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