/*******************************************************************************
 * Copyright (c) 2000, 2005 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
module dwt.internal.image;


/**
 * JPEGHuffmanTable class actually represents two types of object:
 * 1) A DHT (Define Huffman Tables) segment, which may represent
 *  as many as 4 Huffman tables. In this case, the tables are
 *  stored in the allTables array.
 * 2) A single Huffman table. In this case, the allTables array
 *  will be null.
 * The 'reference' field is stored in both types of object, but
 * 'initialize' is only called if the object represents a DHT.
 */
final class JPEGHuffmanTable : JPEGVariableSizeSegment {
    JPEGHuffmanTable[] allTables;
    int tableClass;
    int tableIdentifier;
    int[] dhMaxCodes;
    int[] dhMinCodes;
    int[] dhValPtrs;
    int[] dhValues;
    int[] ehCodes;
    byte[] ehCodeLengths;
    static byte[] DCLuminanceTable = {
        (byte)255, (byte)196, 0, 31, 0, 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0,
        0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11
    };
    static byte[] DCChrominanceTable = {
        (byte)255, (byte)196, 0, 31, 1, 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0,
        0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11
    };
    static byte[] ACLuminanceTable = {
        (byte)255, (byte)196, 0, (byte)181, 16, 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 125, 
        1, 2, 3, 0, 4, 17, 5, 18, 33, 49, 65, 6, 19, 81, 97, 7, 34, 113, 20, 
        50, (byte)129, (byte)145, (byte)161, 8, 35, 66, (byte)177, (byte)193, 21, 82, (byte)209, (byte)240, 36, 51, 98, 
        114, (byte)130, 9, 10, 22, 23, 24, 25, 26, 37, 38, 39, 40, 41, 42, 52, 53, 
        54, 55, 56, 57, 58, 67, 68, 69, 70, 71, 72, 73, 74, 83, 84, 85, 86, 87, 
        88, 89, 90, 99, 100, 101, 102, 103, 104, 105, 106, 115, 116, 117, 118, 
        119, 120, 121, 122, (byte)131, (byte)132, (byte)133, (byte)134, (byte)135, (byte)136, (byte)137, (byte)138, (byte)146, (byte)147, (byte)148, 
        (byte)149, (byte)150, (byte)151, (byte)152, (byte)153, (byte)154, (byte)162, (byte)163, (byte)164, (byte)165, (byte)166, (byte)167, (byte)168, (byte)169, (byte)170, 
        (byte)178, (byte)179, (byte)180, (byte)181, (byte)182, (byte)183, (byte)184, (byte)185, (byte)186, (byte)194, (byte)195, (byte)196, (byte)197, (byte)198, (byte)199, 
        (byte)200, (byte)201, (byte)202, (byte)210, (byte)211, (byte)212, (byte)213, (byte)214, (byte)215, (byte)216, (byte)217, (byte)218, (byte)225, (byte)226, (byte)227, 
        (byte)228, (byte)229, (byte)230, (byte)231, (byte)232, (byte)233, (byte)234, (byte)241, (byte)242, (byte)243, (byte)244, (byte)245, (byte)246, (byte)247, (byte)248, 
        (byte)249, (byte)250
    };
    static byte[] ACChrominanceTable = {
        (byte)255, (byte)196, 0, (byte)181, 17, 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 
        1, 2, 119, 0, 1, 2, 3, 17, 4, 5, 33, 49, 6, 18, 65, 81, 7, 97, 113, 19, 34, 
        50, (byte)129, 8, 20, 66, (byte)145, (byte)161, (byte)177, (byte)193, 9, 35, 
        51, 82, (byte)240, 21, 98, 114, (byte)209, 10, 22, 36, 52, (byte)225, 37, 
        (byte)241, 23, 24, 25, 26, 38, 39, 40, 41, 42, 53, 54, 55, 56, 57, 58, 67, 
        68, 69, 70, 71, 72, 73, 74, 83, 84, 85, 86, 87, 88, 89, 90, 99, 100, 101, 102, 
        103, 104, 105, 106, 115, 116, 117, 118, 119, 120, 121, 122, (byte)130, 
        (byte)131, (byte)132, (byte)133, (byte)134, (byte)135, (byte)136, (byte)137, 
        (byte)138, (byte)146, (byte)147, (byte)148, (byte)149, (byte)150, (byte)151, 
        (byte)152, (byte)153, (byte)154, (byte)162, (byte)163, (byte)164, (byte)165, 
        (byte)166, (byte)167, (byte)168, (byte)169, (byte)170, (byte)178, (byte)179, 
        (byte)180, (byte)181, (byte)182, (byte)183, (byte)184, (byte)185, (byte)186, 
        (byte)194, (byte)195, (byte)196, (byte)197, (byte)198, (byte)199, (byte)200, 
        (byte)201, (byte)202, (byte)210, (byte)211, (byte)212, (byte)213, (byte)214, 
        (byte)215, (byte)216, (byte)217, (byte)218, (byte)226, (byte)227, (byte)228, 
        (byte)229, (byte)230, (byte)231, (byte)232, (byte)233, (byte)234, (byte)242, 
        (byte)243, (byte)244, (byte)245, (byte)246, (byte)247, (byte)248, (byte)249, 
        (byte)250
    };
    
