lmem.h (3435B)
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' 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_int((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) \ 61 cast(t*, luaM_malloc_(L, cast_sizet(n)*sizeof(t), 0)) 62 #define luaM_newvectorchecked(L,n,t) \ 63 (luaM_checksize(L,n,sizeof(t)), luaM_newvector(L,n,t)) 64 65 #define luaM_newobject(L,tag,s) luaM_malloc_(L, (s), tag) 66 67 #define luaM_newblock(L, size) luaM_newvector(L, size, char) 68 69 #define luaM_growvector(L,v,nelems,size,t,limit,e) \ 70 ((v)=cast(t *, luaM_growaux_(L,v,nelems,&(size),sizeof(t), \ 71 luaM_limitN(limit,t),e))) 72 73 #define luaM_reallocvector(L, v,oldn,n,t) \ 74 (cast(t *, luaM_realloc_(L, v, cast_sizet(oldn) * sizeof(t), \ 75 cast_sizet(n) * sizeof(t)))) 76 77 #define luaM_shrinkvector(L,v,size,fs,t) \ 78 ((v)=cast(t *, luaM_shrinkvector_(L, v, &(size), fs, sizeof(t)))) 79 80 LUAI_FUNC l_noret luaM_toobig (lua_State *L); 81 82 /* not to be called directly */ 83 LUAI_FUNC void *luaM_realloc_ (lua_State *L, void *block, size_t oldsize, 84 size_t size); 85 LUAI_FUNC void *luaM_saferealloc_ (lua_State *L, void *block, size_t oldsize, 86 size_t size); 87 LUAI_FUNC void luaM_free_ (lua_State *L, void *block, size_t osize); 88 LUAI_FUNC void *luaM_growaux_ (lua_State *L, void *block, int nelems, 89 int *size, unsigned size_elem, int limit, 90 const char *what); 91 LUAI_FUNC void *luaM_shrinkvector_ (lua_State *L, void *block, int *nelem, 92 int final_n, unsigned size_elem); 93 LUAI_FUNC void *luaM_malloc_ (lua_State *L, size_t size, int tag); 94 95 #endif 96