GH-926 implement log cleaning functionality

Also adds gzip compressed log support

logic/GZip.cpp

@@ -0,0 +1,71 @@
+#include "GZip.h"
+#include <zlib.h>
+#include <QByteArray>
+
+// HACK: workaround for terrible macro crap on Windows
+int wrap_inflate (z_streamp strm, int flush)
+{
+	return inflate(strm, flush);
+}
+
+#ifdef inflate
+	#undef inflate
+#endif
+
+bool GZip::inflate(const QByteArray &compressedBytes, QByteArray &uncompressedBytes)
+{
+	if (compressedBytes.size() == 0)
+	{
+		uncompressedBytes = compressedBytes;
+		return true;
+	}
+
+	unsigned uncompLength = compressedBytes.size();
+	unsigned half_length = compressedBytes.size() / 2;
+	uncompressedBytes.clear();
+	uncompressedBytes.resize(uncompLength);
+
+	z_stream strm;
+	strm.next_in = (Bytef *)compressedBytes.data();
+	strm.avail_in = compressedBytes.size();
+	strm.total_out = 0;
+	strm.zalloc = Z_NULL;
+	strm.zfree = Z_NULL;
+
+	bool done = false;
+
+	if (inflateInit2(&strm, (16 + MAX_WBITS)) != Z_OK)
+	{
+		return false;
+	}
+
+	while (!done)
+	{
+		// If our output buffer is too small
+		if (strm.total_out >= uncompLength)
+		{
+			uncompressedBytes.resize(uncompLength + half_length);
+			uncompLength += half_length;
+		}
+
+		strm.next_out = (Bytef *)(uncompressedBytes.data() + strm.total_out);
+		strm.avail_out = uncompLength - strm.total_out;
+
+		// Inflate another chunk.
+		int err = wrap_inflate(&strm, Z_SYNC_FLUSH);
+		if (err == Z_STREAM_END)
+			done = true;
+		else if (err != Z_OK)
+		{
+			break;
+		}
+	}
+
+	if (inflateEnd(&strm) != Z_OK)
+	{
+		return false;
+	}
+
+	uncompressedBytes.resize(strm.total_out);
+	return true;
+}