client/deps/liblua/lzio.c

   1 /*
   2 ** $Id: lzio.c $
   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