1 /*
2 ** $Id: lmem.c,v 1.70.1.1 2007/12/27 13:02:25 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 "lmem.h"
18 #include "lobject.h"
19 #include "lstate.h"
20
21
22
23 /*
24 ** About the realloc function:
25 ** void * frealloc (void *ud, void *ptr, size_t osize, size_t nsize);
26 ** (`osize' is the old size, `nsize' is the new size)
27 **
28 ** Lua ensures that (ptr == NULL) iff (osize == 0).
29 **
30 ** * frealloc(ud, NULL, 0, x) creates a new block of size `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
luaM_growaux_(lua_State * L,void * block,int * size,size_t size_elems,int limit,const char * errormsg)46 void *luaM_growaux_ (lua_State *L, void *block, int *size, size_t size_elems,
47 int limit, const char *errormsg) {
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, errormsg);
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
luaM_toobig(lua_State * L)66 void *luaM_toobig (lua_State *L) {
67 luaG_runerror(L, "memory allocation error: block too big");
68 return NULL; /* to avoid warnings */
69 }
70
71
72
73 /*
74 ** generic allocation routine.
75 */
luaM_realloc_(lua_State * L,void * block,size_t osize,size_t nsize)76 void *luaM_realloc_ (lua_State *L, void *block, size_t osize, size_t nsize) {
77 global_State *g = G(L);
78 lua_assert((osize == 0) == (block == NULL));
79 block = (*g->frealloc)(g->ud, block, osize, nsize);
80 if (block == NULL && nsize > 0)
81 luaD_throw(L, LUA_ERRMEM);
82 lua_assert((nsize == 0) == (block == NULL));
83 g->totalbytes = (g->totalbytes - osize) + nsize;
84 return block;
85 }
86
87