1 /*

     2 ** $Id: lzio.c,v 1.31.1.1 2007/12/27 13:02:25 roberto Exp $

     3 ** a generic input stream interface

     4 ** See Copyright Notice in lua.h

     5 */

     6 

     7 

     8 #include <string.h>

     9 

    10 #define lzio_c

    11 #define LUA_CORE

    12 

    13 #include "lua.h"

    14 

    15 #include "llimits.h"

    16 #include "lmem.h"

    17 #include "lstate.h"

    18 #include "lzio.h"

    19 

    20 

    21 int luaZ_fill (ZIO *z) {

    22   size_t size;

    23   lua_State *L = z->L;

    24   const char *buff;

    25   lua_unlock(L);

    26   buff = z->reader(L, z->data, &size);

    27   lua_lock(L);

    28   if (buff == NULL || size == 0) return EOZ;

    29   z->n = size - 1;

    30   z->p = buff;

    31   return char2int(*(z->p++));

    32 }

    33 

    34 

    35 int luaZ_lookahead (ZIO *z) {

    36   if (z->n == 0) {

    37     if (luaZ_fill(z) == EOZ)

    38       return EOZ;

    39     else {

    40       z->n++;  /* luaZ_fill removed first byte; put back it */

    41       z->p--;

    42     }

    43   }

    44   return char2int(*z->p);

    45 }

    46 

    47 

    48 void luaZ_init (lua_State *L, ZIO *z, lua_Reader reader, void *data) {

    49   z->L = L;

    50   z->reader = reader;

    51   z->data = data;

    52   z->n = 0;

    53   z->p = NULL;

    54 }

    55 

    56 

    57 /* --------------------------------------------------------------- read --- */

    58 size_t luaZ_read (ZIO *z, void *b, size_t n) {

    59   while (n) {

    60     size_t m;

    61     if (luaZ_lookahead(z) == EOZ)

    62       return n;  /* return number of missing bytes */

    63     m = (n <= z->n) ? n : z->n;  /* min. between n and z->n */

    64     memcpy(b, z->p, m);

    65     z->n -= m;

    66     z->p += m;

    67     b = (char *)b + m;

    68     n -= m;

    69   }

    70   return 0;

    71 }

    72 

    73 /* ------------------------------------------------------------------------ */

    74 char *luaZ_openspace (lua_State *L, Mbuffer *buff, size_t n) {

    75   if (n > buff->buffsize) {

    76     if (n < LUA_MINBUFFER) n = LUA_MINBUFFER;

    77     luaZ_resizebuffer(L, buff, n);

    78   }

    79   return buff->buffer;

    80 }

    81 

    82