1/*
2** $Id: lmem.h $
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#define luaM_error(L) luaD_throw(L, LUA_ERRMEM)
18
19
20/*
21** This macro tests whether it is safe to multiply 'n' by the size of
22** type 't' without overflows. Because 'e' is always constant, it avoids
23** the runtime division MAX_SIZET/(e).
24** (The macro is somewhat complex to avoid warnings: The 'sizeof'
25** comparison avoids a runtime comparison when overflow cannot occur.
26** The compiler should be able to optimize the real test by itself, but
27** when it does it, it may give a warning about "comparison is always
28** false due to limited range of data type"; the +1 tricks the compiler,
29** avoiding this warning but also this optimization.)
30*/
31#define luaM_testsize(n,e) \
32 (sizeof(n) >= sizeof(size_t) && cast_sizet((n)) + 1 > MAX_SIZET/(e))
33
34#define luaM_checksize(L,n,e) \
35 (luaM_testsize(n,e) ? luaM_toobig(L) : cast_void(0))
36
37
38/*
39** Computes the minimum between 'n' and 'MAX_SIZET/sizeof(t)', so that
40** the result is not larger than 'n' and cannot overflow a 'size_t'
41** when multiplied by the size of type 't'. (Assumes that 'n' is an
42** 'int' or 'unsigned int' and that 'int' is not larger than 'size_t'.)
43*/
44#define luaM_limitN(n,t) \
45 ((cast_sizet(n) <= MAX_SIZET/sizeof(t)) ? (n) : \
46 cast_uint((MAX_SIZET/sizeof(t))))
47
48
49/*
50** Arrays of chars do not need any test
51*/
52#define luaM_reallocvchar(L,b,on,n) \
53 cast_charp(luaM_saferealloc_(L, (b), (on)*sizeof(char), (n)*sizeof(char)))
54
55#define luaM_freemem(L, b, s) luaM_free_(L, (b), (s))
56#define luaM_free(L, b) luaM_free_(L, (b), sizeof(*(b)))
57#define luaM_freearray(L, b, n) luaM_free_(L, (b), (n)*sizeof(*(b)))
58
59#define luaM_new(L,t) cast(t*, luaM_malloc_(L, sizeof(t), 0))
60#define luaM_newvector(L,n,t) cast(t*, luaM_malloc_(L, (n)*sizeof(t), 0))
61#define luaM_newvectorchecked(L,n,t) \
62 (luaM_checksize(L,n,sizeof(t)), luaM_newvector(L,n,t))
63
64#define luaM_newobject(L,tag,s) luaM_malloc_(L, (s), tag)
65
66#define luaM_growvector(L,v,nelems,size,t,limit,e) \
67 ((v)=cast(t *, luaM_growaux_(L,v,nelems,&(size),sizeof(t), \
68 luaM_limitN(limit,t),e)))
69
70#define luaM_reallocvector(L, v,oldn,n,t) \
71 (cast(t *, luaM_realloc_(L, v, cast_sizet(oldn) * sizeof(t), \
72 cast_sizet(n) * sizeof(t))))
73
74#define luaM_shrinkvector(L,v,size,fs,t) \
75 ((v)=cast(t *, luaM_shrinkvector_(L, v, &(size), fs, sizeof(t))))
76
77LUAI_FUNC l_noret luaM_toobig (lua_State *L);
78
79/* not to be called directly */
80LUAI_FUNC void *luaM_realloc_ (lua_State *L, void *block, size_t oldsize,
81 size_t size);
82LUAI_FUNC void *luaM_saferealloc_ (lua_State *L, void *block, size_t oldsize,
83 size_t size);
84LUAI_FUNC void luaM_free_ (lua_State *L, void *block, size_t osize);
85LUAI_FUNC void *luaM_growaux_ (lua_State *L, void *block, int nelems,
86 int *size, int size_elem, int limit,
87 const char *what);
88LUAI_FUNC void *luaM_shrinkvector_ (lua_State *L, void *block, int *nelem,
89 int final_n, int size_elem);
90LUAI_FUNC void *luaM_malloc_ (lua_State *L, size_t size, int tag);
91
92#endif
93
94