/*
* Copyright (c) 2001 Sun Microsystems, Inc. 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.
*
* -Redistribution in binary form must reproduct the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* Neither the name of Sun Microsystems, Inc. or the names of contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* This software is provided "AS IS," without a warranty of any kind. ALL
* EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY
* IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR
* NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE
* LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING
* OR DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS
* LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT,
* INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER
* CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF
* OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGES.
*
* You acknowledge that Software is not designed,licensed or intended for use in
* the design, construction, operation or maintenance of any nuclear facility.
*/
package com.fr.third.JAI;
class TIFFFaxEncoder {
/**
* The CCITT numerical definition of white.
*/
private static final int WHITE = 0;
/**
* The CCITT numerical definition of black.
*/
private static final int BLACK = 1;
// --- Begin tables for CCITT compression ---
private static byte[] byteTable = new byte[] {
8, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4, // 0 to 15
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, // 16 to 31
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, // 32 to 47
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, // 48 to 63
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 64 to 79
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 80 to 95
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 96 to 111
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 112 to 127
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 128 to 143
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 144 to 159
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 160 to 175
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 176 to 191
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 192 to 207
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 208 to 223
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 224 to 239
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 // 240 to 255
};
/**
* Terminating codes for black runs.
*/
private static int[] termCodesBlack = new int[] {
/* 0 0x0000 */ 0x0dc0000a, 0x40000003, 0xc0000002, 0x80000002,
/* 4 0x0004 */ 0x60000003, 0x30000004, 0x20000004, 0x18000005,
/* 8 0x0008 */ 0x14000006, 0x10000006, 0x08000007, 0x0a000007,
/* 12 0x000c */ 0x0e000007, 0x04000008, 0x07000008, 0x0c000009,
/* 16 0x0010 */ 0x05c0000a, 0x0600000a, 0x0200000a, 0x0ce0000b,
/* 20 0x0014 */ 0x0d00000b, 0x0d80000b, 0x06e0000b, 0x0500000b,
/* 24 0x0018 */ 0x02e0000b, 0x0300000b, 0x0ca0000c, 0x0cb0000c,
/* 28 0x001c */ 0x0cc0000c, 0x0cd0000c, 0x0680000c, 0x0690000c,
/* 32 0x0020 */ 0x06a0000c, 0x06b0000c, 0x0d20000c, 0x0d30000c,
/* 36 0x0024 */ 0x0d40000c, 0x0d50000c, 0x0d60000c, 0x0d70000c,
/* 40 0x0028 */ 0x06c0000c, 0x06d0000c, 0x0da0000c, 0x0db0000c,
/* 44 0x002c */ 0x0540000c, 0x0550000c, 0x0560000c, 0x0570000c,
/* 48 0x0030 */ 0x0640000c, 0x0650000c, 0x0520000c, 0x0530000c,
/* 52 0x0034 */ 0x0240000c, 0x0370000c, 0x0380000c, 0x0270000c,
/* 56 0x0038 */ 0x0280000c, 0x0580000c, 0x0590000c, 0x02b0000c,
/* 60 0x003c */ 0x02c0000c, 0x05a0000c, 0x0660000c, 0x0670000c
};
/**
* Terminating codes for white runs.
*/
private static int[] termCodesWhite = new int[] {
/* 0 0x0000 */ 0x35000008, 0x1c000006, 0x70000004, 0x80000004,
/* 4 0x0004 */ 0xb0000004, 0xc0000004, 0xe0000004, 0xf0000004,
/* 8 0x0008 */ 0x98000005, 0xa0000005, 0x38000005, 0x40000005,
/* 12 0x000c */ 0x20000006, 0x0c000006, 0xd0000006, 0xd4000006,
/* 16 0x0010 */ 0xa8000006, 0xac000006, 0x4e000007, 0x18000007,
/* 20 0x0014 */ 0x10000007, 0x2e000007, 0x06000007, 0x08000007,
/* 24 0x0018 */ 0x50000007, 0x56000007, 0x26000007, 0x48000007,
/* 28 0x001c */ 0x30000007, 0x02000008, 0x03000008, 0x1a000008,
/* 32 0x0020 */ 0x1b000008, 0x12000008, 0x13000008, 0x14000008,
/* 36 0x0024 */ 0x15000008, 0x16000008, 0x17000008, 0x28000008,
/* 40 0x0028 */ 0x29000008, 0x2a000008, 0x2b000008, 0x2c000008,
/* 44 0x002c */ 0x2d000008, 0x04000008, 0x05000008, 0x0a000008,
/* 48 0x0030 */ 0x0b000008, 0x52000008, 0x53000008, 0x54000008,
/* 52 0x0034 */ 0x55000008, 0x24000008, 0x25000008, 0x58000008,
/* 56 0x0038 */ 0x59000008, 0x5a000008, 0x5b000008, 0x4a000008,
/* 60 0x003c */ 0x4b000008, 0x32000008, 0x33000008, 0x34000008
};
/**
* Make-up codes for black runs.
