Added JpegCompressor abstract class and two implementations -- one cross-platform and another IRIX-specific.


git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@2320 3789f03b-4d11-0410-bbf8-ca57d06f2519
diff --git a/common/rfb/JpegCompressor.h b/common/rfb/JpegCompressor.h
new file mode 100644
index 0000000..93fdc7b
--- /dev/null
+++ b/common/rfb/JpegCompressor.h
@@ -0,0 +1,82 @@
+#ifndef __JPEGCOMPRESSOR_H__
+#define __JPEGCOMPRESSOR_H__
+
+#include <stdio.h>
+#include <sys/types.h>
+extern "C" {
+#include <jpeg/jpeglib.h>
+}
+
+#include <rdr/types.h>
+#include <rfb/PixelFormat.h>
+
+namespace rfb {
+
+  //
+  // An abstract interface for performing JPEG compression.
+  //
+
+  class JpegCompressor
+  {
+  public:
+    virtual ~JpegCompressor() {}
+
+    // Set JPEG quality level (0..100)
+    virtual void setQuality(int level) = 0;
+
+    // Actually compress an image.
+    virtual void compress(const rdr::U32 *buf, const PixelFormat *fmt,
+                          int w, int h, int stride) = 0;
+
+    // Access results of the compression.
+    virtual size_t getDataLength() = 0;
+    virtual const char *getDataPtr() = 0;
+  };
+
+  //
+  // A C++ class for performing JPEG compression via the
+  // Independent JPEG Group's software (free JPEG library).
+  //
+
+  class StandardJpegCompressor : public JpegCompressor
+  {
+  public:
+    StandardJpegCompressor();
+    virtual ~StandardJpegCompressor();
+
+    // Set JPEG quality level (0..100)
+    virtual void setQuality(int level);
+
+    // Actually compress the image.
+    virtual void compress(const rdr::U32 *buf, const PixelFormat *fmt,
+                          int w, int h, int stride);
+
+    // Access results of the compression.
+    virtual size_t getDataLength() { return m_cdata_ready; }
+    virtual const char *getDataPtr() { return (const char *)m_cdata; }
+
+  public:
+    // Our implementation of JPEG destination manager. These three
+    // functions should never be called directly. They are made public
+    // because they should be accessible from C-compatible functions
+    // called by the JPEG library.
+    void initDestination();
+    bool emptyOutputBuffer();
+    void termDestination();
+
+  protected:
+    static const int ALLOC_CHUNK_SIZE;
+    static const int DEFAULT_QUALITY;
+
+    struct jpeg_compress_struct m_cinfo;
+    struct jpeg_error_mgr m_jerr;
+
+    unsigned char *m_cdata;
+    size_t m_cdata_allocated;
+    size_t m_cdata_ready;
+  };
+
+}
+
+#endif // __JPEGCOMPRESSOR_H__
+