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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 |