*/
private static int[] makeupCodesBlack = new int[] {
/* 0 0x0000 */ 0x00000000, 0x03c0000a, 0x0c80000c, 0x0c90000c,
/* 4 0x0004 */ 0x05b0000c, 0x0330000c, 0x0340000c, 0x0350000c,
/* 8 0x0008 */ 0x0360000d, 0x0368000d, 0x0250000d, 0x0258000d,
/* 12 0x000c */ 0x0260000d, 0x0268000d, 0x0390000d, 0x0398000d,
/* 16 0x0010 */ 0x03a0000d, 0x03a8000d, 0x03b0000d, 0x03b8000d,
/* 20 0x0014 */ 0x0290000d, 0x0298000d, 0x02a0000d, 0x02a8000d,
/* 24 0x0018 */ 0x02d0000d, 0x02d8000d, 0x0320000d, 0x0328000d,
/* 28 0x001c */ 0x0100000b, 0x0180000b, 0x01a0000b, 0x0120000c,
/* 32 0x0020 */ 0x0130000c, 0x0140000c, 0x0150000c, 0x0160000c,
/* 36 0x0024 */ 0x0170000c, 0x01c0000c, 0x01d0000c, 0x01e0000c,
/* 40 0x0028 */ 0x01f0000c, 0x00000000, 0x00000000, 0x00000000,
/* 44 0x002c */ 0x00000000, 0x00000000, 0x00000000, 0x00000000,
/* 48 0x0030 */ 0x00000000, 0x00000000, 0x00000000, 0x00000000,
/* 52 0x0034 */ 0x00000000, 0x00000000, 0x00000000, 0x00000000,
/* 56 0x0038 */ 0x00000000, 0x00000000, 0x00000000, 0x00000000
};
/**
* Make-up codes for white runs.
*/
private static int[] makeupCodesWhite = new int[] {
/* 0 0x0000 */ 0x00000000, 0xd8000005, 0x90000005, 0x5c000006,
/* 4 0x0004 */ 0x6e000007, 0x36000008, 0x37000008, 0x64000008,
/* 8 0x0008 */ 0x65000008, 0x68000008, 0x67000008, 0x66000009,
/* 12 0x000c */ 0x66800009, 0x69000009, 0x69800009, 0x6a000009,
/* 16 0x0010 */ 0x6a800009, 0x6b000009, 0x6b800009, 0x6c000009,
/* 20 0x0014 */ 0x6c800009, 0x6d000009, 0x6d800009, 0x4c000009,
/* 24 0x0018 */ 0x4c800009, 0x4d000009, 0x60000006, 0x4d800009,
/* 28 0x001c */ 0x0100000b, 0x0180000b, 0x01a0000b, 0x0120000c,
/* 32 0x0020 */ 0x0130000c, 0x0140000c, 0x0150000c, 0x0160000c,
/* 36 0x0024 */ 0x0170000c, 0x01c0000c, 0x01d0000c, 0x01e0000c,
/* 40 0x0028 */ 0x01f0000c, 0x00000000, 0x00000000, 0x00000000,
/* 44 0x002c */ 0x00000000, 0x00000000, 0x00000000, 0x00000000,
/* 48 0x0030 */ 0x00000000, 0x00000000, 0x00000000, 0x00000000,
/* 52 0x0034 */ 0x00000000, 0x00000000, 0x00000000, 0x00000000,
/* 56 0x0038 */ 0x00000000, 0x00000000, 0x00000000, 0x00000000
};
/**
* Pass mode table.
