1/*	$NetBSD$	*/
2
3/*
4** Id: lzio.c,v 1.31.1.1 2007/12/27 13:02:25 roberto Exp
5** a generic input stream interface
6** See Copyright Notice in lua.h
7*/
8
9
10#include <string.h>
11
12#define lzio_c
13#define LUA_CORE
14
15#include "lua.h"
16
17#include "llimits.h"
18#include "lmem.h"
19#include "lstate.h"
20#include "lzio.h"
21
22
23int 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) return EOZ;
31  z->n = size - 1;
32  z->p = buff;
33  return char2int(*(z->p++));
34}
35
36
37int luaZ_lookahead (ZIO *z) {
38  if (z->n == 0) {
39    if (luaZ_fill(z) == EOZ)
40      return EOZ;
41    else {
42      z->n++;  /* luaZ_fill removed first byte; put back it */
43      z->p--;
44    }
45  }
46  return char2int(*z->p);
47}
48
49
50void luaZ_init (lua_State *L, ZIO *z, lua_Reader reader, void *data) {
51  z->L = L;
52  z->reader = reader;
53  z->data = data;
54  z->n = 0;
55  z->p = NULL;
56}
57
58
59/* --------------------------------------------------------------- read --- */
60size_t luaZ_read (ZIO *z, void *b, size_t n) {
61  while (n) {
62    size_t m;
63    if (luaZ_lookahead(z) == EOZ)
64      return n;  /* return number of missing bytes */
65    m = (n <= z->n) ? n : z->n;  /* min. between n and z->n */
66    memcpy(b, z->p, m);
67    z->n -= m;
68    z->p += m;
69    b = (char *)b + m;
70    n -= m;
71  }
72  return 0;
73}
74
75/* ------------------------------------------------------------------------ */
76char *luaZ_openspace (lua_State *L, Mbuffer *buff, size_t n) {
77  if (n > buff->buffsize) {
78    if (n < LUA_MINBUFFER) n = LUA_MINBUFFER;
79    luaZ_resizebuffer(L, buff, n);
80  }
81  return buff->buffer;
82}
83
84
85