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authorMax Kellermann <max@duempel.org>2014-08-07 17:14:58 +0200
committerMax Kellermann <max@duempel.org>2014-08-08 20:11:29 +0200
commita67a881715ca521347cc86631d770c9e6755c877 (patch)
tree762e32cadee52ea2a229010673e11d5b830b48b5 /src
parent7a048f004dc1c7d35518e38c75861bc167ade945 (diff)
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input/GunzipInputStream: new class
Diffstat (limited to 'src')
-rw-r--r--src/fs/io/GunzipReader.cxx102
-rw-r--r--src/fs/io/GunzipReader.hxx69
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