use "die"use "extremum"use "memops"use "syswrap"use "threadhooks"use "types"use "units"use "bytealloc"use "backtrace"use "memops" /*The allocator implementation here is based on Bonwick's slab allocator. For small allocations (up to Bktmax), it works by requesting large,power of two aligned chunks from the operating system, and breakingthem into a linked list of equal sized chunks. Allocations are thensatisfied by taking the head of the list of chunks. Empty slabsare removed from the freelist. The data structure looks something like this:   Bkts:	[16  byte] -> [slab hdr | chunk -> chunk -> chunk] -> [slab hdr | chunk -> chunk -> chunk]	[32  byte] -> Zslab	[64  byte] -> [slab hdr | chunk -> chunk]	...	[32k byte] -> ... Large allocations are simply satisfied by mmap(). */ pkg std =	generic alloc		: ( -> @a#)	generic zalloc		: ( -> @a#)	generic free		: (v:@a# -> void) 	generic slalloc		: (len : size -> @a[:])	generic slzalloc	: (len : size -> @a[:])	generic slgrow		: (sl : @a[:]#, len : size -> @a[:])	generic slzgrow		: (sl : @a[:]#, len : size -> @a[:])	generic slfree		: (sl : @a[:] -> void);; type slheader = struct	cap	: size	/* capacity in bytes */	magic	: size	/* magic check value */;; /* Allocates an object of type @a, returning a pointer to it. */generic alloc = {-> @a#	-> (bytealloc(sizeof(@a)) : @a#)} generic zalloc = {	-> (zbytealloc(sizeof(@a)) : @a#)} /* Frees a value of type @a */generic free = {v:@a# -> void	bytefree((v : byte#), sizeof(@a))} /* allocates a slice of 'len' elements. */generic slalloc = {len	var p, sz 	if len == 0		-> [][:]	;;	sz = len*sizeof(@a) + align(sizeof(slheader), Align)	sz = allocsz(sz)	p = bytealloc(sz + sizeof(size))	p = inithdr(p, sz)	-> (p : @a#)[0:len]} generic slzalloc = {len	var p, sz 	if len == 0		-> [][:]	;;	sz = len*sizeof(@a) + align(sizeof(slheader), Align)	sz = allocsz(sz)	p = zbytealloc(sz + sizeof(size))	p = inithdr(p, sz)	-> (p : @a#)[0:len]} const inithdr = {p, sz	var phdr, pdat, pend 	phdr = (p : slheader#)	phdr.cap = sz - align(sizeof(slheader), Align) 	/* add start/end magics */	phdr.magic = (0xdeadbeefbadf00d : size)	pdat = (p : size) + align(sizeof(slheader), Align)	pend = ((pdat : size) + sz - align(sizeof(slheader), Align) : size#)	pend# = 0xfee1deadfee1dead 	-> (pdat : byte#)} const checkhdr = {p	var phdr, pend, addr 	addr = (p : size)	addr -= align(sizeof(slheader), Align) 	/* check start/end magics */	phdr = (addr : slheader#)	iassert(phdr.magic == (0xdeadbeefbadf00d : size), "corrupt memory\n")	pend = ((p : size) + phdr.cap : size#)	iassert(pend# == 0xfee1deadfee1dead, "corrupt memory")} /* Frees a slice */generic slfree	 = {sl	var head, sz 	if (sl : byte#) == Zslicep		-> void	;; 	checkhdr((sl : byte#))	head = ((sl : byte#) : size)	head -= align(sizeof(slheader), Align)	sz = slcap((sl : byte#)) + align(sizeof(slheader), Align)	bytefree((head : byte#), sz + sizeof(size))} /* Grows a slice */generic slgrow = {sl : @a[:]#, len	var cap, nel	var new	var n 	/* if the slice doesn't need a bigger bucket, we don't need to realloc. */	cap = 0	if (sl# : byte#) != Zslicep		cap = slcap((sl# : byte#))	;;	if cap >= len*sizeof(@a)		/* cast to pointer to work around bounds check */		sl# = (sl# : @a#)[:len]		-> sl#	;; 	/* grow in factors of 1.5 */	nel = sl#.len	while nel < len		nel += (nel >> 2) + 1	;; 	new = slalloc(nel)	n = min(len, sl#.len)	memblit((new : byte#), (sl# : byte#), n * sizeof(@a))	if sl#.len > 0		slfree(sl#)	;;	sl# = new[:len]	-> sl#} /* Grows a slice, filling new entries with zero bytes */generic slzgrow = {sl : @a[:]#, len	var oldlen	var base 	oldlen = sl#.len	slgrow(sl, len)	base = ((sl# : byte#) : intptr)	if oldlen < len		memfill((sl#[oldlen:] : byte#), 0, (len - oldlen)*sizeof(@a))	;;	-> sl#} const slcap = {p	var phdr 	phdr = ((p : size) - align(sizeof(slheader), Align) : slheader#)	std.iassert(phdr.magic == (0xdeadbeefbadf00d : size), "corrupt memory\n")	-> phdr.cap}