module/lua/lzio.c

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