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1 | /* |
2 | ** $Id: lmem.c,v 1.84 2012/05/23 15:41:53 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 | |
46 | void *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 | |
66 | l_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 | */ |
75 | void *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 | |