mudgangster

Tiny, scriptable MUD client
Log | Files | Refs | README

lmem.h (2439B)

      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 
     59 LUAI_FUNC l_noret luaM_toobig (lua_State *L);
     60 
     61 /* not to be called directly */
     62 LUAI_FUNC void *luaM_realloc_ (lua_State *L, void *block, size_t oldsize,
     63                                                           size_t size);
     64 LUAI_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