lmem.h revision 344220 
1/*
2** $Id: lmem.h,v 1.43.1.1 2017/04/19 17:20:42 roberto Exp $
3** Interface to Memory Manager
4** See Copyright Notice in lua.h
5*/
6
7#ifndef lmem_h
8#define lmem_h
9
10
11#include <stddef.h>
12
13#include "llimits.h"
14#include "lua.h"
15
16
17/*
18** This macro reallocs a vector 'b' from 'on' to 'n' elements, where
19** each element has size 'e'. In case of arithmetic overflow of the
20** product 'n'*'e', it raises an error (calling 'luaM_toobig'). Because
21** 'e' is always constant, it avoids the runtime division MAX_SIZET/(e).
22**
23** (The macro is somewhat complex to avoid warnings:  The 'sizeof'
24** comparison avoids a runtime comparison when overflow cannot occur.
25** The compiler should be able to optimize the real test by itself, but
26** when it does it, it may give a warning about "comparison is always
27** false due to limited range of data type"; the +1 tricks the compiler,
28** avoiding this warning but also this optimization.)
29*/
30#define luaM_reallocv(L,b,on,n,e) \
31  (((sizeof(n) >= sizeof(size_t) && cast(size_t, (n)) + 1 > MAX_SIZET/(e)) \
32      ? luaM_toobig(L) : cast_void(0)) , \
33   luaM_realloc_(L, (b), (on)*(e), (n)*(e)))
34
35/*
36** Arrays of chars do not need any test
37*/
38#define luaM_reallocvchar(L,b,on,n)  \
39    cast(char *, luaM_realloc_(L, (b), (on)*sizeof(char), (n)*sizeof(char)))
40
41#define luaM_freemem(L, b, s)	luaM_realloc_(L, (b), (s), 0)
42#define luaM_free(L, b)		luaM_realloc_(L, (b), sizeof(*(b)), 0)
43#define luaM_freearray(L, b, n)   luaM_realloc_(L, (b), (n)*sizeof(*(b)), 0)
44
45#define luaM_malloc(L,s)	luaM_realloc_(L, NULL, 0, (s))
46#define luaM_new(L,t)		cast(t *, luaM_malloc(L, sizeof(t)))
47#define luaM_newvector(L,n,t) \
48		cast(t *, luaM_reallocv(L, NULL, 0, n, sizeof(t)))
49
50#define luaM_newobject(L,tag,s)	luaM_realloc_(L, NULL, tag, (s))
51
52#define luaM_growvector(L,v,nelems,size,t,limit,e) \
53          if ((nelems)+1 > (size)) \
54            ((v)=cast(t *, luaM_growaux_(L,v,&(size),sizeof(t),limit,e)))
55
56#define luaM_reallocvector(L, v,oldn,n,t) \
57   ((v)=cast(t *, luaM_reallocv(L, v, oldn, n, sizeof(t))))
58
59LUAI_FUNC l_noret luaM_toobig (lua_State *L);
60
61/* not to be called directly */
62LUAI_FUNC void *luaM_realloc_ (lua_State *L, void *block, size_t oldsize,
63                                                          size_t size);
64LUAI_FUNC void *luaM_growaux_ (lua_State *L, void *block, int *size,
65                               size_t size_elem, int limit,
66                               const char *what);
67
68#endif
69
70