external/mit/lua/dist/src/lmem.h

   1 /*      $NetBSD: lmem.h,v 1.3 2015/02/02 14:03:05 lneto Exp $   */
   2
   3 /*
   4 ** Id: lmem.h,v 1.43 2014/12/19 17:26:14 roberto Exp
   5 ** Interface to Memory Manager
   6 ** See Copyright Notice in lua.h
   7 */
   8
   9 #ifndef lmem_h
  10 #define lmem_h
  11
  12
  13 #ifndef _KERNEL
  14 #include <stddef.h>
  15 #endif
  16
  17 #include "llimits.h"
  18 #include "lua.h"
  19
  20
  21 /*
  22 ** This macro reallocs a vector 'b' from 'on' to 'n' elements, where
  23 ** each element has size 'e'. In case of arithmetic overflow of the
  24 ** product 'n'*'e', it raises an error (calling 'luaM_toobig'). Because
  25 ** 'e' is always constant, it avoids the runtime division MAX_SIZET/(e).
  26 **
  27 ** (The macro is somewhat complex to avoid warnings:  The 'sizeof'
  28 ** comparison avoids a runtime comparison when overflow cannot occur.
  29 ** The compiler should be able to optimize the real test by itself, but
  30 ** when it does it, it may give a warning about "comparison is always
  31 ** false due to limited range of data type"; the +1 tricks the compiler,
  32 ** avoiding this warning but also this optimization.)
  33 */
  34 #define luaM_reallocv(L,b,on,n,e) \
  35   (((sizeof(n) >= sizeof(size_t) && cast(size_t, (n)) + 1 > MAX_SIZET/(e)) \
  36       ? luaM_toobig(L) : cast_void(0)) , \
  37    luaM_realloc_(L, (b), (on)*(e), (n)*(e)))
  38
  39 /*
  40 ** Arrays of chars do not need any test
  41 */
  42 #define luaM_reallocvchar(L,b,on,n)  \
  43     cast(char *, luaM_realloc_(L, (b), (on)*sizeof(char), (n)*sizeof(char)))
  44
  45 #define luaM_freemem(L, b, s)   luaM_realloc_(L, (b), (s), 0)
  46 #define luaM_free(L, b)         luaM_realloc_(L, (b), sizeof(*(b)), 0)
  47 #define luaM_freearray(L, b, n)   luaM_realloc_(L, (b), (n)*sizeof(*(b)), 0)
  48
  49 #define luaM_malloc(L,s)        luaM_realloc_(L, NULL, 0, (s))
  50 #define luaM_new(L,t)           cast(t *, luaM_malloc(L, sizeof(t)))
  51 #define luaM_newvector(L,n,t) \
  52                 cast(t *, luaM_reallocv(L, NULL, 0, n, sizeof(t)))
  53
  54 #define luaM_newobject(L,tag,s) luaM_realloc_(L, NULL, tag, (s))
  55
  56 #define luaM_growvector(L,v,nelems,size,t,limit,e) \
  57           if ((nelems)+1 > (size)) \
  58             ((v)=cast(t *, luaM_growaux_(L,v,&(size),sizeof(t),limit,e)))
  59
  60 #define luaM_reallocvector(L, v,oldn,n,t) \
  61    ((v)=cast(t *, luaM_reallocv(L, v, oldn, n, sizeof(t))))
  62
  63 LUAI_FUNC l_noret luaM_toobig (lua_State *L);
  64
  65 /* not to be called directly */
  66 LUAI_FUNC void *luaM_realloc_ (lua_State *L, void *block, size_t oldsize,
  67                                                           size_t size);
  68 LUAI_FUNC void *luaM_growaux_ (lua_State *L, void *block, int *size,
  69                                size_t size_elem, int limit,
  70                                const char *what);
  71
  72 #endif
  73