CMapFormat4(Buffer buffer, int offset) {
buffer.position(offset);
buffer.getChar(); // skip, we already know format=4
int subtableLength = buffer.getChar();
/* Try to recover from some bad fonts which specify a subtable
* length that would overflow the byte buffer holding the whole
* cmap table. If this isn't a recoverable situation an exception
* may be thrown which is caught higher up the call stack.
* Whilst this may seem lenient, in practice, unless the "bad"
* subtable we are using is the last one in the cmap table we
* would have no way of knowing about this problem anyway.
*/
if (offset + subtableLength > buffer.capacity()) {
subtableLength = buffer.capacity() - offset;
}
buffer.getChar(); // skip language
segCount = buffer.getChar() / 2;
buffer.getChar(); // skip searchRange
entrySelector = buffer.getChar();
rangeShift = buffer.getChar() / 2;
startCount = new char[segCount];
endCount = new char[segCount];
idDelta = new short[segCount];
idRangeOffset = new char[segCount];
for (int i = 0; i < segCount; i++) {
endCount[i] = buffer.getChar();
}
buffer.getChar(); // 2 bytes for reserved pad
for (int i = 0; i < segCount; i++) {
startCount[i] = buffer.getChar();
}
for (int i = 0; i < segCount; i++) {
idDelta[i] = (short) buffer.getChar();
}
for (int i = 0; i < segCount; i++) {
char ctmp = buffer.getChar();
idRangeOffset[i] = (char) ((ctmp >> 1) & 0xffff);
}
/* Can calculate the number of glyph IDs by subtracting
* "pos" from the length of the cmap
*/
int pos = (segCount * 8 + 16) / 2;
buffer.position(pos * 2 + offset); // * 2 for chars
int numGlyphIds = (subtableLength / 2 - pos);
glyphIds = new char[numGlyphIds];
for (int i = 0; i < numGlyphIds; i++) {
glyphIds[i] = buffer.getChar();
}
}
