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-rw-r--r--src/fs/output/GzipOutputStream.cxx106
-rw-r--r--src/fs/output/GzipOutputStream.hxx71
2 files changed, 177 insertions, 0 deletions
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;
+}
diff --git a/src/fs/output/GzipOutputStream.hxx b/src/fs/output/GzipOutputStream.hxx
new file mode 100644
index 000000000..4f6d8b357
--- /dev/null
+++ b/src/fs/output/GzipOutputStream.hxx
@@ -0,0 +1,71 @@
+/*
+ * 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_GZIP_OUTPUT_STREAM_HXX
+#define MPD_GZIP_OUTPUT_STREAM_HXX
+
+#include "check.h"
+#include "OutputStream.hxx"
+
+#include <assert.h>
+#include <zlib.h>
+
+class Error;
+class Domain;
+
+extern const Domain zlib_domain;
+
+/**
+ * A filter that compresses data written to it using zlib, forwarding
+ * compressed data in the "gzip" format.
+ *
+ * Don't forget to call Flush() before destructing this object.
+ */
+class GzipOutputStream final : public OutputStream {
+ OutputStream &next;
+
+ z_stream z;
+
+public:
+ /**
+ * Construct the filter. Call IsDefined() to check whether
+ * the constructor has succeeded. If not, #error will hold
+ * information about the failure.
+ */
+ GzipOutputStream(OutputStream &_next, Error &error);
+ ~GzipOutputStream();
+
+ /**
+ * Check whether the constructor has succeeded.
+ */
+ bool IsDefined() const {
+ return z.opaque == nullptr;
+ }
+
+ /**
+ * Finish the file and write all data remaining in zlib's
+ * output buffer.
+ */
+ bool Flush(Error &error);
+
+ /* virtual methods from class OutputStream */
+ bool Write(const void *data, size_t size, Error &error) override;
+};
+
+#endif