Support Adler32 checksum

Adler32 checksum is available for --checksum option and hash element
in Metalink files.  Currently, we use Adler32 implementation in Zlib.

1 files changed, 76 insertions, 0 deletions

diff --git a/src/Adler32MessageDigestImpl.cc b/src/Adler32MessageDigestImpl.cc
new file mode 100644
index 00000000..96ce07ca
--- /dev/null
+++ b/src/Adler32MessageDigestImpl.cc
@@ -0,0 +1,76 @@
+/* <!-- copyright */
+/*
+ * aria2 - The high speed download utility
+ *
+ * Copyright (C) 2014 Tatsuhiro Tsujikawa
+ *
+ * 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
+ *
+ * In addition, as a special exception, the copyright holders give
+ * permission to link the code of portions of this program with the
+ * OpenSSL library under certain conditions as described in each
+ * individual source file, and distribute linked combinations
+ * including the two.
+ * You must obey the GNU General Public License in all respects
+ * for all of the code used other than OpenSSL.  If you modify
+ * file(s) with this exception, you may extend this exception to your
+ * version of the file(s), but you are not obligated to do so.  If you
+ * do not wish to do so, delete this exception statement from your
+ * version.  If you delete this exception statement from all source
+ * files in the program, then also delete it here.
+ */
+/* copyright --> */
+#include "Adler32MessageDigestImpl.h"
+
+#include <cstring>
+
+#include <zlib.h>
+
+#include "a2netcompat.h"
+
+namespace aria2 {
+
+Adler32MessageDigestImpl::Adler32MessageDigestImpl()
+  : adler_(adler32(0, Z_NULL, 0))
+{}
+
+size_t Adler32MessageDigestImpl::getDigestLength() const
+{
+  return length();
+}
+
+void Adler32MessageDigestImpl::reset()
+{
+  adler_ = adler32(0, Z_NULL, 0);
+}
+
+void Adler32MessageDigestImpl::update(const void* data, size_t length)
+{
+  adler_ = adler32(adler_, reinterpret_cast<const unsigned char*>(data),
+                   length);
+}
+
+void Adler32MessageDigestImpl::digest(unsigned char* md)
+{
+  auto adler = htonl(adler_);
+  memcpy(md, &adler, getDigestLength());
+}
+
+size_t Adler32MessageDigestImpl::length()
+{
+  return 4;
+}
+
+} // namespace aria2