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author | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
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committer | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
commit | 554fd8c5195424bdbcabf5de30fdc183aba391bd (patch) | |
tree | 976dc5ab7fddf506dadce60ae936f43f58787092 /libjava/classpath/gnu/javax/imageio/jpeg/JPEGDecoder.java | |
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Diffstat (limited to 'libjava/classpath/gnu/javax/imageio/jpeg/JPEGDecoder.java')
-rw-r--r-- | libjava/classpath/gnu/javax/imageio/jpeg/JPEGDecoder.java | 625 |
1 files changed, 625 insertions, 0 deletions
diff --git a/libjava/classpath/gnu/javax/imageio/jpeg/JPEGDecoder.java b/libjava/classpath/gnu/javax/imageio/jpeg/JPEGDecoder.java new file mode 100644 index 000000000..11d547f4d --- /dev/null +++ b/libjava/classpath/gnu/javax/imageio/jpeg/JPEGDecoder.java @@ -0,0 +1,625 @@ +/* JPEGDecoder.java -- + Copyright (C) 2006 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath 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 for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + +package gnu.javax.imageio.jpeg; + +import java.io.IOException; +import java.nio.ByteOrder; + +import javax.imageio.plugins.jpeg.JPEGHuffmanTable; +import javax.imageio.plugins.jpeg.JPEGQTable; +import javax.imageio.stream.ImageInputStream; + +import java.util.ArrayList; +import java.util.Hashtable; +import java.awt.Point; +import java.awt.Transparency; +import java.awt.color.ColorSpace; +import java.awt.image.BufferedImage; +import java.awt.image.ComponentColorModel; +import java.awt.image.DataBuffer; +import java.awt.image.Raster; +import java.awt.image.WritableRaster; + +public class JPEGDecoder +{ + byte majorVersion; + byte minorVersion; + byte units; + short Xdensity; + short Ydensity; + byte Xthumbnail; + byte Ythumbnail; + byte[] thumbnail; + BufferedImage image; + int width; + int height; + + byte marker; + + /** + * This decoder expects JFIF 1.02 encoding. + */ + public static final byte MAJOR_VERSION = (byte) 1; + public static final byte MINOR_VERSION = (byte) 2; + + /** + * The length of the JFIF field not including thumbnail data. + */ + public static final short JFIF_FIXED_LENGTH = 16; + + /** + * The length of the JFIF extension field not including extension + * data. + */ + public static final short JFXX_FIXED_LENGTH = 8; + + private JPEGImageInputStream jpegStream; + + ArrayList jpegFrames = new ArrayList(); + + JPEGHuffmanTable[] dcTables = new JPEGHuffmanTable[4]; + JPEGHuffmanTable[] acTables = new JPEGHuffmanTable[4]; + JPEGQTable[] qTables = new JPEGQTable[4]; + + public int getHeight() + { + return height; + } + + public int getWidth() + { + return width; + } + public JPEGDecoder(ImageInputStream in) + throws IOException, JPEGException + { + jpegStream = new JPEGImageInputStream(in); + jpegStream.setByteOrder(ByteOrder.LITTLE_ENDIAN); + + if (jpegStream.findNextMarker() != JPEGMarker.SOI) + throw new JPEGException("Failed to find SOI marker."); + + if (jpegStream.findNextMarker() != JPEGMarker.APP0) + throw new JPEGException("Failed to find APP0 marker."); + + int length = jpegStream.readShort(); + if (!(length >= JFIF_FIXED_LENGTH)) + throw new JPEGException("Failed to find JFIF field."); + + byte[] identifier = new byte[5]; + jpegStream.read(identifier); + if (identifier[0] != JPEGMarker.JFIF_J + || identifier[1] != JPEGMarker.JFIF_F + || identifier[2] != JPEGMarker.JFIF_I + || identifier[3] != JPEGMarker.JFIF_F + || identifier[4] != JPEGMarker.X00) + throw new JPEGException("Failed to read JFIF identifier."); + + majorVersion = jpegStream.readByte(); + minorVersion = jpegStream.readByte(); + if (majorVersion != MAJOR_VERSION + || (majorVersion == MAJOR_VERSION + && minorVersion < MINOR_VERSION)) + throw new JPEGException("Unsupported JFIF version."); + + units = jpegStream.readByte(); + if (units > (byte) 2) + throw new JPEGException("Units field is out of range."); + + Xdensity = jpegStream.readShort(); + Ydensity = jpegStream.readShort(); + Xthumbnail = jpegStream.readByte(); + Ythumbnail = jpegStream.readByte(); + + // 3 * for RGB data + int thumbnailLength = 3 * Xthumbnail * Ythumbnail; + if (length > JFIF_FIXED_LENGTH + && thumbnailLength != length - JFIF_FIXED_LENGTH) + throw new JPEGException("Invalid length, Xthumbnail" + + " or Ythumbnail field."); + + if (thumbnailLength > 0) + { + thumbnail = new byte[thumbnailLength]; + if (jpegStream.read(thumbnail) != thumbnailLength) + throw new IOException("Failed to read thumbnail."); + } + } + + public void decode() + throws IOException + { + System.out.println ("DECODE!!!"); + // The frames in this jpeg are loaded into a list. There is + // usually just one frame except in heirarchial progression where + // there are multiple frames. + JPEGFrame frame = null; + + // The restart interval defines how many MCU's we should have + // between the 8-modulo restart marker. The restart markers allow + // us to tell whether or not our decoding process is working + // correctly, also if there is corruption in the image we can + // recover with these restart intervals. (See RSTm DRI). + int resetInterval = 0; + + // The JPEGDecoder constructor parses the JFIF field. At this + // point jpegStream points to the first byte after the JFIF field. + + // Find the first marker after the JFIF field. + byte marker = jpegStream.findNextMarker(); + + // Check for a JFIF extension field directly following the JFIF + // header and advance the current marker to the next marker in the + // stream, if necessary. + decodeJFIFExtension(); + + // Loop through until there are no more markers to read in, at + // that point everything is loaded into the jpegFrames array and + // can be processed. + while (true) + { + switch (marker) + { + // APPn Application Reserved Information - Just throw this + // information away because we wont be using it. + case JPEGMarker.APP0: + case JPEGMarker.APP1: + case JPEGMarker.APP2: + case JPEGMarker.APP3: + case JPEGMarker.APP4: + case JPEGMarker.APP5: + case JPEGMarker.APP6: + case JPEGMarker.APP7: + case JPEGMarker.APP8: + case JPEGMarker.APP9: + case JPEGMarker.APP10: + case JPEGMarker.APP11: + case JPEGMarker.APP12: + case JPEGMarker.APP13: + case JPEGMarker.APP14: + case JPEGMarker.APP15: + jpegStream.skipBytes(jpegStream.readShort() - 2); + break; + + case JPEGMarker.SOF0: + // SOFn Start of Frame Marker, Baseline DCT - This is the start + // of the frame header that defines certain variables that will + // be carried out through the rest of the encoding. Multiple + // frames are used in a heirarchiel system, however most JPEG's + // only contain a single frame. + jpegFrames.add(new JPEGFrame()); + frame = (JPEGFrame) jpegFrames.get(jpegFrames.size() - 1); + // Skip the frame length. + jpegStream.readShort(); + // Bits percision, either 8 or 12. + frame.setPrecision(jpegStream.readByte()); + // Scan lines = to the height of the frame. + frame.setScanLines(jpegStream.readShort()); + // Scan samples per line = to the width of the frame. + frame.setSamplesPerLine(jpegStream.readShort()); + // Number of Color Components (or channels). + frame.setComponentCount(jpegStream.readByte()); + + // Set the color mode for this frame, so far only 2 color + // modes are supported. + if (frame.getComponentCount() == 1) + frame.setColorMode(JPEGFrame.JPEG_COLOR_GRAY); + else + frame.setColorMode(JPEGFrame.JPEG_COLOR_YCbCr); + // Add all of the necessary components to the frame. + for (int i = 0; i < frame.getComponentCount(); i++) + frame.addComponent(jpegStream.readByte(), jpegStream.readByte(), + jpegStream.readByte()); + break; + + case JPEGMarker.SOF2: + jpegFrames.add(new JPEGFrame()); + frame = (JPEGFrame) jpegFrames.get(jpegFrames.size() - 1); + // Skip the frame length. + jpegStream.readShort(); + // Bits percision, either 8 or 12. + frame.setPrecision(jpegStream.readByte()); + // Scan lines = to the height of the frame. + frame.setScanLines(jpegStream.readShort()); + // Scan samples per line = to the width of the