, 0 will display everything but `lw6sys_backtrace` itself.

> Return value: dynamically allocated string

— Function: int lw6sys_default_memory_bazooka ()

> Will set up a default memory bazooka, a slow yet convenient tool to track down and hopefully kill memory leaks. Named bazooka after a night wasted to track down an unfoundable leak... BAZOOOOOOKA!!!

> Return value: 1 if success, 0 if failed.

— Function: void lw6sys_clear_memory_bazooka ()

> Clears the memory bazooka.

> Return value: none.

— Function: int lw6sys_set_memory_bazooka_size (int size)

> size: number of items (calls to malloc) to keep

> Resizes, the memory bazooka. What's this? It's an inelegant yet efficient tool to track down memory leak. Memory bazooka will keep track of every call to malloc, keeping a trace of what has been malloced, where it has been called (from which file, which line), how much memory was allocated, it will even show you what's at the address in a 0-terminated string-friendly fashion. Of course this slows down the program, so in production, you might set this to 0, but for debugging, a million bazooka is worth the megabytes and CPU cycles it wastes.

> Return value: 1 if success, 0 if failure.

— Function: int lw6sys_get_memory_bazooka_size ()

> The companion of `lw6sys_set_memory_bazooka_size`. This function will return how many calls to malloc can be traced. A return value of 0 indicates that feature is disabled.

> Return value: size of the bazooka array.

— Function: int lw6sys_set_memory_bazooka_eraser (int state)

> state: the state of the eraser

> Sets the memory bazooka eraser state. Note that to really work, it requires the memory bazooka to be "big enough".

> Return value: 1 if activated, 0 if not. Note that the main reason for it not to be activated is if the memory bazooka has zero size.

— Function: int lw6sys_get_memory_bazooka_malloc_count ()

> Provided you have always called the `LW6SYS_MALLOC` an `LW6SYS_CALLOC` to allocate memory, this function will tell you how many times `malloc` has been called.

> Return value: the number of calls to `lw6sys_malloc` or `lw6sys_calloc` since program was started.

— Function: int lw6sys_get_memory_bazooka_free_count ()

> Provided you have always called the `LW6SYS_FREE` macro to free memory, this function will tell you how many times `free` has been called.

> Return value: the number of calls to `lw6sys_free` since program was started.

— Function: int lw6sys_get_memory_bazooka_malloc_current_count ()

> Provided you have always called the `LW6SYS_MALLOC` an `LW6SYS_CALLOC` to allocate memory, this function will tell you the current number of pointer returned by `LW6SYS_MALLOC` an `LW6SYS_CALLOC`, currently alive on the heap.

> Return value: the number of calls to `lw6sys_malloc` or `lw6sys_calloc` since program was started.

— Function: int lw6sys_get_memory_bazooka_malloc_max_count ()

> Provided you have always called the `LW6SYS_MALLOC` an `LW6SYS_CALLOC` to allocate memory, this function will tell you the maximum of pointers returned by `malloc` that were present at the same time on the heap.

> Return value: the number of calls to `lw6sys_malloc` or `lw6sys_calloc` since program was started.

— Function: int lw6sys_get_memory_bazooka_malloc_megabytes ()

> Provided you have always called the `LW6SYS_MALLOC` an `LW6SYS_CALLOC` to allocate memory, this function will tell you how many bytes `malloc` has reserved.

> Return value: the number of calls to `lw6sys_malloc` or `lw6sys_calloc` since program was started.

— Function: int lw6sys_get_memory_bazooka_free_megabytes ()

> Provided you have always called the `LW6SYS_FREE` macro to free memory, this function will tell you how many bytes `free` has freed.

> Return value: the number of calls to `lw6sys_free` since program was started.

— Function: int lw6sys_get_memory_bazooka_malloc_current_bytes ()

> Provided you have always called the `LW6SYS_MALLOC` an `LW6SYS_CALLOC` to allocate memory, this function will tell you the current number of bytes returned by `LW6SYS_MALLOC` an `LW6SYS_CALLOC`, currently alive on the heap.

> Return value: the number of calls to `lw6sys_malloc` or `lw6sys_calloc` since program was started.

— Function: int lw6sys_get_memory_bazooka_malloc_max_bytes ()

> Provided you have always called the `LW6SYS_MALLOC` an `LW6SYS_CALLOC` to allocate memory, this function will tell you the maximum bytes returned by `malloc` that were present at the same time on the heap.

> Return value: the number of calls to `lw6sys_malloc` or `lw6sys_calloc` since program was started.

— Function: int lw6sys_is_memory_bazooka_trustable ()

> Returns true if memory bazooka data are perfectly trustable, that is, it has never been resetted or resized.

> Return value: 1 if trustable, 0 if not.

— Function: int lw6sys_memory_bazooka_report ()

> Reports memory bazooka diagnostics on the console. Carefull, this one is not reentrant, call at the end of your program when all threads are joined.

> Return value: 1 if no allocated stuff left, 0 if there are still malloc'ed stuff

— Function: char * lw6sys_build_get_package_tarname ()

> Returns the name of the package. This is the `PACKAGE_TARNAME` constant defined by the GNU Autoconf ./configure script. While it's always possible to use the defined constant directly, using this function will return the value defined when compiling the binary, not the one you're using when compiling another program relying on Liquid War as a library.

> Return value: a non-NULL string "liquidwar6", must not be freed.

— Function: char * lw6sys_build_get_package_name ()

> Returns the name of the package, in a user friendly form, which can include spaces, for instance. This is the `PACKAGE_NAME` constant defined by the GNU Autoconf ./configure script. While it's always possible to use the defined constant directly, using this function will return the value defined when compiling the binary, not the one you're using when compiling another program relying on Liquid War as a library.

> Return value: a non-NULL string "Liquid War 6", must not be freed.

— Function: char * lw6sys_build_get_package_string ()

> Returns the description of the package. This is the `PACKAGE_STRING` constant defined by the GNU Autoconf ./configure script. It's the concatenation of `PACKAGE_NAME` and `VERSION`. While it's always possible to use the defined constant directly, using this function will return the value defined when compiling the binary, not the one you're using when compiling another program relying on Liquid War as a library.

> Return value: a non-NULL string "Liquid War 6 <version>", must not be freed.

— Function: char * lw6sys_build_get_version ()

> Returns the version of the program. This is the `VERSION` constant defined by the GNU Autoconf ./configure script. Same as `PACKAGE_VERSION`. Note that while using a function to get `PACKAGE_TARNAME` might seem useless, having both ways to get the version, that is, a function and a constant, is very usefull. Think, for instance, that a dynamically loaded shared library might need to check its own version against the version of the core program.

> Return value: a non-NULL string, which must not be freed.

— Function: char * lw6sys_build_get_codename ()

> Returns the the program codename. This is the little name of the version. It's been decided that all LW6 releases would take the name of a famous general, warrior, whatever. For instance, it could be "Napoleon".

> Return value: a non-NULL string, traditionnally the name of a famous general, someone which has been involved in war. Must not be freed (I mean, the string, not the general).

— Function: char * lw6sys_build_get_stamp ()

> Returns the program stamp. This is like a serial number. It's is not the same as the version. The version is meant to be set to something readable. This is just a cryptic thing, incremented at each ./configure or each developper's "I feel like it needs to be incremented". The idea is just to keep (one more...) track of which source code is build. Ideally, this would be plugged to the source revision control system but this has some drawbacks, including that it would require it to modify files before commiting them, which is not safe, and almost impossible if you sign archives. One more point: this is a string. It's true the return value is actually a string containing the representation of an integer, but because all other build parameters are strings, and because we don't know what the future reserves, it's a string.

> Return value: a non-NULL string like "42", which must not be freed.

— Function: char * lw6sys_build_get_md5sum ()

> Returns an md5 checkum which is caculated from C (.c and .h) source files. This is complementary with the build stamp. By default the stamp will be enough to check what has been compiled, but one can always imagine a case where Bob compiles something a little different than Alice, with the same stamp, incremented by 1 from a common source tree. They apply their own patches, for instance. This md5sum double-checks that two binaries have been built from the same sources. Note that this is not the md5 checksum of the generated binary. Nor does it include any information about scheme scripts and data.

> Return value: a non-NULL string, which must not be freed.

— Function: char * lw6sys_build_get_copyright ()

> Returns a (very) short copyright information about the program.

> Return value: a non-NULL string, single line whithout '\n' at the end. Must not be freed.

— Function: char * lw6sys_build_get_license ()

> Returns the license for the program (GNU GPL v3 or later).

> Return value: a non-NULL string, single line whithout '\n' at the end. Must not be freed.

— Function: char * lw6sys_build_get_url ()

> Returns the URL of the game, its homepage.

> Return value: a non-NULL string, single line whithout '\n' at the end. Must not be freed.

— Function: char * lw6sys_build_get_configure_args ()

> Returns the arguments passed to the GNU Autoconf ./configure script when buildling the game. Very usefull to know how the binary was generated, that is, what kind of optimizations are peculiar settings it uses.

> Return value: a non-NULL string, which, passed to ./configure again, would hopefully generate the same binary. Must not be freed.

— Function: char * lw6sys_build_get_gcc_version ()

> Returns __VERSION__ GCC preprocessor value, that is, the human readable version of the compiler.

> Return value: a non-NULL string, must not be freed.

— Function: char * lw6sys_build_get_cflags ()

> Returns the arguments which would allow another program to use liquidwar6 as a library. Typically, pass this to gcc when compiling your sources. Basically contains "-I" switches which tell where the headers are.

> Return value: a non-NULL string, which must not be freed.

— Function: char * lw6sys_build_get_ldflags ()

> Returns the arguments which would allow another program to link against liquidwar6. Pass this to gcc or libtool when compiling your program. Basically contains a "-L" option which says where the library is. Note that this will only allow you to link against the main libliquidwar6 library, but not the dynamically loaded modules.

> Return value: a non-NULL string, which must not be freed.

— Function: char * lw6sys_build_get_hostname ()

> Returns the value return by the standard shell `hostname` command on the machine where the game has been built. Usefull to track binaries and know where do they come from.

> Return value: a non-NULL string, must not be freed.

— Function: char * lw6sys_build_get_date ()

> Returns the compilation date. While this information can easily be obtained with the C `__DATE__` macro, having this function is convenient for it returns a value which is the same for the whole program, and does not possibly change in every file.

> Return value: a non-NULL string, must not be freed.

— Function: char * lw6sys_build_get_time ()

> Returns the compilation date. While this information can easily be obtained with the C `__TIME__` macro, having this function is convenient for it returns a value which is the same for the whole program, and does not possibly change in every file.

> Return value: a non-NULL string, must not be freed.

— Function: char * lw6sys_build_get_host_cpu ()

> Returns the CPU this program is designed for. Convenient on i386 compatible CPUs to know which flavor (i386, i586...) the binary is made for.

> Return value: a non-NULL string, must not be freed.

— Function: char * lw6sys_build_get_endianness ()

> Returns the endianness of the computer.

> Return value: 'little' (x86-like) or 'big' (ppc-like), as a string. Must not be freed.

— Function: int lw6sys_build_get_pointer_size ()

> Returns the system pointer size, in bytes.

> Return value: 4 for 32-bit, 8 for 64-bit.

— Function: int lw6sys_build_is_x86 ()

> Tells wether CPU belongs to x86 family or not.

> Return value: 1 if x86, 0 if not

— Function: char * lw6sys_build_get_host_os ()

> Returns the OS this program is designed for. Usefull for bug reports.

> Return value: a non-NULL string, must not be freed.

— Function: int lw6sys_build_is_ms_windows ()

> Tells wether the program was compiled for Microsoft Windows, or not.

> Return value: 1 if compiled on windows, 0 if not

— Function: int lw6sys_build_is_mac_os_x ()

> Tells wether the program was compiled for Mac OS X, or not.

> Return value: 1 if compiled on OS X, 0 if not

— Function: int lw6sys_build_is_gp2x ()

> Tells wether the program was compiled for GP2X, or not.

> Return value: 1 if compiled on OS X, 0 if not

— Function: char * lw6sys_build_get_top_srcdir ()

> Returns the top source directory, when the game was built. This can seem useless and non relevant on the end-user's machine, but... it's a must-have for developpers and packagers. Without this, binaries would never find their associated data, especially when building outside the source tree. Or, testing the game would be impossible without installing it, given the fact that most of the code is in scripts that are stored in /usr/local by default, this would be painfull. So this function is here to help finding data within the source tree when the game is not installed yet. Note that the function is rather clever, since it will automatically try to remove useless '../' sequences at the beginning of a possibly relative path.

> Return value: a non-NULL string, must not be freed.

— Function: char * lw6sys_build_get_prefix ()

> Returns the `prefix` value as given to the GNU Autoconf ./configure script. Used to deduce the path to other directories and files.

> Return value: a non-NULL string, "/usr/local" by default. Must not be freed.

— Function: char * lw6sys_build_get_datadir ()

> Returns the `datadir` value defined by the GNU Autoconf ./configure script. This is not the value which can be overriden by the Liquid War 6 specific. "–data-dir" option. `datadir` is usually something like "/usr/local/share" while the actual Liquid War 6 defined data dir is a more profound path which includes the name of the package, its version, and so on.

> Return value: a non-NULL string, "/usr/local/share" by default. Must not be freed.

— Function: char * lw6sys_build_get_libdir ()

> Returns the `libdir` value defined by the GNU Autoconf ./configure script. This is not the value which can be overriden by the Liquid War 6 specific. "–mod-dir" option. `libdir` is usually something like "/usr/local/lib" while the actual Liquid War 6 defined module dir is a more profound path which includes the name of the package, its version, and so on.

> Return value: a non-NULL string, "/usr/local/lib" by default. Must not be freed.

— Function: char * lw6sys_build_get_includedir ()

> Returns the `includedir` value defined by the GNU Autoconf ./configure script. As for other options, it's interesting to have this value, this enables the program to inform people who want to hack the game of the place headers are supposed to be installed.

> Return value: a non-NULL string, "/usr/local/include" by default. Must not be freed.

— Function: char * lw6sys_build_get_localedir ()

> Returns the `localedir` value defined by the GNU Autoconf ./configure script. Used as an argument for gettext / libintl functions.

> Return value: a non-NULL string, "/usr/local/share/locale" by default. Must not be freed.

