Apple-2-Tools/dmolony-DiskBrowser
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tidying

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This commit is contained in:
Denis Molony 2016-08-18 14:03:13 +10:00
parent c28ecb0486
commit 428767d853
1 changed files with 13 additions and 25 deletions
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32
src/com/bytezone/diskbrowser/wizardry/Huffman.java
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@ -9,11 +9,8 @@ import com.bytezone.diskbrowser.applefile.AbstractFile;
public class Huffman extends AbstractFile public class Huffman extends AbstractFile
{ {
private static final int LEFT = 256; private static final byte[] mask = { 2, 1 }; // bits: 10 or 01
private static final int RIGHT = 512; private static final int[] offset = { 512, 256 }; // offset to left/right nodes
private static final byte[] mask = { 2, 1 };
private static final int[] offset = { RIGHT, LEFT };
private byte depth; private byte depth;
private int msgPtr; private int msgPtr;
@ -51,8 +48,8 @@ public class Huffman extends AbstractFile
if ((depth++ & 0x07) == 0) // every 8th bit if ((depth++ & 0x07) == 0) // every 8th bit
currentByte = message[msgPtr++]; // get a new byte currentByte = message[msgPtr++]; // get a new byte
int currentBit = currentByte & 0x01; // get the next bit to process int currentBit = currentByte & 0x01; // extract the next bit to process
currentByte >>= 1; // and discard it currentByte >>= 1; // and remove it from the byte
// use currentBit to determine whether to use the left or right node // use currentBit to determine whether to use the left or right node
byte nodeValue = buffer[treePtr + offset[currentBit]]; byte nodeValue = buffer[treePtr + offset[currentBit]];
@ -80,23 +77,14 @@ public class Huffman extends AbstractFile
private void walk (int treePtr, String path, StringBuilder text) private void walk (int treePtr, String path, StringBuilder text)
{ {
// check left node for (int currentBit = 1; currentBit >= 0; --currentBit)
if ((buffer[treePtr] & 0x01) == 0) if ((buffer[treePtr] & mask[currentBit]) == 0)
walk (buffer[treePtr + LEFT] & 0xFF, path + "1", text); walk (buffer[treePtr + offset[currentBit]] & 0xFF, path + currentBit, text);
else else
print (path + "1", buffer[treePtr + LEFT], text);
// check right node
if ((buffer[treePtr] & 0x02) == 0)
walk (buffer[treePtr + RIGHT] & 0xFF, path + "0", text);
else
print (path + "0", buffer[treePtr + RIGHT], text);
}
private void print (String path, byte value, StringBuilder text)
{ {
int val = value & 0xFF; int val = buffer[treePtr + offset[currentBit]] & 0xFF;
char c = val < 32 || val >= 127 ? ' ' : (char) val; char c = val < 32 || val >= 127 ? ' ' : (char) val;
text.append (String.format ("%3d %1.1s %s%n", val, c, path)); text.append (String.format ("%3d %1.1s %s%n", val, c, path + currentBit));
}
} }
} }