source: trunk/src/lua/lzio.c @ 2540

Last change on this file since 2540 was 2540, checked in by sam, 10 years ago

core: import pristine lua 5.2.1 in the engine code.

File size: 1.6 KB
Line 
1/*
2** $Id: lzio.c,v 1.35 2012/05/14 13:34:18 roberto Exp $
3** Buffered streams
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
21int 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)
29    return EOZ;
30  z->n = size - 1;  /* discount char being returned */
31  z->p = buff;
32  return cast_uchar(*(z->p++));
33}
34
35
36void luaZ_init (lua_State *L, ZIO *z, lua_Reader reader, void *data) {
37  z->L = L;
38  z->reader = reader;
39  z->data = data;
40  z->n = 0;
41  z->p = NULL;
42}
43
44
45/* --------------------------------------------------------------- read --- */
46size_t luaZ_read (ZIO *z, void *b, size_t n) {
47  while (n) {
48    size_t m;
49    if (z->n == 0) {  /* no bytes in buffer? */
50      if (luaZ_fill(z) == EOZ)  /* try to read more */
51        return n;  /* no more input; return number of missing bytes */
52      else {
53        z->n++;  /* luaZ_fill consumed first byte; put it back */
54        z->p--;
55      }
56    }
57    m = (n <= z->n) ? n : z->n;  /* min. between n and z->n */
58    memcpy(b, z->p, m);
59    z->n -= m;
60    z->p += m;
61    b = (char *)b + m;
62    n -= m;
63  }
64  return 0;
65}
66
67/* ------------------------------------------------------------------------ */
68char *luaZ_openspace (lua_State *L, Mbuffer *buff, size_t n) {
69  if (n > buff->buffsize) {
70    if (n < LUA_MINBUFFER) n = LUA_MINBUFFER;
71    luaZ_resizebuffer(L, buff, n);
72  }
73  return buff->buffer;
74}
75
76
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