package libc

// 7.22 General utilities

when ODIN_OS == "windows" {
	foreign import libc "system:libucrt.lib"
} else {
	foreign import libc "system:c"
}

when ODIN_OS == "windows" {
	RAND_MAX :: 0x7fff;

	@(private="file")
	@(default_calling_convention="c")
	foreign libc {
		___mb_cur_max_func :: proc() -> int ---;
	}

	MB_CUR_MAX :: #force_inline proc() -> size_t {
		return size_t(___mb_cur_max_func());
	}
}

when ODIN_OS == "linux" {
	RAND_MAX :: 0x7fffffff;

	// GLIBC and MUSL only
	@(private="file")
	@(default_calling_convention="c")
	foreign libc {
		__ctype_get_mb_cur_max :: proc() -> size_t ---;
	}

	MB_CUR_MAX :: #force_inline proc() -> size_t {
		return __ctype_get_mb_cur_max();
	}
}

// C does not declare what these values should be, as an implementation is free
// to use any two distinct values it wants to indicate success or failure.
// However, nobody actually does and everyone appears to have agreed upon these
// values.
EXIT_SUCCESS :: 0;
EXIT_FAILURE :: 1;

// C does not declare which order 'quot' and 'rem' should be for the divide
// structures. An implementation could put 'rem' first. However, nobody actually
// does and everyone appears to have agreed upon this layout.
div_t   :: struct { quot, rem: int, }
ldiv_t  :: struct { quot, rem: long, }
lldiv_t :: struct { quot, rem: longlong, }

@(default_calling_convention="c")
foreign libc {
	// 7.22.1 Numeric conversion functions
	atof          :: proc(nptr: cstring) -> double ---;
	atoi          :: proc(nptr: cstring) -> int ---;
	atol          :: proc(nptr: cstring) -> long ---;
	atoll         :: proc(nptr: cstring) -> longlong ---;
	strtod        :: proc(nptr: cstring, endptr: ^^char) -> double ---;
	strtof        :: proc(nptr: cstring, endptr: ^^char) -> float ---;
	strtol        :: proc(nptr: cstring, endptr: ^^char, base: int) -> long ---;
	strtoll       :: proc(nptr: cstring, endptr: ^^char, base: int) -> longlong ---;
	strtoul       :: proc(nptr: cstring, endptr: ^^char, base: int) -> ulong ---;
	strtoull      :: proc(nptr: cstring, endptr: ^^char, base: int) -> ulonglong ---;

	// 7.22.2 Pseudo-random sequence generation functions
	rand          :: proc() -> int ---;
	srand         :: proc(seed: uint) ---;

	// 7.22.3 Memory management functions
	aligned_alloc :: proc(aligment, size: size_t) -> rawptr ---;
	calloc        :: proc(nmemb, size: size_t) -> rawptr ---;
	free          :: proc(ptr: rawptr) ---;
	malloc        :: proc(size: size_t) -> rawptr ---;
	realloc       :: proc(ptr: rawptr, size: size_t) -> rawptr ---;

	// 7.22.4 Communication with the environment
	abort         :: proc() -> ! ---;
	atexit        :: proc(func: proc "c" ()) -> int ---;
	at_quick_exit :: proc(func: proc "c" ()) -> int ---;
	exit          :: proc(status: int) -> ! ---;
	_Exit         :: proc(status: int) -> ! ---;
	getenv        :: proc(name: cstring) -> ^char ---;
	quick_exit    :: proc(status: int) -> ! ---;
	system        :: proc(cmd: cstring) -> int ---;

	// 7.22.5 Searching and sorting utilities
	bsearch       :: proc(key, base: rawptr, nmemb, size: size_t, compar: proc "c" (lhs, rhs: rawptr) -> int) -> rawptr ---;
	qsort         :: proc(base: rawptr, nmemb, size: size_t, compar: proc "c" (lhs, rhs: rawptr) -> int) ---;

	// 7.22.6 Integer arithmetic functions
	abs           :: proc(j: int) -> int ---;
	labs          :: proc(j: long) -> long ---;
	llabs         :: proc(j: longlong) -> longlong ---;
	div           :: proc(numer, denom: int) -> div_t ---;
	ldiv          :: proc(numer, denom: long) -> ldiv_t ---;
	lldiv         :: proc(numer, denom: longlong) -> lldiv_t ---;

	// 7.22.7 Multibyte/wide character conversion functions
	mblen         :: proc(s: cstring, n: size_t) -> int ---;
	mbtowc        :: proc(pwc: ^wchar_t, s: cstring, n: size_t) -> int ---;
	wctomb        :: proc(s: ^char, wc: wchar_t) -> int ---;

	// 7.22.8 Multibyte/wide string conversion functions
	mbstowcs      :: proc(pwcs: ^wchar_t, s: cstring, n: size_t) -> size_t ---;
	wcstombs      :: proc(s: ^char, pwcs: ^wchar_t, n: size_t) -> size_t ---;
}