— Function: char * lw6sys_build_get_docdir ()

> Returns the `docdir` value defined by the GNU Autoconf ./configure script. Used to write consistent XML file headers.

> Return value: a non-NULL string, "/usr/local/share/doc/liquidwar6" by default. Must not be freed.

— Function: char * lw6sys_build_get_enable_console ()

> Tells wether console is enabled or not.

> Return value: "yes" or "no", must no be freed.

— Function: char * lw6sys_build_get_enable_gtk ()

> Tells wether gtk is enabled or not.

> Return value: "yes" or "no", must no be freed.

— Function: char * lw6sys_build_get_enable_mod_gl ()

> Tells wether the graphical mod-gl backend was compiled.

> Return value: "yes" or "no", must no be freed.

— Function: char * lw6sys_build_get_enable_mod_csound ()

> Tells wether the audio mod-csound backend was compiled.

> Return value: "yes" or "no", must no be freed.

— Function: char * lw6sys_build_get_enable_mod_ogg ()

> Tells wether the audio mod-ogg backend was compiled.

> Return value: "yes" or "no", must no be freed.

— Function: char * lw6sys_build_get_enable_mod_http ()

> Tells wether the network mod-http backend was compiled.

> Return value: "yes" or "no", must no be freed.

— Function: char * lw6sys_build_get_enable_openmp ()

> Tells wether the game was compiled with openmp support.

> Return value: "yes" or "no", must no be freed.

— Function: char * lw6sys_build_get_enable_optimize ()

> Tells wether the game was compiled in optimize mode.

> Return value: "yes" or "no", must no be freed.

— Function: char * lw6sys_build_get_enable_allinone ()

> Tells wether the game was compiled in allinone mode.

> Return value: "yes" or "no", must no be freed.

— Function: char * lw6sys_build_get_enable_fullstatic ()

> Tells wether the game was compiled in fullstatic mode.

> Return value: "yes" or "no", must no be freed.

— Function: char * lw6sys_build_get_enable_paranoid ()

> Tells wether the game was compiled with paranoid memory management.

> Return value: "yes" or "no", must no be freed.

— Function: char * lw6sys_build_get_enable_gprof ()

> Tells wether the game was compiled with suitable informations for gprof.

> Return value: "yes" or "no", must no be freed.

— Function: char * lw6sys_build_get_enable_instrument ()

> Tells wether the game was compiled with the '-finstrument-fonctions' GCC flag.

> Return value: "yes" or "no", must no be freed.

— Function: char * lw6sys_build_get_enable_profiler ()

> Tells wether the game was compiled for later use with Google Profiler support.

> Return value: "yes" or "no", must no be freed.

— Function: char * lw6sys_build_get_enable_gcov ()

> Tells wether the game was compiled with suitable informations for gcov.

> Return value: "yes" or "no", must no be freed.

— Function: char * lw6sys_build_get_enable_valgrind ()

> Tells wether the game was compiled for later use with valgrind.

> Return value: "yes" or "no", must no be freed.

— Function: int lw6sys_build_get_bin_id ()

> Returns the internal bin-id value, which does not mean anything but changes at each build.

> Return value: an integer

— Function: void lw6sys_build_log_all ()

> Dumps in the log file the whole program pedigree, host, modules, that is, what are the values of all the build options. Usefull for bug reports.

> Return value: none.

— Function: u_int32_t lw6sys_checksum (unsigned char * data, int len)

> data: the data to process

> len: the length, in bytes, of the data to process

> Creates a checksum from a byte array. This could be mapped on any standard CRC-32 and/or MD5 algorithm, but licence issues for those are such a headache that for the sake of simplicity, it's wrapped here. In LW6 context, we do not really really fear any attack for these checksums are used internally to track bugs and check, for instance, that two game states are actually the same on two distant computers in a network game. Data encryption and security of network links is another debate. Additionnally, this function returns an integer, easier to handle in standard C than any malloc'ed stuff.

> Return value: the checksum, as an integer.

— Function: u_int32_t lw6sys_checksum_str (char * value)

> value: the string to process

> Creates a checksum from a string. This is a convenience function to save the programmer the hassle of calling strlen before any checksum calculation.

> Return value: the checksum, as an integer.

— Function: u_int32_t lw6sys_checksum_int32 (u_int32_t value)

> value: the integer to process

> Creates a checksum from an integer. This is a convenience function to save the programmer the hassle of passing a pointer to the integer with the size of it each time there's a checksum to do. Additionnally, with this one you can pass an int8 or an int16, and function will work just the same indenpendantly of endianness.

> Return value: the checksum, as an integer.

— Function: u_int32_t lw6sys_checksum_int64 (u_int64_t value)

> value: the integer to process

> Creates a checksum from an integer. This is a convenience function to save the programmer the hassle of passing a pointer to the integer with the size of it each time there's a checksum to do. This function handles 64-bit long long integers..

> Return value: the checksum, as an integer.

— Function: u_int32_t lw6sys_checksum_whd (lw6sys_whd_t * whd)

> whd: a pointer to the wh struct to be processed

> Creates a checksum from the given structure. Convenience function to save the hassle of passing a pointer to and the size of the `lw6sys_wh_t` struct each time, knowing that there are very often checksums calculated on it. Also avoids endianess issues.

> Return value: the checksum, as an integer.

— Function: u_int32_t lw6sys_checksum_xyz (lw6sys_xyz_t * xyz)

> xyz: a pointer to the xy struct to be processed

> Creates a checksum from the given structure. Convenience function to save the hassle of passing a pointer to and the size of the `lw6sys_xy_t` struct each time, knowing that there are very often checksums calculated on it. Also avoids endianess issues.

> Return value: the checksum, as an integer.

— Function: void lw6sys_checksum_update (u_int32_t * checksum, unsigned char * data, int len)

> checksum: a pointer to the previous checksum

> data: the data to process

> len: the length, in bytes, of the data to process

> Creates a checksum from the given data. The difference with `lw6sys_checksum` is that this one updates an existing checksum, thus enabling the programmer to call it sequentially and get a global checksum on different sources.

> Return value: none.

— Function: void lw6sys_checksum_update_str (u_int32_t * checksum, char * value)

> checksum: a pointer to the previous checksum

> value: the string to process

> Creates a checksum from the given string. The difference with `lw6sys_checksum_str` is that this one updates an existing checksum, thus enabling the programmer to call it sequentially and get a global checksum on different sources.

> Return value: none.

— Function: void lw6sys_checksum_update_int32 (u_int32_t * checksum, int32_t value)

> checksum: a pointer to the previous checksum

> value: the integer to process

> Creates a checksum from the given integer. The difference with `lw6sys_checksum_int32` is that this one updates an existing checksum, thus enabling the programmer to call it sequentially and get a global checksum on different sources.

> Return value: none.

— Function: void lw6sys_checksum_update_int64 (u_int32_t * checksum, int64_t value)

> checksum: a pointer to the previous checksum

> value: the integer to process

> Creates a checksum from the given integer. The difference with `lw6sys_checksum_int64` is that this one updates an existing checksum, thus enabling the programmer to call it sequentially and get a global checksum on different sources.

> Return value: none.

— Function: void lw6sys_checksum_update_whd (u_int32_t * checksum, lw6sys_whd_t * whd)

> checksum: a pointer to the previous checksum

> whd: a pointer to the wh struct to be processed

> Creates a checksum from the given structure. The difference with `lw6sys_checksum_whd` is that this one updates an existing checksum, thus enabling the programmer to call it sequentially and get a global checksum on different sources.

> Return value: none.

— Function: void lw6sys_checksum_update_xyz (u_int32_t * checksum, lw6sys_xyz_t * xyz)

> checksum: a pointer to the previous checksum

> xyz: a pointer to the xy struct to be processed

> Creates a checksum from the given structure. The difference with `lw6sys_checksum_xyz` is that this one updates an existing checksum, thus enabling the programmer to call it sequentially and get a global checksum on different sources.

> Return value: none.

— Function: u_int8_t lw6sys_color_float2char (float f)

> f: the value to convert, from 0.0f to 1.0f

> Converts a floating point value between 0.0f and 1.0f to its 8-bit equivalent between 0 and 255. Usefull in color conversion.

> Return value: an integer between 0 and 255.

— Function: float lw6sys_color_char2float (u_int8_t i)

> i: the value to convert, from 0 to 255

> Converts an 8-bit value between 0 and 255 to its floating-point equivalent between 0.0f and 1.0f. Usefull in color conversion.

> Return value: a float between 0.0f and 1.0f.

— Function: lw6sys_color_8_t lw6sys_color_f_to_8 (lw6sys_color_f_t * color_f)

> color_f: the color to convert

> Converts a color from floating point format to the integer "0 to 255" common format. All fields (RGBA) are converted.

> Return value: the color in 8-bit format.

— Function: void lw6sys_color_8_to_f (lw6sys_color_f_t * color_f, lw6sys_color_8_t color_8)

> color_f: the converted color (pointer must point to writable memory)

> color_8: the color to convert

> Converts a color from the integer "0 to 255" common format to floating point format. All fields (RGBA) are converted.

> Return value: none.

— Function: u_int32_t lw6sys_color_f_to_i (lw6sys_color_f_t * color_f)

> color_f: the color to convert

> Converts a color from floating point format to a single integer, where all fields (RGBA) are serialized. This serialization is endianess independant. Could be used directly by low-level libraries such as SDL.

> Return value: the color serialized in an integer.

— Function: u_int32_t lw6sys_color_8_to_i (lw6sys_color_8_t color_8)

> color_8: the color to convert

> Converts a color from common "0 to 255" structured format to a single integer, where all fields (RGBA) are serialized. This serialization is endianess independant. Could be used directly by low-level libraries such as SDL.

> Return value: the color serialized in an integer.

— Function: void lw6sys_color_i_to_f (lw6sys_color_f_t * color_f, u_int32_t color_i)

> color_f: the converted color (point must point to writable memory)

> color_i: the color to convert

> Converts a color from a serialized integer format to a floating point structure.

> Return value: none.

— Function: lw6sys_color_8_t lw6sys_color_i_to_8 (u_int32_t color_i)

> color_i: the color to convert

> Converts a color from a serialized integer format to a "0 to 255" based structure.

> Return value: the converted color (structure).

— Function: lw6sys_color_8_t lw6sys_color_a_to_8 (char * ascii)

> ascii: the color to convert

> Converts a color from a human readable string to a "0 to 255" based structure. The string must be of the form "#RRGGBBAA" or "#RGB", in a general manner any HTML-valid value should work.

> Return value: the converted color (structure).

— Function: void lw6sys_color_a_to_f (lw6sys_color_f_t * color_f, char * ascii)

> color_f: the converted color (pointer must point to writable memory)

> ascii: the color to convert

> Converts a color from a human readable string to a float based structure. The string must be of the form "#RRGGBBAA" or "#RGB", in a general manner any HTML-valid value should work.

> Return value: none.

— Function: char * lw6sys_color_8_to_a (lw6sys_color_8_t color_8)

> color_8: the color to convert

> Converts a color from a "0 - 255" integer based structure to its readable form "#RRGGBBAA". If alpha is 255 (0xFF), that is, if it's opaque, then the "AA" part is ommitted.

> Return value: a newly allocated string.

— Function: void lw6sys_color_rgb_to_hsv (lw6sys_color_hsv_t * color_hsv, lw6sys_color_8_t color_8)

> color_hsv: the target color, in HSV format

> color_8: the source color, in RGB 256 format

> Converts from HSV to RGB. Usefull for color manipulation, since most colors are stored in RGB but HSV is convenient for transformation. Alpha layer is kept as is.

> Return value: none.

— Function: lw6sys_color_8_t lw6sys_color_hsv_to_rgb (lw6sys_color_hsv_t * color_hsv)

> color_hsv: the source color, in HSV format

> Converts from RGB to HSV. Usefull to make colors transformed in HSV format usable again by all display routines, which consume RGB. Alpha layer is kept as is.

> Return value: the RGB color.

— Function: lw6sys_color_8_t lw6sys_color_average (int size, lw6sys_color_8_t * colors)

> size: number of the color array (number of items)

> colors: the colors to compute

> Tries to find out the "average" color from an array of colors. The algorithm is far from perfect, but should output a color which reflects the colors passed in.

> Return value: the (inexact) average color.

— Function: lw6sys_color_8_t lw6sys_color_ponderate (lw6sys_color_8_t color1, lw6sys_color_8_t color2, float coeff)

> color1: first color

> color2: second color

> coeff: the ponderation coefficient

> Tries to find a color between the two colors passed as an argument. The coefficient can be used, to set the relative weight of each color. Using 0 will return color1, 1 will return color2 and 0.5 will make an average between the two colors. Any value between 0 and 1 can be used.

> Return value: the (inexact) ponderated color.

— Function: float lw6sys_color_distance (lw6sys_color_8_t color1, lw6sys_color_8_t color2)

> color1: first color

> color2: second color

> Calculates the distance between two colors. The unit is arbitrary, a big value means "colors are different", 0 means they are the same. A distance of 1 corresponds to colors which have barely anything in common, but the result can still be greater than 1. Alpha layer is not taken in account.

> Return value: the distance.

— Function: int lw6sys_color_is_same (lw6sys_color_8_t color1, lw6sys_color_8_t color2)

> color1: the first color to compare

> color2: the second color to compare

> Compares two colors.

> Return value: 1 if they are the same, 0 if not.

— Function: void lw6sys_color_8_solid (lw6sys_color_8_t * color)

> color: the color to modify

> Make a color "solid" that is make it not transparent at all.

> Return value: none.

— Function: void lw6sys_color_f_solid (lw6sys_color_f_t * color)

> color: the color to modify

> Make a color "solid" that is make it not transparent at all.

> Return value: none.

— Function: int lw6sys_atoi (char * str)

> str: string to convert

> Just a plain wrapper on `atoi`, it's here for API consistency.

> Return value: an integer.

— Function: int lw6sys_atob (char * str)

> str: string to convert

> Transform a string into a boolean value. Accepts "0"/"1" in input, but also y/n, yes/no, true/false, on/off.

> Return value: an integer, 0 or 1.

— Function: float lw6sys_atof (char * str)

> str: string to convert

> A wrapper on `atof`, makes sure the locale used is C (default) and won't change the decimal separator whatsoever. Usefull for serialization for instance.

