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