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#579 More reliable CCITT compression type detection

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This commit is contained in:
Harald Kuhr 2020-12-23 11:46:58 +01:00
parent 74902b3fb4
commit 253f04066b
2 changed files with 14 additions and 7 deletions
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5
imageio/imageio-tiff/src/main/java/com/twelvemonkeys/imageio/plugins/tiff/CCITTFaxDecoderStream.java
View File

@ -152,7 +152,7 @@ final class CCITTFaxDecoderStream extends FilterInputStream {
static int findCompressionType(final int type, final InputStream in) throws IOException {
// Discover possible incorrect type, revert to RLE
if (type == TIFFExtension.COMPRESSION_CCITT_T4 && in.markSupported()) {
byte[] streamData = new byte[20];
byte[] streamData = new byte[32];
try {
in.mark(streamData.length);
@ -173,8 +173,9 @@ final class CCITTFaxDecoderStream extends FilterInputStream {
if (streamData[0] != 0 || (streamData[1] >> 4 != 1 && streamData[1] != 1)) {
// Leading EOL (0b000000000001) not found, search further and try RLE if not found
int numBits = streamData.length * 8;
short b = (short) (((streamData[0] << 8) + streamData[1]) >> 4);
for (int i = 12; i < 160; i++) {
for (int i = 12; i < numBits; i++) {
b = (short) ((b << 1) + ((streamData[(i / 8)] >> (7 - (i % 8))) & 0x01));
if ((b & 0xFFF) == 1) {

16
imageio/imageio-tiff/src/test/java/com/twelvemonkeys/imageio/plugins/tiff/CCITTFaxDecoderStreamTest.java
View File

@ -68,14 +68,19 @@ public class CCITTFaxDecoderStreamTest {
};
// group3_2d.tif: EOL|k=1|3W|1B|2W|EOL|k=0|V|V|V|EOL|k=1|3W|1B|2W|EOL|k=0|V-1|V|V|6*F
static final byte[] DATA_G3_2D = { 0x00, 0x1C, 0x27, 0x00, 0x17, 0x00, 0x1C, 0x27, 0x00, 0x12, (byte) 0xC0 };
static final byte[] DATA_G3_2D = {0x00, 0x1C, 0x27, 0x00, 0x17, 0x00, 0x1C, 0x27, 0x00, 0x12, (byte) 0xC0};
// group3_2d_fill.tif
static final byte[] DATA_G3_2D_FILL = { 0x00, 0x01, (byte) 0xC2, 0x70, 0x01, 0x70, 0x01, (byte) 0xC2, 0x70, 0x01,
0x2C };
static final byte[] DATA_G3_2D_FILL = {0x00, 0x01, (byte) 0xC2, 0x70, 0x01, 0x70, 0x01, (byte) 0xC2,
0x70, 0x01, 0x2C};
static final byte[] DATA_G3_2D_lsb2msb = { 0x00, 0x38, (byte) 0xE4, 0x00, (byte) 0xE8, 0x00, 0x38, (byte) 0xE4,
0x00, 0x48, 0x03 };
static final byte[] DATA_G3_2D_lsb2msb = {0x00, 0x38, (byte) 0xE4, 0x00, (byte) 0xE8, 0x00, 0x38, (byte) 0xE4,
0x00, 0x48, 0x03};
static final byte[] DATA_G3_LONG = {0x00, 0x68, 0x0A, (byte) 0xC9, 0x3A, 0x3A, 0x00, 0x68,
(byte) 0x8A, (byte) 0xD8, 0x3A, 0x35, 0x00, 0x68, 0x0A, 0x06,
(byte) 0xDD, 0x3A, 0x19, 0x00, 0x68, (byte) 0x8A, (byte) 0x9E, 0x75,
0x08, 0x00, 0x68};
// group4.tif:
// Line 1: V-3, V-2, V0
@ -189,6 +194,7 @@ public class CCITTFaxDecoderStreamTest {
assertEquals(TIFFExtension.COMPRESSION_CCITT_T4, CCITTFaxDecoderStream.findCompressionType(TIFFExtension.COMPRESSION_CCITT_T4, new ByteArrayInputStream(DATA_G3_2D)));
assertEquals(TIFFExtension.COMPRESSION_CCITT_T4, CCITTFaxDecoderStream.findCompressionType(TIFFExtension.COMPRESSION_CCITT_T4, new ByteArrayInputStream(DATA_G3_2D_FILL)));
assertEquals(TIFFExtension.COMPRESSION_CCITT_T4, CCITTFaxDecoderStream.findCompressionType(TIFFExtension.COMPRESSION_CCITT_T4, new ByteArrayInputStream(DATA_G3_2D_lsb2msb)));
assertEquals(TIFFExtension.COMPRESSION_CCITT_T4, CCITTFaxDecoderStream.findCompressionType(TIFFExtension.COMPRESSION_CCITT_T4, new ByteArrayInputStream(DATA_G3_LONG)));
// Group 4/CCITT_T6
assertEquals(TIFFExtension.COMPRESSION_CCITT_T6, CCITTFaxDecoderStream.findCompressionType(TIFFExtension.COMPRESSION_CCITT_T6, new ByteArrayInputStream(DATA_G4)));