/*
 * Copyright (C) 2015, Ivan Motsch <ivan.motsch@bsiag.com>
 * Copyright (C) 2020, Thomas Wolf <thomas.wolf@paranor.ch> 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.io;

import java.io.IOException;
import java.io.OutputStream;

import org.eclipse.jgit.diff.RawText;

An OutputStream that reduces CRLF to LF.

Existing single CR are not changed to LF, but retained as is.


A binary check on the first 8000 bytes is performed and in case of binary
files, canonicalization is turned off (for the complete file). If the binary
check determines that the input is not binary but text with CR/LF,
canonicalization is also turned off.

Since:
4.3/**
 * An OutputStream that reduces CRLF to LF.
 * <p>
 * Existing single CR are not changed to LF, but retained as is.
 * </p>
 * <p>
 * A binary check on the first 8000 bytes is performed and in case of binary
 * files, canonicalization is turned off (for the complete file). If the binary
 * check determines that the input is not binary but text with CR/LF,
 * canonicalization is also turned off.
 * </p>
 *
 * @since 4.3
 */
public class AutoLFOutputStream extends OutputStream {

	static final int BUFFER_SIZE = 8000;

	private final OutputStream out;

	private int buf = -1;

	private byte[] binbuf = new byte[BUFFER_SIZE];

	private byte[] onebytebuf = new byte[1];

	private int binbufcnt = 0;

	private boolean detectBinary;

	private boolean isBinary;

	
Constructor for AutoLFOutputStream.
Params:
out –  an OutputStream object./**
	 * Constructor for AutoLFOutputStream.
	 *
	 * @param out
	 *            an {@link java.io.OutputStream} object.
	 */
	public AutoLFOutputStream(OutputStream out) {
		this(out, true);
	}

	
Constructor for AutoLFOutputStream.
Params:
out –  an OutputStream object.
detectBinary – 
           whether binaries should be detected/**
	 * Constructor for AutoLFOutputStream.
	 *
	 * @param out
	 *            an {@link java.io.OutputStream} object.
	 * @param detectBinary
	 *            whether binaries should be detected
	 */
	public AutoLFOutputStream(OutputStream out, boolean detectBinary) {
		this.out = out;
		this.detectBinary = detectBinary;
	}

	
{@inheritDoc} /** {@inheritDoc} */
	@Override
	public void write(int b) throws IOException {
		onebytebuf[0] = (byte) b;
		write(onebytebuf, 0, 1);
	}

	
{@inheritDoc} /** {@inheritDoc} */
	@Override
	public void write(byte[] b) throws IOException {
		int overflow = buffer(b, 0, b.length);
		if (overflow > 0) {
			write(b, b.length - overflow, overflow);
		}
	}

	
{@inheritDoc} /** {@inheritDoc} */
	@Override
	public void write(byte[] b, int startOff, int startLen)
			throws IOException {
		final int overflow = buffer(b, startOff, startLen);
		if (overflow <= 0) {
			return;
		}
		final int off = startOff + startLen - overflow;
		final int len = overflow;
		int lastw = off;
		if (isBinary) {
			out.write(b, off, len);
			return;
		}
		for (int i = off; i < off + len; ++i) {
			final byte c = b[i];
			switch (c) {
			case '\r':
				// skip write r but backlog r
				if (lastw < i) {
					out.write(b, lastw, i - lastw);
				}
				lastw = i + 1;
				buf = '\r';
				break;
			case '\n':
				if (buf == '\r') {
					out.write('\n');
					lastw = i + 1;
					buf = -1;
				} else {
					if (lastw < i + 1) {
						out.write(b, lastw, i + 1 - lastw);
					}
					lastw = i + 1;
				}
				break;
			default:
				if (buf == '\r') {
					out.write('\r');
					lastw = i;
				}
				buf = -1;
				break;
			}
		}
		if (lastw < off + len) {
			out.write(b, lastw, off + len - lastw);
		}
	}

	private int buffer(byte[] b, int off, int len) throws IOException {
		if (binbufcnt > binbuf.length) {
			return len;
		}
		int copy = Math.min(binbuf.length - binbufcnt, len);
		System.arraycopy(b, off, binbuf, binbufcnt, copy);
		binbufcnt += copy;
		int remaining = len - copy;
		if (remaining > 0) {
			decideMode();
		}
		return remaining;
	}

	private void decideMode() throws IOException {
		if (detectBinary) {
			isBinary = RawText.isBinary(binbuf, binbufcnt);
			if (!isBinary) {
				isBinary = RawText.isCrLfText(binbuf, binbufcnt);
			}
			detectBinary = false;
		}
		int cachedLen = binbufcnt;
		binbufcnt = binbuf.length + 1; // full!
		write(binbuf, 0, cachedLen);
	}

	
{@inheritDoc} /** {@inheritDoc} */
	@Override
	public void flush() throws IOException {
		if (binbufcnt <= binbuf.length) {
			decideMode();
		}
		out.flush();
	}

	
{@inheritDoc} /** {@inheritDoc} */
	@Override
	public void close() throws IOException {
		flush();
		if (buf == '\r') {
			out.write(buf);
			buf = -1;
		}
		out.close();
	}
}