• Lionello Lunesu (17/17) May 26 2006 I can't get the Compress and UnCompress classes in std.zlib to work.
• Walter Bright (25/25) May 29 2006 Try this:
• Lionello Lunesu (5/5) May 30 2006 Walter Bright wrote:
• Artem Rebrov (82/83) May 29 2006 There is the old bug in Compress.flush() function. I wrote about it here...

Lionello Lunesu <lio lunesu.remove.com> writes:

I can't get the Compress and UnCompress classes in std.zlib to work. 
I've checked the source and noticed they have no unittest.

Should the following code work? If so, please add it to the std.zlib in 
a unittest {...}..

import std.zlib;

void main()
{
	Compress cmp = new Compress;
	UnCompress decmp = new UnCompress;

	void[] input;
	input = "tesatdffadf";

	void[] buf = cmp.compress(input);
	buf ~= cmp.flush();
	void[] output = decmp.uncompress(buf);

	assert( output[] == input[] );
}

L.

Walter Bright <newshound digitalmars.com> writes:

Try this:

void arrayPrint(ubyte[] array)
{
     //printf("array %p,%d\n", (void*)array, array.length);
     for (int i = 0; i < array.length; i++)
     {
         printf("%02x ", array[i]);
         if (((i + 1) & 15) == 0)
             printf("\n");
     }
     printf("\n\n");
}

void testzlib()
{
     ubyte[] src = cast(ubyte[])
"the quick brown fox jumps over the lazy dog\r
the quick brown fox jumps over the lazy dog\r
";
     ubyte[] dst;

     arrayPrint(src);
     dst = cast(ubyte[])std.zlib.compress(cast(void[])src);
     arrayPrint(dst);
     src = cast(ubyte[])std.zlib.uncompress(cast(void[])dst);
     arrayPrint(src);
}

Lionello Lunesu <lio lunesu.remove.com> writes:

Walter Bright wrote:

<snip>

Walter, compress() and uncompress() are working fine, but the two 
classes, Compress and UnCompress, are not working the way they should.

L.

"Artem Rebrov" <ar_other mail.ru> writes:

On Fri, 26 May 2006 18:18:56 +0400, Lionello Lunesu  
<lio lunesu.remove.com> wrote:

 I can't get the Compress and UnCompress classes in std.zlib to work.

There is the old bug in Compress.flush() function. I wrote about it here  
at 04 Oct 2005.

Here is corrected version
------------------------------------------------------------------------------------------
     void[] flush(int mode = Z_FINISH)
     in
     {
	assert(mode == Z_FINISH || mode == Z_SYNC_FLUSH || mode == Z_FULL_FLUSH);
     }
     body
     {
	void[] destbuf, tmpbuf;
	int err;

	if (!inited)
	    return null;


     /*  //old code  Problem : zs.avail_in is set to 0 by deflate in  
previous compress()
     destbuf = new void[zs.avail_in];
     zs.next_out = cast(ubyte*) destbuf;
     zs.avail_out = destbuf.length;
     */

     // new code start
     tmpbuf = new void[zs.avail_out]; // may be  zs.avail_out+<some constnt>
                                      // zs.avail_out is set nonzero by  
deflate in previous compress()
     zs.next_out = cast(ubyte*) tmpbuf;
     zs.avail_out = tmpbuf.length;
     // new code end

     /* //old code
     err = deflate(&zs, mode);
     if (err != Z_STREAM_END)
     {
         delete destbuf;
         if (err == Z_OK)
         err = Z_BUF_ERROR;
         error(err);
     }
     destbuf = cast(void[])((cast(ubyte *)destbuf)[0 .. zs.next_out -  
cast(ubyte*)destbuf]);
     */

     // new code start
     while( (err = deflate(&zs, mode)) != Z_STREAM_END)
         {
         if(err == Z_OK)
             {
             if(zs.avail_out != 0 && mode != Z_FINISH)
                 break;
             else if(zs.avail_out == 0)
                 {
                 destbuf ~= tmpbuf;
                 zs.next_out = cast(ubyte*) tmpbuf;
                 zs.avail_out = tmpbuf.length;
                 continue;
                 }
             err = Z_BUF_ERROR;
             }
         delete destbuf;
         error(err);
         }
     destbuf ~= tmpbuf[0..(tmpbuf.length-zs.avail_out)];
     // new code end

     if (mode == Z_FINISH)
     {
         err = deflateEnd(&zs);
         inited = 0;
         if (err)
         error(err);
     }
     return destbuf;
     }
  ---------------------------------------------------------------------------
Additionally I've changed at the end of Compress.compress() and  
UnCompress.uncompress()

destbuf.length = zs.total_out;
to
destbuf.length = destbuf.length - zs.avail_out;

Now just concatenate buffers from sequential calls of [un]compress() and  
flush()


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