1/* 2** $Id: lmem.c,v 1.84.1.1 2013/04/12 18:48:47 roberto Exp $ 3** Interface to Memory Manager 4** See Copyright Notice in lua.h 5*/ 6 7 8#include <stddef.h> 9 10#define lmem_c 11#define LUA_CORE 12 13#include "lua.h" 14 15#include "ldebug.h" 16#include "ldo.h" 17#include "lgc.h" 18#include "lmem.h" 19#include "lobject.h" 20#include "lstate.h" 21 22 23 24/* 25** About the realloc function: 26** void * frealloc (void *ud, void *ptr, size_t osize, size_t nsize); 27** (`osize' is the old size, `nsize' is the new size) 28** 29** * frealloc(ud, NULL, x, s) creates a new block of size `s' (no 30** matter 'x'). 31** 32** * frealloc(ud, p, x, 0) frees the block `p' 33** (in this specific case, frealloc must return NULL); 34** particularly, frealloc(ud, NULL, 0, 0) does nothing 35** (which is equivalent to free(NULL) in ANSI C) 36** 37** frealloc returns NULL if it cannot create or reallocate the area 38** (any reallocation to an equal or smaller size cannot fail!) 39*/ 40 41 42 43#define MINSIZEARRAY 4 44 45 46void *luaM_growaux_ (lua_State *L, void *block, int *size, size_t size_elems, 47 int limit, const char *what) { 48 void *newblock; 49 int newsize; 50 if (*size >= limit/2) { /* cannot double it? */ 51 if (*size >= limit) /* cannot grow even a little? */ 52 luaG_runerror(L, "too many %s (limit is %d)", what, limit); 53 newsize = limit; /* still have at least one free place */ 54 } 55 else { 56 newsize = (*size)*2; 57 if (newsize < MINSIZEARRAY) 58 newsize = MINSIZEARRAY; /* minimum size */ 59 } 60 newblock = luaM_reallocv(L, block, *size, newsize, size_elems); 61 *size = newsize; /* update only when everything else is OK */ 62 return newblock; 63} 64 65 66l_noret luaM_toobig (lua_State *L) { 67 luaG_runerror(L, "memory allocation error: block too big"); 68} 69 70 71 72/* 73** generic allocation routine. 74*/ 75void *luaM_realloc_ (lua_State *L, void *block, size_t osize, size_t nsize) { 76 void *newblock; 77 global_State *g = G(L); 78 size_t realosize = (block) ? osize : 0; 79 lua_assert((realosize == 0) == (block == NULL)); 80#if defined(HARDMEMTESTS) 81 if (nsize > realosize && g->gcrunning) 82 luaC_fullgc(L, 1); /* force a GC whenever possible */ 83#endif 84 newblock = (*g->frealloc)(g->ud, block, osize, nsize); 85 if (newblock == NULL && nsize > 0) { 86 api_check(L, nsize > realosize, 87 "realloc cannot fail when shrinking a block"); 88 if (g->gcrunning) { 89 luaC_fullgc(L, 1); /* try to free some memory... */ 90 newblock = (*g->frealloc)(g->ud, block, osize, nsize); /* try again */ 91 } 92 if (newblock == NULL) 93 luaD_throw(L, LUA_ERRMEM); 94 } 95 lua_assert((nsize == 0) == (newblock == NULL)); 96 g->GCdebt = (g->GCdebt + nsize) - realosize; 97 return newblock; 98} 99 100