/*
 * @(#)ImageFileDirectory.java
 *
 * $Date: 2014-03-13 04:15:48 -0400 (Thu, 13 Mar 2014) $
 *
 * Copyright (c) 2011 by Jeremy Wood.
 * All rights reserved.
 *
 * The copyright of this software is owned by Jeremy Wood. 
 * You may not use, copy or modify this software, except in  
 * accordance with the license agreement you entered into with  
 * Jeremy Wood. For details see accompanying license terms.
 * 
 * This software is probably, but not necessarily, discussed here:
 * https://javagraphics.java.net/
 * 
 * That site should also contain the most recent official version
 * of this software.  (See the SVN repository for more details.)
 *
Modified BSD License

Copyright (c) 2015, Jeremy Wood.
All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
* The name of the contributors may not be used to endorse or promote products derived from this software without specific prior written permission.
*
 *THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package gr.iti.mklab.reveal.forensics.util.ThumbnailExtractor.image.jpeg;

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Hashtable;

class ImageFileDirectory {
	static Hashtable<Integer, String> TYPE_LUT = new Hashtable<Integer, String>();
	static {
		TYPE_LUT.put(new Integer(256),"Image Width");
		TYPE_LUT.put(new Integer(257),"Image Length");
		TYPE_LUT.put(new Integer(258),"BitsPerSample");
		TYPE_LUT.put(new Integer(259),"Compression");
		TYPE_LUT.put(new Integer(262),"PhotometricInterpretation");
		TYPE_LUT.put(new Integer(270),"ImageDescription");
		TYPE_LUT.put(new Integer(271),"Make");
		TYPE_LUT.put(new Integer(272),"Model");
		TYPE_LUT.put(new Integer(273),"StripOffsets");
		TYPE_LUT.put(new Integer(274),"Orientation");
		TYPE_LUT.put(new Integer(277),"SamplesPerPixel");
		TYPE_LUT.put(new Integer(278),"RowsPerStrip");
		TYPE_LUT.put(new Integer(279),"StripByteCounts");
		TYPE_LUT.put(new Integer(282),"XResolution");
		TYPE_LUT.put(new Integer(283),"YResolution");
		TYPE_LUT.put(new Integer(284),"PlanarConfiguration");
		TYPE_LUT.put(new Integer(296),"ResolutionUnit");
		TYPE_LUT.put(new Integer(301),"TranserFunction");
		TYPE_LUT.put(new Integer(305),"Software");
		TYPE_LUT.put(new Integer(306),"DateTime");
		TYPE_LUT.put(new Integer(315),"Artist");
		TYPE_LUT.put(new Integer(318),"WhitePoint");
		TYPE_LUT.put(new Integer(319),"PrimaryChromaticities");
		TYPE_LUT.put(new Integer(513),"JPEGInterchangeFormat");
		TYPE_LUT.put(new Integer(514),"JPEGInterchangeFormatLength");
		TYPE_LUT.put(new Integer(529),"YCbCrCoefficients");
		TYPE_LUT.put(new Integer(530),"YCbCrSubSampling");
		TYPE_LUT.put(new Integer(531),"YCbCrPositioning");
		TYPE_LUT.put(new Integer(532),"ReferenceBlackWhite");
		TYPE_LUT.put(new Integer(33432),"Copyright");
		TYPE_LUT.put(new Integer(34665),"Exif IFD Pointer");
		TYPE_LUT.put(new Integer(34853),"GPSInfo IFD Pointer");
		TYPE_LUT.put(new Integer(33434),"ExposureTime");
		TYPE_LUT.put(new Integer(33437),"FNumber");
		TYPE_LUT.put(new Integer(34850),"ExposureProgram");
		TYPE_LUT.put(new Integer(34852),"SpectralSensitivity");
		TYPE_LUT.put(new Integer(34855),"ISOSpeedRatings");
		TYPE_LUT.put(new Integer(34856),"OECF");
		TYPE_LUT.put(new Integer(36864),"ExifVersion");
		TYPE_LUT.put(new Integer(36867),"DateTimeOriginal");
		TYPE_LUT.put(new Integer(36868),"DateTimeDigitized");
		TYPE_LUT.put(new Integer(37121),"ComponentsConfiguration");
		TYPE_LUT.put(new Integer(37122),"CompressedBitsPerPixel");
		TYPE_LUT.put(new Integer(37377),"ShutterSpeedValue");
		TYPE_LUT.put(new Integer(37378),"ApertureValue");
		TYPE_LUT.put(new Integer(37379),"BrightnessValue");
		TYPE_LUT.put(new Integer(37380),"ExposureBiasValue");
		TYPE_LUT.put(new Integer(37381),"MaxApertureValue");
		TYPE_LUT.put(new Integer(37382),"SubjectDistance");
		TYPE_LUT.put(new Integer(37383),"MeteringMode");
		TYPE_LUT.put(new Integer(37384),"LightSource");
		TYPE_LUT.put(new Integer(37385),"Flash");
		TYPE_LUT.put(new Integer(37386),"FocalLength");
		TYPE_LUT.put(new Integer(37396),"SubjectArea");
		TYPE_LUT.put(new Integer(37500),"MakerNote");
		TYPE_LUT.put(new Integer(37510),"UserComment");
		TYPE_LUT.put(new Integer(37520),"SubSecTime");
		TYPE_LUT.put(new Integer(37521),"SubSecTimeOriginal");
		TYPE_LUT.put(new Integer(37522),"SubSecTimeDigitized");

