v1.4.4

source/core/StarCompression.hpp

@@ -0,0 +1,59 @@
+#ifndef STAR_COMPRESSION_HPP
+#define STAR_COMPRESSION_HPP
+
+#include "StarIODevice.hpp"
+#include "StarString.hpp"
+
+namespace Star {
+
+STAR_CLASS(CompressedFile);
+
+// Zlib compression level, ranges from 0 to 9
+typedef int CompressionLevel;
+
+CompressionLevel const LowCompression = 2;
+CompressionLevel const MediumCompression = 5;
+CompressionLevel const HighCompression = 9;
+
+void compressData(ByteArray const& in, ByteArray& out, CompressionLevel compression = MediumCompression);
+ByteArray compressData(ByteArray const& in, CompressionLevel compression = MediumCompression);
+
+void uncompressData(ByteArray const& in, ByteArray& out);
+ByteArray uncompressData(ByteArray const& in);
+
+// Random access to a (potentially) compressed file.
+class CompressedFile : public IODevice {
+public:
+  static CompressedFilePtr open(String const& filename, IOMode mode, CompressionLevel comp = MediumCompression);
+
+  CompressedFile();
+  CompressedFile(String filename);
+  virtual ~CompressedFile();
+
+  void setFilename(String filename);
+  void setCompression(CompressionLevel compression);
+
+  StreamOffset pos() override;
+  // Only seek forward is supported on writes.  Seek is emulated *slowly* on
+  // reads.
+  void seek(StreamOffset pos, IOSeek seek = IOSeek::Absolute) override;
+  bool atEnd() override;
+  size_t read(char* data, size_t len) override;
+  size_t write(char const* data, size_t len) override;
+
+  void open(IOMode mode) override;
+  // Compression is ignored on read.  Always truncates on write
+  void open(IOMode mode, CompressionLevel compression);
+
+  void sync() override;
+  void close() override;
+
+private:
+  String m_filename;
+  void* m_file;
+  CompressionLevel m_compression;
+};
+
+}
+
+#endif