Streamline Java wrapper

java/org/libjpegturbo/turbojpeg/TJDecompressor.java

@@ -34,6 +34,75 @@ public class TJDecompressor {
     init();
   }
 
+  public TJDecompressor(byte [] buf) throws Exception {
+    setJPEGBuffer(buf);
+  }
+
+  public void setJPEGBuffer(byte [] buf) throws Exception {
+    if(handle == 0) init();
+    if(buf == null) throw new Exception("Invalid argument in setJPEGBuffer()");
+    jpegBuf = buf;
+    decompressHeader();
+  }
+
+  public int getWidth() throws Exception {
+    if(header.width < 1) throw new Exception("JPEG buffer not initialized");
+    return header.width;
+  }
+
+  public int getHeight() throws Exception {
+    if(header.height < 1) throw new Exception("JPEG buffer not initialized");
+    return header.height;
+  }
+
+  public int getSubsamp() throws Exception {
+    if(header.subsamp < 0) throw new Exception("JPEG buffer not initialized");
+    return header.subsamp;
+  }
+
+  public int getScaledWidth(int desired_width, int desired_height)
+    throws Exception {
+    if(header.width < 1 || header.height < 1)
+      throw new Exception("JPEG buffer not initialized");
+    return getScaledWidth(header.width, header.height, desired_width,
+      desired_height);
+  }
+
+  public int getScaledHeight(int output_width, int output_height)
+    throws Exception {
+    if(header.width < 1 || header.height < 1)
+      throw new Exception("JPEG buffer not initialized");
+    return getScaledHeight(header.width, header.height, output_width,
+      output_height);
+  }
+
+  public void decompress(byte [] dstBuf, int width, int pitch,
+    int height, int pixelFormat, int flags) throws Exception {
+    if(jpegBuf == null) throw new Exception("JPEG buffer not initialized");
+    decompress(jpegBuf, jpegBuf.length, dstBuf, width, pitch, height,
+      TJ.getPixelSize(pixelFormat), flags | TJ.getFlags(pixelFormat));
+  }
+
+  public byte [] decompress(int width, int pitch, int height,
+    int pixelFormat, int flags) throws Exception {
+    if(width < 0 || height < 0 || pitch < 0 || pixelFormat < 0
+      || pixelFormat >= TJ.NUMPIXFORMATS)
+      throw new Exception("Invalid argument in decompress()");
+    int pixelSize = TJ.getPixelSize(pixelFormat);
+    int scaledWidth = getScaledWidth(width, height);
+    int scaledHeight = getScaledHeight(width, height);
+    if(pitch == 0) pitch = scaledWidth * pixelSize;
+    long bufSize;
+    if(pixelFormat == TJ.YUV)
+      bufSize = TJ.bufSizeYUV(width, height, header.subsamp);
+    else bufSize = pitch * scaledHeight;
+    byte [] buf = new byte[(int)bufSize];
+    if(jpegBuf == null) throw new Exception("JPEG buffer not initialized");
+    decompress(jpegBuf, jpegBuf.length, buf, width, pitch, height,
+      TJ.getPixelSize(pixelFormat), flags | TJ.getFlags(pixelFormat));
+    return buf;
+  }
+
   public void close() throws Exception {
     destroy();
   }
@@ -52,16 +121,28 @@ public class TJDecompressor {
 
   private native void destroy() throws Exception;
 
-  public native TJHeaderInfo decompressHeader(byte [] srcbuf, long size)
+  private native TJHeaderInfo decompressHeader(byte [] srcBuf, long size)
     throws Exception;
 
-  public native void decompress(byte [] srcbuf, long size, byte [] dstbuf,
-    int width, int pitch, int height, int pixelsize, int flags)
+  private void decompressHeader() throws Exception {
+    header = decompressHeader(jpegBuf, jpegBuf.length);
+  }
+
+  private native void decompress(byte [] srcBuf, long size, byte [] dstBuf,
+    int width, int pitch, int height, int pixelSize, int flags)
     throws Exception;
 
+  private native int getScaledWidth(int input_width, int input_height,
+    int output_width, int output_height) throws Exception;
+
+  private native int getScaledHeight(int input_width, int input_height,
+    int output_width, int output_height) throws Exception;
+
   static {
     System.loadLibrary("turbojpeg");
   }
 
   private long handle = 0;
+  private byte [] jpegBuf = null;
+  TJHeaderInfo header = null;
 };