		TYPE_LUT.put(new Integer(40960),"FlashpixVersion");
		TYPE_LUT.put(new Integer(40961),"ColorSpace");
		TYPE_LUT.put(new Integer(40962),"PixelXDimension");
		TYPE_LUT.put(new Integer(40963),"PixelYDimension");
		TYPE_LUT.put(new Integer(40964),"RelatedSoundFile");
		TYPE_LUT.put(new Integer(40965),"Interoperability IFD Pointer");
		TYPE_LUT.put(new Integer(41483),"FlashEnergy");
		TYPE_LUT.put(new Integer(41484),"SpatialFrequencyResponse");
		TYPE_LUT.put(new Integer(41486),"FocalPlaneXResolution");
		TYPE_LUT.put(new Integer(41487),"FocalPlaneYResolution");
		TYPE_LUT.put(new Integer(41488),"FocalPlaneResolutionUnit");
		TYPE_LUT.put(new Integer(41492),"SubjectLocation");
		TYPE_LUT.put(new Integer(41493),"ExposureIndex");
		TYPE_LUT.put(new Integer(41495),"SensingMethod");
		TYPE_LUT.put(new Integer(41728),"FileSource");
		TYPE_LUT.put(new Integer(41729),"SceneType");
		TYPE_LUT.put(new Integer(41730),"CFAPattern");
		TYPE_LUT.put(new Integer(41985),"CustomRendered");
		TYPE_LUT.put(new Integer(41986),"ExposureMode");
		TYPE_LUT.put(new Integer(41987),"WhiteBalance");
		TYPE_LUT.put(new Integer(41988),"DigitalZoomRatio");
		TYPE_LUT.put(new Integer(41989),"FocalLengthIn35mmFilm");
		TYPE_LUT.put(new Integer(41990),"SceneCaptureType");
		TYPE_LUT.put(new Integer(41991),"GainControl");
		TYPE_LUT.put(new Integer(41992),"Contrast");
		TYPE_LUT.put(new Integer(41993),"Saturation");
		TYPE_LUT.put(new Integer(41994),"Sharpness");
		TYPE_LUT.put(new Integer(41995),"DeviceSettingDescription");
		TYPE_LUT.put(new Integer(41996),"SubjectDistanceRange");
		TYPE_LUT.put(new Integer(42016),"ImageUniqueID");
	}
	
	static class DirectoryEntry {
		int tagNumber;
		
		int dataFormat;
		
		int componentCount;
		
		/** This is a 4-byte value that either:
		 * contains the data of this entry OR
		 * points to the offset after the TIFF
		 * header when we should read this data
		 * if it is more than 4 bytes long.
		 */
		byte[] fieldValue;
		Object value;
		
