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net.clementlevallois.utils.DiffSpelling Maven / Gradle / Ivy
///*
// * Diff Match and Patch
// *
// * Copyright 2006 Google Inc.
// * http://code.google.com/p/google-diff-match-patch/
// *
// * Licensed under the Apache License, Version 2.0 (the "License");
// * you may not use this file except in compliance with the License.
// * You may obtain a copy of the License at
// *
// * http://www.apache.org/licenses/LICENSE-2.0
// *
// * Unless required by applicable law or agreed to in writing, software
// * distributed under the License is distributed on an "AS IS" BASIS,
// * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// * See the License for the specific language governing permissions and
// * limitations under the License.
// */
//package net.clementlevallois.utils;
//
//import java.io.UnsupportedEncodingException;
//import java.net.URLDecoder;
//import java.net.URLEncoder;
//import java.util.ArrayList;
//import java.util.Arrays;
//import java.util.HashMap;
//import java.util.LinkedList;
//import java.util.List;
//import java.util.ListIterator;
//import java.util.Map;
//import java.util.Stack;
//import java.util.regex.Matcher;
//import java.util.regex.Pattern;
//
///*
// * Functions for diff, match and patch.
// * Computes the difference between two texts to create a patch.
// * Applies the patch onto another text, allowing for errors.
// *
// * @author [email protected] (Neil Fraser)
// */
///**
// * Class containing the diff, match and patch methods. Also contains the
// * behaviour settings.
// */
//public class DiffSpelling {
//
// // Defaults.
// // Set these on your diff_match_patch instance to override the defaults.
// /**
// * Number of seconds to map a diff before giving up (0 for infinity).
// */
// public float Diff_Timeout = 1.0f;
// /**
// * Cost of an empty edit operation in terms of edit characters.
// */
// public short Diff_EditCost = 4;
// /**
// * At what point is no match declared (0.0 = perfection, 1.0 = very loose).
// */
// public float Match_Threshold = 0.5f;
// /**
// * How far to search for a match (0 = exact location, 1000+ = broad match).
// * A match this many characters away from the expected location will add 1.0
// * to the score (0.0 is a perfect match).
// */
// public int Match_Distance = 1000;
// /**
// * When deleting a large block of text (over ~64 characters), how close do
// * the contents have to be to match the expected contents. (0.0 =
// * perfection, 1.0 = very loose). Note that Match_Threshold controls how
// * closely the end points of a delete need to match.
// */
// public float Patch_DeleteThreshold = 0.5f;
// /**
// * Chunk size for context length.
// */
// public short Patch_Margin = 4;
// /**
// * The number of bits in an int.
// */
// private short Match_MaxBits = 32;
//
// /**
// * Internal class for returning results from diff_linesToChars(). Other less
// * paranoid languages just use a three-element array.
// */
// protected static class LinesToCharsResult {
//
// /**
// *
// */
// protected String chars1;
//
// /**
// *
// */
// protected String chars2;
//
// /**
// *
// */
// protected List lineArray;
//
// /**
// *
// * @param chars1
// * @param chars2
// * @param lineArray
// */
// protected LinesToCharsResult(String chars1, String chars2,
// List lineArray) {
// this.chars1 = chars1;
// this.chars2 = chars2;
// this.lineArray = lineArray;
// }
// }
//
// // DIFF FUNCTIONS
// /**
// * The data structure representing a diff is a Linked list of Diff objects:
// * {Diff(Operation.DELETE, "Hello"), Diff(Operation.INSERT, "Goodbye"),
// * Diff(Operation.EQUAL, " world.")} which means: delete "Hello", add
// * "Goodbye" and keep " world."
// */
// public enum Operation {
//
// /**
// *
// */
// DELETE,
//
// /**
// *
// */
// INSERT,
//
// /**
// *
// */
// EQUAL
// }
//
// /**
// * Find the differences between two texts. Run a faster, slightly less
// * optimal diff. This method allows the 'checklines' of diff_main() to be
// * optional. Most of the time checklines is wanted, so default to true.
