/*
    * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org> and others
    *
    * This program and the accompanying materials are made available under the
    * terms of the Eclipse Distribution License v. 1.0 which is available at
    * https://www.eclipse.org/org/documents/edl-v10.php.
    *
    * SPDX-License-Identifier: BSD-3-Clause
    */
  
  package org.eclipse.jgit.util;
  
  /**
   * A rough character sequence around a raw byte buffer.
   * <p>
   * Characters are assumed to be 8-bit US-ASCII.
   */
  public final class RawCharSequence implements CharSequence {
  	/** A zero-length character sequence. */
  	public static final RawCharSequencee.html#RawCharSequence">RawCharSequence EMPTY = new RawCharSequence(null, 0, 0);
  
  	final byte[] buffer;
  
  	final int startPtr;
  
  	final int endPtr;
  
  	/**
  	 * Create a rough character sequence around the raw byte buffer.
  	 *
  	 * @param buf
  	 *            buffer to scan.
  	 * @param start
  	 *            starting position for the sequence.
  	 * @param end
  	 *            ending position for the sequence.
  	 */
  	public RawCharSequence(byte[] buf, int start, int end) {
  		buffer = buf;
  		startPtr = start;
  		endPtr = end;
  	}
  
  	/** {@inheritDoc} */
  	@Override
  	public char charAt(int index) {
  		return (char) (buffer[startPtr + index] & 0xff);
  	}
  
  	/** {@inheritDoc} */
  	@Override
  	public int length() {
  		return endPtr - startPtr;
  	}
  
  	/** {@inheritDoc} */
  	@Override
  	public CharSequence subSequence(int start, int end) {
  		return new RawCharSequence(buffer, startPtr + start, startPtr + end);
  	}
  
  	/** {@inheritDoc} */
  	@Override
  	public String toString() {
  		final int n = length();
  		final StringBuilder b = new StringBuilder(n);
  		for (int i = 0; i < n; i++)
  			b.append(charAt(i));
  		return b.toString();
  	}
  }