module/lua/lzio.c

   1 /* BEGIN CSTYLED */
   2 /*
   3 ** $Id: lzio.c,v 1.35.1.1 2013/04/12 18:48:47 roberto Exp $
   4 ** Buffered streams
   5 ** See Copyright Notice in lua.h
   6 */
   7
   8
   9 #define lzio_c
  10 #define LUA_CORE
  11
  12 #include <sys/lua/lua.h>
  13
  14 #include "llimits.h"
  15 #include "lmem.h"
  16 #include "lstate.h"
  17 #include "lzio.h"
  18
  19
  20 int luaZ_fill (ZIO *z) {
  21   size_t size;
  22   lua_State *L = z->L;
  23   const char *buff;
  24   lua_unlock(L);
  25   buff = z->reader(L, z->data, &size);
  26   lua_lock(L);
  27   if (buff == NULL || size == 0)
  28     return EOZ;
  29   z->n = size - 1;  /* discount char being returned */
  30   z->p = buff;
  31   return cast_uchar(*(z->p++));
  32 }
  33
  34
  35 void luaZ_init (lua_State *L, ZIO *z, lua_Reader reader, void *data) {
  36   z->L = L;
  37   z->reader = reader;
  38   z->data = data;
  39   z->n = 0;
  40   z->p = NULL;
  41 }
  42
  43
  44 /* --------------------------------------------------------------- read --- */
  45 size_t luaZ_read (ZIO *z, void *b, size_t n) {
  46   while (n) {
  47     size_t m;
  48     if (z->n == 0) {  /* no bytes in buffer? */
  49       if (luaZ_fill(z) == EOZ)  /* try to read more */
  50         return n;  /* no more input; return number of missing bytes */
  51       else {
  52         z->n++;  /* luaZ_fill consumed first byte; put it back */
  53         z->p--;
  54       }
  55     }
  56     m = (n <= z->n) ? n : z->n;  /* min. between n and z->n */
  57     memcpy(b, z->p, m);
  58     z->n -= m;
  59     z->p += m;
  60     b = (char *)b + m;
  61     n -= m;
  62   }
  63   return 0;
  64 }
  65
  66 /* ------------------------------------------------------------------------ */
  67 char *luaZ_openspace (lua_State *L, Mbuffer *buff, size_t n) {
  68   if (n > buff->buffsize) {
  69     if (n < LUA_MINBUFFER) n = LUA_MINBUFFER;
  70     luaZ_resizebuffer(L, buff, n);
  71   }
  72   return buff->buffer;
  73 }
  74 /* END CSTYLED */