1 /* 2 ** $Id: lzio.c,v 1.31.1.1 2007/12/27 13:02:25 roberto Exp $ 3 ** a generic input stream interface 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) return EOZ; 29 z->n = size - 1; 30 z->p = buff; 31 return char2int(*(z->p++)); 32 } 33 34 35 int luaZ_lookahead (ZIO *z) { 36 if (z->n == 0) { 37 if (luaZ_fill(z) == EOZ) 38 return EOZ; 39 else { 40 z->n++; /* luaZ_fill removed first byte; put back it */ 41 z->p--; 42 } 43 } 44 return char2int(*z->p); 45 } 46 47 48 void luaZ_init (lua_State *L, ZIO *z, lua_Reader reader, void *data) { 49 z->L = L; 50 z->reader = reader; 51 z->data = data; 52 z->n = 0; 53 z->p = NULL; 54 } 55 56 57 /* --------------------------------------------------------------- read --- */ 58 size_t luaZ_read (ZIO *z, void *b, size_t n) { 59 while (n) { 60 size_t m; 61 if (luaZ_lookahead(z) == EOZ) 62 return n; /* return number of missing bytes */ 63 m = (n <= z->n) ? n : z->n; /* min. between n and z->n */ 64 memcpy(b, z->p, m); 65 z->n -= m; 66 z->p += m; 67 b = (char *)b + m; 68 n -= m; 69 } 70 return 0; 71 } 72 73 /* ------------------------------------------------------------------------ */ 74 char *luaZ_openspace (lua_State *L, Mbuffer *buff, size_t n) { 75 if (n > buff->buffsize) { 76 if (n < LUA_MINBUFFER) n = LUA_MINBUFFER; 77 luaZ_resizebuffer(L, buff, n); 78 } 79 return buff->buffer; 80 } 81 82 83