--- /dev/null
+/*
+ * Copyright 2002-2015 Drew Noakes
+ *
+ * More information about this project is available at:
+ *
+ * https://drewnoakes.com/code/exif/
+ * https://github.com/drewnoakes/metadata-extractor
+ */
+package tim.prune.jpeg.drew;
+
+
+import java.io.IOException;
+import java.util.HashSet;
+import java.util.Set;
+
+import tim.prune.jpeg.JpegData;
+
+/**
+ * Processes TIFF-formatted data, using an ExifTiffHandler
+ *
+ * @author Drew Noakes https://drewnoakes.com
+ */
+public class TiffProcessor
+{
+ /**
+ * Processes a TIFF data sequence.
+ *
+ * @param reader the {@link RandomAccessReader} from which the data should be read
+ * @param jpegData the data to populate
+ * @param tiffHeaderOffset the offset within <code>reader</code> at which the TIFF header starts
+ * @throws ExifException if an error occurred during the processing of TIFF data that could
+ * not be ignored or recovered from
+ * @throws IOException an error occurred while accessing the required data
+ */
+ public static void processTiff(final ByteArrayReader reader, JpegData jpegData,
+ final int tiffHeaderOffset) throws ExifException, IOException
+ {
+ // This must be either "MM" or "II".
+ short byteOrderIdentifier = reader.getInt16(tiffHeaderOffset);
+
+ if (byteOrderIdentifier == 0x4d4d) { // "MM"
+ reader.setMotorolaByteOrder(true);
+ } else if (byteOrderIdentifier == 0x4949) { // "II"
+ reader.setMotorolaByteOrder(false);
+ } else {
+ throw new ExifException("Unclear distinction between Motorola/Intel byte ordering: " + byteOrderIdentifier);
+ }
+
+
+ int firstIfdOffset = reader.getInt32(4 + tiffHeaderOffset) + tiffHeaderOffset;
+
+ // David Ekholm sent a digital camera image that has this problem
+ if (firstIfdOffset >= reader.getLength() - 1) {
+ //handler.warn("First IFD offset is beyond the end of the TIFF data segment -- trying default offset");
+ // First directory normally starts immediately after the offset bytes, so try that
+ firstIfdOffset = tiffHeaderOffset + 2 + 2 + 4;
+ }
+
+ // Make a handler object to use for the processing
+ ExifTiffHandler handler = new ExifTiffHandler(jpegData);
+
+ Set<Integer> processedIfdOffsets = new HashSet<Integer>();
+ processDirectory(handler, reader, processedIfdOffsets, firstIfdOffset, tiffHeaderOffset, 0);
+
+ handler.completed(reader, tiffHeaderOffset);
+ }
+
+ /**
+ * Processes a TIFF IFD.
+ *
+ * IFD Header:
+ * <ul>
+ * <li><b>2 bytes</b> number of tags</li>
+ * </ul>
+ * Tag structure:
+ * <ul>
+ * <li><b>2 bytes</b> tag type</li>
+ * <li><b>2 bytes</b> format code (values 1 to 12, inclusive)</li>
+ * <li><b>4 bytes</b> component count</li>
+ * <li><b>4 bytes</b> inline value, or offset pointer if too large to fit in four bytes</li>
+ * </ul>
+ *
+ * @param handler the {@link ExifTiffHandler} that will coordinate processing and accept read values
+ * @param reader the byte reader from which the data should be read
+ * @param processedIfdOffsets the set of visited IFD offsets, to avoid revisiting the same IFD in an endless loop
+ * @param ifdOffset the offset within <code>reader</code> at which the IFD data starts
