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4.5
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00001 /* 00002 ** $Id: lzio.c,v 1.24 2003/03/20 16:00:56 roberto Exp $ 00003 ** a generic input stream interface 00004 ** See Copyright Notice in lua.h 00005 */ 00006 00007 00008 #include <string.h> 00009 00010 #define lzio_c 00011 00012 #include "lua.h" 00013 00014 #include "llimits.h" 00015 #include "lmem.h" 00016 #include "lzio.h" 00017 00018 00019 int luaZ_fill (ZIO *z) { 00020 size_t size; 00021 const char *buff = z->reader(NULL, z->data, &size); 00022 if (buff == NULL || size == 0) return EOZ; 00023 z->n = size - 1; 00024 z->p = buff; 00025 return char2int(*(z->p++)); 00026 } 00027 00028 00029 int luaZ_lookahead (ZIO *z) { 00030 if (z->n == 0) { 00031 int c = luaZ_fill(z); 00032 if (c == EOZ) return c; 00033 z->n++; 00034 z->p--; 00035 } 00036 return char2int(*z->p); 00037 } 00038 00039 00040 void luaZ_init (ZIO *z, lua_Chunkreader reader, void *data, const char *name) { 00041 z->reader = reader; 00042 z->data = data; 00043 z->name = name; 00044 z->n = 0; 00045 z->p = NULL; 00046 } 00047 00048 00049 /* --------------------------------------------------------------- read --- */ 00050 size_t luaZ_read (ZIO *z, void *b, size_t n) { 00051 while (n) { 00052 size_t m; 00053 if (z->n == 0) { 00054 if (luaZ_fill(z) == EOZ) 00055 return n; /* return number of missing bytes */ 00056 else { 00057 ++z->n; /* filbuf removed first byte; put back it */ 00058 --z->p; 00059 } 00060 } 00061 m = (n <= z->n) ? n : z->n; /* min. between n and z->n */ 00062 memcpy(b, z->p, m); 00063 z->n -= m; 00064 z->p += m; 00065 b = (char *)b + m; 00066 n -= m; 00067 } 00068 return 0; 00069 } 00070 00071 /* ------------------------------------------------------------------------ */ 00072 char *luaZ_openspace (lua_State *L, Mbuffer *buff, size_t n) { 00073 if (n > buff->buffsize) { 00074 if (n < LUA_MINBUFFER) n = LUA_MINBUFFER; 00075 luaM_reallocvector(L, buff->buffer, buff->buffsize, n, char); 00076 buff->buffsize = n; 00077 } 00078 return buff->buffer; 00079 } 00080 00081