*/
private static int[] passMode = new int[] {
0x10000004 // 0001
};
/**
* Vertical mode table.
*/
private static int[] vertMode = new int[] {
0x06000007, // 0000011
0x0c000006, // 000011
0x60000003, // 011
0x80000001, // 1
0x40000003, // 010
0x08000006, // 000010
0x04000007 // 0000010
};
/**
* Horizontal mode table.
*/
private static int[] horzMode = new int[] {
0x20000003 // 001
};
/**
* Black and white terminating code table.
*/
private static int[][] termCodes =
new int[][] {termCodesWhite, termCodesBlack};
/**
* Black and white make-up code table.
*/
private static int[][] makeupCodes =
new int[][] {makeupCodesWhite, makeupCodesBlack};
/**
* Black and white pass mode table.
*/
private static int[][] pass = new int[][] {passMode, passMode};
/**
* Black and white vertical mode table.
*/
private static int[][] vert = new int[][] {vertMode, vertMode};
/**
* Black and white horizontal mode table.
*/
private static int[][] horz = new int[][] {horzMode, horzMode};
// --- End tables for CCITT compression ---
/**
* Whether bits are inserted in reverse order (TIFF FillOrder 2).
*/
private boolean inverseFill;
/**
* Output bit buffer.
*/
private int bits;
/**
* Number of bits in the output bit buffer.
*/
private int ndex;
/**
* Constructs a TIFFFaxEncoder for CCITT bilevel encoding.
*
* @param inverseFill Whether bits are inserted in reverse order
* (TIFF FillOrder 2).
*/
TIFFFaxEncoder(boolean inverseFill) {
this.inverseFill = inverseFill;
}
/**
* Return min of maxOffset or offset of first pixel
* different from pixel at bitOffset.
*/
private int nextState(byte[] data,
int base,
int bitOffset,
int maxOffset)
{
if(data == null) {
return maxOffset;
}
int next = base + (bitOffset>>>3);
int end = base + (maxOffset>>>3) - 1;
int extra = bitOffset & 0x7;
int testbyte;
if((data[next] & (0x80 >>> extra)) != 0) { // look for "0"
testbyte = ~(data[next]) & (0xff >>> extra);
while (next < end) {
if (testbyte != 0) {
break;
}
testbyte = ~(data[++next]) & 0xff;
}
} else { // look for "1"
if ((testbyte = (data[next] & (0xff >>> extra))) != 0) {
bitOffset = (next-base)*8 + byteTable[testbyte];
return ((bitOffset < maxOffset) ? bitOffset : maxOffset);
}
while (next < end) {
if ((testbyte = data[++next]&0xff) != 0) {
// "1" is in current byte
bitOffset = (next-base)*8 + byteTable[testbyte];
return ((bitOffset < maxOffset) ? bitOffset : maxOffset);
}
}
}
bitOffset = (next-base)*8 + byteTable[testbyte];
return ((bitOffset < maxOffset) ? bitOffset : maxOffset);
}
/**
* Initialize bit buffer machinery.
*/
private void initBitBuf()
{
ndex = 0;
bits = 0x00000000;
}
/**
* Get code for run and add to compressed bitstream.
*/
private int add1DBits(byte[] buf,
int where, // byte offs
int count, // #pixels in run
int color) // color of run
{
int sixtyfours;
int mask;
int len = where;
sixtyfours = count >>> 6; // count / 64;
count = count & 0x3f; // count % 64
if (sixtyfours != 0) {
for ( ; sixtyfours > 40; sixtyfours -= 40) {
mask = makeupCodes[color][40];
bits |= (mask & 0xfff80000) >>> ndex;
ndex += (int)(mask & 0x0000ffff);
while (ndex > 7) {
buf[len++] = (byte)(bits >>> 24);
bits <<= 8;
ndex -= 8;
}
}
mask = makeupCodes[color][sixtyfours];
bits |= (mask & 0xfff80000) >>> ndex;
ndex += (int)(mask & 0x0000ffff);
while (ndex > 7) {
buf[len++] = (byte)(bits >>> 24);
bits <<= 8;
ndex -= 8;
}
}
mask = termCodes[color][count];
bits |= (mask & 0xfff80000) >>> ndex;
ndex += (int)(mask & 0x0000ffff);
while (ndex > 7) {
buf[len++] = (byte)(bits >>> 24);
bits <<= 8;
ndex -= 8;
}
return(len - where);
}
/**
* Place entry from mode table into compressed bitstream.