+ * @param tiffHeaderOffset the offset within <code>reader</code> at which the TIFF header starts
+ * @param inDirectoryId directory id
+ * @throws IOException an error occurred while accessing the required data
+ */
+ private static void processDirectory(final ExifTiffHandler handler,
+ final ByteArrayReader reader, final Set<Integer> processedIfdOffsets,
+ final int ifdOffset, final int tiffHeaderOffset, int inDirectoryId) throws ExifException
+ {
+ // check for directories we've already visited to avoid stack overflows when recursive/cyclic directory structures exist
+ if (processedIfdOffsets.contains(Integer.valueOf(ifdOffset))) {
+ return;
+ }
+
+ // remember that we've visited this directory so that we don't visit it again later
+ processedIfdOffsets.add(ifdOffset);
+
+ if (ifdOffset >= reader.getLength() || ifdOffset < 0) {
+ //handler.error("Ignored IFD marked to start outside data segment");
+ return;
+ }
+
+ // First two bytes in the IFD are the number of tags in this directory
+ int dirTagCount = reader.getUInt16(ifdOffset);
+
+ int dirLength = (2 + (12 * dirTagCount) + 4);
+ if (dirLength + ifdOffset > reader.getLength()) {
+ //handler.error("Illegally sized IFD");
+ return;
+ }
+
+
+ // Handle each tag in this directory
+ //
+ int invalidTiffFormatCodeCount = 0;
+ for (int tagNumber = 0; tagNumber < dirTagCount; tagNumber++)
+ {
+ final int tagOffset = calculateTagOffset(ifdOffset, tagNumber);
+
+ // 2 bytes for the tag id
+ final int childTagId = reader.getUInt16(tagOffset);
+
+ // 2 bytes for the format code
+ final int formatCode = reader.getUInt16(tagOffset + 2);
+ final int componentSizeInBytes = TiffDataFormat.getComponentSize(formatCode);
+
+ if (componentSizeInBytes == 0)
+ {
+ // This error suggests that we are processing at an incorrect index and will generate
+ // rubbish until we go out of bounds (which may be a while).
+ if (++invalidTiffFormatCodeCount > 5) {
+ //handler.error("Stopping processing as too many errors seen in TIFF IFD");
+ return;
+ }
+ continue;
+ }
+
+ // 4 bytes dictate the number of components in this tag's data
+ final int componentCount = reader.getInt32(tagOffset + 4);
+ if (componentCount < 0) {
+ //handler.error("Negative TIFF tag component count");
+ continue;
+ }
+
+ final int byteCount = componentCount * componentSizeInBytes;
+
+ final int tagValueOffset;
+ if (byteCount > 4)
+ {
+ // If it's bigger than 4 bytes, the dir entry contains an offset.
+ final int offsetVal = reader.getInt32(tagOffset + 8);
+ if (offsetVal + byteCount > reader.getLength()) {
+ // Bogus pointer offset and / or byteCount value
+ //handler.error("Illegal TIFF tag pointer offset");
+ continue;
+ }
+ tagValueOffset = tiffHeaderOffset + offsetVal;
+ }
+ else {
+ // 4 bytes or less and value is in the dir entry itself.
+ tagValueOffset = tagOffset + 8;
+ }
+
+ if (tagValueOffset < 0 || tagValueOffset > reader.getLength()) {
+ //handler.error("Illegal TIFF tag pointer offset");
+ continue;
+ }
+
+ // Check that this tag isn't going to allocate outside the bounds of the data array.
+ // This addresses an uncommon OutOfMemoryError.
