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d99a0153 CW |
1 | /* |
2 | ** $Id: lzio.c,v 1.35.1.1 2013/04/12 18:48:47 roberto Exp $ | |
3 | ** Buffered streams | |
4 | ** See Copyright Notice in lua.h | |
5 | */ | |
6 | ||
7 | ||
8 | #define lzio_c | |
9 | #define LUA_CORE | |
10 | ||
11 | #include <sys/lua/lua.h> | |
12 | ||
13 | #include "llimits.h" | |
14 | #include "lmem.h" | |
15 | #include "lstate.h" | |
16 | #include "lzio.h" | |
17 | ||
18 | ||
19 | int luaZ_fill (ZIO *z) { | |
20 | size_t size; | |
21 | lua_State *L = z->L; | |
22 | const char *buff; | |
23 | lua_unlock(L); | |
24 | buff = z->reader(L, z->data, &size); | |
25 | lua_lock(L); | |
26 | if (buff == NULL || size == 0) | |
27 | return EOZ; | |
28 | z->n = size - 1; /* discount char being returned */ | |
29 | z->p = buff; | |
30 | return cast_uchar(*(z->p++)); | |
31 | } | |
32 | ||
33 | ||
34 | void luaZ_init (lua_State *L, ZIO *z, lua_Reader reader, void *data) { | |
35 | z->L = L; | |
36 | z->reader = reader; | |
37 | z->data = data; | |
38 | z->n = 0; | |
39 | z->p = NULL; | |
40 | } | |
41 | ||
42 | ||
43 | /* --------------------------------------------------------------- read --- */ | |
44 | size_t luaZ_read (ZIO *z, void *b, size_t n) { | |
45 | while (n) { | |
46 | size_t m; | |
47 | if (z->n == 0) { /* no bytes in buffer? */ | |
48 | if (luaZ_fill(z) == EOZ) /* try to read more */ | |
49 | return n; /* no more input; return number of missing bytes */ | |
50 | else { | |
51 | z->n++; /* luaZ_fill consumed first byte; put it back */ | |
52 | z->p--; | |
53 | } | |
54 | } | |
55 | m = (n <= z->n) ? n : z->n; /* min. between n and z->n */ | |
56 | memcpy(b, z->p, m); | |
57 | z->n -= m; | |
58 | z->p += m; | |
59 | b = (char *)b + m; | |
60 | n -= m; | |
61 | } | |
62 | return 0; | |
63 | } | |
64 | ||
65 | /* ------------------------------------------------------------------------ */ | |
66 | char *luaZ_openspace (lua_State *L, Mbuffer *buff, size_t n) { | |
67 | if (n > buff->buffsize) { | |
68 | if (n < LUA_MINBUFFER) n = LUA_MINBUFFER; | |
69 | luaZ_resizebuffer(L, buff, n); | |
70 | } | |
71 | return buff->buffer; | |
72 | } |