public JPEGHuffmanTable(byte[] reference) {
    super(reference);
}

public JPEGHuffmanTable(LEDataInputStream byteStream) {
    super(byteStream);
    initialize();
}

public JPEGHuffmanTable[] getAllTables() {
    return allTables;
}

public static JPEGHuffmanTable getDefaultACChrominanceTable() {
    JPEGHuffmanTable result = new JPEGHuffmanTable(ACChrominanceTable);
    result.initialize();
    return result;
}

public static JPEGHuffmanTable getDefaultACLuminanceTable() {
    JPEGHuffmanTable result = new JPEGHuffmanTable(ACLuminanceTable);
    result.initialize();
    return result;
}

public static JPEGHuffmanTable getDefaultDCChrominanceTable() {
    JPEGHuffmanTable result = new JPEGHuffmanTable(DCChrominanceTable);
    result.initialize();
    return result;
}

public static JPEGHuffmanTable getDefaultDCLuminanceTable() {
    JPEGHuffmanTable result = new JPEGHuffmanTable(DCLuminanceTable);
    result.initialize();
    return result;
}

public int[] getDhMaxCodes() {
    return dhMaxCodes;
}

public int[] getDhMinCodes() {
    return dhMinCodes;
}

public int[] getDhValPtrs() {
    return dhValPtrs;
}

public int[] getDhValues() {
    return dhValues;
}

public int getTableClass() {
    return tableClass;
}

public int getTableIdentifier() {
    return tableIdentifier;
}

void initialize() {
    int totalLength = getSegmentLength() - 2;
    int ofs = 4;
    int[] bits = new int[16];
    JPEGHuffmanTable[] huffTables = new JPEGHuffmanTable[8]; // maximum is 4 AC + 4 DC
    int huffTableCount = 0;
    while (totalLength > 0) {
        int tc = (reference[ofs] & 0xFF) >> 4; // table class: AC (1) or DC (0)
        int tid = reference[ofs] & 0xF; // table id: 0-1 baseline, 0-3 prog/ext
        ofs++;
        
        /* Read the 16 count bytes and add them together to get the table size. */
        int count = 0;
        for (int i = 0; i < bits.length; i++) {
            int bCount = reference[ofs + i] & 0xFF;
            bits[i] = bCount;
            count += bCount;
        }
        ofs += 16;
        totalLength -= 17;
        
        /* Read the table. */
        int[] huffVals = new int[count];
        for (int i = 0; i < count; i++) {
            huffVals[i] = reference[ofs + i] & 0xFF;
        }
        ofs += count;
        totalLength -= count;
        
