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 77
