client/deps/liblua/lmem.h

   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
  77 LUAI_FUNC l_noret luaM_toobig(lua_State *L);
  78
  79 /* not to be called directly */
  80 LUAI_FUNC void *luaM_realloc_(lua_State *L, void *block, size_t oldsize,
  81                               size_t size);
  82 LUAI_FUNC void *luaM_saferealloc_(lua_State *L, void *block, size_t oldsize,
  83                                   size_t size);
  84 LUAI_FUNC void luaM_free_(lua_State *L, void *block, size_t osize);
  85 LUAI_FUNC void *luaM_growaux_(lua_State *L, void *block, int nelems,
  86                               int *size, int size_elem, int limit,
  87                               const char *what);
  88 LUAI_FUNC void *luaM_shrinkvector_(lua_State *L, void *block, int *nelem,
  89                                    int final_n, int size_elem);
  90 LUAI_FUNC void *luaM_malloc_(lua_State *L, size_t size, int tag);
  91
  92 #endif
  93