frame. + frame.setSamplesPerLine(jpegStream.readShort()); + // Number of Color Components (or channels). + frame.setComponentCount(jpegStream.readByte()); + + // Set the color mode for this frame, so far only 2 color + // modes are supported. + if (frame.getComponentCount() == 1) + frame.setColorMode(JPEGFrame.JPEG_COLOR_GRAY); + else + frame.setColorMode(JPEGFrame.JPEG_COLOR_YCbCr); + + // Add all of the necessary components to the frame. + for (int i = 0; i < frame.getComponentCount(); i++) + frame.addComponent(jpegStream.readByte(), jpegStream.readByte(), + jpegStream.readByte()); + break; + + case JPEGMarker.DHT: + // DHT non-SOF Marker - Huffman Table is required for decoding + // the JPEG stream, when we receive a marker we load in first + // the table length (16 bits), the table class (4 bits), table + // identifier (4 bits), then we load in 16 bytes and each byte + // represents the count of bytes to load in for each of the 16 + // bytes. We load this into an array to use later and move on 4 + // huffman tables can only be used in an image. + int huffmanLength = (jpegStream.readShort() - 2); + + // Keep looping until we are out of length. + int index = huffmanLength; + + // Multiple tables may be defined within a DHT marker. This + // will keep reading until there are no tables left, most + // of the time there are just one tables. + while (index > 0) + { + // Read the identifier information and class + // information about the Huffman table, then read the + // 16 byte codelength in and read in the Huffman values + // and put it into table info. + byte huffmanInfo = jpegStream.readByte(); + byte tableClass = (byte) (huffmanInfo >> 4); + byte huffmanIndex = (byte) (huffmanInfo & 0x0f); + short[] codeLength = new short[16]; + jpegStream.readFully(codeLength, 0, codeLength.length); + int huffmanValueLen = 0; + for (int i = 0; i < 16; i++) + huffmanValueLen += codeLength[i]; + index -= (huffmanValueLen + 17); + short[] huffmanVal = new short[huffmanValueLen]; + for (int i = 0; i < huffmanVal.length; i++) + huffmanVal[i] = jpegStream.readByte(); + // Assign DC Huffman Table. + if (tableClass == HuffmanTable.JPEG_DC_TABLE) + dcTables[(int) huffmanIndex] = new JPEGHuffmanTable(codeLength, + huffmanVal); + // Assign AC Huffman Table. + else if (tableClass == HuffmanTable.JPEG_AC_TABLE) + acTables[(int) huffmanIndex] = new JPEGHuffmanTable(codeLength, + huffmanVal); + } + break; + case JPEGMarker.DQT: + // DQT non-SOF Marker - This defines the quantization + // coeffecients, this allows us to figure out the quality of + // compression and unencode the data. The data is loaded and + // then stored in to an array. + short quantizationLength = (short) (jpegStream.readShort() - 2); + for (int j = 0; j < quantizationLength / 65; j++) + { + byte quantSpecs = jpegStream.readByte(); + int[] quantData = new int[64]; + if ((byte) (quantSpecs >> 4) == 0) + // Precision 8 bit. + { + for (int i = 0; i < 64; i++) + quantData[i] = jpegStream.readByte(); + + } + else if ((byte) (quantSpecs >> 4) == 1) + // Precision 16 bit. + { + for (int i = 0; i < 64; i++) + quantData[i] = jpegStream.readShort(); + } + qTables[(int) (quantSpecs & 0x0f)] = new JPEGQTable (quantData); + } + break; + case JPEGMarker.SOS: + // SOS non-SOF Marker - Start Of Scan Marker, this is where the + // actual data is stored in a interlaced or non-interlaced with + // from 1-4 components of color data, if three components most + // likely a YCrCb model, this is a fairly complex process. + + // Read in the scan length. + jpegStream.readShort(); + // Number of components in the scan. + byte numberOfComponents = jpegStream.readByte(); + byte[] componentSelector = new byte[numberOfComponents]; + for (int i = 0; i < numberOfComponents; i++) + { + // Component ID, packed byte containing the Id for the + // AC table and DC table. + byte componentID = jpegStream.readByte(); + byte tableInfo = jpegStream.readByte(); + frame.setHuffmanTables(componentID, + acTables[(byte) (tableInfo >> 4)], + dcTables[(byte) (tableInfo & 0x0f)]); + componentSelector[i] = componentID; + } + byte