private static void addLookupTreeNode(
short code, NonLeafLookupTreeNode root, LookupTreeNode leaf) {
int codeLength = code >> 8;
int pattern = code & 0xFF;
NonLeafLookupTreeNode node = root;
for (int p = codeLength - 1; p > 0; p--) {
int bit = (pattern >> p) & 0x01;
LookupTreeNode child = node.get(bit);
if (child == null) {
child = new NonLeafLookupTreeNode();
node.set(bit, child);
}
if (child instanceof NonLeafLookupTreeNode) {
node = (NonLeafLookupTreeNode) child;
} else {
throw new IllegalStateException(
"NonLeafLookupTreeNode expected, was " + child.getClass().getName());
}
}
int bit = pattern & 0x01;
if (node.get(bit) != null) {
throw new IllegalStateException("Two codes conflicting in lookup tree");
}
node.set(bit, leaf);
}
public CodeWord getNextCodeWord(CCITTFaxG31DDecodeInputStream decoder) throws IOException {
int bit = decoder.readBit();
if (bit < 0) {
return null;
}
LookupTreeNode node = get(bit);
if (node != null) {
return node.getNextCodeWord(decoder);
}
throw new IOException("Invalid code word encountered");
}
private boolean decodeLine() throws IOException {
if (encodedByteAlign && this.bitPos != 0) {
readByte();
}
if (this.bits < 0) {
return false; // Shortcut after EOD
}
this.y++;
// System.out.println("decodeLine " + this.y);
int x = 0;
if (this.rows > 0 && this.y >= this.rows) {
return false; // All rows decoded, ignore further bits
}
this.decodedLine.clear();
this.decodedWritePos = 0;
int expectRTC = 6;
boolean white = true;
while (x < this.columns || this.accumulatedRunLength > 0) {
CodeWord code;
LookupTreeNode root = white ? WHITE_LOOKUP_TREE_ROOT : BLACK_LOOKUP_TREE_ROOT;
code = root.getNextCodeWord(this);
if (code == null) {
// no more code words (EOD)
if (x > 0) {
// Have last line
this.decodedReadPos = 0;
return true;
} else {
return false;
}
} else if (code.getType() == SIGNAL_EOL) {
expectRTC--;
if (expectRTC == 0) {
// System.out.println("Return to Control");
return false; // Return to Control = End Of Data
}
if (x == 0) {
// System.out.println("Ignoring leading EOL");
continue; // Ignore leading EOL
}
} else {
expectRTC = -1;
x += code.execute(this);
if (this.accumulatedRunLength == 0) {
// Only switch if not using make-up codes
white = !white;
}
}
}
this.decodedReadPos = 0;
return true;
}
