Attachment 93710 Details for Bug 57382 – Patch for tif lzw decompression

Some Eclipse Foundation services are deprecated, or will be soon. Please ensure you've read this important communication.

[patch] Patch for tif lzw decompression

patch-lzw.txt (text/plain), 10.86 KB, created by Michael Baumgärtner

on 2008-03-26 18:15:10 EDT

(hide)

Description:

Filename:

MIME Type:

Creator: Michael Baumgärtner

Created: 2008-03-26 18:15:10 EDT

Size: 10.86 KB

patch

obsolete

>Index: Eclipse SWT/common/org/eclipse/swt/internal/image/TIFFDirectory.java
>===================================================================
>RCS file: /cvsroot/eclipse/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/internal/image/TIFFDirectory.java,v
>retrieving revision 1.5
>diff -u -r1.5 TIFFDirectory.java
>--- Eclipse SWT/common/org/eclipse/swt/internal/image/TIFFDirectory.java	9 May 2006 19:47:06 -0000	1.5
>+++ Eclipse SWT/common/org/eclipse/swt/internal/image/TIFFDirectory.java	26 Mar 2008 22:09:03 -0000
>@@ -34,6 +34,10 @@
> 	int[] stripByteCounts;
> 	int t4Options;
> 	int colorMapOffset;
>+    int predictor = 1;
>+    
>+    /* LZW fields */
>+    TIFFLZWDecoder lzwdecoder;
> 	
> 	/* Encoder fields */
> 	ImageData image;
>@@ -55,7 +59,8 @@
> 	static final short TAG_T4Options = 292;
> 	static final short TAG_ResolutionUnit = 296;
> 	static final short TAG_ColorMap = 320;
>-	
>+    static final short TAG_Predictor = 317;
>+
> 	static final int TYPE_BYTE = 1;
> 	static final int TYPE_ASCII = 2;
> 	static final int TYPE_SHORT = 3;
>@@ -63,9 +68,15 @@
> 	static final int TYPE_RATIONAL = 5;
> 	
> 	/* Different compression schemes */
>-	static final int COMPRESSION_NONE = 1;
>-	static final int COMPRESSION_CCITT_3_1 = 2;
>-	static final int COMPRESSION_PACKBITS = 32773;
>+    static final int COMPRESSION_NONE = 1;
>+    static final int COMPRESSION_CCITT_3_1 = 2;
>+    static final int COMPRESSION_CCITT_3_2 = 3;
>+    static final int COMPRESSION_CCITT_4_2 = 4;
>+    static final int COMPRESSION_LZW = 5;
>+    static final int COMPRESSION_JPEG_OLD = 6;
>+    static final int COMPRESSION_JPEG_TTN2 = 7;
>+    static final int COMPRESSION_PACKBITS = 32773;
>+    static final int COMPRESSION_DEFLATE = 32946;
> 	
> 	static final int IFD_ENTRY_SIZE = 12;
> 	
>@@ -149,7 +160,7 @@
> 			destIndex += data.length;
> 		} else if (compression == COMPRESSION_PACKBITS) {
> 			destIndex += decodePackBits(data, imageData, destIndex);
>-		} else if (compression == COMPRESSION_CCITT_3_1 || compression == 3) {
>+		} else if (compression == COMPRESSION_CCITT_3_1 || compression == COMPRESSION_CCITT_3_2) {
> 			TIFFModifiedHuffmanCodec codec = new TIFFModifiedHuffmanCodec();
> 			int nRows = rowsPerStrip;
> 			if (i == length -1) {
>@@ -158,6 +169,9 @@
> 			}
> 			destIndex += codec.decode(data, imageData, destIndex, imageWidth, nRows);
> 		}
>+        else if(compression == COMPRESSION_LZW){
>+            destIndex = lzwdecoder.decode(data, imageData, destIndex, rowsPerStrip);
>+        }
> 		if (loader.hasListeners()) {
> 			loader.notifyListeners(new ImageLoaderEvent(loader, image, i, i == length - 1));
> 		}
>@@ -370,8 +384,25 @@
> 				colorMapOffset = getEntryValue(TYPE_LONG, buffer, offset);
> 				break;
> 			}
>-		}
>-	}
>+            case TAG_Predictor:{
>+                // Option for lzw compression
>+                predictor = getEntryValue(type, buffer, offset); 
>+                if (predictor != 1 && predictor != 2) {
>+                    SWT.error(SWT.ERROR_UNSUPPORTED_FORMAT);
>+                    //throw new RuntimeException("TIFFImage8");
>+                }
>+
>+                if (predictor == 2 && bitsPerSample[0] != 8) {
>+                    SWT.error(SWT.ERROR_UNSUPPORTED_FORMAT);
