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#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
46void *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
66l_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*/
75void *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
100