1 /* $NetBSD: lmem.c,v 1.4 2015/10/08 13:21:00 mbalmer Exp $ */
2
3 /*
4 ** Id: lmem.c,v 1.91 2015/03/06 19:45:54 roberto Exp
5 ** Interface to Memory Manager
6 ** See Copyright Notice in lua.h
7 */
8
9 #define lmem_c
10 #define LUA_CORE
11
12 #include "lprefix.h"
13
14
15 #ifndef _KERNEL
16 #include <stddef.h>
17 #endif
18
19 #include "lua.h"
20
21 #include "ldebug.h"
22 #include "ldo.h"
23 #include "lgc.h"
24 #include "lmem.h"
25 #include "lobject.h"
26 #include "lstate.h"
27
28
29
30 /*
31 ** About the realloc function:
32 ** void * frealloc (void *ud, void *ptr, size_t osize, size_t nsize);
33 ** ('osize' is the old size, 'nsize' is the new size)
34 **
35 ** * frealloc(ud, NULL, x, s) creates a new block of size 's' (no
36 ** matter 'x').
37 **
38 ** * frealloc(ud, p, x, 0) frees the block 'p'
39 ** (in this specific case, frealloc must return NULL);
40 ** particularly, frealloc(ud, NULL, 0, 0) does nothing
41 ** (which is equivalent to free(NULL) in ISO C)
42 **
43 ** frealloc returns NULL if it cannot create or reallocate the area
44 ** (any reallocation to an equal or smaller size cannot fail!)
45 */
46
47
48
49 #define MINSIZEARRAY 4
50
51
luaM_growaux_(lua_State * L,void * block,int * size,size_t size_elems,int limit,const char * what)52 void *luaM_growaux_ (lua_State *L, void *block, int *size, size_t size_elems,
53 int limit, const char *what) {
54 void *newblock;
55 int newsize;
56 if (*size >= limit/2) { /* cannot double it? */
57 if (*size >= limit) /* cannot grow even a little? */
58 luaG_runerror(L, "too many %s (limit is %d)", what, limit);
59 newsize = limit; /* still have at least one free place */
60 }
61 else {
62 newsize = (*size)*2;
63 if (newsize < MINSIZEARRAY)
64 newsize = MINSIZEARRAY; /* minimum size */
65 }
66 newblock = luaM_reallocv(L, block, *size, newsize, size_elems);
67 *size = newsize; /* update only when everything else is OK */
68 return newblock;
69 }
70
71
luaM_toobig(lua_State * L)72 l_noret luaM_toobig (lua_State *L) {
73 luaG_runerror(L, "memory allocation error: block too big");
74 }
75
76
77
78 /*
79 ** generic allocation routine.
80 */
luaM_realloc_(lua_State * L,void * block,size_t osize,size_t nsize)81 void *luaM_realloc_ (lua_State *L, void *block, size_t osize, size_t nsize) {
82 void *newblock;
83 global_State *g = G(L);
84 size_t realosize = (block) ? osize : 0;
85 lua_assert((realosize == 0) == (block == NULL));
86 #if defined(HARDMEMTESTS)
87 if (nsize > realosize && g->gcrunning)
88 luaC_fullgc(L, 1); /* force a GC whenever possible */
89 #endif
90 newblock = (*g->frealloc)(g->ud, block, osize, nsize);
91 if (newblock == NULL && nsize > 0) {
92 lua_assert(nsize > realosize); /* cannot fail when shrinking a block */
93 if (g->version) { /* is state fully built? */
94 luaC_fullgc(L, 1); /* try to free some memory... */
95 newblock = (*g->frealloc)(g->ud, block, osize, nsize); /* try again */
96 }
97 if (newblock == NULL)
98 luaD_throw(L, LUA_ERRMEM);
99 }
100 lua_assert((nsize == 0) == (newblock == NULL));
101 g->GCdebt = (g->GCdebt + nsize) - realosize;
102 return newblock;
103 }
104
105