> Return value: a float.

— Function: char * lw6sys_itoa (int value)

> value: the integer to convert

> Converts an integer to a string, the advantage of this function is it allocates memory, and does the dirty job.

> Return value: a newly allocated pointer, must be freed, may be NULL.

— Function: char * lw6sys_btoa (int value)

> value: the boolean to convert

> Converts a boolean to a string, the advantage of this function is it allocates memory, and does the dirty job.

> Return value: a newly allocated pointer, must be freed, may be NULL.

— Function: char * lw6sys_ftoa (float value)

> value: the float to convert

> Converts a float to a string, the advantage of this function is it allocates memory, and does the dirty job.

> Return value: a newly allocated pointer, must be freed, may be NULL.

— Function: char * lw6sys_daemon_pid_file (int argc, char * [] argv)

> argc: argc as passed to `main`

> argv: argv as passed to `main`

> Get the default pid file, used to lock daemon and avoid 2 daemons running at the same time.

> Return value: newly allocated string

— Function: int lw6sys_daemon_start (char * pid_file)

> pid_file: the pid file used for the daemon

> Calls `fork`() internally to put the process in the program, make it a daemon. Note this won't work on all platforms, for instance it won't work on MS-Windows but this is rarely an issue as MS-Windows users are rarely concerned with detaching a program from a tty. Note that this isn't a wrapper on `fork`(), the return value is different, 1 on success, 0 if failed.

> Return value: a process ID on success, 0 on failure.

— Function: int lw6sys_daemon_stop (char * pid_file)

> pid_file: the pid file used for the daemon

> Removes the daemon pid file. Can be called safely even if daemon wasn't started.

> Return value: 1 on success, 0 on failure

— Function: int lw6sys_debug_get ()

> Gets the debug mode.

— Function: void lw6sys_debug_set (int mode)

> mode: the debug mode, 1 if set, 0 if not.

> Sets the debug mode.

— Function: void lw6sys_dump_clear (char * user_dir)

> user_dir: the user directory, where user can write data.

> Clears the dump file. That is, resets it to a "0 byte" file.

> Return value: none.

— Function: int lw6sys_dump (char * user_dir, char * content)

> user_dir: the user directory, where user can write data.

> content: the content to be written in the dump file.

> Writes the dump file onto the disk. The dump is used for special error messages which do not really fit in the standard log, and require a special treatment. In pratice, it's used to log fatal script (Guile) errors.

> Return value: 1 if success, 0 if failure.

— Function: char lw6sys_env_separator_char ()

> Gets the ENV separator, that is, for instance, the character used to separate paths in environment variables. Typically, this would be ":" on GNU and ";" on Microsft platforms.

> Return value: the ascii character code.

— Function: char * lw6sys_env_separator_str ()

> Gets the ENV separator, that is, for instance, the character used to separate paths in environment variables. Typically, this would be ":" on GNU and ";" on Microsft platforms.

> Return value: a pointer to a single 0-terminated character string which contains the character. Must not be freed.

— Function: char * lw6sys_env_concat (char * value1, char * value2)

> value1: the left part to be concatenated

> value2: the right part to be concatenated

> Concatenates two values and puts the ENV separator, as returned by `lw6sys_env_separator_char` between them.

> Return value: the concatenated string, must be freed.

— Function: int lw6sys_env_exists_prefixed (char * keyword)

> keyword: the keyword to be searched in the environment variables.

> Searches environment variables for the given keyword. The keyword will be fixed so that all dashes "-" characters are replaced by underscores "_" characters. Characters will be changed to uppercase. Any non alphanumeric character will be replaced by "_". Finally, an "LW6_" prefix will be added. That is to say, calling this function with "my-param" will search for the "LW6_MY_PARAM" environment variable.

> Return value: 1 if the environment variable exists, 0 if not.

— Function: char * lw6sys_getenv (char * key)

> key: the environment variable to get.

> Searches environment variables for the given value. This is a wrapper over the standard C getenv, the difference is it will return a dynamically allocated pointer, and on some platforms will query specific OS functions.

> Return value: the value for the given keyword. May be NULL. Must be freed.

— Function: char * lw6sys_getenv_prefixed (char * keyword)

> keyword: the keyword to be searched in the environment variables.

> Searches environment variables for the given value. The keyword will be fixed so that all dashes "-" characters are replaced by underscores "_" characters. Characters will be changed to uppercase. Any non alphanumeric character will be replaced by "_". Finally, an "LW6_" prefix will be added. That is to say, calling this function with "my-param" will search for the "LW6_MY_PARAM" environment variable.

> Return value: the value for the given keyword. May be NULL. Must be freed.

— Function: int lw6sys_setenv (char * keyword, char * value)

> keyword: the environment variable to set

> value: the value of the environment variable to set

> Sets the environment variable to a given value. If value is NULL, variable is unset. Note that unlike lw6sys_getenv_prefixed, this function does not transform the keyword into "LW6_..." before setting the value, so it's your responsability to call "lw6sys_keyword_as_env" if needed.

> Return value: 1 if success, 0 if failed

— Function: int lw6sys_setenv_prefixed (char * keyword, char * value)

> keyword: the keyword to be searched in the environment variables.

> value: the value of the environment variable to set

> Sets the environment variable to the given value. The keyword will be fixed so that all dashes "-" characters are replaced by underscores "_" characters. Characters will be changed to uppercase. Any non alphanumeric character will be replaced by "_". Finally, an "LW6_" prefix will be added. That is to say, calling this function with "my-param" will set the "LW6_MY_PARAM" environment variable.

> Return value: 1 if success, 0 if failure

— Function: lw6sys_list_t * lw6sys_env_split (char * value)

> value: the value, a list of item separated by... the separator

> Splits the environment value into a list of strings containing each element. All strings are dynamically allocated, but they will be freed automatically when the list is freed.

> Return value: a list of strings.

— Function: char * lw6sys_get_home ()

> Gets the home directory of the user. Used internally to calculate the `user`-dir value. Note that Liquid War 6, by default, never stores files under '$HOME', instead it put things in '$HOME/.liquidwar6', that is 'user-dir'. If the environment variable 'HOME' is not set, will return '.'.

> Return value: a newly allocated pointer, must be freed.

— Function: char * lw6sys_get_username ()

> Gets the name of the current user. Difference with the standard function `getlogin` is that this function will returned a dynamically allocated pointer, and provide a default value if it's undefined. Also, if will look at the content of the 'LOGNAME' environment variable if needed, and will even provide a default value.

> Return value: a newly allocated pointer, must be freed.

— Function: char * lw6sys_get_hostname ()

> Gets the name of the current host. The name of the computer. Might not work perfectly, this function is just used to provide default values for player names and such things.

> Return value: a newly allocated pointer, must be freed.

— Function: char * lw6sys_escape_http_uri (char * src)

> src: the string to escape

> Transforms a string so that it does not contain any non-valid URL chars, it will mostly convert chars over 128 into their XY form where XY is the hexadecimal code. Note that this function is non really standard compliant for it won't encode '%' but keep it the same. This is to allow using it several times on the same string and avoid double-triple encoding of '%'. In practice it's not recommended to have public_url for nodes with '%' in them, and the program will never generate such url when guessing urls.

> Return value: newly allocated string.

— Function: char * lw6sys_escape_html_attribute (char * src)

> src: the string to escape

> Transforms a string so that it can fit in a html field, this is typically for alt="" or title="" fields so it will convert " into `quot`;.

> Return value: newly allocated string.

— Function: char * lw6sys_escape_sql_value (char * src)

> src: the string to escape

> Transforms a string so that it can fit as an SQL parameter, it will get rid URL chars, it will mostly convert chars over 128 into their XY form where XY is the hexadecimal code.

> Return value: newly allocated string.

— Function: char * lw6sys_exec_find_myself (int argc, char * [] argv)

> argc: number of args as passed to main

> argv: array of args as passed to main

> Finds the path of the program currently run, this is typically to pass it to `lw6sys_exec_again` and run it again.

> Return value: the path (newly allocated string).

— Function: int lw6sys_is_executed_again (int argc, char * [] argv)

> argc: number of args as passed to main

> argv: array of args as passed to main

> Tells wether the program is already executed by itself by `lw6sys_exec_again` function. Based on environment and command switches.

> Return value: 1 if executed again, 0 if not.

— Function: int lw6sys_exec_again (int argc, char * [] argv)

> argc: number of args as passed to main

> argv: array of args as passed to main

> Runs the program from itsef, that is fires a new program (the same running) and ends up the current one. This is used to fix some environment variable issues. If LW6_EXECUTED_AGAIN (environment variable) is set, will not run the program so this is not really like `exec` as in the C standard library, this function will actually return and be successfull even if no other process was started. It's just designed to bootstrap/launch the process once.

> Return value: 1 on success, 0 on failure (always fail)

— Function: int lw6sys_exec_restart (int argc, char * [] argv)

> argc: number of args as passed to main

> argv: array of args as passed to main

> Restart the program with exactly the same arguments it was given the first time.

> Return value: 1 on success, 0 on failure (always fail)

— Function: int lw6sys_clear_file (char * filename)

> filename: absolute or relative filename

> Clears a file, that is, make it a 0 byte file, empty, ready to be filled if needed. If this function is called successfully, program can reasonnably assume file will be writable during its execution.

> Return value: 1 if success, 0 if failure.

— Function: char * lw6sys_read_file_content (char * filename)

> filename: absolute or relative filename

> Reads the content of a file, and returns it as a string. Note that content might or might not be ascii or binary, the function will however put a tailing 0 character at the end so that low-level standard C functions do not segfault when used with the returned value.

> Return value: a newly allocated pointer, must be freed.

— Function: void * lw6sys_read_file_content_bin (int * filesize, char * filename)

> filesize: will contain the file size, in bytes

> filename: absolute or relative filename

> Reads the content of a file, and returns it as a binary buffer. Even if not ascii or binary, the function will however put a tailing 0 character at the end so that low-level standard C functions do not segfault when used with the returned value. This 0 character is not included in `filesize` so if there are 4 bytes in the file the 5 bytes will be allocated, this is just for string functions not to explode if called by accident. The `filesize` can be NULL, in that case function is just like the `lw6sys_read_file_content` function.

> Return value: a newly allocated pointer, must be freed.

— Function: int lw6sys_write_file_content (char * filename, char * content)

> filename: absolute or relative filename

> content: the content to be written.

> Writes the content into the file. Content is assumed to be a string, function will segfault if it's not correctly 0 terminated as in C string convention. So this function will not allow you to write down arbitrary binary data, however LW6 uses mostly text files to store information, and opaque binary data usage is not recommended.

— Function: lw6sys_hash_t * lw6sys_hash_new (lw6sys_free_func_t free_func, int size)

> free_func: optional callback used to free memory when stored date is a pointer. Can be NULL when one stores non dynamically allocated data, such as an integer or a static array.

> size: the estimated size of the hash table. Note that this is an estimation only. You could theorically fit 1000000 objects in a 3-sized hash. Problem -> this is inefficient, you'd better use an assoc or a bigger hash. If you store 3 elements in a 1000000-sized hash, you'll waste memory. It might be wise to use a prime number as the estimated size. 421 is prime ;)

> Creates an empty hash. There's a difference between NULL and an empty hash.

> Return value: a pointer to the newly allocated hash table. Must be freed with `lw6sys_hash_free`.

— Function: void lw6sys_hash_free (lw6sys_hash_t * hash)

> hash: the hash to be freed.

> The function will cascade delete all elements, using (if not NULL...) the callback passed when first creating the hash.

> Return value: void

— Function: int lw6sys_hash_has_key (lw6sys_hash_t * hash, char * key)

> hash: the hash to test

> key: the key to search

> Not a very fast function, since on a "big" hash, strcmp will be called internally until the key is found.

> Return value: non-zero if there's an entry with the corresponding key.

— Function: void * lw6sys_hash_get (lw6sys_hash_t * hash, char * key)

> hash: the hash to query

> key: the key of which we want the value

> Return value: a void pointer to the data contained in the hash. Note that the pointer on the actual data is returned, that is, if it's static data, you must not try to free it... As long as memory management is concerned, destroying the hash will actually free the data if needed.

— Function: void lw6sys_hash_set (lw6sys_hash_t * hash, char * key, void * value)

> hash: the hash to modify

> key: the key we want to updated

> value: the new value

> Sets a value in a hash table. The key pointer need not be persistent, it can be freed after affectation. In fact a new string will be created internally. This is not true for the value, it's hard to find way to copy "any object". So if you want a hash table of strings, key can disappear after calling this function, but not value. The function passed as free_func when creating the hash will be used to free stuff whenever needed (unset or free).

> Return value: void

— Function: void lw6sys_hash_unset (lw6sys_hash_t * hash, char * key)

> hash: the hash concerned

> key: the key to unset

> Clears an entry in a hash table. The callback passed when creating the hash will be called if needed, to free the data automatically.

> Return value: void

— Function: lw6sys_list_t * lw6sys_hash_keys (lw6sys_hash_t * hash)

> hash: the hash to work on

> Returns a list containing all the keys of the hash. The list must be free with lw6sys_list_free by the caller. This list copies all the keys of the hash, so it is safe to use it once the hash is deleted. However the keys will of course be of little interest in this case. But the program won't segfault.

> Return value: the list of keys.

— Function: void lw6sys_hash_map (lw6sys_hash_t * hash, lw6sys_assoc_callback_func_t func, void * func_data)

> hash: the hash to work on

> func: a callback to call on each entry

> func_data: a pointer on some data which will be passed to the callback

> Executes a function on all hash items. The func_data parameter allows you to pass extra values to the function, such as a file handler or any variable which can not be inferred from list item values, and you of course do not want to make global...

> Return value: void

— Function: void lw6sys_hash_sort_and_map (lw6sys_hash_t * hash, lw6sys_assoc_callback_func_t func, void * func_data)

> hash: the hash to work on

> func: a callback to call on each entry, may be NULL

> func_data: a pointer on some data which will be passed to the callback

> Executes a function on all hash items, like `lw6sys_hash_sort_and_map` but befor doing so, sorts all entries in alphabetical order.

