Initial community commit

Src/external_dependencies/openmpt-trunk/unarchiver/ungzip.h

@@ -0,0 +1,74 @@
+/*
+ * ungzip.h
+ * --------
+ * Purpose: Header file for .gz loader
+ * Notes  : (currently none)
+ * Authors: OpenMPT Devs
+ * The OpenMPT source code is released under the BSD license. Read LICENSE for more details.
+ */
+
+#pragma once
+
+#include "openmpt/all/BuildSettings.hpp"
+#include "openmpt/base/Endian.hpp"
+
+#include "archive.h"
+
+OPENMPT_NAMESPACE_BEGIN
+
+#if defined(MPT_WITH_ZLIB) || defined(MPT_WITH_MINIZ)
+
+class CGzipArchive : public ArchiveBase
+{
+public:
+	struct GZheader
+	{
+		uint8le magic1;  // 0x1F
+		uint8le magic2;  // 0x8B
+		uint8le method;  // 0-7 = reserved, 8 = deflate
+		uint8le flags;   // See GZ_F* constants
+		uint32le mtime;  // UNIX time
+		uint8le xflags;  // Available for use by specific compression methods. We ignore this.
+		uint8le os;      // Which OS was used to compress the file? We also ignore this.
+	};
+
+	struct GZtrailer
+	{
+		uint32le crc32_;  // CRC32 of decompressed data
+		uint32le isize;   // Size of decompressed data modulo 2^32
+	};
+
+protected:
+	enum MagicBytes
+	{
+		GZ_HMAGIC1   = 0x1F,
+		GZ_HMAGIC2   = 0x8B,
+		GZ_HMDEFLATE = 0x08,
+	};
+
+	enum HeaderFlags
+	{
+		GZ_FTEXT     = 0x01,  // File is probably ASCII text (who cares)
+		GZ_FHCRC     = 0x02,  // CRC16 present
+		GZ_FEXTRA    = 0x04,  // Extra fields present
+		GZ_FNAME     = 0x08,  // Original filename present
+		GZ_FCOMMENT  = 0x10,  // Comment is present
+		GZ_FRESERVED = (~(GZ_FTEXT | GZ_FHCRC | GZ_FEXTRA | GZ_FNAME | GZ_FCOMMENT))
+	};
+
+	GZheader header;
+
+public:
+
+	bool ExtractFile(std::size_t index) override;
+
+	CGzipArchive(const FileReader &file);
+	~CGzipArchive() override;
+};
+
+MPT_BINARY_STRUCT(CGzipArchive::GZheader, 10)
+MPT_BINARY_STRUCT(CGzipArchive::GZtrailer, 8)
+
+#endif // MPT_WITH_ZLIB || MPT_WITH_MINIZ
+
+OPENMPT_NAMESPACE_END