startSpectralSelection = jpegStream.readByte(); + byte endSpectralSelection = jpegStream.readByte(); + byte successiveApproximation = jpegStream.readByte(); + + int mcuIndex = 0; + int mcuTotalIndex = 0; + // This loops through until a MarkerTagFound exception is + // found, if the marker tag is a RST (Restart Marker) it + // simply skips it and moves on this system does not handle + // corrupt data streams very well, it could be improved by + // handling misplaced restart markers. + while (true) + { + try + { + // Loop though capturing MCU, instruct each + // component to read in its necessary count, for + // scaling factors the components automatically + // read in how much they need + for (int compIndex = 0; compIndex < numberOfComponents; compIndex++) + { + JPEGComponent comp = frame.components.getComponentByID(componentSelector[compIndex]); + comp.readComponentMCU(jpegStream); + } + mcuIndex++; + mcuTotalIndex++; + } + // We've found a marker, see if the marker is a restart + // marker or just the next marker in the stream. If + // it's the next marker in the stream break out of the + // while loop, if it's just a restart marker skip it + catch (JPEGMarkerFoundException bse) + { + // Handle JPEG Restart Markers, this is where the + // count of MCU's per interval is compared with + // the count actually obtained, if it's short then + // pad on some MCU's ONLY for components that are + // greater than one. Also restart the DC prediction + // to zero. + if (marker == JPEGMarker.RST0 + || marker == JPEGMarker.RST1 + || marker == JPEGMarker.RST2 + || marker == JPEGMarker.RST3 + || marker == JPEGMarker.RST4 + || marker == JPEGMarker.RST5 + || marker == JPEGMarker.RST6 + || marker == JPEGMarker.RST7) + { + for (int compIndex = 0; compIndex < numberOfComponents; compIndex++) + { + JPEGComponent comp = frame.components.getComponentByID(componentSelector[compIndex]); + if (compIndex > 1) + comp.padMCU(mcuTotalIndex, resetInterval - mcuIndex); + comp.resetInterval(); + } + mcuTotalIndex += (resetInterval - mcuIndex); + mcuIndex = 0; + } + else + { + // We're at the end of our scan, exit out. + break; + } + } + } + break; + case JPEGMarker.DRI: + // DRI - This defines the restart interval, if we have a + // restart interval when we reach our restart modulo calculate + // whether the count of MCU's specified in the restart + // interval have been reached, if they havent then pad with + // whatever MCU was last used, this is supposed to be a form of + // error recovery but it turns out that some JPEG encoders + // purposely cause missing MCU's on repeating MCU's to compress + // data even more (even though it adds an extra layer of + // complexity.. But since when is JPEG easy? + jpegStream.skipBytes(2); + resetInterval = jpegStream.readShort(); + break; + case JPEGMarker.COM: + // COM - This is a comment that was inserted into the JPEG, we + // simply skip over the comment because it's really of no + // importance, usually contains a verbal description of the + // application or author who created the JPEG. + jpegStream.skipBytes(jpegStream.readShort() - 2); + break; + case JPEGMarker.DNL: + // DNL - This sets the height of the image. This is the Define + // Number Lines for the image, I'm not sure exactly why we need + // this but, whatever we'll abide. + frame.setScanLines(jpegStream.readShort()); + break; + case JPEGMarker.EOI: + // EOI - End of Image, this processes the frames and turns the + // frames into a buffered image. + + if (jpegFrames.size() == 0) + { + return; + } + else if (jpegFrames.size() == 1) + { + // Only one frame, JPEG Non-Heirarchial Frame. + + DCT myDCT = new DCT(); + WritableRaster raster = + Raster.createInterleavedRaster(DataBuffer.TYPE_BYTE, + frame.width, + frame.height, + frame.getComponentCount(), + new Point(0, 0)); + + // Unencode the data. + for (int i = 0; i < frame.getComponentCount(); i++) + { + JPEGComponent comp = frame.components.get(i); + comp.setQuantizationTable(qTables[comp.quant_id].getTable()); + comp.quantitizeData(); + comp.idctData(myDCT); + } + // Scale