> Return value: void

— Function: lw6sys_hash_t * lw6sys_hash_dup (lw6sys_hash_t * hash, lw6sys_dup_func_t dup_func)

> hash: the hash to duplicate, can be NULL

> dup_func: the function which will be called to duplicate data

> Duplicates an hash. All keys will be copied so that if the first hash is deleted, the duplicated one is fine. Additionnaly, dup_func will be called with all data fields. If dup_func is NULL, then data values will simply be copied. This is likely to be usefull when data is not dynamically allocated.

> Returned value: a newly allocated hash.

— Function: lw6sys_hexa_serializer_t * lw6sys_hexa_serializer_new (char * hexa_string)

> hexa_string: an initialization string, can be NULL.

> Creates an hexa serializer object. It can be initialized or not, if an initialization string is provided it must of course be valid hexadecimal ascii code, and all serialized content will simply be appended to it.

> Return value: a newly allocated object.

— Function: void lw6sys_hexa_serializer_free (lw6sys_hexa_serializer_t * hexa_serializer)

> hexa_serializer: an hexa serializer object

> Frees an hexa serializer object.

> Return value: none.

— Function: void lw6sys_hexa_serializer_rewind (lw6sys_hexa_serializer_t * hexa_serializer)

> hexa_serializer: an hexa serializer object

> Rewinds the serializer pointer, that is, make it point to start. Usefull before calling pop functions, when one wants to be sure to get the first object.

> Return value: none.

— Function: int lw6sys_hexa_serializer_eof (lw6sys_hexa_serializer_t * hexa_serializer)

> hexa_serializer: an hexa serializer object

> Tests wether we're at EOF. Usefull when one wants to know if there's still some data or if all objects have been correctly popped.

> Return value: 1 if at end of file, 0 if not.

— Function: char * lw6sys_hexa_serializer_as_string (lw6sys_hexa_serializer_t * hexa_serializer)

> hexa_serializer: an hexa serializer object

> Exports the current content of the serializer as a string. String can then safely be sent on the network, for instance. String is copied from internal value, so it's safe to use it after serializer has been freed or modified.

> Return value: a newly allocated string, must be freed.

— Function: int lw6sys_hexa_serializer_push_int64 (lw6sys_hexa_serializer_t * hexa_serializer, int64_t value)

> hexa_serializer: an hexa serializer object

> value: value to push

> Pushes a 64 bit integer in the serializer object.

> Return value: 1 if success, 0 if failure

— Function: int lw6sys_hexa_serializer_push_int32 (lw6sys_hexa_serializer_t * hexa_serializer, int32_t value)

> hexa_serializer: an hexa serializer object

> value: value to push

> Pushes a 32 bit integer in the serializer object.

> Return value: 1 if success, 0 if failure

— Function: int lw6sys_hexa_serializer_push_int16 (lw6sys_hexa_serializer_t * hexa_serializer, int16_t value)

> hexa_serializer: an hexa serializer object

> value: value to push

> Pushes a 16 bit integer in the serializer object.

> Return value: 1 if success, 0 if failure

— Function: int lw6sys_hexa_serializer_push_int8 (lw6sys_hexa_serializer_t * hexa_serializer, int8_t value)

> hexa_serializer: an hexa serializer object

> value: value to push

> Pushes an 8 bit integer in the serializer object.

> Return value: 1 if success, 0 if failure

— Function: int lw6sys_hexa_serializer_push_float (lw6sys_hexa_serializer_t * hexa_serializer, float value)

> hexa_serializer: an hexa serializer object

> value: value to push

> Pushes a floating point value in the serializer object.

> Return value: 1 if success, 0 if failure

— Function: int lw6sys_hexa_serializer_push_str (lw6sys_hexa_serializer_t * hexa_serializer, char * value)

> hexa_serializer: an hexa serializer object

> value: value to push

> Pushes a string in the serializer object. Note that the string is not directly copied in the serializer, instead all its characters are converted to their ASCII equivalent, then appended.

> Return value: 1 if success, 0 if failure

— Function: int lw6sys_hexa_serializer_push_xyz (lw6sys_hexa_serializer_t * hexa_serializer, lw6sys_xyz_t value)

> hexa_serializer: an hexa serializer object

> value: value to push

> Pushes a lw6sys_xyz_t structure in the serializer object. Calling this avoids calling push for 2 integers separately.

> Return value: 1 if success, 0 if failure

— Function: int lw6sys_hexa_serializer_push_whd (lw6sys_hexa_serializer_t * hexa_serializer, lw6sys_whd_t value)

> hexa_serializer: an hexa serializer object

> value: value to push

> Pushes a lw6sys_whd_t structure in the serializer object. Calling this avoids calling push for 2 integers separately.

> Return value: 1 if success, 0 if failure

— Function: int lw6sys_hexa_serializer_push_color (lw6sys_hexa_serializer_t * hexa_serializer, lw6sys_color_8_t value)

> hexa_serializer: an hexa serializer object

> value: value to push

> Pushes a color structure in the serializer object.

> Return value: 1 if success, 0 if failure

— Function: int lw6sys_hexa_serializer_pop_int64 (lw6sys_hexa_serializer_t * hexa_serializer, int64_t * value)

> hexa_serializer: an hexa serializer object

> value: value to pop (returned value)

> Pops a 64 bit integer from the serializer object.

> Return value: 1 if success, 0 if failure

— Function: int lw6sys_hexa_serializer_pop_int32 (lw6sys_hexa_serializer_t * hexa_serializer, int32_t * value)

> hexa_serializer: an hexa serializer object

> value: value to pop (returned value)

> Pops a 32 bit integer from the serializer object.

> Return value: 1 if success, 0 if failure

— Function: int lw6sys_hexa_serializer_pop_int16 (lw6sys_hexa_serializer_t * hexa_serializer, int16_t * value)

> hexa_serializer: an hexa serializer object

> value: value to pop (returned value)

> Pops a 16 bit integer from the serializer object.

> Return value: 1 if success, 0 if failure

— Function: int lw6sys_hexa_serializer_pop_int8 (lw6sys_hexa_serializer_t * hexa_serializer, int8_t * value)

> hexa_serializer: an hexa serializer object

> value: value to pop (returned value)

> Pops an 8 bit integer from the serializer object.

> Return value: 1 if success, 0 if failure

— Function: int lw6sys_hexa_serializer_pop_float (lw6sys_hexa_serializer_t * hexa_serializer, float * value)

> hexa_serializer: an hexa serializer object

> value: value to pop (returned value)

> Pops a floating point value from the serializer object.

> Return value: 1 if success, 0 if failure

— Function: int lw6sys_hexa_serializer_pop_str (lw6sys_hexa_serializer_t * hexa_serializer, char ** value)

> hexa_serializer: an hexa serializer object

> value: value to pop (returned value)

> Pops a string from the serializer object. The returned value is a newly allocated pointer, which must be freed, you don't need to provide a buffer, just a valid pointer on a NULL pointer.

> Return value: 1 if success, 0 if failure

— Function: int lw6sys_hexa_serializer_pop_xyz (lw6sys_hexa_serializer_t * hexa_serializer, lw6sys_xyz_t * value)

> hexa_serializer: an hexa serializer object

> value: value to pop (returned value)

> Pops a lw6sys_xyz_t structure from the serializer object. Avoids calling two integer pops.

> Return value: 1 if success, 0 if failure

— Function: int lw6sys_hexa_serializer_pop_whd (lw6sys_hexa_serializer_t * hexa_serializer, lw6sys_whd_t * value)

> hexa_serializer: an hexa serializer object

> value: value to pop (returned value)

> Pops a lw6sys_whd_t structure from the serializer object. Avoids calling two integer pops.

> Return value: 1 if success, 0 if failure

— Function: int lw6sys_hexa_serializer_pop_color (lw6sys_hexa_serializer_t * hexa_serializer, lw6sys_color_8_t * value)

> hexa_serializer: an hexa serializer object

> value: value to pop (returned value)

> Pops a color from the serializer object.

> Return value: 1 if success, 0 if failure

— Function: int lw6sys_hexa_str_to_buf (void * buf, int size, char * str)

> buf: binary buffer to convert

> size: binary buffer length

> str: the source string

> Converts the stringified hexa representation of a string to its source binary buffer. Buffer must be exactly `strlen`(str)/2

> Return value: 1 on success

— Function: char * lw6sys_hexa_buf_to_str (void * buf, int size)

> buf: the buffer to stringify

> size: the length of the buffer

> Transforms a binary buffer into its hexa representation.

> Return value: newly allocated string.

— Function: void * lw6sys_hexa_str_to_ptr (char * str)

> str: the string containing an hexa representation of pointer

> Transforms a string into a pointer, this is typically used to store pointers in temporary agnostic storage such as a database. Beware not to use that to exchange data with other computers and/or use it for persistent data. This is a high-risk function as it lets you do real dirty stuff but it really does save time compared to using a key returned by the database engine and then search this key in a user-space hash table. Direct pointer access is definitely faster.

> Return value: the pointer, or NULL is str is invalid.

— Function: char * lw6sys_hexa_ptr_to_str (void * ptr)

> ptr: pointer to convert into string representation

> Transforms a pointer into a string, this is typically used to store pointers in temporary agnostic storage such as a database. Beware not to use that to exchange data with other computers and/or use it for persistent data. This is a high-risk function as it lets you do real dirty stuff but it really does save time compared to using a key returned by the database engine and then search this key in a user-space hash table. Direct pointer access is definitely faster.

> Return value: the string, can be NULL on errror, must be freed.

— Function: void lw6sys_history_init ()

> Initializes the history system. Not initializing won't cause any segfault, but data will be inconsistent.

> Return value: none.

— Function: void lw6sys_history_register (char * msg)

> msg: the message to register.

> Registers a message in the history log, that is, adds it.

> Return value: none.

— Function: char_ptr_t * lw6sys_history_get (int64_t timeout)

> timeout: the message age limit.

> Get all the messages that are younger than timeout (in seconds).

> Return value: a pointer on string pointers. May be NULL. Last pointer is NULL too, that's how you know the array is over.

— Function: void lw6sys_history_free (char ** history)

> history: the data to free

> Frees a pointer returned by `lw6sys_history_get`.

> Return value: none.

— Function: char * lw6sys_locale_to_utf8 (char * string)

> string: the string to convert

> Used to force strings into UTF-8 mode, this is basically to match the TTF font settings used when displaying stuff on OpenGL. Indeed, in this case, the standard _ gettext function won't work, we need to force UTF-8 mode. If the locale is UTF-8, then function does nothing, but at least it's transparent usage won't hurt.

> Returned value: a newly allocated string, always in UTF-8 no matter what the locale is.

— Function: u_int16_t lw6sys_generate_id_16 ()

> Long 16-bit ID generator, calls the random function internally. As usual, those are not perfect random numbers, however the function implementation emphasizes more on 'real randomness' rather than relying on performance. Generating twice the same number should be fairly rare.

— Function: u_int32_t lw6sys_generate_id_32 ()

> Long 32-bit ID generator, calls the random function internally. As usual, those are not perfect random numbers, however the function implementation emphasizes more on 'real randomness' rather than relying on performance. Generating twice the same number should be fairly rare.

— Function: u_int64_t lw6sys_generate_id_64 ()

> Long 64-bit ID generator, calls the random function internally. As usual, those are not perfect random numbers, however the function implementation emphasizes more on 'real randomness' rather than relying on performance. Generating twice the same number should be fairly rare.

— Function: int lw6sys_check_id_16 (u_int16_t id_16)

> id_16: the id to check

> Checks wether the given id is a valid 16-bit id.

> Return value: 1 if OK, 0 if not a valid id.

— Function: int lw6sys_check_id_32 (u_int32_t id_32)

> id_32: the id to check

> Checks wether the given id is a valid 32-bit id.

> Return value: 1 if OK, 0 if not a valid id.

— Function: int lw6sys_check_id_64 (u_int64_t id_64)

> id_64: the id to check

> Checks wether the given id is a valid 64-bit id.

> Return value: 1 if OK, 0 if not a valid id.

— Function: int lw6sys_check_id (u_int64_t id)

> id: the id to check

> Checks wether the given id is a valid id (16, 32 or 64-bit).

> Return value: 1 if OK, 0 if not a valid id.

— Function: char * lw6sys_id_ltoa (u_int64_t id)

> id: the id to convert

> Transform an id into its string representation. Error checking is done, if the id is invalid, returned value is NULL. All ids (16, 32 and 64-bit) are handled.

> Return value: a newly allocated string, might be NULL.

— Function: u_int64_t lw6sys_id_atol (char * id)

> id: the id to convert

> Transform an id into a long integer. Error checking is done, if the id is invalid, returned value is 0. All ids (16, 32 and 64-bit) are handled.

> Return value: the id as a long integer, 0 if incorrect source id.

— Function: char * lw6sys_keyword_as_key (char * keyword)

> keyword: the keyword to transform

> Transforms a keyword into a "key", that is, removes all heading dashes, switches to lowercase, and other stuff. This is used internally to match options and config file parameters, for instance.

> Return value: a newly allocated pointer, must be freed.

— Function: char * lw6sys_keyword_as_arg (char * keyword)

> keyword: the keyword to transform

> Transforms a keyword into a command-line parameter to be matched. Does the same as `lw6sys_keyword_as_key`, and adds a "–" prefix.

> Return value: a newly allocated pointer, must be freed.

— Function: char * lw6sys_keyword_as_env (char * keyword)

> keyword: the keyword to transform

> Transforms a keyword into the corresponding environment variable name. It will uppercase the name, replace "-" by "_", and add a "LW6_" prefix. "my-param" will become "LW6_MY_PARAM".

> Return value: a newly allocated pointer, must be freed.

— Function: char * lw6sys_keyword_as_xml (char * keyword)

> keyword: the keyword to transform

> Transforms a keyword into the corresponding config file entry. In practice, just the same as `lw6sys_keyword_as_key`.

> Return value: a newly allocated pointer, must be freed.

— Function: lw6sys_list_t * lw6sys_list_new (lw6sys_free_func_t free_func)

> free_func: a callback which will be called on data when freeing the list

> Creates an empty list. There's a difference between NULL and an empty list. The empty list would (in Scheme) be '() whereas NULL corresponds to undefined "is not a list and will generate errors if you ever call list functions on it".

> Return value: a pointer to the created object, may be NULL.

— Function: void lw6sys_list_free (lw6sys_list_t * list)

> list: the list to delete.