+ if (byteCount < 0 || tagValueOffset + byteCount > reader.getLength()) {
+ //handler.error("Illegal number of bytes for TIFF tag data: " + byteCount);
+ continue;
+ }
+
+ // Special handling for tags that point to other IFDs
+ if (byteCount == 4 && handler.isTagIfdPointer(childTagId)) {
+ final int subDirOffset = tiffHeaderOffset + reader.getInt32(tagValueOffset);
+ processDirectory(handler, reader, processedIfdOffsets, subDirOffset, tiffHeaderOffset, childTagId);
+ }
+ else if (handler.isInterestingTag(inDirectoryId, childTagId))
+ {
+ processTag(handler, childTagId, tagValueOffset, componentCount, formatCode, reader);
+ }
+ }
+
+ // at the end of each IFD is an optional link to the next IFD
+ final int finalTagOffset = calculateTagOffset(ifdOffset, dirTagCount);
+ int nextIfdOffset = reader.getInt32(finalTagOffset);
+ if (nextIfdOffset != 0)
+ {
+ nextIfdOffset += tiffHeaderOffset;
+ if (nextIfdOffset >= reader.getLength()) {
+ // Last 4 bytes of IFD reference another IFD with an address that is out of bounds
+ // Note this could have been caused by jhead 1.3 cropping too much
+ return;
+ }
+ else if (nextIfdOffset < ifdOffset) {
+ // Last 4 bytes of IFD reference another IFD with an address that is before the start of this directory
+ return;
+ }
+
+ processDirectory(handler, reader, processedIfdOffsets, nextIfdOffset, tiffHeaderOffset, inDirectoryId);
+ }
+ }
+
+
+ /**
+ * Process a single tag value
+ */
+ private static void processTag(final ExifTiffHandler handler,
+ final int tagId, final int tagValueOffset,
+ final int componentCount, final int formatCode,
+ final ByteArrayReader reader) throws ExifException
+ {
+ switch (formatCode)
+ {
+ case TiffDataFormat.CODE_STRING:
+ handler.setString(tagId, reader.getNullTerminatedString(tagValueOffset, componentCount));
+ break;
+ case TiffDataFormat.CODE_RATIONAL_S:
+ if (componentCount == 1) {
+ handler.setRational(tagId, new Rational(reader.getInt32(tagValueOffset), reader.getInt32(tagValueOffset + 4)));
+ } else if (componentCount > 1) {
+ Rational[] array = new Rational[componentCount];
+ for (int i = 0; i < componentCount; i++)
+ array[i] = new Rational(reader.getInt32(tagValueOffset + (8 * i)), reader.getInt32(tagValueOffset + 4 + (8 * i)));
+ handler.setRationalArray(tagId, array);
+ }
+ break;
+ case TiffDataFormat.CODE_RATIONAL_U:
+ if (componentCount == 1) {
+ handler.setRational(tagId, new Rational(reader.getUInt32(tagValueOffset), reader.getUInt32(tagValueOffset + 4)));
+ } else if (componentCount > 1) {
+ Rational[] array = new Rational[componentCount];
+ for (int i = 0; i < componentCount; i++)
+ array[i] = new Rational(reader.getUInt32(tagValueOffset + (8 * i)), reader.getUInt32(tagValueOffset + 4 + (8 * i)));
+ handler.setRationalArray(tagId, array);
+ }
+ break;
+ case TiffDataFormat.CODE_INT8_S:
+ if (componentCount == 1) {
+ handler.setIntegerValue(tagId, reader.getInt8(tagValueOffset));
+ }
+ break;
+ case TiffDataFormat.CODE_INT8_U:
+ if (componentCount == 1) {
+ handler.setIntegerValue(tagId, reader.getUInt8(tagValueOffset));
+ }
+ break;
+ case TiffDataFormat.CODE_INT16_S:
+ if (componentCount == 1) {
+ handler.setIntegerValue(tagId, reader.getInt16(tagValueOffset));
+ }
+ break;
+ case TiffDataFormat.CODE_INT16_U:
+ if (componentCount == 1) {
+ handler.setIntegerValue(tagId, reader.getUInt16(tagValueOffset));
+ }
+ break;
+ case TiffDataFormat.CODE_INT32_S:
+ // NOTE 'long' in this case means 32 bit, not 64
+ if (componentCount == 1) {
+ handler.setIntegerValue(tagId, reader.getInt32(tagValueOffset));
+ }
+ break;
+ case TiffDataFormat.CODE_INT32_U:
+ // NOTE 'long' in this case means 32 bit, not 64
+ if (componentCount == 1) {
+ handler.setRational(tagId, new Rational(reader.getUInt32(tagValueOffset), 1L));
+ }
+ break;
+ case TiffDataFormat.CODE_SINGLE:
+ case TiffDataFormat.CODE_DOUBLE:
+ case TiffDataFormat.CODE_UNDEFINED:
+ default:
+ break;
+ }
+ }
+
+ /**
+ * Determine the offset of a given tag within the specified IFD.
+ *
+ * @param ifdStartOffset the offset at which the IFD starts
+ * @param entryNumber the zero-based entry number
+ */
+ private static int calculateTagOffset(int ifdStartOffset, int entryNumber)
+ {
+ // Add 2 bytes for the tag count.
+ // Each entry is 12 bytes.
+ return ifdStartOffset + 2 + (12 * entryNumber);
+ }
+}
projects / GpsPrune.git / blobdiff