mudgangster

Tiny, scriptable MUD client
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lzio.cc (1365B)


      1 /*
      2 ** $Id: lzio.c,v 1.37.1.1 2017/04/19 17:20:42 roberto Exp $
      3 ** Buffered streams
      4 ** See Copyright Notice in lua.h
      5 */
      6 
      7 #define lzio_c
      8 #define LUA_CORE
      9 
     10 #include "lprefix.h"
     11 
     12 
     13 #include <string.h>
     14 
     15 #include "lua.h"
     16 
     17 #include "llimits.h"
     18 #include "lmem.h"
     19 #include "lstate.h"
     20 #include "lzio.h"
     21 
     22 
     23 int luaZ_fill (ZIO *z) {
     24   size_t size;
     25   lua_State *L = z->L;
     26   const char *buff;
     27   lua_unlock(L);
     28   buff = z->reader(L, z->data, &size);
     29   lua_lock(L);
     30   if (buff == NULL || size == 0)
     31     return EOZ;
     32   z->n = size - 1;  /* discount char being returned */
     33   z->p = buff;
     34   return cast_uchar(*(z->p++));
     35 }
     36 
     37 
     38 void luaZ_init (lua_State *L, ZIO *z, lua_Reader reader, void *data) {
     39   z->L = L;
     40   z->reader = reader;
     41   z->data = data;
     42   z->n = 0;
     43   z->p = NULL;
     44 }
     45 
     46 
     47 /* --------------------------------------------------------------- read --- */
     48 size_t luaZ_read (ZIO *z, void *b, size_t n) {
     49   while (n) {
     50     size_t m;
     51     if (z->n == 0) {  /* no bytes in buffer? */
     52       if (luaZ_fill(z) == EOZ)  /* try to read more */
     53         return n;  /* no more input; return number of missing bytes */
     54       else {
     55         z->n++;  /* luaZ_fill consumed first byte; put it back */
     56         z->p--;
     57       }
     58     }
     59     m = (n <= z->n) ? n : z->n;  /* min. between n and z->n */
     60     memcpy(b, z->p, m);
     61     z->n -= m;
     62     z->p += m;
     63     b = (char *)b + m;
     64     n -= m;
     65   }
     66   return 0;
     67 }
     68