> Delete a list, this will cascade delete all the following items in the list.

> Return value: none.

— Function: lw6sys_list_t * lw6sys_list_next (lw6sys_list_t * list)

> list: the current position in the list

> It's safer to call this rather than dig right into the internals of the list.

> Return value: a new position in the list, may be NULL.

— Function: int lw6sys_list_is_empty (lw6sys_list_t * list)

> list: the list we want informations about

> Checks wether the list is empty or not. Note that being empty and being NULL is not the same. An empty list is a valid pointer on a list where there's no item, a NULL pointer is not a list at all. Do *NOT* call this function on NULL.

> Return value: 1 if empty, 0 if there is at list one item.

— Function: int lw6sys_list_length (lw6sys_list_t * list)

> list: the list we want informations about

> Calculates the length of the list. This is a performance killer for lists are inadapted to this. But it can still be usefull.

> Return value: the number of elements, 0 is none (empty list).

— Function: void lw6sys_list_map (lw6sys_list_t * list, lw6sys_list_callback_func_t func, void * func_data)

> list: the list where elements will be taken

> func: the function which will be executed

> func_data: additionnal data to be passed to `func`

> Executes a function on all list items. The `func_data` parameter allows you to pass extra values to the function, such as a file handler or any variable which can not be inferred from list item values, and you of course do not want to make global... Not as convenient as a real "for each" construct as can be found in any modern langage, but does the job. No return value, if you really want one, pass a structure in `func_data` and modify something in it on success, failure, whatever.

> Return value: none.

— Function: void lw6sys_list_filter (lw6sys_list_t ** list, lw6sys_list_filter_func_t func, void * func_data)

> list: the list where elements will be taken

> func: the function which will be executed

> func_data: additionnal data to be passed to `func`

> Executes a function on all list items and keeps only those for which the function returned non zero (true). The `func_data` parameter allows you to pass extra values to the function, such as a file handler or any variable which can not be inferred from list item values, and you of course do not want to make global...

> Return value: none.

— Function: void lw6sys_list_push_front (lw6sys_list_t ** list, void * data)

> list: a pointer to the list (pointer on pointer, read/write value)

> data: the data to be pushed

> Pushes data on the list. The `free_func` function is copied from the previous element. The pointer on the list is changed "in place" (in/out). Note that if there's a `malloc` problem it might end-up being NULL... This should be rare but it *can* happen. You cannot push something else than a pointer, pushing an int is a very bad idea. Push a pointer on the integer, and ensure it's always there, or `malloc` it and pass `lw6sys_free_callback` when creating the list. If you think you can cast an integer into a pointer, think 64-bit machines...

> Return value: none.

— Function: void * lw6sys_list_pop_front (lw6sys_list_t ** list)

> list: a pointer to the list (pointer on pointer, read/write value)

> Pops data from the list, the returned value is what was passed to list_push. The pointer on the list is changed "in place" (in/out). When data is popped, that needs some freeing (i.e. free_func was not NULL when creating the list) then it's the responsibility of the caller to free it when popping it. One popped it's not freed, but it's out of the list scope. Of course the lw6sys_list_t is freed, but not the data. If you happen to store non-NULL data in your list, you can call this function without bothering calling `lw6sys_list_is_empty` and assume that when you get NULL, there's no data left. At this stage, the list won't exist anymore BTW, you won't even need to free it. The idea is: popping a list which has no elements left (empty list) destroys the list and returns NULL.

> Return value: a pointer on the popped data, whatever you pushed.

— Function: void lw6sys_list_push_back (lw6sys_list_t ** list, void * data)

> list: a pointer to the list (pointer on pointer, read/write value)

> data: the data to be pushed

> Pushes data on the list. The `free_func` function is copied from the previous element. The pointer on the list is changed "in place" (in/out). Note that if there's a `malloc` problem it might end-up being NULL... This should be rare but it *can* happen. You cannot push something else than a pointer, pushing an int is a very bad idea. Push a pointer on the integer, and ensure it's always there, or `malloc` it and pass `lw6sys_free_callback` when creating the list. If you think you can cast an integer into a pointer, think 64-bit machines...

> Return value: none.

— Function: void * lw6sys_list_pop_back (lw6sys_list_t ** list)

> list: a pointer to the list (pointer on pointer, read/write value)

> Pops data from the list, the returned value is what was passed to list_push. The pointer on the list is changed "in place" (in/out). When data is popped, that needs some freeing (i.e. free_func was not NULL when creating the list) then it's the responsibility of the caller to free it when popping it. One popped it's not freed, but it's out of the list scope. Of course the lw6sys_list_t is freed, but not the data. If you happen to store non-NULL data in your list, you can call this function without bothering calling `lw6sys_list_is_empty` and assume that when you get NULL, there's no data left. At this stage, the list won't exist anymore BTW, you won't even need to free it. The idea is: popping a list which has no elements left (empty list) destroys the list and returns NULL.

> Return value: a pointer on the popped data, whatever you pushed.

— Function: lw6sys_list_t * lw6sys_list_dup (lw6sys_list_t * list, lw6sys_dup_func_t dup_func)

> list: the list to duplicate, can be NULL

> dup_func: the function which will be called to duplicate data

> Duplicates a list. All data will be copied so that if the first list is deleted, the duplicated one is fine. Addtionnally, dup_func will be called to filter all data, and possibly allocated new pointers if needed, for instance. If dup_func is NULL, then data values will simply be copied. This is likely to be usefull when data is not dynamically allocated.

> Returned value: a newly allocated list.

— Function: void lw6sys_log_set_file (char * filename)

> filename: the name of the log file.

> Sets up the log file. Until you call this function, messages all logged to the default log file, as returned by the `lw6sys_get_default_log_file` function.

> Return value: void

— Function: void lw6sys_log_clear (char * filename)

> filename: the name of the log file.

> Clears the log file, this function would typically be called at the beginning of the program. If filename is NULL, then the default log file is cleared.

> Return value: void

— Function: void lw6sys_log (int level_id, char * file, int line, char * fmt, ...)

> level_id: the log level to use. Possible values are, by order, LW6SYS_LOG_ERROR_ID (0), LW6SYS_LOG_WARNING_ID (1), LW6SYS_LOG_NOTICE_ID (2), LW6SYS_LOG_INFO_ID (3), LW6SYS_LOG_DEBUG_ID (4) and LW6SYS_LOG_TMP_ID (5).

> file: the name of the source file where the function is called, one can use __FILE__

> line: the line in the source file where the function is called, one can use __LINE__

> fmt: a printf-like format string ...: printf-like arguments, corresponding to `fmt`.

> This function is usually called with the first three arguments packed into a single macro. For instance the `LW6SYS_LOG_WARNING` macro expands and fills the first 3 args, so there's no need to type __FILE__ and __LINE__ again and again. Note that this function will reset errno. The idea is to call it whenever there's something to do with errno (if you deal with errno, it's a good habit to log it) then errno is cleared so that it won't interfere with next log messages.

— Function: void lw6sys_log_critical (char * fmt, ...)

> fmt: a printf-like format string ...: printf-like arguments, corresponding to `fmt`.

> This function is a special log function which will dump informations on the console only, without opening any log file whatsoever. The idea is that it's a "never fail" function. Additionnally, it will never return but quit the program. This can be used as an ultimate emergency function, use it when the program won't run for sure, and displaying an immediate error message is the only issue.

— Function: int lw6sys_log_get_level ()
— Function: void lw6sys_log_set_level (int level)

> level: the log level, integer between 0 & 4. 4 is very verbose (debug), 0 displays errors only.

— Function: void lw6sys_math_poly_wy1y2s1 (float * y, float * s, float x, float w, float y1, float y2, float s1)

> y: the return value (position, may be NULL)

> s: the return value (speed, may be NULL)

> x: the x parameter, the value to iterate on

> w: the width, that is, the x value after which output is constant

> y1: the initial value, when v is s1 and x=0

> y2: the target value, when v=0 and x>=w

> s1: the initial speed, that is dy/dx at x=0

> A function which can be used to implement smooth moving. It will extrapolate, for values of x>=0, an y position with a continuous derivate (dy/dx is continuous, function is 2nd order polynom) and which ends up at x=w with a constant value, that is dy/dx=v=0. Typically an item set with an initial speed of v with this function

— Function: float lw6sys_math_angle_360 (int x, int y)

> x: x coordinate

> y: y coordinate

> This is a wrapper over the standard `atan` function which will handle internally the special x == 0 case and the various positive/negative values of `x` and `y`.

> Return value: the angle, in degrees

— Function: float lw6sys_math_heartbeat (int64_t x, int period, float y1, float y2)

> x: the parameter (typically a timestamp)

> period: the period (typically something like 1000 milliseconds)

> y1: the low value (heart at rest)

> y2: the high value (when bumping)

> A heartbeat function, typically usefull to power up eye-candy, but it could do something else.

— Function: int lw6sys_math_blink (int64_t x, int period)

> x: the parameter (typically a timestamp)

> period: the period (typically something like 1000 milliseconds)

> This function will alternatively return 1 or 0, usefull to handle blinking for instance.

> Return value: 0 or 1

— Function: void * lw6sys_malloc (int size, char * file, int line)

> size: number of bytes to allocate.

> file: name of the file calling the function, use `__FILE__x_`

> line: line in the file calling the function, use `__LINE__x_`

> This is a wrapper over the standard `malloc` function. Additionnally it will keep track of the call with an internal program-wide counter, thus enabling memory leak checks. You should not use this function directly but use the macro `LW6SYS_MALLOC` which has the same syntax, without the last two parameters, which are automatically provided by macro expansion.

> Return value: the newly allocated pointer. Data is not initialized.

— Function: void * lw6sys_calloc (int size, char * file, int line)

> size: number of bytes to allocate.

> file: name of the file calling the function, use `__FILE__x_`

> line: line in the file calling the function, use `__LINE__x_`

> This is a wrapper over the standard `calloc` function. Additionnally it will keep track of the call with an internal program-wide counter, thus enabling memory leak checks. You should not use this function directly but use the macro `LW6SYS_CALLOC` which has the same syntax, without the last two parameters, which are automatically provided by macro expansion.

> Return value: the newly allocated pointer. Data is filled with zeros.

— Function: void * lw6sys_realloc (void * ptr, int size, char * file, int line)

> ptr: the pointer to reallocate.

> size: number of bytes to allocate.

> file: name of the file calling the function, use `__FILE__x_`

> line: line in the file calling the function, use `__LINE__x_`

> This is a wrapper over the standard `realloc` function. You should not use this function directly but use the macro `LW6SYS_REALLOC` which has the same syntax, without the last two parameters, which are automatically provided by macro expansion.

> Return value: the newly allocated pointer.

— Function: void lw6sys_free (void * ptr, char * file, int line)

> ptr: the pointer to free.

> file: name of the file calling the function, use `__FILE__x_`

> line: line in the file calling the function, use `__LINE__x_`

> This is a wrapper over the standard `free` function. Additionnally it will keep track of the call with an internal program-wide counter, thus enabling memory leak checks. You should not use this function directly but use the macro `LW6SYS_FREE` which has the same syntax, without the last two parameters, which are automatically provided by macro expansion.

> Return value: none.

— Function: void lw6sys_free_callback (void * ptr)

> ptr: the pointer to free.

> This is a callback to be used when the `lw6sys_free` does not fit. A good example is a list, which, to free its elements, requires you to provide a callback that only takes 1 arg, the pointer to free. Problem, `lw6sys_free` takes 3 args. And the `LW6SYS_FREE` macro is not usable in such a context. And you can't use standard `free` either for it would mess up the `malloc` / `free` automatical count which is so convenient to track memory leaks. So this callback is here, it's only drawback is that in case of an error, the error will not be reported with the real file and line parameters. It's still better than nothing.

> Return value: none.

— Function: int lw6sys_megabytes_available ()

> Gives a raw approximation of available memory, in megabytes. Value is to be taken with distance, but it can give good hints when system is running short of ressources.

> Return value: number of megabytes (physical memory) available.

— Function: int lw6sys_is_big_endian ()

> Checks the endianess of the machine. PPC is big endian, for instance.

> Return value: 1 if system is big endian, 0 if little endian.

— Function: int lw6sys_is_little_endian ()

> Checks the endianess of the machine. x86 is little endian, for instance.

> Return value: 1 if system is little endian, 0 if big endian.

— Function: int lw6sys_check_types_size ()

> Checks of common types and usefull structures, this is a debugging function which helps finding compiler strange behaviors and programmer's bad intuitions.

> Return value: 1 if everything is OK, 0 if error.

— Function: void * lw6sys_mutex_create ()

> Creates a mutex object.

> Return value: newly allocated pointer.

— Function: void lw6sys_mutex_destroy (void * mutex)

> mutex: the mutex to destroy.

> Destroys a mutex object.

> Return value: none.

— Function: int lw6sys_mutex_lock (void * mutex)

> mutex: the mutex to use

> Locks the mutex. Note that this should never fail unless there's a serious initialization problem, instead, function will wait forever until mutex is released.

> Return value: 1 if success, 0 if failure.

— Function: int lw6sys_mutex_trylock (void * mutex)

> mutex: the mutex to use

> Tries to locks the mutex. That is, tells wether mutex can be locked immediately or not. Note that this does not mean there's 100% chance next call to lock will terminated immediately, since lock can still be acquired by another thread.

> Return value: 1 if mutex unlocked, 0 if locked or error.

— Function: int lw6sys_mutex_unlock (void * mutex)

> mutex: the mutex to use

> Unlocks a mutex.

> Return value: 1 if sucess, 0 if error.

— Function: int lw6sys_get_mutex_lock_count ()

> Returns how many mutexes have been locked since program start. Usefull for sanity checking when debugging.

> Return value: number of calls to lock

— Function: int lw6sys_get_mutex_unlock_count ()

> Returns how many mutexes have been unlocked since program start. Usefull for sanity checking when debugging.

> Return value: number of calls to unlock

— Function: int lw6sys_check_mutex_count ()

> Checks wether unlock has been called as many times as lock. Usefull for sanity checking when debugging.

> Return value: 1 if OK, 0 if inconsistency.

— Function: int lw6sys_true ()

> Function which returns always true, that is, something different than 0.

