/*
    * Copyright (C) 2008, Google Inc.
    * 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,
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   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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  package org.eclipse.jgit.patch;
  
  import static org.eclipse.jgit.util.RawParseUtils.nextLF;
  import static org.eclipse.jgit.util.RawParseUtils.parseBase10;
  
  import java.io.IOException;
  import java.io.OutputStream;
  import java.text.MessageFormat;
  
  import org.eclipse.jgit.internal.JGitText;
  import org.eclipse.jgit.lib.AbbreviatedObjectId;
  import org.eclipse.jgit.util.MutableInteger;
  
  /** Hunk header for a hunk appearing in a "diff --cc" style patch. */
  public class CombinedHunkHeader extends HunkHeader {
  	private static abstract class CombinedOldImage extends OldImage {
  		int nContext;
  	}
  
  	private CombinedOldImage[] old;
  
  	CombinedHunkHeader(final CombinedFileHeader fh, final int offset) {
  		super(fh, offset, null);
  		old = new CombinedOldImage[fh.getParentCount()];
  		for (int i = 0; i < old.length; i++) {
  			final int imagePos = i;
  			old[i] = new CombinedOldImage() {
  				@Override
  				public AbbreviatedObjectId getId() {
  					return fh.getOldId(imagePos);
  				}
  			};
  		}
  	}
  
  	@Override
  	public CombinedFileHeader getFileHeader() {
  		return (CombinedFileHeader) super.getFileHeader();
  	}
  
  	@Override
  	public OldImage getOldImage() {
  		return getOldImage(0);
  	}
  
  	/**
  	 * Get the OldImage data related to the nth ancestor
  	 *
  	 * @param nthParent
  	 *            the ancestor to get the old image data of
  	 * @return image data of the requested ancestor.
  	 */
  	public OldImage getOldImage(final int nthParent) {
  		return old[nthParent];
  	}
  
 	@Override
 	void parseHeader() {
 		// Parse "@@@ -55,12 -163,13 +163,15 @@@ protected boolean"
 		//
 		final byte[] buf = file.buf;
 		final MutableInteger ptr = new MutableInteger();
 		ptr.value = nextLF(buf, startOffset, ' ');
 
 		for (int n = 0; n < old.length; n++) {
 			old[n].startLine = -parseBase10(buf, ptr.value, ptr);
 			if (buf[ptr.value] == ',')
 				old[n].lineCount = parseBase10(buf, ptr.value + 1, ptr);
 			else
 				old[n].lineCount = 1;
 		}
 
 		newStartLine = parseBase10(buf, ptr.value + 1, ptr);
 		if (buf[ptr.value] == ',')
 			newLineCount = parseBase10(buf, ptr.value + 1, ptr);
 		else
 			newLineCount = 1;
 	}
 
 	@Override
 	int parseBody(final Patch script, final int end) {
 		final byte[] buf = file.buf;
 		int c = nextLF(buf, startOffset);
 
 		for (final CombinedOldImage o : old) {
 			o.nDeleted = 0;
 			o.nAdded = 0;
 			o.nContext = 0;
 		}
 		nContext = 0;
 		int nAdded = 0;
 
 		SCAN: for (int eol; c < end; c = eol) {
 			eol = nextLF(buf, c);
 
 			if (eol - c < old.length + 1) {
 				// Line isn't long enough to mention the state of each
 				// ancestor. It must be the end of the hunk.
 				break SCAN;
 			}
 
 			switch (buf[c]) {
 			case ' ':
 			case '-':
 			case '+':
 				break;
 
 			default:
 				// Line can't possibly be part of this hunk; the first
 				// ancestor information isn't recognizable.
 				//
 				break SCAN;
 			}
 
 			int localcontext = 0;
 			for (int ancestor = 0; ancestor < old.length; ancestor++) {
 				switch (buf[c + ancestor]) {
 				case ' ':
 					localcontext++;
 					old[ancestor].nContext++;
 					continue;
 
 				case '-':
 					old[ancestor].nDeleted++;
 					continue;
 
 				case '+':
 					old[ancestor].nAdded++;
 					nAdded++;
 					continue;
 
 				default:
 					break SCAN;
 				}
 			}
 			if (localcontext == old.length)
 				nContext++;
 		}
 
