mirror of https://github.com/lua/lua
141 lines
3.0 KiB
C
141 lines
3.0 KiB
C
/*
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** $Id: lmem.c,v 1.16 1999/05/20 20:43:06 roberto Exp roberto $
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** Interface to Memory Manager
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** See Copyright Notice in lua.h
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*/
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#include <stdlib.h>
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#include "lmem.h"
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#include "lstate.h"
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#include "lua.h"
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/*
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** real ANSI systems do not need these tests;
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** but some systems (Sun OS) are not that ANSI...
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*/
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#ifdef OLD_ANSI
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#define realloc(b,s) ((b) == NULL ? malloc(s) : (realloc)(b, s))
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#define free(b) if (b) (free)(b)
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#endif
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#define MINSIZE 8 /* minimum size for "growing" vectors */
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static unsigned long power2 (unsigned long n) {
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unsigned long p = MINSIZE;
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while (p<=n) p<<=1;
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return p;
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}
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void *luaM_growaux (void *block, unsigned long nelems, int inc, int size,
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char *errormsg, unsigned long limit) {
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unsigned long newn = nelems+inc;
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if (newn >= limit) lua_error(errormsg);
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if ((newn ^ nelems) <= nelems || /* still the same power of 2 limit? */
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(nelems > 0 && newn < MINSIZE)) /* or block already is MINSIZE? */
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return block; /* do not need to reallocate */
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else /* it crossed a power of 2 boundary; grow to next power */
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return luaM_realloc(block, power2(newn)*size);
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}
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#ifndef DEBUG
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/*
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** generic allocation routine.
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*/
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void *luaM_realloc (void *block, unsigned long size) {
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size_t s = (size_t)size;
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if (s != size)
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lua_error("memory allocation error: block too big");
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if (size == 0) {
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free(block); /* block may be NULL, that is OK for free */
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return NULL;
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}
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block = realloc(block, s);
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if (block == NULL)
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lua_error(memEM);
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return block;
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}
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#else
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/* DEBUG */
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#include <string.h>
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#define HEADER (sizeof(double))
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#define MARKSIZE 16
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#define MARK 55
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#define blocksize(b) ((unsigned long *)((char *)(b) - HEADER))
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unsigned long numblocks = 0;
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unsigned long totalmem = 0;
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static void *checkblock (void *block) {
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if (block == NULL)
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return NULL;
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else {
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unsigned long *b = blocksize(block);
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unsigned long size = *b;
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int i;
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for (i=0;i<MARKSIZE;i++)
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LUA_ASSERT(*(((char *)b)+HEADER+size+i) == MARK+i, "corrupted block");
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numblocks--;
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totalmem -= size;
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return b;
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}
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}
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static void freeblock (void *block) {
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if (block)
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memset(block, -1, *blocksize(block)); /* erase block */
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free(checkblock(block));
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}
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void *luaM_realloc (void *block, unsigned long size) {
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unsigned long realsize = HEADER+size+MARKSIZE;
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if (realsize != (size_t)realsize)
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lua_error("memory allocation error: block too big");
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if (size == 0) {
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freeblock(block);
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return NULL;
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}
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else {
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char *newblock = malloc(realsize);
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int i;
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if (block) {
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unsigned long oldsize = *blocksize(block);
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if (oldsize > size) oldsize = size;
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memcpy(newblock+HEADER, block, oldsize);
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freeblock(block); /* erase (and check) old copy */
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}
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if (newblock == NULL)
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lua_error(memEM);
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totalmem += size;
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numblocks++;
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*(unsigned long *)newblock = size;
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for (i=0;i<MARKSIZE;i++)
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*(newblock+HEADER+size+i) = MARK+i;
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return newblock+HEADER;
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}
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}
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#endif
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