>+                    //throw new RuntimeException(sampleSize + "TIFFImage9");
>+                }
>+                break;
>+            }
>+		}
>+	}
>+    if(compression == COMPRESSION_LZW){
>+        lzwdecoder = new TIFFLZWDecoder(imageWidth, predictor, samplesPerPixel);
>+    }
> }
> 
> public ImageData read() throws IOException {
>Index: Eclipse SWT/common/org/eclipse/swt/internal/image/TIFFLZWDecoder.java
>===================================================================
>RCS file: Eclipse SWT/common/org/eclipse/swt/internal/image/TIFFLZWDecoder.java
>diff -N Eclipse SWT/common/org/eclipse/swt/internal/image/TIFFLZWDecoder.java
>--- /dev/null	1 Jan 1970 00:00:00 -0000
>+++ Eclipse SWT/common/org/eclipse/swt/internal/image/TIFFLZWDecoder.java	1 Jan 1970 00:00:00 -0000
>@@ -0,0 +1,243 @@
>+package org.eclipse.swt.internal.image;
>+
>+/*
>+
>+   Licensed to the Apache Software Foundation (ASF) under one or more
>+   contributor license agreements.  See the NOTICE file distributed with
>+   this work for additional information regarding copyright ownership.
>+   The ASF licenses this file to You 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.
>+
>+*/
>+
>+/**
>+ * A class for performing LZW decoding.
>+ *
>+ * @version $Id$
>+ */
>+public class TIFFLZWDecoder {
>+
>+    byte[][] stringTable;
>+    byte[] data = null;
>+    byte[] uncompData;
>+    int tableIndex, bitsToGet = 9;
>+    int bytePointer, bitPointer;
>+    int dstIndex;
>+    int w, h;
>+    int predictor, samplesPerPixel;
>+    int nextData = 0;
>+    int nextBits = 0;
>+
>+    int[] andTable = {
>+        511,
>+        1023,
>+        2047,
>+        4095
>+    };
>+
>+    public TIFFLZWDecoder(int w, int predictor, int samplesPerPixel) {
>+        this.w = w;
>+        this.predictor = predictor;
>+        this.samplesPerPixel = samplesPerPixel;
>+    }
>+
>+    /**
>+     * Method to decode LZW compressed data.
>+     *
>+     * @param data            The compressed data.
>+     * @param uncompData      Array to return the uncompressed data in.
>+     * @param h               The number of rows the compressed data contains.
>+     */
>+    public int decode(byte[] data, byte[] uncompData, int destIndex, int h) {
>+
>+        if(data[0] == (byte)0x00 && data[1] == (byte)0x01) {
>+            throw new UnsupportedOperationException("TIFFLZWDecoder0");
>+        }
>+
>+        initializeStringTable();
>+
>+        this.data = data;
>+        this.h = h;
>+        this.uncompData = uncompData;
>+
>+        // Initialize pointers
>+        bytePointer = 0;
>+        bitPointer = 0;
>+        dstIndex = destIndex;
>+
>+
>+        nextData = 0;
>+        nextBits = 0;
>+
>+        int code, oldCode = 0;
>+        byte[] string;
>+
>+        while ( ((code = getNextCode()) != 257) &&
>+                dstIndex != uncompData.length) {
>+
>+            if (code == 256) {
>+
>+                initializeStringTable();
>+                code = getNextCode();
>+
>+                if (code == 257) {
>+                    break;
>+                }
>+
>+                writeString(stringTable[code]);
>+                oldCode = code;
>+
>+            } else {
>+
>+                if (code < tableIndex) {
>+
>+                    string = stringTable[code];
>+
>+                    writeString(string);
>+                    addStringToTable(stringTable[oldCode], string[0]);
>+                    oldCode = code;
>+
>+                } else {
>+
>+                    string = stringTable[oldCode];
>+                    string = composeString(string, string[0]);
>+                    writeString(string);
>+                    addStringToTable(string);
>+                    oldCode = code;
