Copyright (c) 2000, 2006 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation
/*******************************************************************************
 * Copyright (c) 2000, 2006 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.team.internal.core.subscribers;

import org.eclipse.osgi.util.NLS;
import org.eclipse.team.core.TeamException;
import org.eclipse.team.internal.core.Messages;

Utility for managing slash separated sync information fields.
/**
 * Utility for managing slash separated sync information fields.
 */
public class SyncByteConverter {

	protected static final byte SEPARATOR_BYTE = (byte)'/';

	
Change the slot to the given bytes
Params:
syncBytes – the sync bytes
slot – the slot location
newBytes – the bytes to be put in the slot
Throws:
TeamException – 
Returns:
the new sync bytes/**
	 * Change the slot to the given bytes
	 * @param syncBytes the sync bytes
	 * @param slot the slot location
	 * @param newBytes the bytes to be put in the slot
	 * @return the new sync bytes
	 * @throws TeamException
	 */
	public static byte[] setSlot(byte[] syncBytes, int slot, byte[] newBytes) throws TeamException {
		int start = startOfSlot(syncBytes, slot);
		if (start == -1) {
			throw new TeamException(NLS.bind(Messages.SyncByteConverter_1, new String[] { new String(syncBytes) }));
		}
		int end = startOfSlot(syncBytes, slot + 1);
		int totalLength = start + 1 + newBytes.length;
		if (end != -1) {
			totalLength += syncBytes.length - end;
		}
		byte[] result = new byte[totalLength];
		System.arraycopy(syncBytes, 0, result, 0, start + 1);
		System.arraycopy(newBytes, 0, result, start + 1, newBytes.length);
		if (end != -1) {
			System.arraycopy(syncBytes, end, result, start + 1 + newBytes.length, syncBytes.length - end);
		}
		return result;
	}

	
Method startOfSlot returns the index of the slash that occurs before the
given slot index. The provided index should be >= 1 which assumes that
slot zero occurs before the first slash.
Params:
syncBytes – 
i – 
Returns:
int/**
	 * Method startOfSlot returns the index of the slash that occurs before the
	 * given slot index. The provided index should be >= 1 which assumes that
	 * slot zero occurs before the first slash.
	 *
	 * @param syncBytes
	 * @param i
	 * @return int
	 */
	private static int startOfSlot(byte[] syncBytes, int slot) {
		int count = 0;
		for (int j = 0; j < syncBytes.length; j++) {
			if (syncBytes[j] == SEPARATOR_BYTE) {
				count++;
				if (count == slot) return j;
			}
		}
		return -1;
	}

	
Return the offset the the Nth delimeter from the given start index.
Params:
bytes – 
delimiter – 
start – 
n – 
Returns:
int/**
	 * Return the offset the the Nth delimeter from the given start index.
	 * @param bytes
	 * @param delimiter
	 * @param start
	 * @param n
	 * @return int
	 */
	private static int getOffsetOfDelimeter(byte[] bytes, byte delimiter, int start, int n) {
		int count = 0;
		for (int i = start; i < bytes.length; i++) {
			if (bytes[i] == delimiter) count++;
			if (count == n) return i;
		}
		// the Nth delimeter was not found
		return -1;
	}

	
Get the bytes in the given slot.
Params:
bytes – the sync bytes
index – the slot location
includeRest – whether to include the rest
Returns:
the bytes in the given slot/**
	 * Get the bytes in the given slot.
	 * @param bytes the sync bytes
	 * @param index the slot location
	 * @param includeRest whether to include the rest
	 * @return the bytes in the given slot
	 */
	public static byte[] getSlot(byte[] bytes, int index, boolean includeRest) {
		// Find the starting index
		byte delimiter = SEPARATOR_BYTE;
		int start;
		if (index == 0) {
			// make start -1 so that end determination will start at offset 0.
			start = -1;
		} else {
			start = getOffsetOfDelimeter(bytes, delimiter, 0, index);
			if (start == -1) return null;
		}
		// Find the ending index
		int end = getOffsetOfDelimeter(bytes, delimiter, start + 1, 1);
		// Calculate the length
		int length;
		if (end == -1 || includeRest) {
			length = bytes.length - start - 1;
		} else {
			length = end - start - 1;
		}
		byte[] result = new byte[length];
		System.arraycopy(bytes, start + 1, result, 0, length);
		return result;
	}

	public static byte[] toBytes(String[] slots) {
		StringBuilder buffer = new StringBuilder();
		for (String string : slots) {
			buffer.append(string);
			buffer.append(new String(new byte[] {SyncByteConverter.SEPARATOR_BYTE }));
		}
		return buffer.toString().getBytes();
	}
}