1 files changed, 81 insertions, 0 deletions
diff --git a/klm/util/read_compressed.hh b/klm/util/read_compressed.hh
new file mode 100644
index 00000000..8b54c9e8
--- /dev/null
+++ b/klm/util/read_compressed.hh
@@ -0,0 +1,81 @@
+#ifndef UTIL_READ_COMPRESSED__
+#define UTIL_READ_COMPRESSED__
+
+#include "util/exception.hh"
+#include "util/scoped.hh"
+
+#include <cstddef>
+
+#include <stdint.h>
+
+namespace util {
+
+class CompressedException : public Exception {
+  public:
+    CompressedException() throw();
+    virtual ~CompressedException() throw();
+};
+
+class GZException : public CompressedException {
+  public:
+    GZException() throw();
+    ~GZException() throw();
+};
+
+class BZException : public CompressedException {
+  public:
+    BZException() throw();
+    ~BZException() throw();
+};
+
+class XZException : public CompressedException {
+  public:
+    XZException() throw();
+    ~XZException() throw();
+};
+
+class ReadBase;
+
+class ReadCompressed {
+  public:
+    static const std::size_t kMagicSize = 6;
+    // Must have at least kMagicSize bytes.  
+    static bool DetectCompressedMagic(const void *from);
+
+    // Takes ownership of fd.   
+    explicit ReadCompressed(int fd);
+
+    // Try to avoid using this.  Use the fd instead.
+    // There is no decompression support for istreams.
+    explicit ReadCompressed(std::istream &in);
+
+    // Must call Reset later.
+    ReadCompressed();
+
+    ~ReadCompressed();
+
+    // Takes ownership of fd.  
+    void Reset(int fd);
+
+    // Same advice as the constructor.
+    void Reset(std::istream &in);
+
+    std::size_t Read(void *to, std::size_t amount);
+
+    uint64_t RawAmount() const { return raw_amount_; }
+
+  private:
+    friend class ReadBase;
+
+    scoped_ptr<ReadBase> internal_;
+
+    uint64_t raw_amount_;
+
+    // No copying.  
+    ReadCompressed(const ReadCompressed &);
+    void operator=(const ReadCompressed &);
+};
+
+} // namespace util
+
+#endif // UTIL_READ_COMPRESSED__