— Function: int lw6sys_false ()

> Function which returns always false, that is, 0. This can seem totally useless but it does have some utility. It's used for instance to "fool" the compiler and force it to compile and link functions in binaries, so that, afterwards, dynamically loaded .so files can find in the main binary some functions which would otherwise be stripped during the final link.

— Function: char * lw6sys_get_default_user_dir ()

> Returns the default user directory. Note that this value is not static, it can depend, for instance, of the environment variable `HOME`.

> Return value: a newly allocated string.

— Function: char * lw6sys_get_default_config_file ()

> Returns the default config file. Note that this value is not static, it can depend, for instance, of the environment variable `HOME`.

> Return value: a newly allocated string.

— Function: char * lw6sys_get_default_log_file ()

> Returns the default log file. Note that this value is not static, it can depend, for instance, of the environment variable `HOME`.

> Return value: a newly allocated string.

— Function: char * lw6sys_get_default_prefix ()

> Returns the default prefix, could be /usr/local for instance.

> Return value: a newly allocated string.

— Function: char * lw6sys_get_default_mod_dir ()

> Returns the default module directory (dynamically loaded libraries).

> Return value: a newly allocated string.

— Function: char * lw6sys_get_default_data_dir ()

> Returns the default data directory.

> Return value: a newly allocated string.

— Function: char * lw6sys_get_default_music_dir ()

> Returns the default music directory.

> Return value: a newly allocated string.

— Function: char * lw6sys_get_default_music_path ()

> Returns the default music path, which can be composed of several directories.

> Return value: a newly allocated string.

— Function: char * lw6sys_get_default_map_dir ()

> Returns the default map directory.

> Return value: a newly allocated string.

— Function: char * lw6sys_get_default_map_path ()

> Returns the default map path, which can be composed of several directories.

> Return value: a newly allocated string.

— Function: char * lw6sys_get_default_script_file ()

> Returns the default script file.

> Return value: a newly allocated string.

— Function: void lw6sys_options_log_defaults ()

> Logs all default values to log file. Usefull for debugging, to know where the program is searching for its informations.

— Function: char * lw6sys_get_cwd ()

> Returns the current working directory (absolute path).

> Return value: a newly allocated string.

— Function: char * lw6sys_get_run_dir (int argc, char * [] argv)

> argc: argc, number of arguments, as given to `main`

> argv: argv, pointer to arguments, as given to `main`

> Returns the binary directory, that is, the directory the binary is stored in. This is calculated dynamically, by interpreting command-line arguments.

> Return value: a newly allocated string.

— Function: char * lw6sys_get_user_dir (int argc, char * [] argv)

> argc: argc, number of arguments, as given to `main`

> argv: argv, pointer to arguments, as given to `main`

> Returns the user dir, taking in account command-line and environment variables. However config file content has no impact on the result.

> Return value: a newly allocated string.

— Function: char * lw6sys_get_config_file (int argc, char * [] argv)

> argc: argc, number of arguments, as given to `main`

> argv: argv, pointer to arguments, as given to `main`

> Returns the config file, taking in account command-line and environment variables. However config file content has no impact on the result.

> Return value: a newly allocated string.

— Function: char * lw6sys_get_log_file (int argc, char * [] argv)

> argc: argc, number of arguments, as given to `main`

> argv: argv, pointer to arguments, as given to `main`

> Returns the log file, taking in account command-line and environment variables. However config file content has no impact on the result.

> Return value: a newly allocated string.

— Function: char * lw6sys_get_prefix (int argc, char * [] argv)

> argc: argc, number of arguments, as given to `main`

> argv: argv, pointer to arguments, as given to `main`

> Returns the prefix, taking in account command-line and environment variables. However config file content has no impact on the result.

> Return value: a newly allocated string.

— Function: char * lw6sys_get_mod_dir (int argc, char * [] argv)

> argc: argc, number of arguments, as given to `main`

> argv: argv, pointer to arguments, as given to `main`

> Returns the mod dir (modules, shared .so), taking in account command-line and environment variables. However config file content has no impact on the result.

> Return value: a newly allocated string.

— Function: char * lw6sys_get_data_dir (int argc, char * [] argv)

> argc: argc, number of arguments, as given to `main`

> argv: argv, pointer to arguments, as given to `main`

> Returns the data dir, taking in account command-line and environment variables. However config file content has no impact on the result.

> Return value: a newly allocated string.

— Function: char * lw6sys_get_music_dir (int argc, char * [] argv)

> argc: argc, number of arguments, as given to `main`

> argv: argv, pointer to arguments, as given to `main`

> Returns the music dir, taking in account command-line and environment variables. However config file content has no impact on the result.

> Return value: a newly allocated string.

— Function: char * lw6sys_get_music_path (int argc, char * [] argv)

> argc: argc, number of arguments, as given to `main`

> argv: argv, pointer to arguments, as given to `main`

> Returns the music path, taking in account command-line and environment variables. However config file content has no impact on the result. Music path can contain several directories.

> Return value: a newly allocated string.

— Function: char * lw6sys_get_map_dir (int argc, char * [] argv)

> argc: argc, number of arguments, as given to `main`

> argv: argv, pointer to arguments, as given to `main`

> Returns the map dir, taking in account command-line and environment variables. However config file content has no impact on the result.

> Return value: a newly allocated string.

— Function: char * lw6sys_get_map_path (int argc, char * [] argv)

> argc: argc, number of arguments, as given to `main`

> argv: argv, pointer to arguments, as given to `main`

> Returns the map path, taking in account command-line and environment variables. However config file content has no impact on the result. Map path can contain several directories.

> Return value: a newly allocated string.

— Function: char * lw6sys_get_script_file (int argc, char * [] argv)

> argc: argc, number of arguments, as given to `main`

> argv: argv, pointer to arguments, as given to `main`

> Returns the script file, taking in account command-line and environment variables. However config file content has no impact on the result.

> Return value: a newly allocated string.

— Function: void lw6sys_options_log (int argc, char * [] argv)

> argc: argc, number of arguments, as given to `main`

> argv: argv, pointer to arguments, as given to `main`

> Logs all the main options values which are not config-file dependant but depend on built-in defaults, command-line arguments and environment variables. Usefull to debug and know where the program is searching for things.

— Function: int lw6sys_file_exists (char * filename)

> filename: the file to test

> Tests the existence of a file on the filesystem. File is considered to exists if it's at least readable.

> Return value: 1 if OK, 0 if file doesn't exist or can't be read.

— Function: int lw6sys_dir_exists (char * dirname)

> dirname: the directory to test

> Tests the existence of a directory on the filesystem.

> Return value: 1 if OK, 0 if directory doesn't exist.

— Function: int lw6sys_create_dir (char * dirname)

> dirname: the directory to create

> Creates a directory, performing sanity checks such as verifying the directory really exists after being created.

> Return value: 1 if OK, 0 if error.

— Function: int lw6sys_create_dir_silent (char * dirname)

> dirname: the directory to create

> Creates a directory like `lw6sys_create_dir` but this function is silent in the sense that it won't log any error. Usefull to create the log directory itself, for instance, and avoid infinite loops on error.

> Return value: 1 if OK, 0 if error.

— Function: char * lw6sys_path_add_slash (char * path)

> path: a path

> Adds a slash, or in a general manner, a directory separator, at the end of a path, if needed. So /foo/bar will become /foo/bar/ but /bar/foo/ will remain /bar/foo/.

> Return value: a newly allocated string, must be freed.

— Function: char * lw6sys_path_strip_slash (char * path)

> path: a path

> Strips the slash, or in a general manner, the directory separator, at the end of a path, if needed. So /foo/bar/ will become /foo/bar but /bar/foo will remain /bar/foo.

> Return value: a newly allocated string, must be freed.

— Function: char * lw6sys_path_concat (char * path1, char * path2)

> path1: left part of the path

> path2: right part of the path

> Concatenates 2 parts of a path. Function will try to avoid stupid "double-slash" when concatenating /foo/ with /bar/ and conversely insert a directory separator when concatenating /foo with bar/.

> Return value: a newly allocated string, must be freed.

— Function: lw6sys_list_t * lw6sys_path_split (char * path)

> path: a path

> Splits a path into all its parts. For instance /boo/bar/foo2/bar2 returns a 4 elements list. This is more than a plain split, for heading and tailing slashes will be ignored, and various path separators will be interpreted (depends on platform).

> Return value: a list containing 0-terminated strings.

— Function: char * lw6sys_file_only (char * path)

> path: a path

> Returns the file name only, without heading directories.

> Return value: file name, must be freed

— Function: int lw6sys_path_is_relative (char * path)

> path: a path

> Checks wether a path is relative or absolute.

> Return value: 1 if relative, 0 if absolute.

— Function: int lw6sys_path_is_cwd (char * path)

> path: a path

> Checks wether a path is "." or not. Will also trap "" and "./".

> Return value: 1 if relative, 0 if absolute.

— Function: char * lw6sys_path_parent (char * path)

> path: a path

> Returns the parent path. That will return /foo when given /foo/bar in input.

> Return value: a newly allocated string, must be freed.

— Function: char * lw6sys_path_unparent (char * path)

> path: a path

> Given the ../foo/bar path, will return foo/bar. Usefull to get rid of heading ../ when a path is known to start with it.

> Return value: a newly allocated string, must be freed.

— Function: char * lw6sys_path_unparent_no_malloc (char * path)

> path: a path

> Given the ../foo/bar path, will return foo/bar. Usefull to get rid of heading ../ when a path is known to start with it. This is different from `lw6sys_path_unparent` just because the result is not dynamically allocated and copied from source.

> Return value: a pointer which points somewhere within the string passed as an argument.

— Function: lw6sys_list_t * lw6sys_dir_list (char * dir, lw6sys_dir_list_filter_func_t filter_func, void * func_data, int * n)

> dir: the path of the directory to list

> filter_func: a function which will filter entries, can be NULL

> func_data: additionnal data passed to filter_func

> n: will contain the number of items found

> This list a directory. The filter will be passed the file path as an argument. If it returns 1, the file is kept, if it returns 0 it's suppressed from the list.

> Return value: a list containing strings (file paths).

— Function: lw6sys_list_t * lw6sys_path_list (char * path, lw6sys_dir_list_filter_func_t filter_func, void * func_data, int * n)

> path: the path of the path to list

> filter_func: a function which will filter entries, can be NULL

> func_data: additionnal data passed to filter_func

> n: will contain the number of items found

> This list a directory. By path we mean here a list of separated directories, separated by : for instance. The filter will be passed the file path as an argument. If it returns 1, the file is kept, if it returns 0 it's suppressed from the list. It's like performing a call to `lw6sys_dir_list` on each of the path members.

> Return value: a list containing strings (file paths).

— Function: char * lw6sys_find_in_dir_and_path (char * dir, char * path, char * file)

> dir: a directory, when to search the file first

> path: the path to search too, a separated list of dirs

> file: the filename to search for

> Tries to find a file in the given paths. The function is typically used to find music files. First it tries to find the file in dir, then it tries to find it in each dir of path. `file` must be only a file name and not contain any directory. The function will use the filename only anyway.

> Return value: the full path of the found file.

— Function: void lw6sys_print_xml_header (FILE * f, char * comment)

> f: file to output content to

> Prints a standard Liquid War compliant XML header in the given file.

> Return value: none.

— Function: void lw6sys_print_xml_footer (FILE * f)

> f: file to output content to

> Prints a standard Liquid War 6 compliant XML footer in the given file.

> Return value: none.

— Function: int lw6sys_profiler_check (int verbose)

> verbose: wether to display informations on the console

> Checks wether Google Profiler support has been built, and if it's set, outputs the log file. If CPUPROFILE is defined but binary has no support for it, will display a warning message.

> Return value: 1 if google profile enabled and activated, 0 if not

— Function: void lw6sys_progress_default (lw6sys_progress_t * progress, float * value)

> progress: the progress struct to initialize

> value: the value to point to

> Sets a progress struct to default values, that is, ranging from 0.0f to 1.0f.

> Return value: none.

— Function: void lw6sys_progress_update (lw6sys_progress_t * progress, int min, int max, int value)

> progress: the progress struct to update

> min: the min value

> max: the max value

> value: the current value

> Updates a progress struct. This is typically the function used by a callback to show the progress of a process. Note that this is note an initializer. Rather, the progress struct was initialized before, and this call is done in a loop with min being 0, max being the last value in the loop, and value the current index in the loop. NULL pointers correctly handled internally, so call this with any parameters, it's safe.

> Return value: none.

— Function: void lw6sys_progress_split (lw6sys_progress_t * progress1, lw6sys_progress_t * progress2, lw6sys_progress_t * progress_src)

> progress1: the first part of the splitted progress progress2: the second part of the splitted progress progress_src: the progress to split

> Utility function to split a progress struct, that is, if a progress was ranging from a to b, make 2 progress structs, ranging from a to c and from c to b, c being between a and b.

> Return value: none

— Function: void lw6sys_progress_split_here (lw6sys_progress_t * progress1, lw6sys_progress_t * progress2, lw6sys_progress_t * progress_src, float here)

> progress1: the first part of the splitted progress progress2: the second part of the splitted progress progress_src: the progress to split here: where to split

> Utility function to split a progress struct, that is, if a progress was ranging from a to b, make 2 progress structs, ranging from a to c and from c to b, c being between a and b. The here value controls what c is. If here=0, then c=a. If here=1, then c=b.

> Return value: none

— Function: void lw6sys_progress_split3 (lw6sys_progress_t * progress1, lw6sys_progress_t * progress2, lw6sys_progress_t * progress3, lw6sys_progress_t * progress_src)

> progress1: the first part of the splitted progress progress2: the second part of the splitted progress progress3: the third part of the splitted progress progress_src: the progress to split

> Utility function to split a progress struct, this one will split it into 3 equal parts.

> Return value: none

— Function: void lw6sys_progress_split4 (lw6sys_progress_t * progress1, lw6sys_progress_t * progress2, lw6sys_progress_t * progress3, lw6sys_progress_t * progress4, lw6sys_progress_t * progress_src)

> progress1: the first part of the splitted progress progress2: the second part of the splitted progress progress3: the third part of the splitted progress progress4: the fourth part of the splitted progress progress_src: the progress to split

> Utility function to split a progress struct, this one will split it into 4 equal parts.

