lmem.c
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上传日期:2020-08-09
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文件大小:2k
- /*
- ** $Id: lmem.c,v 1.70 2005/12/26 13:35:47 roberto Exp $
- ** Interface to Memory Manager
- ** See Copyright Notice in lua.h
- */
- #include <stddef.h>
- #define lmem_c
- #define LUA_CORE
- #include "lua.h"
- #include "ldebug.h"
- #include "ldo.h"
- #include "lmem.h"
- #include "lobject.h"
- #include "lstate.h"
- /*
- ** About the realloc function:
- ** void * frealloc (void *ud, void *ptr, size_t osize, size_t nsize);
- ** (`osize' is the old size, `nsize' is the new size)
- **
- ** Lua ensures that (ptr == NULL) iff (osize == 0).
- **
- ** * frealloc(ud, NULL, 0, x) creates a new block of size `x'
- **
- ** * frealloc(ud, p, x, 0) frees the block `p'
- ** (in this specific case, frealloc must return NULL).
- ** particularly, frealloc(ud, NULL, 0, 0) does nothing
- ** (which is equivalent to free(NULL) in ANSI C)
- **
- ** frealloc returns NULL if it cannot create or reallocate the area
- ** (any reallocation to an equal or smaller size cannot fail!)
- */
- #define MINSIZEARRAY 4
- void *luaM_growaux_ (lua_State *L, void *block, int *size, size_t size_elems,
- int limit, const char *errormsg) {
- void *newblock;
- int newsize;
- if (*size >= limit/2) { /* cannot double it? */
- if (*size >= limit) /* cannot grow even a little? */
- luaG_runerror(L, errormsg);
- newsize = limit; /* still have at least one free place */
- }
- else {
- newsize = (*size)*2;
- if (newsize < MINSIZEARRAY)
- newsize = MINSIZEARRAY; /* minimum size */
- }
- newblock = luaM_reallocv(L, block, *size, newsize, size_elems);
- *size = newsize; /* update only when everything else is OK */
- return newblock;
- }
- void *luaM_toobig (lua_State *L) {
- luaG_runerror(L, "memory allocation error: block too big");
- return NULL; /* to avoid warnings */
- }
- /*
- ** generic allocation routine.
- */
- void *luaM_realloc_ (lua_State *L, void *block, size_t osize, size_t nsize) {
- global_State *g = G(L);
- lua_assert((osize == 0) == (block == NULL));
- block = (*g->frealloc)(g->ud, block, osize, nsize);
- if (block == NULL && nsize > 0)
- luaD_throw(L, LUA_ERRMEM);
- lua_assert((nsize == 0) == (block == NULL));
- g->totalbytes = (g->totalbytes - osize) + nsize;
- return block;
- }