TTFInput.java

package org.freehep.graphicsio.font.truetype;

import java.io.IOException;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Stack;

/**
 * Data input for true type files. All methods are named as the data formats in
 * the true type specification.
 * 
 * @author Simon Fischer
 * @version $Id: TTFInput.java,v 1.5 2009-08-17 21:44:45 murkle Exp $
 */
public abstract class TTFInput {

	private Stack filePosStack = new Stack();

	private int tempFlags;

	// --------------- IO ---------------

	public abstract void seek(long offset) throws IOException;

	abstract long getPointer() throws IOException;

	public void pushPos() throws IOException {
		filePosStack.push(new Long(getPointer()));
	}

	public void popPos() throws IOException {
		seek(((Long) filePosStack.pop()).longValue());
	}

	// ---------- Simple Data Types --------------

	public abstract int readRawByte() throws IOException;

	public abstract int readByte() throws IOException;

	public abstract short readShort() throws IOException;

	public abstract int readUShort() throws IOException;

	public abstract long readULong() throws IOException;

	public abstract int readLong() throws IOException;

	public abstract byte readChar() throws IOException;

	public final short readFWord() throws IOException {
		return readShort();
	}

	public final int readUFWord() throws IOException {
		return readUShort();
	}

	public final double readFixed() throws IOException {
		int major = readShort();
		int minor = readShort();
		return major + minor / 16384d;
	}

	public final double readF2Dot14() throws IOException {
		int major = readByte();
		int minor = readByte();
		int fraction = minor + ((major & 0x3f) << 8);
		int mantissa = major >> 6;
		if (mantissa >= 2) {
			mantissa -= 4;
		}
		return mantissa + fraction / 16384d;
	}

	// ------------------------------------------------------------

	public final void checkShortZero() throws IOException {
		if (readShort() != 0) {
			System.err.println("Reserved bit should be 0.");
		}
	}

	public static final boolean checkZeroBit(int b, int bit, String name)
			throws IOException {
		if (flagBit(b, bit)) {
			System.err
					.println("Reserved bit " + bit + " in " + name + " not 0.");
			return false;
		}
		return true;
	}

	// ---------------- Flags --------------------

	/**
	 * Reads unsigned short flags into a temporary variable which can be queried
	 * using the flagBit method.
	 */
	public void readUShortFlags() throws IOException {
		tempFlags = readUShort();
	}

	/**
	 * Reads byte flags into a temporary variable which can be queried using the
	 * flagBit method.
	 */
	public void readByteFlags() throws IOException {
		tempFlags = readByte();
	}

	public boolean flagBit(int bit) {
		return flagBit(tempFlags, bit);
	}

	public static boolean flagBit(int b, int bit) {
		return (b & (1 << bit)) > 0;
	}

	// ---------------- Arrays -------------------

	public abstract void readFully(byte[] b) throws IOException;

	public int[] readFFFFTerminatedUShortArray() throws IOException {
		List values = new LinkedList();
		int ushort = -1;
		do {
			ushort = readUShort();
			values.add(Integer.valueOf(ushort));
		} while (ushort != 0xFFFF);
		int[] shorts = new int[values.size()];
		Iterator i = values.iterator();
		int j = 0;
		while (i.hasNext()) {
			shorts[j++] = ((Integer) i.next()).intValue();
		}
		return shorts;
	}

	public int[] readUShortArray(int n) throws IOException {
		int[] temp = new int[n];
		for (int i = 0; i < temp.length; i++) {
			temp[i] = readUShort();
		}
		return temp;
	}

	public short[] readShortArray(int n) throws IOException {
		short[] temp = new short[n];
		for (int i = 0; i < temp.length; i++) {
			temp[i] = readShort();
		}
		return temp;
	}

}