> Return value: none

— Function: void lw6sys_progress_split5 (lw6sys_progress_t * progress1, lw6sys_progress_t * progress2, lw6sys_progress_t * progress3, lw6sys_progress_t * progress4, lw6sys_progress_t * progress5, lw6sys_progress_t * progress_src)

> progress1: the first part of the splitted progress progress2: the second part of the splitted progress progress3: the third part of the splitted progress progress4: the fourth part of the splitted progress progress5: the fourth part of the splitted progress progress_src: the progress to split

> Utility function to split a progress struct, this one will split it into 5 equal parts.

> Return value: none

— Function: void lw6sys_progress_begin (lw6sys_progress_t * progress)

> progress: the progress to update

> Sets the progress to its min value, NULL values correctly handled.

> Return value: none

— Function: void lw6sys_progress_half (lw6sys_progress_t * progress)

> progress: the progress to update

> Sets the progress to the average between min and max, NULL values correctly handled.

> Return value: none

— Function: void lw6sys_progress_end (lw6sys_progress_t * progress)

> progress: the progress to update

> Sets the progress to its max value, NULL values correctly handled.

> Return value: none

— Function: u_int32_t lw6sys_random (u_int32_t range)

> range: the high limit for random generated numbers. If you want random numbers between 0 and 5, set this to 6.

> Wrapper over standard random function. This one is thread safe. This idea is not to provide cryptographic-proof random numbers, rather generate sequences which are random enough to generate unique server ids and such things. The function is initialized on its first call, and results depend on timestamp, host name, user name, and memory available.

— Function: float lw6sys_random_float (float min, float max)

> min: the min value, as a float

> max: the max value, as a float

> Returns a random float number between min & max. Can be equal to min or max.

— Function: int lw6sys_sdl_register ()

> Function used to avoid initializing SDL several times in a program. AFAIK Allegro has a `was_init` function, but SDL doesn't. With this function - which every LW6 sub-module should use - one can know globally, for the whole program, wether SDL has been initialized or not.

— Function: int lw6sys_sdl_unregister ()

> Call this whenever you are done with SDL and exit it, so that the `lw6sys_sdl_register` function works correctly.

> Return value: 1 if SDL needs to be unregistered, that is, if it has already been initialized, else 0.

— Function: void lw6sys_serialize_int64 (unsigned char * data, int64_t value)

> data: pointer to the data, must contain at least 8 bytes of writable space

> value: the integer to serialize

> Serializes a 64-bit integer in a byte buffer. Result is not dependant on machine endianess. Typically used for checksums or high-level serializations.

— Function: int64_t lw6sys_unserialize_int64 (unsigned char * data)

> data: pointer to the data, must contain at least 8 bytes

> Recovers a 64-bit integer from a byte buffer created, for instance, with `lw6sys_serialize_int64`.

— Function: void lw6sys_serialize_int32 (unsigned char * data, int32_t value)

> data: pointer to the data, must contain at least 4 bytes of writable space

> value: the integer to serialize

> Serializes a 32-bit integer in a byte buffer. Result is not dependant on machine endianess. Typically used for checksums or high-level serializations.

— Function: int32_t lw6sys_unserialize_int32 (unsigned char * data)

> data: pointer to the data, must contain at least 4 bytes

> Recovers a 32-bit integer from a byte buffer created, for instance, with `lw6sys_serialize_int32`.

— Function: void lw6sys_serialize_int16 (unsigned char * data, int16_t value)

> data: pointer to the data, must contain at least 2 bytes of writable space

> value: the integer to serialize

> Serializes a 16-bit integer in a byte buffer. Result is not dependant on machine endianess. Typically used for checksums or high-level serializations.

— Function: int16_t lw6sys_unserialize_int16 (unsigned char * data)

> data: pointer to the data, must contain at least 2 bytes

> Recovers a 16-bit integer from a byte buffer created, for instance, with `lw6sys_serialize_int16`.

— Function: int lw6sys_shape_check_min_max_whd (lw6sys_whd_t * shape, lw6sys_whd_t * min, lw6sys_whd_t * max)

> shape: the dimensions to control

> min: the minimum shape allowed

> max: the maximum shape allowed

> Will check wether the given shape respects some basic constraints, being not to small and not too big.

> Return value: 1 if OK, 0 if not.

— Function: int lw6sys_shape_check_pos (lw6sys_whd_t * shape, lw6sys_xyz_t * pos)

> shape: the boundary box

> pos: the position

> Checks wether position is within the given boundary box.

> Return value: 1 if OK, 0 if not.

— Function: int lw6sys_shape_is_same (lw6sys_whd_t * shape_a, lw6sys_whd_t * shape_b)

> shape_a: the first shape to compare

> shape_b: the other shape to compare

> Compares two shapes.

> Return value: 1 if same, 0 if not.

— Function: int lw6sys_shape_is_same_xy (lw6sys_whd_t * shape_a, lw6sys_whd_t * shape_b)

> shape_a: the first shape to compare

> shape_b: the other shape to compare

> Compares two shapes, but ignores the z (d) parameter.

> Return value: 1 if same_xy, 0 if not.

— Function: void lw6sys_signal_custom ()

> Set up our signal handlers. This will probably be overrided later by other libs such as libSDL, but at least in pure server mode it gives a way to treat SIGTERM the right way.

> Return value: none.

— Function: void lw6sys_signal_default ()

> Restore default signal handlers for those modified by `lw6sys_signal_custom`.

> Return value: none.

— Function: void lw6sys_signal_term_handler (int signum)

> signum: SIGTERM

> The own TERM signal handler, will basically call the `lw6sys_signal_send_quit` function, which will set a flag used later by `lw6sys_signal_poll_quit`.

> Return value: none.

— Function: void lw6sys_signal_int_handler (int signum)

> signum: SIGINT

> The own INT signal handler, will basically call the `lw6sys_signal_send_quit` function, which will set a flag used later by `lw6sys_signal_poll_quit`.

> Return value: none.

— Function: void lw6sys_signal_hup_handler (int signum)

> signum: SIGTERM

> The own HUP signal handler, will basically do something that shows the program is alive, typically display a NOTICE message.

> Return value: none.

— Function: void lw6sys_signal_send_quit ()

> Sets the quit flag to 1, so that `lw6sys_signal_poll_quit` returns true, that is, tells the polling loop to stop.

> Return value: none.

— Function: int lw6sys_signal_poll_quit ()

> Tests wether we need to stop right now.

> Return value: 1 if we need to stop now, 0 if program can continue.

— Function: int lw6sys_sort_int_callback (lw6sys_list_t ** list_a, lw6sys_list_t ** list_b)

> list_a: pointer to a list of int item

> list_b: pointer to a list of int item

> A typicall sort callback function, can be passed to `lw6sys_sort` to sort a list of integers.

> Return value: -1 if `list_a` < `list_b` , 0 if `list_a` == `list_b`, 1 if `list_a` > `list_b`

— Function: int lw6sys_sort_int_desc_callback (lw6sys_list_t ** list_a, lw6sys_list_t ** list_b)

> list_a: pointer to a list of int item

> list_b: pointer to a list of int item

> A typicall sort callback function, can be passed to `lw6sys_sort` to sort a list of integers. This one will sort in reverse mode.

> Return value: 1 if `list_a` < `list_b` , 0 if `list_a` == `list_b`, -1 if `list_a` > `list_b`

— Function: int lw6sys_sort_float_callback (lw6sys_list_t ** list_a, lw6sys_list_t ** list_b)

> list_a: pointer to a list of float item

> list_b: pointer to a list of float item

> A typicall sort callback function, can be passed to `lw6sys_sort` to sort a list of floating point numbers.

> Return value: -1 if `list_a` < `list_b` , 0 if `list_a` == `list_b`, 1 if `list_a` > `list_b`

— Function: int lw6sys_sort_float_desc_callback (lw6sys_list_t ** list_a, lw6sys_list_t ** list_b)

> list_a: pointer to a list of float item

> list_b: pointer to a list of float item

> A typicall sort callback function, can be passed to `lw6sys_sort` to sort a list of floating point numbers. This one will sort in reverse mode.

> Return value: 1 if `list_a` < `list_b` , 0 if `list_a` == `list_b`, -1 if `list_a` > `list_b`

— Function: int lw6sys_sort_str_callback (lw6sys_list_t ** list_a, lw6sys_list_t ** list_b)

> list_a: pointer to a list of string item

> list_b: pointer to a list of string item

> A typicall sort callback function, can be passed to `lw6sys_sort` to sort a list of 0-terminated strings.

> Return value: -1 if `list_a` < `list_b` , 0 if `list_a` == `list_b`, 1 if `list_a` > `list_b`

— Function: int lw6sys_sort_str_desc_callback (lw6sys_list_t ** list_a, lw6sys_list_t ** list_b)

> list_a: pointer to a list of string item

> list_b: pointer to a list of string item

> A typicall sort callback function, can be passed to `lw6sys_sort` to sort a list of 0-terminated strings. This one will sort in reverse mode.

> Return value: 1 if `list_a` < `list_b` , 0 if `list_a` == `list_b`, -1 if `list_a` > `list_b`

— Function: void lw6sys_sort (lw6sys_list_t ** list, lw6sys_sort_callback_func_t sort_func)

> list: the list to sort, might be modified by the function

> sort_func: the callback function used to sort

> A general sorting function. Internally, will use the glibc `qsort` function, but this one is adapted to the LW6 specific data structures, more exactly, the `lw6sys_list` structure. Several default sort callbacks are defined, but one is free to use any callback, provided it has the right prototype.

— Function: void * lw6sys_spinlock_create ()

> Creates a spinlock object.

> Return value: newly allocated pointer.

— Function: void lw6sys_spinlock_destroy (void * spinlock)

> spinlock: the spinlock to destroy.

> Destroys a spinlock object.

> Return value: none.

— Function: int lw6sys_spinlock_lock (void * spinlock)

> spinlock: the spinlock to use

> Locks the spinlock. Note that this should never fail unless there's a serious initialization problem, instead, function will wait forever until spinlock is released.

> Return value: 1 if success, 0 if failure.

— Function: int lw6sys_spinlock_trylock (void * spinlock)

> spinlock: the spinlock to use

> Tries to locks the spinlock. That is, tells wether spinlock can be locked immediately or not. Note that this does not mean there's 100% chance next call to lock will terminated immediately, since lock can still be acquired by another thread.

> Return value: 1 if spinlock unlocked, 0 if locked or error.

— Function: int lw6sys_spinlock_unlock (void * spinlock)

> spinlock: the spinlock to use

> Unlocks a spinlock.

> Return value: 1 if sucess, 0 if error.

— Function: char * lw6sys_str_copy (char * src)

> src: the string to copy

> Duplicate a string, creating a new pointer on it, which must be freed afterwards. The main difference with `strdup` is that here we use the LW6SYS_MALLOC macro to track down possible memory leaks.

> Return value: a newly allocated pointer, must be freed.

— Function: char * lw6sys_str_concat (char * str1, char * str2)

> str1: the left part to be concatenated

> str2: the right part to be concatenated

> Concatenate 2 strings, and put the result in a newly allocated string. Unlike `strcat` which uses the same pointer.

> Return value: a newly allocated pointer, must be freed.

— Function: char * lw6sys_new_sprintf (char * fmt, ...)

> fmt: a format string, like the one you would pass to `printf` ...: optional arguments, like the ones you would pass to `printf`

> An sprintf like function, except it allocates a new string automatically, with "enough space". This is not a highly optimized function, it will allocate plenty of memory, possibly several times, and thus consume time and resources. But it has the great advantage of freeing the programmer of the dirty work of guessing "how log will the sprintf'ed string be?" before even generating it. So it's a time saver for the programmer. Additionnally, helps avoiding memory leaks and buffer overflows.

> Return value: a new allocated string, must be freed.

— Function: int lw6sys_buf_sprintf (char * buf, int len, char * fmt, ...)

> buf: a buffer of len+1 chars

> len: the max length of string

> fmt: a format string, like the one you would pass to `printf` ...: optional arguments, like the ones you would pass to `printf`

> Almost like snprintf except that it will *always* append a char 0 ('\0') at the end of the string. Therefore buf must be of size len+1.

> Return value: 1 if success, 0 if failed.

— Function: int lw6sys_str_is_blank (char * str)

> str: the string to test

> Tests wether a string is blank, that is, if it's composed of space, tabs, or carriage returns only.

> Return value: 1 if blank, 0 if not.

— Function: int lw6sys_str_is_null_or_empty (char * str)

> str: the string to test

> Tests wether a string is NULL or empty (string with 0 chars "").

> Return value: 1 if NULL or empty, 0 if contains something.

— Function: char * lw6sys_str_empty_if_null (char * str)

> str: the string to test

> Returns always a non-NULL string, if string is NULL, returns ""

> Return value: source string or "" if it was NULL

— Function: int lw6sys_str_is_same (char * str_a, char * str_b)

> str_a: 1st string to compare, can be NULL

> str_b: 2nd string to compare, can be NULL

> Compares two strings for equality. Difference with strcmp is that this one won't check for alphabetical order and return -1 or +1, but will check for NULL args. of space, tabs, or carriage returns only.

> Return value: 1 if same, 0 if not.

— Function: int lw6sys_str_is_same_no_case (char * str_a, char * str_b)

> str_a: 1st string to compare, can be NULL

> str_b: 2nd string to compare, can be NULL

> Compares two strings for equality. Difference with strcmp is that this one won't check for alphabetical order and return -1 or +1, but will check for NULL args. of space, tabs, or carriage returns only. This function is not case sensitive.

> Return value: 1 if same, 0 if not.

— Function: int lw6sys_str_starts_with (char * str, char * beginning)

> str: the string to analyse

> beginning: the pattern to search

> Tells wether string starts with a given beginning.

> Return value: 1 if `str` starts with `beginning`, 0 if not

— Function: int lw6sys_str_starts_with_no_case (char * str, char * beginning)

> str: the string to analyse

> beginning: the pattern to search

> Tells wether string starts with a given beginning. This function is not case sensitive.

> Return value: 1 if `str` starts with `beginning`, 0 if not

— Function: int lw6sys_skip_blanks (char ** str_ptr)

> str_ptr: a pointer to a string pointer (read/write parameter).

> Skips blanks at the beginning of a string. The passed parameter is modifed in place. Usefull for parsing.