		DirectoryEntry(InputStream in,boolean reverse) throws IOException {
			byte[] array = new byte[4];
			
			if(JPEGMarkerInputStream.readFully(in, array, 2, reverse)!=2)
				throw new IOException();
			tagNumber = (array[0] & 0xff)*256 + (array[1] & 0xff);

			if(JPEGMarkerInputStream.readFully(in, array, 2, reverse)!=2)
				throw new IOException();
			dataFormat = (array[0] & 0xff)*256 + (array[1] & 0xff);

			if(JPEGMarkerInputStream.readFully(in, array, 4, reverse)!=4)
				throw new IOException();
			componentCount = ((array[0] & 0xff) << 24) + ((array[1] & 0xff) << 16) +
							((array[2] & 0xff) << 8) + ((array[3] & 0xff) << 0);

			fieldValue = new byte[4];
			if(JPEGMarkerInputStream.readFully(in, fieldValue, 4, reverse)!=4)
				throw new IOException();
		}
		
		String getPropertyName() {
			Integer key = new Integer(tagNumber);
			String propertyName = (String)TYPE_LUT.get(key);
			if(propertyName!=null) return propertyName;
			return null;
		}
		
		private int getValueByteLength() throws IOException {
			int bytesPerComponent;
			switch(dataFormat) {

			case 1 : //byte
				bytesPerComponent = 1;
				break;
			case 2 : //ASCII
				bytesPerComponent = 1;
				break;
			case 3 : //short
				bytesPerComponent = 2;
				break;
			case 4 : //long
				bytesPerComponent = 4;
				break;
			case 5 : //rational
				bytesPerComponent = 8;
				break;
			case 6 : //signed byte
				bytesPerComponent = 1;
				break;
			case 7 : //undefined
				bytesPerComponent = 8;
				break;
			case 8 : //signed short
				bytesPerComponent = 2;
				break;
			case 9 : //signed long
				bytesPerComponent = 8;
				break;
			case 10 : //signed rational
				bytesPerComponent = 8;
				break;
			case 0: //unknown, but this occurred in some JPEGs on my hard disk
				return 0;
			default :
				throw new IOException("unrecognized data type ("+dataFormat+")");
			}
			return bytesPerComponent*componentCount;
		}
		
		/** Returns a 1-byte unsigned int.
		 * (The names of these "read" values are based on the exif specs,
		 * not on Java's definition of primitives.)
		 */
		int readByte(byte[] data,int offset) {
			return ( data[offset] & 0xff );
		}
		
		/** Returns a 1-byte signed int.
		 * (The names of these "read" values are based on the exif specs,
		 * not on Java's definition of primitives.)
		 */
		int readSignedByte(byte[] data,int offset) {
			return ( data[offset] );
		}

		/** Returns a 2-byte unsigned int.
		 * (The names of these "read" values are based on the exif specs,
		 * not on Java's definition of primitives.)
		 */
		int readShort(byte[] data,int offset) {
			return ( ((data[offset] & 0xff) << 8) + ((data[offset+1] & 0xff) << 0) );
		}

		/** Returns a 2-byte signed int.
		 * (The names of these "read" values are based on the exif specs,
		 * not on Java's definition of primitives.)
		 */
		int readSignedShort(byte[] data,int offset) {
			//TODO: implement two's complement here.
			return ( ((data[offset] & 0xff) << 8) + ((data[offset+1] & 0xff) << 0) );
		}

		/** Returns a 4-byte unsigned int.
		 * (The names of these "read" values are based on the exif specs,
		 * not on Java's definition of primitives.)
		 */
		int readLong(byte[] data,int offset) {
			return ( ((data[offset+0] & 0xff) << 24) + ((data[offset+1] & 0xff) << 16) +
					((data[offset+2] & 0xff) << 8) + ((data[offset+3] & 0xff) << 0) );
		}

