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- /*
- * Copyright (C) 2009, Google Inc.
- * Copyright (C) 2008-2009, Johannes E. Schindelin <johannes.schindelin@gmx.de>
- * and other copyright owners as documented in the project's IP log.
- *
- * This program and the accompanying materials are made available
- * under the terms of the Eclipse Distribution License v1.0 which
- * accompanies this distribution, is reproduced below, and is
- * available at http://www.eclipse.org/org/documents/edl-v10.php
- *
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or
- * without modification, are permitted provided that the following
- * conditions are met:
- *
- * - Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *
- * - Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following
- * disclaimer in the documentation and/or other materials provided
- * with the distribution.
- *
- * - Neither the name of the Eclipse Foundation, Inc. nor the
- * names of its contributors may be used to endorse or promote
- * products derived from this software without specific prior
- * written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
- * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
- * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
- * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
- * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
- * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
- * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
- * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
- * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
- * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
- * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
- package org.eclipse.jgit.diff;
-
- import java.io.File;
- import java.io.IOException;
- import java.io.OutputStream;
-
- import org.eclipse.jgit.util.IO;
- import org.eclipse.jgit.util.IntList;
- import org.eclipse.jgit.util.RawParseUtils;
-
- /**
- * A Sequence supporting UNIX formatted text in byte[] format.
- * <p>
- * Elements of the sequence are the lines of the file, as delimited by the UNIX
- * newline character ('\n'). The file content is treated as 8 bit binary text,
- * with no assumptions or requirements on character encoding.
- * <p>
- * Note that the first line of the file is element 0, as defined by the Sequence
- * interface API. Traditionally in a text editor a patch file the first line is
- * line number 1. Callers may need to subtract 1 prior to invoking methods if
- * they are converting from "line number" to "element index".
- */
- public class RawText implements Sequence {
- /** The file content for this sequence. */
- protected final byte[] content;
-
- /** Map of line number to starting position within {@link #content}. */
- protected final IntList lines;
-
- /** Hash code for each line, for fast equality elimination. */
- protected final IntList hashes;
-
- /**
- * Create a new sequence from an existing content byte array.
- * <p>
- * The entire array (indexes 0 through length-1) is used as the content.
- *
- * @param input
- * the content array. The array is never modified, so passing
- * through cached arrays is safe.
- */
- public RawText(final byte[] input) {
- content = input;
- lines = RawParseUtils.lineMap(content, 0, content.length);
- hashes = computeHashes();
- }
-
- /**
- * Create a new sequence from a file.
- * <p>
- * The entire file contents are used.
- *
- * @param file
- * the text file.
- * @throws IOException if Exceptions occur while reading the file
- */
- public RawText(File file) throws IOException {
- this(IO.readFully(file));
- }
-
- public int size() {
- // The line map is always 2 entries larger than the number of lines in
- // the file. Index 0 is padded out/unused. The last index is the total
- // length of the buffer, and acts as a sentinel.
- //
- return lines.size() - 2;
- }
-
- public boolean equals(final int i, final Sequence other, final int j) {
- return equals(this, i + 1, (RawText) other, j + 1);
- }
-
- private static boolean equals(final RawText a, final int ai,
- final RawText b, final int bi) {
- if (a.hashes.get(ai) != b.hashes.get(bi))
- return false;
-
- int as = a.lines.get(ai);
- int bs = b.lines.get(bi);
- final int ae = a.lines.get(ai + 1);
- final int be = b.lines.get(bi + 1);
-
- if (ae - as != be - bs)
- return false;
-
- while (as < ae) {
- if (a.content[as++] != b.content[bs++])
- return false;
- }
- return true;
- }
-
- /**
- * Write a specific line to the output stream, without its trailing LF.
- * <p>
- * The specified line is copied as-is, with no character encoding
- * translation performed.
- * <p>
- * If the specified line ends with an LF ('\n'), the LF is <b>not</b>
- * copied. It is up to the caller to write the LF, if desired, between
- * output lines.
- *
- * @param out
- * stream to copy the line data onto.
- * @param i
- * index of the line to extract. Note this is 0-based, so line
- * number 1 is actually index 0.
- * @throws IOException
- * the stream write operation failed.
- */
- public void writeLine(final OutputStream out, final int i)
- throws IOException {
- final int start = lines.get(i + 1);
- int end = lines.get(i + 2);
- if (content[end - 1] == '\n')
- end--;
- out.write(content, start, end - start);
- }
-
- /**
- * Determine if the file ends with a LF ('\n').
- *
- * @return true if the last line has an LF; false otherwise.
- */
- public boolean isMissingNewlineAtEnd() {
- final int end = lines.get(lines.size() - 1);
- if (end == 0)
- return true;
- return content[end - 1] != '\n';
- }
-
- private IntList computeHashes() {
- final IntList r = new IntList(lines.size());
- r.add(0);
- for (int lno = 1; lno < lines.size() - 1; lno++) {
- final int ptr = lines.get(lno);
- final int end = lines.get(lno + 1);
- r.add(hashLine(content, ptr, end));
- }
- r.add(0);
- return r;
- }
-
- /**
- * Compute a hash code for a single line.
- *
- * @param raw
- * the raw file content.
- * @param ptr
- * first byte of the content line to hash.
- * @param end
- * 1 past the last byte of the content line.
- * @return hash code for the region <code>[ptr, end)</code> of raw.
- */
- protected int hashLine(final byte[] raw, int ptr, final int end) {
- int hash = 5381;
- for (; ptr < end; ptr++)
- hash = (hash << 5) ^ (raw[ptr] & 0xff);
- return hash;
- }
- }
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