1 /* $NetBSD: lmem.c,v 1.1.1.1 2010/10/31 11:16:57 mbalmer Exp $ */ 2 3 /* 4 ** Id: lmem.c,v 1.70.1.1 2007/12/27 13:02:25 roberto Exp 5 ** Interface to Memory Manager 6 ** See Copyright Notice in lua.h 7 */ 8 9 10 #include <stddef.h> 11 12 #define lmem_c 13 #define LUA_CORE 14 15 #include "lua.h" 16 17 #include "ldebug.h" 18 #include "ldo.h" 19 #include "lmem.h" 20 #include "lobject.h" 21 #include "lstate.h" 22 23 24 25 /* 26 ** About the realloc function: 27 ** void * frealloc (void *ud, void *ptr, size_t osize, size_t nsize); 28 ** (`osize' is the old size, `nsize' is the new size) 29 ** 30 ** Lua ensures that (ptr == NULL) iff (osize == 0). 31 ** 32 ** * frealloc(ud, NULL, 0, x) creates a new block of size `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 ANSI 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 *errormsg) { 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, errormsg); 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 void *luaM_toobig (lua_State *L) { 69 luaG_runerror(L, "memory allocation error: block too big"); 70 return NULL; /* to avoid warnings */ 71 } 72 73 74 75 /* 76 ** generic allocation routine. 77 */ 78 void *luaM_realloc_ (lua_State *L, void *block, size_t osize, size_t nsize) { 79 global_State *g = G(L); 80 lua_assert((osize == 0) == (block == NULL)); 81 block = (*g->frealloc)(g->ud, block, osize, nsize); 82 if (block == NULL && nsize > 0) 83 luaD_throw(L, LUA_ERRMEM); 84 lua_assert((nsize == 0) == (block == NULL)); 85 g->totalbytes = (g->totalbytes - osize) + nsize; 86 return block; 87 } 88 89