		/** Returns a 4-byte signed int.
		 * (The names of these "read" values are based on the exif specs,
		 * not on Java's definition of primitives.)
		 */
		int readSignedLong(byte[] data,int offset) {
			//TODO: implement two's complement here.
			return ( ((data[offset+0] & 0xff) << 24) + ((data[offset+1] & 0xff) << 16) +
					((data[offset+2] & 0xff) << 8) + ((data[offset+3] & 0xff) << 0) );
		}
		
		/** Returns the position after the TIFF header where this data
		 * resides, or -1 if the data is actually contained in the 4-byte
		 * value field already retrieved.
		 */
		int positionAfterTIFFHeader() throws IOException {
			int byteLength = getValueByteLength();
			if(byteLength>4) {
				int positionAfterTIFFHeader = readLong(fieldValue, 0);
				return positionAfterTIFFHeader;
			}
			return -1;
		}

		/**
		 * 
		 * @param in a BufferedInputStream that was last marked at the start of
		 * the TIFF header.
		 * @throws IOException
		 */
		void resolveValue(BufferedInputStream in) throws IOException {
			int byteLength = getValueByteLength();
			byte[] data;
			if(byteLength>4) {
				//we have to read this data:
				byte[] newData = new byte[byteLength];
				int positionAfterTIFFHeader = readLong(fieldValue, 0);
				in.reset();
				if(JPEGMarkerInputStream.skipFully(in, positionAfterTIFFHeader)!=positionAfterTIFFHeader)
					throw new IOException();
				JPEGMarkerInputStream.readFully(in, newData, byteLength, false);
				data = newData;
			} else {
				data = fieldValue;
			}

			if(dataFormat==7 || dataFormat==0) { //UNDEFINED
				value = data;
				return;
			} else if(dataFormat==2) { //ASCII
				StringBuffer buffer = new StringBuffer();
				for(int a = 0; a<componentCount; a++) {
					int i = (data[a] & 0xff);
					if(i==0) {
						break;
					}
					char c = (char)i;
					buffer.append(c );
					
				}
				value = buffer.toString();
				return;
			}
			Object[] valueArray;
			if(dataFormat==1 || //BYTE
					dataFormat==6 || //SIGNED BYTE
					dataFormat==3 || //SHORT
					dataFormat==8 || //SIGNED SHORT
					dataFormat==4 || //LONG
					dataFormat==9) { //SIGNED LONG
				valueArray = new Integer[componentCount];
			} else if(dataFormat==5 || //RATIONAL
					dataFormat==10) { //SIGNED RATIONAL 
				valueArray = new Double[componentCount];
			} else {
				throw new RuntimeException("unexpected data format ("+dataFormat+")");
			}
			
			for(int a = 0; a<componentCount; a++) {
				switch(dataFormat) {
					case 1 : //byte
						valueArray[a] = new Integer( readByte(data, a*1) );
						break;
					case 6 : //signed byte
						valueArray[a] = new Integer( readSignedByte(data, a*1) );
						break;
					case 3 : //short
						valueArray[a] = new Integer( readShort(data, a*2) );
						break;
					case 8 : //signed short
						valueArray[a] = new Integer( readSignedShort(data, a*2) );
						break;
					case 4 : //long
						valueArray[a] = new Integer( readLong(data, a*4) );
						break;
					case 9 : //signed long
						valueArray[a] = new Integer( readSignedLong(data, a*4) );
						break;
					case 5 : //rational
						double numerator = readLong( data, a*4);
						double denominator = readLong( data, a*4+4);
						valueArray[a] = new Double( numerator / denominator );
						break;
					case 10 : //signed rational
						double numerator2 = readSignedLong( data, a*4);
						double denominator2 = readSignedLong( data, a*4+4);
						valueArray[a] = new Double( numerator2 / denominator2 );
						break;
					default :
						throw new RuntimeException("Unexpected condition.");
				}
			}
			
			if(valueArray.length==1) {
				value = valueArray[0];
			} else {
				value = valueArray;
			}
		}

