package org.gcube.common.homelibrary.jcr.workspace.util;



/*
 *	SimpleImageInfo.java
 *
 *	@version 0.1
 *	@author  Jaimon Mathew <http://www.jaimon.co.uk>
 *
 *	A Java class to determine image width, height and MIME types for a number of image file formats without loading the whole image data.
 *
 *	Revision history
 *	0.1 - 29/Jan/2011 - Initial version created
 *
 *  -------------------------------------------------------------------------------
 
 	This code is licensed under the Apache License, Version 2.0 (the "License"); 
 	You may not use this file except in compliance with the License. 

 	You may obtain a copy of the License at 

 	http://www.apache.org/licenses/LICENSE-2.0 

	Unless required by applicable law or agreed to in writing, software 
	distributed under the License is distributed on an "AS IS" BASIS, 
	WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
	See the License for the specific language governing permissions and 
	limitations under the License.
	
 *  -------------------------------------------------------------------------------
 */



import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

@SuppressWarnings("all")
public class SimpleImageInfo {
	private int height;
	private int width;
	private String mimeType;

	private SimpleImageInfo() {

	}

	public SimpleImageInfo(File file) throws IOException {
		InputStream is = new FileInputStream(file);
		try {
			processStream(is);
		} finally {
			is.close();
		}
	}

	public SimpleImageInfo(InputStream is) throws IOException {
		processStream(is);
	}

	public SimpleImageInfo(byte[] bytes) throws IOException {
		InputStream is = new ByteArrayInputStream(bytes);
		try {
			processStream(is);
		} finally {
			is.close();
		}
	}

	private void processStream(InputStream is) throws IOException {
		int c1 = is.read();
		int c2 = is.read();
		int c3 = is.read();

		mimeType = null;
		width = height = -1;

		if (c1 == 'G' && c2 == 'I' && c3 == 'F') { // GIF
			is.skip(3);
			width = readInt(is,2,false);
			height = readInt(is,2,false);
			mimeType = "image/gif";
		} else if (c1 == 0xFF && c2 == 0xD8) { // JPG
			while (c3 == 255) {
				int marker = is.read();
				int len = readInt(is,2,true);
				if (marker == 192 || marker == 193 || marker == 194) {
					is.skip(1);
					height = readInt(is,2,true);
					width = readInt(is,2,true);
					mimeType = "image/jpeg";
					break;
				}
				is.skip(len - 2);
				c3 = is.read();
			}
		} else if (c1 == 137 && c2 == 80 && c3 == 78) { // PNG
			is.skip(15);
			width = readInt(is,2,true);
			is.skip(2);
			height = readInt(is,2,true);
			mimeType = "image/png";
		} else if (c1 == 66 && c2 == 77) { // BMP
			is.skip(15);
			width = readInt(is,2,false);
			is.skip(2);
			height = readInt(is,2,false);
			mimeType = "image/bmp";
		} else {
			int c4 = is.read();
			if ((c1 == 'M' && c2 == 'M' && c3 == 0 && c4 == 42)
					|| (c1 == 'I' && c2 == 'I' && c3 == 42 && c4 == 0)) { //TIFF
				boolean bigEndian = c1 == 'M';
				int ifd = 0;
				int entries;
				ifd = readInt(is,4,bigEndian);
				is.skip(ifd - 8);
				entries = readInt(is,2,bigEndian);
				for (int i = 1; i <= entries; i++) {
					int tag = readInt(is,2,bigEndian);
					int fieldType = readInt(is,2,bigEndian);
					long count = readInt(is,4,bigEndian);
					int valOffset;
					if ((fieldType == 3 || fieldType == 8)) {
						valOffset = readInt(is,2,bigEndian);
						is.skip(2);
					} else {
						valOffset = readInt(is,4,bigEndian);
					}
					if (tag == 256) {
						width = valOffset;
					} else if (tag == 257) {
						height = valOffset;
					}
					if (width != -1 && height != -1) {
						mimeType = "image/tiff";
						break;
					}
				}
			}
		}
		if (mimeType == null) {
			throw new IOException("Unsupported image type");
		}
	}
	
	private int readInt(InputStream is, int noOfBytes, boolean bigEndian) throws IOException {
		int ret = 0;
		int sv = bigEndian ? ((noOfBytes - 1) * 8) : 0;
		int cnt = bigEndian ? -8 : 8;
		for(int i=0;i<noOfBytes;i++) {
			ret |= is.read() << sv;
			sv += cnt;
		}
		return ret;
	}

	public int getHeight() {
		return height;
	}

	public void setHeight(int height) {
		this.height = height;
	}

	public int getWidth() {
		return width;
	}

	public void setWidth(int width) {
		this.width = width;
	}

	public String getMimeType() {
		return mimeType;
	}

	public void setMimeType(String mimeType) {
		this.mimeType = mimeType;
	}

	@Override
	public String toString() {
		return "MIME Type : " + mimeType + "\t Width : " + width + "\t Height : " + height; 
	}
}

