input/GunzipInputStream: new class

2 files changed, 171 insertions, 0 deletions

diff --git a/src/fs/io/GunzipReader.cxx b/src/fs/io/GunzipReader.cxx
new file mode 100644
index 000000000..388b26412
--- /dev/null
+++ b/src/fs/io/GunzipReader.cxx
@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2003-2014 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+#include "GunzipReader.hxx"
+#include "util/Error.hxx"
+#include "util/Domain.hxx"
+
+const Domain zlib_domain("zlib");
+
+GunzipReader::GunzipReader(Reader &_next, Error &error)
+	:next(_next), eof(false)
+{
+	z.next_in = nullptr;
+	z.avail_in = 0;
+	z.zalloc = Z_NULL;
+	z.zfree = Z_NULL;
+	z.opaque = Z_NULL;
+
+	int result = inflateInit2(&z, 16 + MAX_WBITS);
+	if (result != Z_OK) {
+		z.opaque = this;
+		error.Set(zlib_domain, result, zError(result));
+	}
+}
+
+GunzipReader::~GunzipReader()
+{
+	if (IsDefined())
+		inflateEnd(&z);
+}
+
+inline bool
+GunzipReader::FillBuffer(Error &error)
+{
+	auto w = buffer.Write();
+	assert(!w.IsEmpty());
+
+	size_t nbytes = next.Read(w.data, w.size, error);
+	if (nbytes == 0)
+		return false;
+
+	buffer.Append(nbytes);
+	return true;
+}
+
+size_t
+GunzipReader::Read(void *data, size_t size, Error &error)
+{
+	if (eof)
+		return 0;
+
+	z.next_out = (Bytef *)data;
+	z.avail_out = size;
+
+	while (true) {
+		int flush = Z_NO_FLUSH;
+
+		auto r = buffer.Read();
+		if (r.IsEmpty()) {
+			if (FillBuffer(error))
+				r = buffer.Read();
+			else if (error.IsDefined())
+				return 0;
+			else
+				flush = Z_FINISH;
+		}
+
+		z.next_in = r.data;
+		z.avail_in = r.size;
+
+		int result = inflate(&z, flush);
+		if (result == Z_STREAM_END) {
+			eof = true;
+			return size - z.avail_out;
+		} else if (result != Z_OK) {
+			error.Set(zlib_domain, result, zError(result));
+			return 0;
+		}
+
+		buffer.Consume(r.size - z.avail_in);
+
+		if (z.avail_out < size)
+			return size - z.avail_out;
+	}
+}
diff --git a/src/fs/io/GunzipReader.hxx b/src/fs/io/GunzipReader.hxx
new file mode 100644
index 000000000..689125a6a
--- /dev/null
+++ b/src/fs/io/GunzipReader.hxx
@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2003-2014 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef MPD_GUNZIP_READER_HXX
+#define MPD_GUNZIP_READER_HXX
+
+#include "check.h"
+#include "Reader.hxx"
+#include "util/StaticFifoBuffer.hxx"
+
+#include <zlib.h>
+
+class Error;
+class Domain;
+
+extern const Domain zlib_domain;
+
+/**
+ * A filter that decompresses data using zlib.
+ */
+class GunzipReader final : public Reader {
+	Reader &next;
+
+	bool eof;
+
+	z_stream z;
+
+	StaticFifoBuffer<Bytef, 4096> buffer;
+
+public:
+	/**
+	 * Construct the filter.  Call IsDefined() to check whether
+	 * the constructor has succeeded.  If not, #error will hold
+	 * information about the failure.
+	 */
+	GunzipReader(Reader &_next, Error &error);
+	~GunzipReader();
+
+	/**
+	 * Check whether the constructor has succeeded.
+	 */
+	bool IsDefined() const {
+		return z.opaque == nullptr;
+	}
+
+	/* virtual methods from class Reader */
+	virtual size_t Read(void *data, size_t size, Error &error) override;
+
+private:
+	bool FillBuffer(Error &error);
+};
+
+#endif