mirror of https://github.com/lua/lua
100 lines
2.6 KiB
C
100 lines
2.6 KiB
C
/*
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** $Id: lmem.c,v 1.83 2011/11/30 12:42:49 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 <stddef.h>
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#define lmem_c
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#define LUA_CORE
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#include "lua.h"
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#include "ldebug.h"
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#include "ldo.h"
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#include "lgc.h"
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#include "lmem.h"
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#include "lobject.h"
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#include "lstate.h"
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/*
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** About the realloc function:
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** void * frealloc (void *ud, void *ptr, size_t osize, size_t nsize);
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** (`osize' is the old size, `nsize' is the new size)
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**
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** * frealloc(ud, NULL, x, s) creates a new block of size `s' (no
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** matter 'x').
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**
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** * frealloc(ud, p, x, 0) frees the block `p'
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** (in this specific case, frealloc must return NULL);
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** particularly, frealloc(ud, NULL, 0, 0) does nothing
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** (which is equivalent to free(NULL) in ANSI C)
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**
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** frealloc returns NULL if it cannot create or reallocate the area
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** (any reallocation to an equal or smaller size cannot fail!)
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*/
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#define MINSIZEARRAY 4
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void *luaM_growaux_ (lua_State *L, void *block, int *size, size_t size_elems,
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int limit, const char *what) {
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void *newblock;
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int newsize;
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if (*size >= limit/2) { /* cannot double it? */
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if (*size >= limit) /* cannot grow even a little? */
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luaG_runerror(L, "too many %s (limit is %d)", what, limit);
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newsize = limit; /* still have at least one free place */
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}
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else {
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newsize = (*size)*2;
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if (newsize < MINSIZEARRAY)
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newsize = MINSIZEARRAY; /* minimum size */
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}
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newblock = luaM_reallocv(L, block, *size, newsize, size_elems);
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*size = newsize; /* update only when everything else is OK */
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return newblock;
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}
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l_noret luaM_toobig (lua_State *L) {
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luaG_runerror(L, "memory allocation error: block too big");
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}
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/*
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** generic allocation routine.
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*/
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void *luaM_realloc_ (lua_State *L, void *block, size_t osize, size_t nsize) {
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void *newblock;
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global_State *g = G(L);
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size_t realosize = (block) ? osize : 0;
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lua_assert((realosize == 0) == (block == NULL));
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#if defined(HARDMEMTESTS)
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if (nsize > realosize && g->gcrunning)
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luaC_fullgc(L, 1); /* force a GC whenever possible */
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#endif
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newblock = (*g->frealloc)(g->ud, block, osize, nsize);
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if (newblock == NULL && nsize > 0) {
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api_check(L, nsize > realosize,
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"realloc cannot fail when shrinking a block");
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if (g->gcrunning) {
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luaC_fullgc(L, 1); /* try to free some memory... */
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newblock = (*g->frealloc)(g->ud, block, osize, nsize); /* try again */
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}
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if (newblock == NULL)
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luaD_throw(L, LUA_ERRMEM);
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}
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lua_assert((nsize == 0) == (newblock == NULL));
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g->GCdebt = (g->GCdebt + nsize) - realosize;
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return newblock;
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}
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