| /* |
| * Copyright (c) 2005, 2016, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| package com.sun.imageio.plugins.tiff; |
| |
| import java.io.EOFException; |
| import java.io.IOException; |
| |
| public class TIFFNullDecompressor extends TIFFDecompressor { |
| |
| /** |
| * Whether to read the active source region only. |
| */ |
| private boolean isReadActiveOnly = false; |
| |
| /** The original value of {@code srcMinX}. */ |
| private int originalSrcMinX; |
| |
| /** The original value of {@code srcMinY}. */ |
| private int originalSrcMinY; |
| |
| /** The original value of {@code srcWidth}. */ |
| private int originalSrcWidth; |
| |
| /** The original value of {@code srcHeight}. */ |
| private int originalSrcHeight; |
| |
| public TIFFNullDecompressor() {} |
| |
| // |
| // This approach to reading the active region is a not the best |
| // as the original values of the entire source region are stored, |
| // overwritten, and then restored. It would probably be better to |
| // revise TIFFDecompressor such that this were not necessary, i.e., |
| // change beginDecoding() and decode() to use the active region values |
| // when random access is easy and the entire region values otherwise. |
| // |
| public void beginDecoding() { |
| // Determine number of bits per pixel. |
| int bitsPerPixel = 0; |
| for(int i = 0; i < bitsPerSample.length; i++) { |
| bitsPerPixel += bitsPerSample[i]; |
| } |
| |
| // Can read active region only if row starts on a byte boundary. |
| if((activeSrcMinX != srcMinX || activeSrcMinY != srcMinY || |
| activeSrcWidth != srcWidth || activeSrcHeight != srcHeight) && |
| ((activeSrcMinX - srcMinX)*bitsPerPixel) % 8 == 0) { |
| // Set flag. |
| isReadActiveOnly = true; |
| |
| // Cache original region. |
| originalSrcMinX = srcMinX; |
| originalSrcMinY = srcMinY; |
| originalSrcWidth = srcWidth; |
| originalSrcHeight = srcHeight; |
| |
| // Replace region with active region. |
| srcMinX = activeSrcMinX; |
| srcMinY = activeSrcMinY; |
| srcWidth = activeSrcWidth; |
| srcHeight = activeSrcHeight; |
| } else { |
| // Clear flag. |
| isReadActiveOnly = false; |
| } |
| |
| super.beginDecoding(); |
| } |
| |
| public void decode() throws IOException { |
| super.decode(); |
| |
| // Reset state. |
| if(isReadActiveOnly) { |
| // Restore original source region values. |
| srcMinX = originalSrcMinX; |
| srcMinY = originalSrcMinY; |
| srcWidth = originalSrcWidth; |
| srcHeight = originalSrcHeight; |
| |
| // Unset flag. |
| isReadActiveOnly = false; |
| } |
| } |
| |
| public void decodeRaw(byte[] b, |
| int dstOffset, |
| int bitsPerPixel, |
| int scanlineStride) throws IOException { |
| if(isReadActiveOnly) { |
| // Read the active source region only. |
| |
| int activeBytesPerRow = (activeSrcWidth*bitsPerPixel + 7)/8; |
| int totalBytesPerRow = (originalSrcWidth*bitsPerPixel + 7)/8; |
| int bytesToSkipPerRow = totalBytesPerRow - activeBytesPerRow; |
| |
| // |
| // Seek to the start of the active region: |
| // |
| // active offset = original offset + |
| // number of bytes to start of first active row + |
| // number of bytes to first active pixel within row |
| // |
| // Since the condition for reading from the active region only is |
| // |
| // ((activeSrcMinX - srcMinX)*bitsPerPixel) % 8 == 0 |
| // |
| // the bit offset to the first active pixel within the first |
| // active row is a multiple of 8. |
| // |
| stream.seek(offset + |
| (activeSrcMinY - originalSrcMinY)*totalBytesPerRow + |
| ((activeSrcMinX - originalSrcMinX)*bitsPerPixel)/8); |
| |
| int lastRow = activeSrcHeight - 1; |
| for (int y = 0; y < activeSrcHeight; y++) { |
| int bytesRead = stream.read(b, dstOffset, activeBytesPerRow); |
| if (bytesRead < 0) { |
| throw new EOFException(); |
| } else if (bytesRead != activeBytesPerRow) { |
| break; |
| } |
| dstOffset += scanlineStride; |
| |
| // Skip unneeded bytes (row suffix + row prefix). |
| if(y != lastRow) { |
| stream.skipBytes(bytesToSkipPerRow); |
| } |
| } |
| } else { |
| // Read the entire source region. |
| stream.seek(offset); |
| int bytesPerRow = (srcWidth*bitsPerPixel + 7)/8; |
| if(bytesPerRow == scanlineStride) { |
| if (stream.read(b, dstOffset, bytesPerRow*srcHeight) < 0) { |
| throw new EOFException(); |
| } |
| } else { |
| for (int y = 0; y < srcHeight; y++) { |
| int bytesRead = stream.read(b, dstOffset, bytesPerRow); |
| if (bytesRead < 0) { |
| throw new EOFException(); |
| } else if (bytesRead != bytesPerRow) { |
| break; |
| } |
| dstOffset += scanlineStride; |
| } |
| } |
| } |
| } |
| } |