| 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 | |
| 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) |
| 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 | |
| 36 | void 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 --- */ |
| 46 | size_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 | /* ------------------------------------------------------------------------ */ |
| 68 | char *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 | |