 		for (int ancestor = 0; ancestor < old.length; ancestor++) {
 			final CombinedOldImage o = old[ancestor];
 			final int cmp = o.nContext + o.nDeleted;
 			if (cmp < o.lineCount) {
 				final int missingCnt = o.lineCount - cmp;
 				script.error(buf, startOffset, MessageFormat.format(
 						JGitText.get().truncatedHunkLinesMissingForAncestor,
 						Integer.valueOf(missingCnt),
 						Integer.valueOf(ancestor + 1)));
 			}
 		}
 
 		if (nContext + nAdded < newLineCount) {
 			final int missingCount = newLineCount - (nContext + nAdded);
 			script.error(buf, startOffset, MessageFormat.format(
 					JGitText.get().truncatedHunkNewLinesMissing,
 					Integer.valueOf(missingCount)));
 		}
 
 		return c;
 	}
 
 	@Override
 	void extractFileLines(final OutputStream[] out) throws IOException {
 		final byte[] buf = file.buf;
 		int ptr = startOffset;
 		int eol = nextLF(buf, ptr);
 		if (endOffset <= eol)
 			return;
 
 		// Treat the hunk header as though it were from the ancestor,
 		// as it may have a function header appearing after it which
 		// was copied out of the ancestor file.
 		//
 		out[0].write(buf, ptr, eol - ptr);
 
 		SCAN: for (ptr = eol; ptr < endOffset; ptr = eol) {
 			eol = nextLF(buf, ptr);
 
 			if (eol - ptr < old.length + 1) {
 				// Line isn't long enough to mention the state of each
 				// ancestor. It must be the end of the hunk.
 				break SCAN;
 			}
 
 			switch (buf[ptr]) {
 			case ' ':
 			case '-':
 			case '+':
 				break;
 
 			default:
 				// Line can't possibly be part of this hunk; the first
 				// ancestor information isn't recognizable.
 				//
 				break SCAN;
 			}
 
 			int delcnt = 0;
 			for (int ancestor = 0; ancestor < old.length; ancestor++) {
 				switch (buf[ptr + ancestor]) {
 				case '-':
 					delcnt++;
 					out[ancestor].write(buf, ptr, eol - ptr);
 					continue;
 
 				case ' ':
 					out[ancestor].write(buf, ptr, eol - ptr);
 					continue;
 
 				case '+':
 					continue;
 
 				default:
 					break SCAN;
 				}
 			}
 			if (delcnt < old.length) {
 				// This line appears in the new file if it wasn't deleted
 				// relative to all ancestors.
 				//
 				out[old.length].write(buf, ptr, eol - ptr);
 			}
 		}
 	}
 
 	void extractFileLines(final StringBuilder sb, final String[] text,
 			final int[] offsets) {
 		final byte[] buf = file.buf;
 		int ptr = startOffset;
 		int eol = nextLF(buf, ptr);
 		if (endOffset <= eol)
 			return;
 		copyLine(sb, text, offsets, 0);
 		SCAN: for (ptr = eol; ptr < endOffset; ptr = eol) {
 			eol = nextLF(buf, ptr);
 
 			if (eol - ptr < old.length + 1) {
 				// Line isn't long enough to mention the state of each
 				// ancestor. It must be the end of the hunk.
 				break SCAN;
 			}
 
 			switch (buf[ptr]) {
 			case ' ':
 			case '-':
 			case '+':
 				break;
 
 			default:
 				// Line can't possibly be part of this hunk; the first
 				// ancestor information isn't recognizable.
 				//
 				break SCAN;
 			}
 
 			boolean copied = false;
 			for (int ancestor = 0; ancestor < old.length; ancestor++) {
 				switch (buf[ptr + ancestor]) {
 				case ' ':
 				case '-':
 					if (copied)
 						skipLine(text, offsets, ancestor);
 					else {
 						copyLine(sb, text, offsets, ancestor);
 						copied = true;
 					}
 					continue;
 
 				case '+':
 					continue;
 
 				default:
 					break SCAN;
 				}
 			}
 			if (!copied) {
 				// If none of the ancestors caused the copy then this line
 				// must be new across the board, so it only appears in the
 				// text of the new file.
 				//
 				copyLine(sb, text, offsets, old.length);
 			}
 		}
 	}
 }