| /* |
| ** $Id: lzio.c,v 1.20 2002/08/05 18:45:02 roberto Exp roberto $ |
| ** a generic input stream interface |
| ** See Copyright Notice in lua.h |
| */ |
| |
| |
| #include <string.h> |
| |
| #include "lua.h" |
| |
| #include "llimits.h" |
| #include "lzio.h" |
| |
| |
| |
| int luaZ_fill (ZIO *z) { |
| size_t size; |
| const char *buff = z->reader(NULL, z->data, &size); |
| if (buff == NULL || size == 0) return EOZ; |
| z->n = size - 1; |
| z->p = buff; |
| return *(z->p++); |
| } |
| |
| |
| int luaZ_lookahead (ZIO *z) { |
| if (z->n == 0) { |
| int c = luaZ_fill(z); |
| if (c == EOZ) return c; |
| z->n++; |
| z->p--; |
| } |
| return *z->p; |
| } |
| |
| |
| void luaZ_init (ZIO *z, lua_Chunkreader reader, void *data, const char *name) { |
| z->reader = reader; |
| z->data = data; |
| z->name = name; |
| z->n = 0; |
| z->p = NULL; |
| } |
| |
| |
| /* --------------------------------------------------------------- read --- */ |
| size_t luaZ_read (ZIO *z, void *b, size_t n) { |
| while (n) { |
| size_t m; |
| if (z->n == 0) { |
| if (luaZ_fill(z) == EOZ) |
| return n; /* return number of missing bytes */ |
| else { |
| ++z->n; /* filbuf removed first byte; put back it */ |
| --z->p; |
| } |
| } |
| m = (n <= z->n) ? n : z->n; /* min. between n and z->n */ |
| memcpy(b, z->p, m); |
| z->n -= m; |
| z->p += m; |
| b = (char *)b + m; |
| n -= m; |
| } |
| return 0; |
| } |
| |