		public String toString() {
			StringBuffer sb = new StringBuffer();
			sb.append("[ ");
			String typeName = (String)TYPE_LUT.get(new Integer(tagNumber));
			if(typeName==null) {
				sb.append("UNKNOWN ");
			} else {
				sb.append(typeName);
				sb.append(' ');
			}
			

			if(dataFormat==1) {
				sb.append("BYTE ");
			} else if(dataFormat==2) {
				sb.append("ASCII ");
			} else if(dataFormat==3) {
				sb.append("SHORT ");
			} else if(dataFormat==4) {
				sb.append("LONG ");
			} else if(dataFormat==5) {
				sb.append("RATIONAL ");
			} else if(dataFormat==7) {
				sb.append("UNDEFINED ");
			} else if(dataFormat==9) {
				sb.append("SLONG ");
			} else if(dataFormat==10) {
				sb.append("SRATIONAL ");
			} else {
				sb.append("UNRECOGNIZED ");
			}
			sb.append(componentCount+" ");
			if(value==null) {
				sb.append( readLong(fieldValue,0)+" ]");
			} else {
				sb.append(value+" ]");
			}
			return sb.toString();
		}
	}

	DirectoryEntry[] entries;
	long nextIFDPosition;
	
	ImageFileDirectory(BufferedInputStream bufferedIn,long positionAfterTIFFHeader,boolean reverse) throws IOException {
		bufferedIn.reset();
		if(JPEGMarkerInputStream.skipFully(bufferedIn, positionAfterTIFFHeader)!=positionAfterTIFFHeader)
			throw new IOException();
		
		byte[] array = new byte[4];
		if(JPEGMarkerInputStream.readFully(bufferedIn, array,2,reverse)!=2) 
			throw new IOException("Corrupt image file directory.");
		
		int numberOfEntries = (array[0] & 0xff)*256+(array[1] & 0xff);

		entries = new DirectoryEntry[ numberOfEntries ];
		for(int a = 0; a<numberOfEntries; a++) {
			try {
				DirectoryEntry entry = new DirectoryEntry(bufferedIn, reverse);
				entries[a] = (entry);
			} catch(RuntimeException e) {
				System.err.println(a+" / "+numberOfEntries);
				throw e;
			}
		}
		
		/** According to the specs: what is supposed to follow is a 4-byte
		 * pointer to the next IFD.  However I found an APP1 block
		 * that omits these 4 bytes and instead contains some DirectoryEntries.
		 * 
		 * So first I'll scan through the entries and see if any of them believe
		 * they should start here, and if so we just assume there is no
		 * next IFD to point to.  (If anything this errs on the side of
		 * omitting data, instead of trying to read data where the isn't any.)
		 * 
		 */
		long positionToExpectIFDPtr = positionAfterTIFFHeader+2+12*numberOfEntries;
		boolean missingIFDPtr = false;
		for(int a = 0; a<numberOfEntries && (!missingIFDPtr); a++) {
			int k = entries[a].positionAfterTIFFHeader();
			if(k!=-1 && k==positionToExpectIFDPtr) {
				missingIFDPtr = true;
			}
		}
		
		if(missingIFDPtr) {
			//there is no space for the IFD position to be, so assume it's zero.
			nextIFDPosition = 0;
		} else {
			if(JPEGMarkerInputStream.readFully(bufferedIn, array,4,reverse)!=4) 
				throw new IOException("Corrupt image file directory.");
	
			nextIFDPosition = ((array[0] & 0xff) << 24)+
				((array[1] & 0xff) << 16)+
				((array[2] & 0xff) << 8)+
				(array[3] & 0xff);
		}
	}
	
	/** Returns the value associated with a tag number.
	 * This should only be called after entries have been prompted
	 * to resolve.
	 * 
	 * @param tagNumber the tag number to search for
	 * @return the value of that tag, or null if the tag
	 * was not found.
	 */
	Object getProperty(int tagNumber) {
		for(int a = 0; a<entries.length; a++) {
			if(entries[a].tagNumber==tagNumber) {
				return entries[a].value;
			}
		}
		return null;
	}
	
	public String toString() {
		return "ImageFileDirectory[ "+entries+" ]";
	}
}
