On the presumption that the supplied data is zipped by gzip, this functions writes the date to a temporary file, calls 'gunzip' via a system call on this file and reads in the unziped data. The temporary file and it's unziped associate are then unlinked. Note: Do not unzip files that contain multiple files and/or accross mutiple directories. It won't work and will leave a mess!

Declared in file: hzCodec.h
Defined in file : hzCodec.cpp

Function Logic:

Function body:

hzEcode Gunzip (hzChain& orig)hzChain& gzipped, 
{
   //  Category: Codec
   //  
   //  On the presumption that the supplied data is zipped by gzip, this functions writes the date to a temporary file, calls 'gunzip' via a system call on this file and reads in
   //  the unziped data. The temporary file and it's unziped associate are then unlinked.
   //  
   //  Arguments: 1) orig The chain to be populated with the unzipped data
   //     2) gzipped The chain containing the original (zipped) data
   //  
   //  Returns: E_NODATA If there is nothing to do
   //     E_WRITEFAIL If the original data could not be written out to the temporary file
   //     E_SYSERROR If the gunzip command could not be found or failed to process the data
   //     E_READFIAL If the unzipped data could not be read back from the temporary file
   //     E_OK  If the operation was successful
   //  
   //  Note: Do not unzip files that contain multiple files and/or accross mutiple directories. It won't work and will leave a mess!
   _hzfunc(__func__) ;
   z_stream    infstream ;     //  Input
   chIter      zi ;            //  Chain iterator
   char*       tmp ;           //  Zipped buffer
   char*       buf ;           //  Unzipped buffer
   uint32_t    n ;             //  Buffer iterator
   tmp = new char[gzipped.Size()+1];
   buf = new char[20480];
   for (n = 0,zi = gzipped ; !zi.eof() ; n++, zi++)
       tmp[n] = *zi ;
   infstream.zalloc = Z_NULL;
   infstream.zfree = Z_NULL;
   infstream.opaque = Z_NULL;
   //  setup "b" as the input and "c" as the compressed output
   infstream.avail_in = (uInt) gzipped.Size() ;    //  size of input
   infstream.next_in = (Bytef*)tmp ;                       //  input char array
   infstream.avail_out = 20480;                        //  size of output
   infstream.next_out = (Bytef*)buf ;                      //  output char array
   //  the actual DE-compression work.
   if (inflateInit2(&infstream, 31)!=Z_OK)
       return E_NOINIT ;
   inflate(&infstream, Z_NO_FLUSH);
   inflateEnd(&infstream);
   for (n = 0; n < infstream.total_out ; n++)
       orig.AddByte(buf[n]) ;
   delete tmp ;
   delete buf ;
   return E_OK ;
}