From 6d071123cc3455f55cf7c3db5d05ca8a23cd2e9a Mon Sep 17 00:00:00 2001
From: Ykkrosh <philip@wildfiregames.com>
Date: Thu, 27 Oct 2011 14:21:58 +0000
Subject: [PATCH] Add simple functions for zlib compression with embedded
 length headers

This was SVN commit r10436.
---
 source/ps/Compress.cpp | 63 ++++++++++++++++++++++++++++++++++++++++++
 source/ps/Compress.h   | 30 ++++++++++++++++++++
 2 files changed, 93 insertions(+)
 create mode 100644 source/ps/Compress.cpp
 create mode 100644 source/ps/Compress.h

diff --git a/source/ps/Compress.cpp b/source/ps/Compress.cpp
new file mode 100644
index 0000000000..e7acdc481d
--- /dev/null
+++ b/source/ps/Compress.cpp
@@ -0,0 +1,63 @@
+/* Copyright (C) 2011 Wildfire Games.
+ * This file is part of 0 A.D.
+ *
+ * 0 A.D. 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.
+ *
+ * 0 A.D. 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 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "precompiled.h"
+
+#include "Compress.h"
+
+#include "lib/byte_order.h"
+#include "lib/external_libraries/zlib.h"
+
+void CompressZLib(const std::string& data, std::string& out, bool includeLengthHeader)
+{
+	uLongf maxCompressedSize = compressBound(data.size());
+	uLongf destLen = maxCompressedSize;
+
+	out.clear();
+
+	if (includeLengthHeader)
+	{
+		// Add a 4-byte uncompressed length header to the output
+		out.resize(maxCompressedSize + 4);
+		write_le32((void*)out.c_str(), data.size());
+		int zok = compress((Bytef*)out.c_str() + 4, &destLen, (const Bytef*)data.c_str(), data.size());
+		ENSURE(zok == Z_OK);
+		out.resize(destLen + 4);
+	}
+	else
+	{
+		out.resize(maxCompressedSize);
+		int zok = compress((Bytef*)out.c_str(), &destLen, (const Bytef*)data.c_str(), data.size());
+		ENSURE(zok == Z_OK);
+		out.resize(destLen);
+	}
+}
+
+void DecompressZLib(const std::string& data, std::string& out, bool includeLengthHeader)
+{
+	ENSURE(includeLengthHeader); // otherwise we don't know how much to allocate
+
+	out.clear();
+	out.resize(read_le32(data.c_str()));
+
+	uLongf destLen = out.size();
+	int zok = uncompress((Bytef*)out.c_str(), &destLen, (const Bytef*)data.c_str() + 4, data.size() - 4);
+	ENSURE(zok == Z_OK);
+	ENSURE(destLen == out.size());
+
+	// TODO: better error reporting might be nice
+}
\ No newline at end of file
diff --git a/source/ps/Compress.h b/source/ps/Compress.h
new file mode 100644
index 0000000000..e7e71b9922
--- /dev/null
+++ b/source/ps/Compress.h
@@ -0,0 +1,30 @@
+/* Copyright (C) 2011 Wildfire Games.
+ * This file is part of 0 A.D.
+ *
+ * 0 A.D. 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.
+ *
+ * 0 A.D. 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 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef INCLUDED_COMPRESS
+#define INCLUDED_COMPRESS
+
+/**
+ * @file
+ * Simple (non-streaming) compression functions.
+ */
+
+void CompressZLib(const std::string& data, std::string& out, bool includeLengthHeader);
+
+void DecompressZLib(const std::string& data, std::string& out, bool includeLengthHeader);
+
+#endif // INCLUDED_COMPRESS
\ No newline at end of file