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  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. #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.