*/
private int add2DBits(byte[] buf, // compressed buffer
int where, // byte offset into compressed buffer
int[][] mode, // 2-D mode to be encoded
int entry) // mode entry (0 unless vertical)
{
int mask;
int len = where;
int color = 0;
mask = mode[color][entry];
bits |= (mask & 0xfff80000) >>> ndex;
ndex += (int)(mask & 0x0000ffff);
while (ndex > 7) {
buf[len++] = (byte)(bits >>> 24);
bits <<= 8;
ndex -= 8;
}
return(len - where);
}
/**
* Add an End-of-Line (EOL == 0x001) to the compressed bitstream
* with optional byte alignment.
*/
private int addEOL(boolean is1DMode,// 1D encoding
boolean addFill, // byte aligned EOLs
boolean add1, // add1 ? EOL+1 : EOL+0
byte[] buf, // compressed buffer address
int where) // current byte offset into buffer
{
int len = where;
//
// Add zero-valued fill bits such that the EOL is aligned as
//
// xxxx 0000 0000 0001
//
if(addFill) {
//
// Simply increment the bit count. No need to feed bits into
// the output buffer at this point as there are at most 7 bits
// in the bit buffer, at most 7 are added here, and at most
// 13 below making the total 7+7+13 = 27 before the bit feed
// at the end of this routine.
//
ndex += ((ndex <= 4) ? 4 - ndex : 12 - ndex);
}
//
// Write EOL into buffer
//
if(is1DMode) {
bits |= 0x00100000 >>> ndex;
ndex += 12;
} else {
bits |= (add1 ? 0x00180000 : 0x00100000) >>> ndex;
ndex += 13;
}
while (ndex > 7) {
buf[len++] = (byte)(bits >>> 24);
bits <<= 8;
ndex -= 8;
}
return(len - where);
}
/**
* Add an End-of-Facsimile-Block (EOFB == 0x001001) to the compressed
* bitstream.
*/
private int addEOFB(byte[] buf, // compressed buffer
int where) // byte offset into compressed buffer
{
int len = where;
//
// eofb code
//
bits |= 0x00100100 >>> ndex;
//
// eofb code length
//
ndex += 24;
//
// flush all pending bits
//
while(ndex > 0) {
buf[len++] = (byte)(bits >>> 24);
bits <<= 8;
ndex -= 8;
}
return(len - where);
}
/**
* One-dimensionally encode a row of data using CCITT Huffman compression.
* The bit buffer should be initialized as required before invoking this
* method and should be flushed after the method returns. The fill order
* is always highest-order to lowest-order bit so the calling routine
* should handle bit inversion.
*/
private int encode1D(byte[] data,
int rowOffset,
int colOffset,
int rowLength,
byte[] compData,
int compOffset) {
int lineAddr = rowOffset;
int bitIndex = colOffset;
int last = bitIndex + rowLength;
int outIndex = compOffset;
//
// Is first pixel black
//
int testbit =
((data[lineAddr + (bitIndex>>>3)]&0xff) >>>
(7-(bitIndex & 0x7))) & 0x1;
int currentColor = BLACK;
if(testbit != 0) {
outIndex += add1DBits(compData, outIndex, 0, WHITE);
} else {
currentColor = WHITE;
}
//
// Run-length encode line
//
while(bitIndex < last) {
int bitCount =
nextState(data, lineAddr, bitIndex, last) - bitIndex;
outIndex +=
add1DBits(compData, outIndex, bitCount, currentColor);
bitIndex += bitCount;
currentColor ^= 0x00000001;
}
return outIndex - compOffset;
}
/**
* Encode a row of data using Modified Huffman Compression also known as
* CCITT RLE (Run Lenth Encoding).
