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comparison dwt/internal/image/PngDecodingDataStream.d @ 34:5123b17c98ef

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Ported dwt.events.*, dwt.graphics.GC, Region, dwt.internal.image.*
author Jacob Carlborg <doob@me.com> <jacob.carlborg@gmail.com>
date Sun, 14 Sep 2008 01:45:57 +0200
parents e831403a80a9
children
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33:965ac0a77267 34:5123b17c98ef
5 * which accompanies this distribution, and is available at 5 * which accompanies this distribution, and is available at
6 * http://www.eclipse.org/legal/epl-v10.html 6 * http://www.eclipse.org/legal/epl-v10.html
7 * 7 *
8 * Contributors: 8 * Contributors:
9 * IBM Corporation - initial API and implementation 9 * IBM Corporation - initial API and implementation
10 * Port to the D programming language:
11 * Frank Benoit <benoit@tionex.de>
10 *******************************************************************************/ 12 *******************************************************************************/
11 module dwt.internal.image; 13 module dwt.internal.image.PngDecodingDataStream;
12 14
13 15
14 import java.io.IOException; 16 import dwt.dwthelper.InputStream;
15 import java.io.InputStream;
16 17
17 import dwt.DWT; 18 import dwt.DWT;
19 import dwt.internal.image.PngLzBlockReader;
18 20
19 public class PngDecodingDataStream : InputStream { 21 public class PngDecodingDataStream : InputStream {
22
23 alias InputStream.read read;
24
20 InputStream stream; 25 InputStream stream;
21 byte currentByte; 26 byte currentByte;
22 int nextBitIndex; 27 int nextBitIndex;
23 28
24 PngLzBlockReader lzBlockReader; 29 PngLzBlockReader lzBlockReader;
25 int adlerValue; 30 int adlerValue;
26 31
27 static final int PRIME = 65521; 32 static final int PRIME = 65521;
28 static final int MAX_BIT = 7; 33 static final int MAX_BIT = 7;
29 34
30 this(InputStream stream) { 35 this(InputStream stream) {
31 super(); 36 super();
32 this.stream = stream; 37 this.stream = stream;
33 nextBitIndex = MAX_BIT + 1; 38 nextBitIndex = MAX_BIT + 1;
34 adlerValue = 1; 39 adlerValue = 1;
38 } 43 }
39 44
40 /** 45 /**
41 * This method should be called when the image decoder thinks 46 * This method should be called when the image decoder thinks
42 * that all of the compressed image data has been read. This 47 * that all of the compressed image data has been read. This
43 * method will ensure that the next data value is an end of 48 * method will ensure that the next data value is an end of
44 * block marker. If there are more blocks after this one, 49 * block marker. If there are more blocks after this one,
45 * the method will read them and ensure that they are empty. 50 * the method will read them and ensure that they are empty.
