From c9a71a7176f13cbd86c8270c523c0e506b2ab424 Mon Sep 17 00:00:00 2001
From: Max Kellermann <max@duempel.org>
Date: Wed, 30 Jul 2014 22:26:24 +0200
Subject: fs/GzipOutputStream: new class wrapping zlib

---
 src/fs/output/GzipOutputStream.cxx | 106 +++++++++++++++++++++++++++++++++++++
 1 file changed, 106 insertions(+)
 create mode 100644 src/fs/output/GzipOutputStream.cxx

(limited to 'src/fs/output/GzipOutputStream.cxx')

diff --git a/src/fs/output/GzipOutputStream.cxx b/src/fs/output/GzipOutputStream.cxx
new file mode 100644
index 000000000..d05645d9e
--- /dev/null
+++ b/src/fs/output/GzipOutputStream.cxx
@@ -0,0 +1,106 @@
+/*
+ * 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 "GzipOutputStream.hxx"
+#include "util/Error.hxx"
+#include "util/Domain.hxx"
+
+const Domain zlib_domain("zlib");
+
+GzipOutputStream::GzipOutputStream(OutputStream &_next, Error &error)
+	:next(_next)
+{
+	z.next_in = nullptr;
+	z.avail_in = 0;
+	z.zalloc = Z_NULL;
+	z.zfree = Z_NULL;
+	z.opaque = Z_NULL;
+
+	constexpr int windowBits = 15;
+	constexpr int gzip_encoding = 16;
+
+	int result = deflateInit2(&z, Z_DEFAULT_COMPRESSION, Z_DEFLATED,
+				  windowBits | gzip_encoding,
+				  8, Z_DEFAULT_STRATEGY);
+	if (result != Z_OK) {
+		z.opaque = this;
+		error.Set(zlib_domain, result, zError(result));
+	}
+}
+
+GzipOutputStream::~GzipOutputStream()
+{
+	if (IsDefined())
+		deflateEnd(&z);
+}
+
+bool
+GzipOutputStream::Flush(Error &error)
+{
+	/* no more input */
+	z.next_in = nullptr;
+	z.avail_in = 0;
+
+	while (true) {
+		Bytef output[4096];
+		z.next_out = output;
+		z.avail_out = sizeof(output);
+
+		int result = deflate(&z, Z_FINISH);
+		if (z.next_out > output &&
+		    !next.Write(output, z.next_out - output, error))
+			return false;
+
+		if (result == Z_STREAM_END)
+			return true;
+		else if (result != Z_OK) {
+			error.Set(zlib_domain, result, zError(result));
+			return false;
+		}
+    }
+}
+
+bool
+GzipOutputStream::Write(const void *_data, size_t size, Error &error)
+{
+	/* zlib's API requires non-const input pointer */
+	void *data = const_cast<void *>(_data);
+
+	z.next_in = reinterpret_cast<Bytef *>(data);
+	z.avail_in = size;
+
+	while (z.avail_in > 0) {
+		Bytef output[4096];
+		z.next_out = output;
+		z.avail_out = sizeof(output);
+
+		int result = deflate(&z, Z_NO_FLUSH);
+		if (result != Z_OK) {
+			error.Set(zlib_domain, result, zError(result));
+			return false;
+		}
+
+		if (z.next_out > output &&
+		    !next.Write(output, z.next_out - output, error))
+			return false;
+	}
+
+	return true;
+}
-- 
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