*
* @param data The row of data to compress.
* @param rowOffset Starting index in data.
* @param colOffset Bit offset within first data[rowOffset].
* @param rowLength Number of bits in the row.
* @param compData The compressed data.
*
* @return The number of bytes saved in the compressed data array.
*/
synchronized int encodeRLE(byte[] data,
int rowOffset,
int colOffset,
int rowLength,
byte[] compData) {
//
// Initialize bit buffer machinery.
//
initBitBuf();
//
// Run-length encode line.
//
int outIndex =
encode1D(data, rowOffset, colOffset, rowLength, compData, 0);
//
// Flush pending bits
//
while(ndex > 0) {
compData[outIndex++] = (byte)(bits >>> 24);
bits <<= 8;
ndex -= 8;
}
//
// Flip the bytes if inverse fill was requested.
//
if(inverseFill) {
byte[] flipTable = TIFFFaxDecoder.flipTable;
for(int i = 0; i < outIndex; i++) {
compData[i] = flipTable[compData[i]&0xff];
}
}
return outIndex;
}
/**
* Encode a buffer of data using CCITT T.4 Compression also known as
* Group 3 facsimile compression.
*
* @param is1DMode Whether to perform one-dimensional encoding.
* @param isEOLAligned Whether EOL bit sequences should be padded.
* @param data The row of data to compress.
* @param lineStride Byte step between the same sample in different rows.
* @param colOffset Bit offset within first data[rowOffset].
* @param width Number of bits in the row.
* @param height Number of rows in the buffer.
* @param compData The compressed data.
*
* @return The number of bytes saved in the compressed data array.
*/
synchronized int encodeT4(boolean is1DMode,
boolean isEOLAligned,
byte[] data,
int lineStride,
int colOffset,
int width,
int height,
byte[] compData)
{
//
// ao, a1, a2 are bit indices in the current line
// b1 and b2 are bit indices in the reference line (line above)
// color is the current color (WHITE or BLACK)
//
byte[] refData = data;
int lineAddr = 0;
int outIndex = 0;
initBitBuf();
int KParameter = 2;
for(int numRows = 0; numRows < height; numRows++) {
if(is1DMode || (numRows % KParameter) == 0) { // 1D encoding
// Write EOL+1
outIndex += addEOL(is1DMode, isEOLAligned, true,
compData, outIndex);
// Encode row
outIndex += encode1D(data, lineAddr, colOffset, width,
compData, outIndex);
} else { // 2D encoding.
// Write EOL+0
outIndex += addEOL(is1DMode, isEOLAligned, false,
compData, outIndex);
// Set reference to previous line
int refAddr = lineAddr - lineStride;
// Encode row
int a0 = colOffset;
int last = a0 + width;
int testbit =
((data[lineAddr + (a0>>>3)]&0xff) >>>
(7-(a0 & 0x7))) & 0x1;
int a1 = testbit != 0 ?
a0 : nextState(data, lineAddr, a0, last);
testbit = ((refData[refAddr + (a0>>>3)]&0xff) >>>
(7-(a0 & 0x7))) & 0x1;
int b1 = testbit != 0 ?
a0 : nextState(refData, refAddr, a0, last);
// The current color is set to WHITE at line start
int color = WHITE;
while(true) {
int b2 = nextState(refData, refAddr, b1, last);
if(b2 < a1) { // pass mode
outIndex += add2DBits(compData, outIndex, pass, 0);
a0 = b2;
} else {
int tmp = b1 - a1 + 3;
if((tmp <= 6) && (tmp >= 0)) { // vertical mode
outIndex +=
add2DBits(compData, outIndex, vert, tmp);
a0 = a1;
} else { // horizontal mode
int a2 = nextState(data, lineAddr, a1, last);
outIndex +=
add2DBits(compData, outIndex, horz, 0);
outIndex +=
add1DBits(compData, outIndex, a1-a0, color);
outIndex +=
add1DBits(compData, outIndex, a2-a1, color^1);
a0 = a2;
}
}
if(a0 >= last) {
break;
}
color = ((data[lineAddr + (a0>>>3)]&0xff) >>>
(7-(a0 & 0x7))) & 0x1;
a1 = nextState(data, lineAddr, a0, last);
b1 = nextState(refData, refAddr, a0, last);
testbit = ((refData[refAddr + (b1>>>3)]&0xff) >>>
(7-(b1 & 0x7))) & 0x1;
if(testbit == color) {
b1 = nextState(refData, refAddr, b1, last);
}
}
}
// Skip to next line.