46 */ 51 */
47 void assertImageDataAtEnd() { 52 void assertImageDataAtEnd() {
48 lzBlockReader.assertCompressedDataAtEnd(); 53 lzBlockReader.assertCompressedDataAtEnd();
49 } 54 }
50 55
51 public void close() { 56 public override void close() {
52 assertImageDataAtEnd(); 57 assertImageDataAtEnd();
53 checkAdler(); 58 checkAdler();
54 } 59 }
55 60
56 int getNextIdatBits(int length) { 61 int getNextIdatBits(int length) {
67 nextBitIndex = 0; 72 nextBitIndex = 0;
68 } 73 }
69 return (currentByte & (1 << nextBitIndex)) >> nextBitIndex++; 74 return (currentByte & (1 << nextBitIndex)) >> nextBitIndex++;
70 } 75 }
71 76
72 byte getNextIdatByte() { 77 byte getNextIdatByte() {
73 byte nextByte = cast(byte)stream.read(); 78 byte nextByte = cast(byte)stream.read();
74 nextBitIndex = MAX_BIT + 1; 79 nextBitIndex = MAX_BIT + 1;
75 return nextByte; 80 return nextByte;
76 } 81 }
77 82
82 low = (low + valueInt) % PRIME; 87 low = (low + valueInt) % PRIME;
83 high = (low + high) % PRIME; 88 high = (low + high) % PRIME;
84 adlerValue = (high << 16) | low; 89 adlerValue = (high << 16) | low;
85 } 90 }
86 91
87 public int read() { 92 public override int read() {
88 byte nextDecodedByte = lzBlockReader.getNextByte(); 93 byte nextDecodedByte = lzBlockReader.getNextByte();
89 updateAdler(nextDecodedByte); 94 updateAdler(nextDecodedByte);
90 return nextDecodedByte & 0xFF; 95 return nextDecodedByte & 0xFF;
91 } 96 }
92 97
93 public int read(byte[] buffer, int off, int len) { 98 public override int read(byte[] buffer, int off, int len) {
94 for (int i = 0; i < len; i++) { 99 for (int i = 0; i < len; i++) {
95 int b = read(); 100 int b = read();
96 if (b is -1) return i; 101 if (b is -1) return i;
97 buffer[off + i] = cast(byte)b; 102 buffer[off + i] = cast(byte)b;
98 } 103 }
104 } 109 }
105 110
106 private void readCompressedDataHeader() { 111 private void readCompressedDataHeader() {
107 byte headerByte1 = getNextIdatByte(); 112 byte headerByte1 = getNextIdatByte();
108 byte headerByte2 = getNextIdatByte(); 113 byte headerByte2 = getNextIdatByte();
109 114
110 int number = ((headerByte1 & 0xFF) << 8) | (headerByte2 & 0xFF); 115 int number = ((headerByte1 & 0xFF) << 8) | (headerByte2 & 0xFF);
111 if (number % 31 !is 0) error(); 116 if (number % 31 !is 0) error();
112 117
113 int compressionMethod = headerByte1 & 0x0F; 118 int compressionMethod = headerByte1 & 0x0F;
114 if (compressionMethod !is 8) error(); 119 if (compressionMethod !is 8) error();
115 120
116 int windowSizeHint = (headerByte1 & 0xF0) >> 4; 121 int windowSizeHint = (headerByte1 & 0xF0) >> 4;
117 if (windowSizeHint > 7) error(); 122 if (windowSizeHint > 7) error();
118 int windowSize = (1 << (windowSizeHint + 8)); 123 int windowSize = (1 << (windowSizeHint + 8));
119 lzBlockReader.setWindowSize(windowSize); 124 lzBlockReader.setWindowSize(windowSize);
120 125
121 int dictionary = (headerByte2 & (1 << 5)); 126 int dictionary = (headerByte2 & (1 << 5));
122 if (dictionary !is 0) error(); 127 if (dictionary !is 0) error();
123 128
124 // int compressionLevel = (headerByte2 & 0xC0) >> 6; 129 // int compressionLevel = (headerByte2 & 0xC0) >> 6;
125 } 130 }
126 131
127 void checkAdler() { 132 void checkAdler() {
128 int storedAdler = ((getNextIdatByte() & 0xFF) << 24) 133 int storedAdler = 0;
129 | ((getNextIdatByte() & 0xFF) << 16) 134 storedAdler |= ((getNextIdatByte() & 0xFF) << 24);
130 | ((getNextIdatByte() & 0xFF) << 8) 135 storedAdler |= ((getNextIdatByte() & 0xFF) << 16);
131 | (getNextIdatByte() & 0xFF); 136 storedAdler |= ((getNextIdatByte() & 0xFF) << 8);
137 storedAdler |= (getNextIdatByte() & 0xFF);
132 if (storedAdler !is adlerValue) error(); 138 if (storedAdler !is adlerValue) error();
133 } 139 }
134 140
135 } 141 }