1 /* 2 ** $Id: lmem.c,v 1.91.1.1 2017/04/19 17:20:42 roberto Exp $ 3 ** Interface to Memory Manager 4 ** See Copyright Notice in lua.h 5 */ 6 7 #define lmem_c 8 #define LUA_CORE 9 10 #include "lprefix.h" 11 12 13 #include <stddef.h> 14 15 #include "lua.h" 16 17 #include "ldebug.h" 18 #include "ldo.h" 19 #include "lgc.h" 20 #include "lmem.h" 21 #include "lobject.h" 22 #include "lstate.h" 23 24 25 26 /* 27 ** About the realloc function: 28 ** void * frealloc (void *ud, void *ptr, size_t osize, size_t nsize); 29 ** ('osize' is the old size, 'nsize' is the new size) 30 ** 31 ** * frealloc(ud, NULL, x, s) creates a new block of size 's' (no 32 ** matter 'x'). 33 ** 34 ** * frealloc(ud, p, x, 0) frees the block 'p' 35 ** (in this specific case, frealloc must return NULL); 36 ** particularly, frealloc(ud, NULL, 0, 0) does nothing 37 ** (which is equivalent to free(NULL) in ISO C) 38 ** 39 ** frealloc returns NULL if it cannot create or reallocate the area 40 ** (any reallocation to an equal or smaller size cannot fail!) 41 */ 42 43 44 45 #define MINSIZEARRAY 4 46 47 48 void *luaM_growaux_ (lua_State *L, void *block, int *size, size_t size_elems, 49 int limit, const char *what) { 50 void *newblock; 51 int newsize; 52 if (*size >= limit/2) { /* cannot double it? */ 53 if (*size >= limit) /* cannot grow even a little? */ 54 luaG_runerror(L, "too many %s (limit is %d)", what, limit); 55 newsize = limit; /* still have at least one free place */ 56 } 57 else { 58 newsize = (*size)*2; 59 if (newsize < MINSIZEARRAY) 60 newsize = MINSIZEARRAY; /* minimum size */ 61 } 62 newblock = luaM_reallocv(L, block, *size, newsize, size_elems); 63 *size = newsize; /* update only when everything else is OK */ 64 return newblock; 65 } 66 67 68 l_noret luaM_toobig (lua_State *L) { 69 luaG_runerror(L, "memory allocation error: block too big"); 70 } 71 72 73 74 /* 75 ** generic allocation routine. 76 */ 77 void *luaM_realloc_ (lua_State *L, void *block, size_t osize, size_t nsize) { 78 void *newblock; 79 global_State *g = G(L); 80 size_t realosize = (block) ? osize : 0; 81 lua_assert((realosize == 0) == (block == NULL)); 82 #if defined(HARDMEMTESTS) 83 if (nsize > realosize && g->gcrunning) 84 luaC_fullgc(L, 1); /* force a GC whenever possible */ 85 #endif 86 newblock = (*g->frealloc)(g->ud, block, osize, nsize); 87 if (newblock == NULL && nsize > 0) { 88 lua_assert(nsize > realosize); /* cannot fail when shrinking a block */ 89 if (g->version) { /* is state fully built? */ 90 luaC_fullgc(L, 1); /* try to free some memory... */ 91 newblock = (*g->frealloc)(g->ud, block, osize, nsize); /* try again */ 92 } 93 if (newblock == NULL) 94 luaD_throw(L, LUA_ERRMEM); 95 } 96 lua_assert((nsize == 0) == (newblock == NULL)); 97 g->GCdebt = (g->GCdebt + nsize) - realosize; 98 return newblock; 99 } 100 101