lineAddr += lineStride;
}
for(int i = 0; i < 6; i++) {
outIndex += addEOL(is1DMode, isEOLAligned, true,
compData, outIndex);
}
//
// flush all pending bits
//
while(ndex > 0) {
compData[outIndex++] = (byte)(bits >>> 24);
bits <<= 8;
ndex -= 8;
}
// Flip the bytes if inverse fill was requested.
if(inverseFill) {
for(int i = 0; i < outIndex; i++) {
compData[i] = TIFFFaxDecoder.flipTable[compData[i]&0xff];
}
}
return outIndex;
}
/**
* Encode a buffer of data using CCITT T.6 Compression also known as
* Group 4 facsimile compression.
*
* @param data The row of data to compress.
* @param lineStride Byte step between the same sample in different rows.
* @param colOffset Bit offset within first data[rowOffset].
* @param width Number of bits in the row.
* @param height Number of rows in the buffer.
* @param compData The compressed data.
*
* @return The number of bytes saved in the compressed data array.
*/
public synchronized int encodeT6(byte[] data,
int lineStride,
int colOffset,
int width,
int height,
byte[] compData)
{
//
// ao, a1, a2 are bit indices in the current line
// b1 and b2 are bit indices in the reference line (line above)
// color is the current color (WHITE or BLACK)
//
byte[] refData = null;
int refAddr = 0;
int lineAddr = 0;
int outIndex = 0;
initBitBuf();
//
// Iterate over all lines
//
while(height-- != 0) {
int a0 = colOffset;
int last = a0 + width;
int testbit =
((data[lineAddr + (a0>>>3)]&0xff) >>>
(7-(a0 & 0x7))) & 0x1;
int a1 = testbit != 0 ?
a0 : nextState(data, lineAddr, a0, last);
testbit = refData == null ?
0: ((refData[refAddr + (a0>>>3)]&0xff) >>>
(7-(a0 & 0x7))) & 0x1;
int b1 = testbit != 0 ?
a0 : nextState(refData, refAddr, a0, last);
//
// The current color is set to WHITE at line start
//
int color = WHITE;
while(true) {
int b2 = nextState(refData, refAddr, b1, last);
if(b2 < a1) { // pass mode
outIndex += add2DBits(compData, outIndex, pass, 0);
a0 = b2;
} else {
int tmp = b1 - a1 + 3;
if((tmp <= 6) && (tmp >= 0)) { // vertical mode
outIndex += add2DBits(compData, outIndex, vert, tmp);
a0 = a1;
} else { // horizontal mode
int a2 = nextState(data, lineAddr, a1, last);
outIndex += add2DBits(compData, outIndex, horz, 0);
outIndex += add1DBits(compData, outIndex, a1-a0, color);
outIndex += add1DBits(compData, outIndex, a2-a1, color^1);
a0 = a2;
}
}
if(a0 >= last) {
break;
}
color = ((data[lineAddr + (a0>>>3)]&0xff) >>>
(7-(a0 & 0x7))) & 0x1;
a1 = nextState(data, lineAddr, a0, last);
b1 = nextState(refData, refAddr, a0, last);
testbit = refData == null ?
0: ((refData[refAddr + (b1>>>3)]&0xff) >>>
(7-(b1 & 0x7))) & 0x1;
if(testbit == color) {
b1 = nextState(refData, refAddr, b1, last);
}
}
refData = data;
refAddr = lineAddr;
lineAddr += lineStride;
} // End while(height--)
//
// append eofb
//
outIndex += addEOFB(compData, outIndex);
// Flip the bytes if inverse fill was requested.
if(inverseFill) {
for(int i = 0; i < outIndex; i++) {
compData[i] = TIFFFaxDecoder.flipTable[compData[i]&0xff];
}
}
return outIndex;
}
}