lua/lmem.c
Roberto Ierusalimschy 190c3be739 details
2000-05-31 13:53:30 -03:00

146 lines
3.6 KiB
C

/*
** $Id: lmem.c,v 1.31 2000/05/29 14:48:03 roberto Exp roberto $
** Interface to Memory Manager
** See Copyright Notice in lua.h
*/
#include <stdlib.h>
#define LUA_REENTRANT
#include "lmem.h"
#include "lobject.h"
#include "lstate.h"
#include "lua.h"
/*
** Real ISO (ANSI) systems do not need these tests;
** but some systems (Sun OS) are not that ISO...
*/
#ifdef OLD_ANSI
#define realloc(b,s) ((b) == NULL ? malloc(s) : (realloc)(b, s))
#define free(b) if (b) (free)(b)
#endif
#ifdef DEBUG
/*
** {======================================================================
** Controlled version for realloc.
** =======================================================================
*/
#include <assert.h>
#include <string.h>
#undef realloc
#undef malloc
#undef free
#define realloc(b, s) debug_realloc(b, s)
#define malloc(b) debug_realloc(NULL, 0)
#define free(b) debug_realloc(b, 0)
/* ensures maximum alignment for HEADER */
#define HEADER (sizeof(union { double d; char *s; long l; }))
#define MARKSIZE 16
#define MARK 0x55 /* 01010101 (a nice pattern) */
#define blocksize(b) ((unsigned long *)((char *)(b) - HEADER))
unsigned long memdebug_numblocks = 0;
unsigned long memdebug_total = 0;
unsigned long memdebug_maxmem = 0;
static void *checkblock (void *block) {
unsigned long *b = blocksize(block);
unsigned long size = *b;
int i;
for (i=0;i<MARKSIZE;i++)
assert(*(((char *)b)+HEADER+size+i) == MARK+i); /* corrupted block? */
memdebug_numblocks--;
memdebug_total -= size;
return b;
}
static void freeblock (void *block) {
if (block) {
size_t size = *blocksize(block);
block = checkblock(block);
memset(block, -1, size+HEADER+MARKSIZE); /* erase block */
(free)(block); /* free original block */
}
}
static void *debug_realloc (void *block, size_t size) {
if (size == 0) {
freeblock(block);
return NULL;
}
else {
size_t realsize = HEADER+size+MARKSIZE;
char *newblock = (char *)(malloc)(realsize); /* alloc a new block */
int i;
if (realsize < size) return NULL; /* overflow! */
if (newblock == NULL) return NULL;
if (block) {
size_t oldsize = *blocksize(block);
if (oldsize > size) oldsize = size;
memcpy(newblock+HEADER, block, oldsize);
freeblock(block); /* erase (and check) old copy */
}
memdebug_total += size;
if (memdebug_total > memdebug_maxmem) memdebug_maxmem = memdebug_total;
memdebug_numblocks++;
*(unsigned long *)newblock = size;
for (i=0;i<MARKSIZE;i++)
*(newblock+HEADER+size+i) = (char)(MARK+i);
return newblock+HEADER;
}
}
/* }====================================================================== */
#endif
void *luaM_growaux (lua_State *L, void *block, size_t nelems,
int inc, size_t size, const char *errormsg, size_t limit) {
size_t newn = nelems+inc;
if (nelems >= limit-inc) lua_error(L, errormsg);
if ((newn ^ nelems) <= nelems || /* still the same power-of-2 limit? */
(nelems > 0 && newn < MINPOWER2)) /* or block already is MINPOWER2? */
return block; /* do not need to reallocate */
else /* it crossed a power-of-2 boundary; grow to next power */
return luaM_realloc(L, block, luaO_power2(newn)*size);
}
/*
** generic allocation routine.
*/
void *luaM_realloc (lua_State *L, void *block, lint32 size) {
if (size == 0) {
free(block); /* block may be NULL; that is OK for free */
return NULL;
}
else if (size >= MAX_SIZET)
lua_error(L, "memory allocation error: block too big");
block = realloc(block, size);
if (block == NULL)
lua_error(L, memEM);
return block;
}