        /* Calculate the lengths. */
        int[] huffCodeLengths = new int[50]; // start with 50 and increment as needed
        int huffCodeLengthsIndex = 0;
        for (int i = 0; i < 16; i++) {
            for (int j = 0; j < bits[i]; j++) {
                if (huffCodeLengthsIndex >= huffCodeLengths.length) {
                    int[] newHuffCodeLengths = new int[huffCodeLengths.length + 50];
                    System.arraycopy(huffCodeLengths, 0, newHuffCodeLengths, 0, huffCodeLengths.length);
                    huffCodeLengths = newHuffCodeLengths;
                }
                huffCodeLengths[huffCodeLengthsIndex] = i + 1;
                huffCodeLengthsIndex++;
            }
        }
        
        /* Truncate huffCodeLengths to the correct size. */
        if (huffCodeLengthsIndex < huffCodeLengths.length) {
            int[] newHuffCodeLengths = new int[huffCodeLengthsIndex];
            System.arraycopy(huffCodeLengths, 0, newHuffCodeLengths, 0, huffCodeLengthsIndex);
            huffCodeLengths = newHuffCodeLengths;
        }
        
        /* Calculate the Huffman codes. */
        int[] huffCodes = new int[50]; // start with 50 and increment as needed
        int huffCodesIndex = 0;
        int k = 1;
        int code = 0;
        int si = huffCodeLengths[0];
        int p = 0;
        while (p < huffCodeLengthsIndex) {
            while ((p < huffCodeLengthsIndex) && (huffCodeLengths[p] is si)) {
                if (huffCodesIndex >= huffCodes.length) {
                    int[] newHuffCodes = new int[huffCodes.length + 50];
                    System.arraycopy(huffCodes, 0, newHuffCodes, 0, huffCodes.length);
                    huffCodes = newHuffCodes;
                }
                huffCodes[huffCodesIndex] = code;
                huffCodesIndex++;
                code++;
                p++;
            }
            code *= 2;
            si++;
        }
        
        /* Truncate huffCodes to the correct size. */
        if (huffCodesIndex < huffCodes.length) {
            int[] newHuffCodes = new int[huffCodesIndex];
            System.arraycopy(huffCodes, 0, newHuffCodes, 0, huffCodesIndex);
            huffCodes = newHuffCodes;
        }
        
        /* Calculate the maximum and minimum codes */
        k = 0;
        int[] maxCodes = new int[16];
        int[] minCodes = new int[16];
        int[] valPtrs = new int[16];
        for (int i = 0; i < 16; i++) {
            int bSize = bits[i];
            if (bSize is 0) {
                maxCodes[i] = -1;
            } else {
                valPtrs[i] = k;
                minCodes[i] = huffCodes[k];
                k += bSize;
                maxCodes[i] = huffCodes[k - 1];
            }
        }
        
        /* Calculate the eHuffman codes and lengths. */
        int[] eHuffCodes = new int[256];
        byte[] eHuffSize = new byte[256];
        for (int i = 0; i < huffCodesIndex; i++) {
            eHuffCodes[huffVals[i]] = huffCodes[i];
            eHuffSize[huffVals[i]] = (byte)huffCodeLengths[i];
        }
        
        /* Create the new JPEGHuffmanTable and add it to the allTables array. */
        JPEGHuffmanTable dhtTable = new JPEGHuffmanTable(reference);
        dhtTable.tableClass = tc;
        dhtTable.tableIdentifier = tid;
        dhtTable.dhValues = huffVals;
        dhtTable.dhMinCodes = minCodes;
        dhtTable.dhMaxCodes = maxCodes;
        dhtTable.dhValPtrs = valPtrs;
        dhtTable.ehCodes = eHuffCodes;
        dhtTable.ehCodeLengths = eHuffSize;
        huffTables[huffTableCount] = dhtTable;
        huffTableCount++;
    }
    allTables = new JPEGHuffmanTable[huffTableCount];
    System.arraycopy(huffTables, 0, allTables, 0, huffTableCount);
}

public int signature() {
    return JPEGFileFormat.DHT;
}
}