> Return value: 1 if blanks were found, else 0.

— Function: void lw6sys_str_cleanup (char * str)

> str: a pointer to the string, which will be modified in-place.

> Used to clean up some strings, for instance if they come from the network, we don't necessarly want system chars to be displayed on the console. Basically it removes all characters with an ASCII code inferior to 32, that is, all system characters. This way, there won't be any tab, linefeed, or any of such characters left.

> Return value: none.

— Function: void lw6sys_str_cleanup_ascii7 (char * str)

> str: a pointer to the string, which will be modified in-place.

> Used to clean up some strings, for instance if they come from the network, we don't necessarly want system chars to be displayed on the console. Basically it removes all characters with an ASCII code inferior to 32, that is, all system characters. This way, there won't be any tab, linefeed, or any of such characters left. This function will even remove any character above ASCII 127.

> Return value: none.

— Function: char * lw6sys_str_reformat (char * str, char * prefix, int nb_columns)

> str: a pointer to the string we want to modify

> prefix: a prefix to put before each line

> Reformats a string, that is, insert newline characters in the right places to that it fits in a given number of columns. A prefix is appended at the beginning of each line. Will not handle strings which already contain newline characters perfectly.

> Return value: a newly allocated string, must be freed.

— Function: void lw6sys_str_reformat_this (char * str, int nb_columns)

> str: a pointer to the string we want to modify

> Reformats a string, that is, insert newline characters in the right places to that it fits in a given number of columns. This function will modify the buffer so `str` must be writeable. Will not handle strings which already contain newline characters perfectly.

> Return value: none

— Function: char * lw6sys_eol ()

> Returns the value of EOL, that is, the "end of line" sequence. Will simply return "\n" on UNIX and "\r\n" on Microsoft platforms. Note that while this is convenient to write config and example files, for instance, it's a bad idea to use this to generate network messages, because this kind of message needs to be platform independant. Thus any network protocol oriented string would use chr(10) and char(13) directly.

> Return value: the EOL string, must not be freed.

— Function: lw6sys_list_t * lw6sys_str_split (char * str, char c)

> str: a string

> c: the delimiter to split with

> Splits a string, for instance 'foo,bar' splited with 'o' will return 'f', ” and ',bar'.

> Return value: a list containing 0-terminated strings.

— Function: lw6sys_list_t * lw6sys_str_split_no_0 (char * str, char c)

> str: a string

> c: the delimiter to split with

> Splits a string, ignoring empty '0-length' members. For instance 'foo,bar' splited with 'o' will return 'f' and ',bar'.

> Return value: a list containing 0-terminated strings.

— Function: lw6sys_list_t * lw6sys_str_split_config_item (char * str)

> str: a string

> Splits a string, ignoring empty '0-length' members, and using the comma ',' as a separator. This is typically usefull for config elements such as backend lists. Only paths need another separator (platform-dependant).

> Return value: a list containing 0-terminated strings.

— Function: void lw6sys_str_toupper (char * str)

> str: the string to modify

> Transforms a string to upper case, the pointer must point to modifiable data.

> Return value: none, `str` pointed data modified in-place

— Function: void lw6sys_str_tolower (char * str)

> str: the string to modify

> Transforms a string to lower case, the pointer must point to modifiable data.

> Return value: none, `str` pointed data modified in-place

— Function: void lw6sys_str_truncate (char * str, int len)

> str: the string to truncate

> len: the new length

> Truncates a string to the max given length. If truncated to 3, "abcdef" becomes "abc".

> Return value: none, `str` pointed data modified in-place

— Function: char * lw6sys_str_random (int len)

> len: the length of the random string to generate.

> Generates a random string, this is usefull for testing.

> Return value: newly allocated string

— Function: int lw6sys_str_is_bin (char * buf, int len)

> buf: the buffer to test

> len: the length of the buffer

> Tests wether a buffer is likely to contain a string. This is not a bulletproof function, just a simple heuristic based estimator.

> Return value: 1 if probably binary, 0 if probably text

— Function: char * lw6sys_stream_file_to_str (FILE * f)

> f: file to get input from, typically stdin

> Will read file/stream and return it as a string. This is not for serious stream operation since it will return only when stream is closed, and read all file into memory before doing anything. It's also limited in size since it uses a fixed length buffer, so this is just for quick testing, typically used by command line switches which are used to test encoding/decoding functions. Do not use it to read a filesystem file, `lw6sys_read_file_content` is much better.

> Return value: newly allocated string.

— Function: void lw6sys_stream_str_to_file (FILE * f, char * str)

> f: file to receive the string

> str: the string to output

> Here only for API consistency, will just put string to file (just a simple fprint).

> Return value: none.

— Function: int lw6sys_test_exec (int argc, char * [] argv, int mode)

> argc: number of args as passed to main

> argv: array of args as passed to main

> mode: 0 for check only, 1 for full test

> Runs the `sys` module test suite which is specific to exec functions, these ones require `argc` and `argv` to be correctly set so the extra argument justifies putting it outside `lw6sys_test`. Additionnally, it's not fool proof...

> Return value: 1 if test is successfull, 0 on error.

— Function: int lw6sys_test (int mode)

> mode: 0 for check only, 1 for full test

> Runs the `sys` module test suite, testing most (if not all...) functions. Note that some tests perform file system operations and might therefore fail on a read-only filesystem, or if user permissions are not sufficient.

> Return value: 1 if test is successfull, 0 on error.

— Function: void * lw6sys_thread_create (lw6sys_thread_callback_func_t callback_func, lw6sys_thread_callback_func_t callback_join, void * callback_data)

> callback_func: the main callback, the function that will run the thread

> callback_join: function which will be called when joining, at the end

> callback_data: data which will be passed to the callback

> Creates a thread. All threads must be joined. This is because we really do not want the game to leak, and detached threads are typically the kind of thing that leaves stuff in the heap. Note that callback_func is just something which will be called when joining it can be NULL. The idea is to put in it free & delete functions, which you can't call before joining when you want the main thread to get the results of the callback_func.

> Return value: an opaque pointer on the thread. Can be NULL if failed.

— Function: int lw6sys_thread_is_callback_done (void * thread_handler)

> thread_handler: thread to work on

> Tells wether the callback is done, that is to say, wether the results are available, and we can join.

> Return value: 1 if done, else 0.

— Function: int lw6sys_thread_get_id (void * thread_handler)

> thread_handler: thread to query

> Returns the id of the thread, this is an internal value, unique for each process, which can help identifying the thread.

> Return value: the id, should be >0.

— Function: void * lw6sys_thread_get_data (void * thread_handler)

> thread_handler: thread to query

> Returns the data associated to the thread, that is, the pointer which was passed to the callback function.

> Return value: a pointer.

— Function: void lw6sys_thread_join (void * thread_handler)

> thread_handler: thread to end

> Joins the thread, that's to say wait until the thread is over, and destroys the ressources associated to it. Note that if the thread is looping forever, this function will just wait forever. This is the only way to end a thread.

> Return value: none.

— Function: int lw6sys_get_thread_create_count ()

> Utility function used to check how many threads where created and joined.

> Return value: how many threads were created.

— Function: int lw6sys_get_thread_join_count ()

> Utility function used to check how many threads where created and joined.

> Return value: how many threads were joined.

— Function: int lw6sys_check_thread_count ()

> Utility function used to check how many threads where created and joined. This one will compare the results of `lw6sys_get_thread_create_count` and `lw6sys_get_thread_join_count`.

> Return value: 1 if both are equals, 0 if not (error...).

— Function: int64_t lw6sys_get_timestamp ()

> Returns a 64-bit timestamp, for general purpose. The unit is milliseconds, should return the number of milliseconds since EPOCH. Don't use this for accurate date handling, but rather to technical stamp events.

> Return value: the timestamp.

— Function: int64_t lw6sys_get_uptime ()

> Returns the number of milliseconds since program was started. Milliseconds are often referred to as 'ticks'.

> Return value: the number of milliseconds (64-bit)

— Function: int32_t lw6sys_get_cycle ()

> Returns a 32-bit timestamp, which is likely to "loop" and have twice the same value during a single program execution. The idea here is just to provide a 32-bit value, not too big, for animation purposes. The idea is that with 64-bit values, numbers are too big and if the goal is just to animate a cursor or spin a sphere, one does not care if every ten hours there's a display glitch because value became zero again. Besides, those values are often used for their "rest" in a module operation, to translate textures for instance, and having too big numbers causes floating point imprecisions. In fact those values or even only 20-bit. The function is based on `lw6sys_get_uptime`() so it will return 0 at game startup.

> Return value: the cycle value, a 20-bit integer.

— Function: void lw6sys_timer_update (int64_t * timestamp, int64_t * uptime, int32_t * cycle)

> timestamp: the timestamp in msec since EPOCH (output), can be NULL

> uptime: the uptime in msec since startup (output), can be NULL

> cycle: a 20-bit value for animation purpose.

> Returns timestamp & uptime with only one system call.

> Return value: none (parameters modified).

— Function: void lw6sys_sleep (float seconds)

> seconds: the number of seconds to wait, fractions allowed

> Will sleep for the given amount of seconds. Same as `lw6sys_delay` only input is provided as a floating number of seconds instead of ticks.

— Function: void lw6sys_delay (int msec)

> msec: the number of milliseconds (ticks) to wait

> Will sleep for the given amount of seconds. Provides accurate timing and has "about-millisecond" precision, since it uses `select` internally. Might however be interrupted in some cases, so consider function can always return quicker than specified. A common usage of this function is polling loops, where you don't care if 2 polls are very close, but simply want to avoid polling continuously, therefore consumming 100% of the CPU for nothing.

— Function: void lw6sys_idle ()

> Will sleep for a minimal amount of time, just giving the OS a chance to let other threads/processes execute themselves. This can make a big difference in polling loops between a process that eats 100% CPU and a process that has a very moderate load. of ticks.

— Function: void lw6sys_snooze ()

> Will sleep for some time, like `lw6sys_idle`, except it's a "longer" time, use this when you don't really care about reactivity but are more concerned about saving CPU, not running uselessly the same polling code.

— Function: void lw6sys_time_init ()

> Global initializations required to handle time properly.

— Function: char * lw6sys_date_rfc1123 (int seconds_from_now)

> seconds_from_now: an offset to add to current time

> Gives the date according to RFC1123, this is typically usefull for HTTP protocol.

> Return value: newly allocated string.

— Function: char * lw6sys_date_clf ()

> Gives the date in a format which is compatible with Apache CLF Common Log Format.

> Return value: newly allocated string.

— Function: char * lw6sys_readable_uptime (int64_t timestamp_delta)

> timestamp_delta: the duration to show, in msec

> Returns a readable form of an uptime, typically 1d 12:34:06 for one day, 12 hours, 34 min, 6 sec or 7:03:45 for 7 hours, 3 minutes 45 sec.

> Return value: newly allocated string

— Function: extern char * lw6sys_url_http_from_ip_port (char * ip, int port)

> ip: IP address

> port: IP port

> Returns an http URL pointing to ip: port that is, adds a heading http:// and a trailing /, and treats port 80 as default. This is used to create public_url in net modules.

> Return value: a newly allocated string, NULL on error.

— Function: lw6sys_url_t * lw6sys_url_parse (char * url)

> url: the URL to parse

> Parses a URL, this is not a complete RFC compliant parser, it's only used to transform URLs into their 'canonical' form as well as getting basic info such as on which port one should connect.

> Return value: a newly allocated struct, NULL on error

— Function: void lw6sys_url_free (lw6sys_url_t * url)

> url: the url struct to free

> Frees a URL struct and all its members.

> Return value: none.

— Function: char * lw6sys_url_canonize (char * url)

> url: the url to check & transform

> Checks if a given URL is correct and, if it is, transforms it into its canonical form. This is mostly to get rid of typesettings error, add a tailing /, transform all domain into lowercase, among other things. A canonized url passed into this function should come out exactly the same.

> Return value: a newly allocated string.

— Function: int lw6sys_url_is_canonized (char * url)

> url: the URL to check

> Checks wether an URL is in its canonized form.

> Return value: 1 if OK (canonized form), 0 if not

— Function: int lw6sys_vthread_run (lw6sys_thread_callback_func_t callback_func, lw6sys_thread_callback_func_t callback_join, void * callback_data)

> callback_func: the main callback, the function that will run the thread

> callback_join: function which will be called when joining, at the end

> callback_data: data which will be passed to the callback

> This function is similar to `lw6sys_thread_create`, but it's dedicated to creating a unique (one per process only) thread, which, in turn, will be able to run commands in the main thread itself. This is a hack to allow apparently spawned child threads to be actually handled by main. This is because some libraries, which LW6 uses in threads, need to be actually called in the main thread. SDL, for instance. Note that after running this you loose control on the main thread, this one will only wait for possible commands from the spawned thread, typically sent with the `lw6sys_vthread_create` function.

> Return value: 1 on success, 0 on failure.

— Function: int lw6sys_vthread_is_running ()

> Returns true if `lw6sys_vthread_run` has been called. Note that this is not bullet proof, it will return true in a correct manner only if you call it from the vthread itself. In practise this shouldn't be a problem, the idea is just to write portable code for the main control thread and be able to decide on the fly wether to create a thread we should prefer the `lw6sys_thread_create` or its equivalent the `lw6sys_vthread_create` function.

> Return value: 1 on success, 0 on failure.

— Function: int lw6sys_vthread_create (lw6sys_thread_callback_func_t callback_func, lw6sys_thread_callback_func_t callback_join, void * callback_data)

> callback_func: the main callback, the function that will run the thread

> callback_join: function which will be called when joining, at the end

> callback_data: data which will be passed to the callback

> The equivalent of `lw6sys_thread_create` but for the vthread infrastructure. The idea is to pretend firing a spawned thread, but in fact it's the main thread that runs the code. This function must imperatively be called within the `lw6sys_vthread_run` function, else it will fail or be buggy.

> Return value: 1 on success, 0 on failure.

— Function: void lw6sys_vthread_join ()

> The equivalent of `lw6sys_thread_join` but for the vthread infrastructure. The idea is to pretend firing a spawned thread, but in fact it's the main thread that runs the code. This function must imperatively be called within the `lw6sys_vthread_run` function, else it will fail or be buggy.

> Return value: none.