the image and write the data to the raster. + for (int i = 0; i < frame.getComponentCount(); i++) + { + JPEGComponent comp = frame.components.get(i); + comp.scaleByFactors(); + comp.writeData(raster, i); + // Ensure garbage collection. + comp = null; + } + // Grayscale Color Image (1 Component). + if (frame.getComponentCount() == 1) + { + ColorSpace cs = ColorSpace.getInstance(ColorSpace.CS_GRAY); + ComponentColorModel ccm = + new ComponentColorModel(cs, false, false, + Transparency.OPAQUE, + DataBuffer.TYPE_BYTE); + image = new BufferedImage(ccm, raster, false, + new Hashtable()); + } + // YCbCr Color Image (3 Components). + else if (frame.getComponentCount() == 3) + { + ComponentColorModel ccm = + new ComponentColorModel(new YCbCr_ColorSpace(), false, + false, Transparency.OPAQUE, + DataBuffer.TYPE_BYTE); + image = new BufferedImage(ccm, raster, false, + new Hashtable()); + } + // Possibly CMYK or RGBA ? + else + { + throw new JPEGException("Unsupported Color Mode: 4 " + + "Component Color Mode found."); + } + height = frame.height; + width = frame.width; + } + else + { + //JPEG Heirarchial Frame (progressive or baseline). + throw new JPEGException("Unsupported Codec Type:" + + " Hierarchial JPEG"); + } + break; + case JPEGMarker.SOF1: + // ERROR - If we encounter any of the following marker codes + // error out with a codec exception, progressive, heirarchial, + // differential, arithmetic, lossless JPEG's are not supported. + // This is where enhancements can be made for future versions. + // Thankfully 99% of all JPEG's are baseline DCT. + throw new JPEGException("Unsupported Codec Type: Extended " + + "Sequential DCT JPEG's Not-Supported"); + //case JPEGMarker.SOF2: + // throw new JPEGException("Unsupported Codec Type: Progressive DCT JPEG's Not-Supported"); + case JPEGMarker.SOF3: + throw new JPEGException("Unsupported Codec Type:" + + " Lossless (sequential)"); + case JPEGMarker.SOF5: + throw new JPEGException("Unsupported Codec Type:" + + " Differential sequential DCT"); + case JPEGMarker.SOF6: + throw new JPEGException("Unsupported Codec Type:" + + " Differential progressive DCT"); + case JPEGMarker.SOF7: + throw new JPEGException("Unsupported Codec Type:" + + " Differential lossless"); + case JPEGMarker.SOF9: + case JPEGMarker.SOF10: + case JPEGMarker.SOF11: + case JPEGMarker.SOF13: + case JPEGMarker.SOF14: + case JPEGMarker.SOF15: + throw new JPEGException("Unsupported Codec Type:" + + " Arithmetic Coding Frame"); + default: + // Unknown marker found, ignore it. + } + marker = jpegStream.findNextMarker(); + } + } + + // If the current marker is APP0, tries to decode a JFIF extension + // and advances the current marker to the next marker in the stream. + private void decodeJFIFExtension() throws IOException + { + if (marker == JPEGMarker.APP0) + { + int length = jpegStream.readShort(); + + if (length >= JFXX_FIXED_LENGTH) + { + byte[] identifier = new byte[5]; + jpegStream.read(identifier); + if (identifier[0] != JPEGMarker.JFIF_J + || identifier[1] != JPEGMarker.JFIF_F + || identifier[2] != JPEGMarker.JFIF_X + || identifier[3] != JPEGMarker.JFIF_X + || identifier[4] != JPEGMarker.X00) + // Not a JFXX field. Ignore it and continue. + jpegStream.skipBytes(length - 7); + else + { + byte extension_code = jpegStream.readByte(); + + switch (extension_code) + { + case JPEGMarker.JFXX_JPEG: + // FIXME: add support for JFIF Extension: + // Thumbnail coded using JPEG. + jpegStream.skipBytes(length - 8); + case JPEGMarker.JFXX_ONE_BPP: + // FIXME: add support for JFIF Extension: + // Thumbnail stored using 1 byte/pixel. + jpegStream.skipBytes(length - 8); + case JPEGMarker.JFXX_THREE_BPP: + // FIXME: add support for JFIF Extension: + // Thumbnail stored using 3 bytes/pixel. + jpegStream.skipBytes(length - 8); + } + } + } + else + { + // Unknown APP0 marker. Ignore it and continue. + jpegStream.skipBytes(length - 2); + } + marker = jpegStream.findNextMarker(); + } + } + + public BufferedImage getImage() + { + return image; + } +} |