>+                }
>+
>+            }
>+
>+        }
>+
>+        // Horizontal Differencing Predictor
>+        if (predictor == 2) {
>+
>+            int count;
>+            for (int j = 0; j < h; j++) {
>+
>+                count = samplesPerPixel * (j * w + 1)+ destIndex;
>+
>+                for (int i = samplesPerPixel; i < w * samplesPerPixel; i++) {
>+
>+                    uncompData[count] += uncompData[count - samplesPerPixel];
>+                    count++;
>+                }
>+            }
>+        }
>+
>+        return dstIndex;
>+    }
>+
>+
>+    /**
>+     * Initialize the string table.
>+     */
>+    public void initializeStringTable() {
>+
>+        stringTable = new byte[4096][];
>+
>+        for (int i=0; i<256; i++) {
>+            stringTable[i] = new byte[1];
>+            stringTable[i][0] = (byte)i;
>+        }
>+
>+        tableIndex = 258;
>+        bitsToGet = 9;
>+    }
>+
>+    /**
>+     * Write out the string just uncompressed.
>+     */
>+    public void writeString(byte[] string) {
>+
>+        for (int i=0; i<string.length; i++) {
>+            uncompData[dstIndex++] = string[i];
>+        }
>+    }
>+
>+    /**
>+     * Add a new string to the string table.
>+     */
>+    public void addStringToTable(byte[] oldString, byte newString) {
>+        int length = oldString.length;
>+        byte[] string = new byte[length + 1];
>+        System.arraycopy(oldString, 0, string, 0, length);
>+        string[length] = newString;
>+
>+        // Add this new String to the table
>+        stringTable[tableIndex++] = string;
>+
>+        if (tableIndex == 511) {
>+            bitsToGet = 10;
>+        } else if (tableIndex == 1023) {
>+            bitsToGet = 11;
>+        } else if (tableIndex == 2047) {
>+            bitsToGet = 12;
>+        }
>+    }
>+
>+    /**
>+     * Add a new string to the string table.
>+     */
>+    public void addStringToTable(byte[] string) {
>+
>+        // Add this new String to the table
>+        stringTable[tableIndex++] = string;
>+
>+        if (tableIndex == 511) {
>+            bitsToGet = 10;
>+        } else if (tableIndex == 1023) {
>+            bitsToGet = 11;
>+        } else if (tableIndex == 2047) {
>+            bitsToGet = 12;
>+        }
>+    }
>+
>+    /**
>+     * Append <code>newString</code> to the end of <code>oldString</code>.
>+     */
>+    public byte[] composeString(byte[] oldString, byte newString) {
>+        int length = oldString.length;
>+        byte[] string = new byte[length + 1];
>+        System.arraycopy(oldString, 0, string, 0, length);
>+        string[length] = newString;
>+
>+        return string;
>+    }
>+
>+    // Returns the next 9, 10, 11 or 12 bits
>+    public int getNextCode() {
>+        // Attempt to get the next code. The exception is caught to make
>+        // this robust to cases wherein the EndOfInformation code has been
>+        // omitted from a strip. Examples of such cases have been observed
>+        // in practice.
>+        try {
>+            nextData = (nextData << 8) | (data[bytePointer++] & 0xff);
>+            nextBits += 8;
>+
>+            if (nextBits < bitsToGet) {
>+                nextData = (nextData << 8) | (data[bytePointer++] & 0xff);
>+                nextBits += 8;
>+            }
>+
>+            int code =
>+                (nextData >> (nextBits - bitsToGet)) & andTable[bitsToGet-9];
>+            nextBits -= bitsToGet;
>+
>+            return code;
>+        } catch(ArrayIndexOutOfBoundsException e) {
>+            // Strip not terminated as expected: return EndOfInformation code.
>+            return 257;
>+        }
>+    }
>+}

Actions: View | Diff

Attachments on bug 57382: 9214 | 10355 | 30351 | 93710 | 164213