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Re: Filtering streams for bz2 [message #49448 is a reply to message #49428]

Sun, 11 February 2018 21:22

Novo
Messages: 1358
Registered: December 2006

Ultimate Contributor

mirek wrote on Fri, 09 February 2018 03:54

I have tried to resolve the issue with Gate<> FilterEof in InFilterStream. That should work. Please check trunk.

Solution with FilterEof works. Thank you.

mirek wrote on Fri, 09 February 2018 03:54

BUT, after further thinking, I believe even that is overkill. In fact, I now believe that it should work without adding anything: After encountering BZ_STREAM_END, no more data are decompressed, so no more output is produced and we get nice eof via:
int InFilterStream::_Term()
{
	while(ptr == rdlim && !eof)
		Fetch();
	return ptr == rdlim ? -1 : *ptr;
}
(because after Fetch, ptr == rdlime)

What do you think?

Mirek

Setting up of FilterEof cannot be skipped because in Fetch we have this:

	Stream::buffer = ptr = buffer.begin();
	rdlim = buffer.end();

And ptr != rdlim.

Below is my test.

#include <Core/Core.h>
#include <plugin/bz2/bz2.h>

using namespace Upp;

CONSOLE_APP_MAIN
{
	enum { BUF_SIZE = 65536 };
	const Vector<String>& cmdline = CommandLine();
	if (cmdline.GetCount() < 2)
		return;
	FileIn in(cmdline[0]);
	FileOut out(cmdline[1]);
#if 0
	bz2::DecompressStream bz2(in);
	char buff[BUF_SIZE];
	while (!bz2.IsEof()) {
		const int n = bz2.Get(buff, BUF_SIZE);
		out.Put(buff, n);
	}
#endif
#if 1
	// Read only a first stream.
	bz2::DecompressStream bz2(in, false);
	char buff[BUF_SIZE];
	while (!bz2.IsEof()) {
		const int n = bz2.Get(buff, BUF_SIZE);
		out.Put(buff, n);
	}
#endif
#if 0
	bz2::CompressStream bz2(out);
	char buff[BUF_SIZE];
	while (!in.IsEof()) {
		const int n = in.Get(buff, BUF_SIZE);
		bz2.Put(buff, n);
	}
#endif
}

Current version of code in svn/git works fine.
Thank you again!

Regards,
Novo

[Updated on: Sun, 11 February 2018 21:27]

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