// *
// * @param text1 Old string to be diffed.
// * @param text2 New string to be diffed.
// * @return Linked List of Diff objects.
// */
// public LinkedList diff_main(String text1, String text2) {
// return diff_main(text1, text2, true);
// }
//
// /**
// * Find the differences between two texts.
// *
// * @param text1 Old string to be diffed.
// * @param text2 New string to be diffed.
// * @param checklines Speedup flag. If false, then don't run a line-level
// * diff first to identify the changed areas. If true, then run a faster
// * slightly less optimal diff.
// * @return Linked List of Diff objects.
// */
// public LinkedList diff_main(String text1, String text2,
// boolean checklines) {
// // Set a deadline by which time the diff must be complete.
// long deadline;
// if (Diff_Timeout <= 0) {
// deadline = Long.MAX_VALUE;
// } else {
// deadline = System.currentTimeMillis() + (long) (Diff_Timeout * 1000);
// }
// return diff_main(text1, text2, checklines, deadline);
// }
//
// /**
// * Find the differences between two texts. Simplifies the problem by
// * stripping any common prefix or suffix off the texts before diffing.
// *
// * @param text1 Old string to be diffed.
// * @param text2 New string to be diffed.
// * @param checklines Speedup flag. If false, then don't run a line-level
// * diff first to identify the changed areas. If true, then run a faster
// * slightly less optimal diff.
// * @param deadline Time when the diff should be complete by. Used internally
// * for recursive calls. Users should set DiffTimeout instead.
// * @return Linked List of Diff objects.
// */
// private LinkedList diff_main(String text1, String text2,
// boolean checklines, long deadline) {
// // Check for null inputs.
// if (text1 == null || text2 == null) {
// throw new IllegalArgumentException("Null inputs. (diff_main)");
// }
//
// // Check for equality (speedup).
// LinkedList diffs;
// if (text1.equals(text2)) {
// diffs = new LinkedList();
// if (text1.length() != 0) {
// diffs.add(new Diff(Operation.EQUAL, text1));
// }
// return diffs;
// }
//
// // Trim off common prefix (speedup).
// int commonlength = diff_commonPrefix(text1, text2);
// String commonprefix = text1.substring(0, commonlength);
// text1 = text1.substring(commonlength);
// text2 = text2.substring(commonlength);
//
// // Trim off common suffix (speedup).
// commonlength = diff_commonSuffix(text1, text2);
// String commonsuffix = text1.substring(text1.length() - commonlength);
// text1 = text1.substring(0, text1.length() - commonlength);
// text2 = text2.substring(0, text2.length() - commonlength);
//
// // Compute the diff on the middle block.
// diffs = diff_compute(text1, text2, checklines, deadline);
//
// // Restore the prefix and suffix.
// if (commonprefix.length() != 0) {
// diffs.addFirst(new Diff(Operation.EQUAL, commonprefix));
// }
// if (commonsuffix.length() != 0) {
// diffs.addLast(new Diff(Operation.EQUAL, commonsuffix));
// }
//
// diff_cleanupMerge(diffs);
// return diffs;
// }
//
// /**
// * Find the differences between two texts. Assumes that the texts do not
// * have any common prefix or suffix.
// *
// * @param text1 Old string to be diffed.
// * @param text2 New string to be diffed.
// * @param checklines Speedup flag. If false, then don't run a line-level
// * diff first to identify the changed areas. If true, then run a faster
// * slightly less optimal diff.
// * @param deadline Time when the diff should be complete by.
// * @return Linked List of Diff objects.
// */
// private LinkedList diff_compute(String text1, String text2,
// boolean checklines, long deadline) {
// LinkedList diffs = new LinkedList();
//
// if (text1.length() == 0) {
// // Just add some text (speedup).
// diffs.add(new Diff(Operation.INSERT, text2));
// return diffs;
// }
//
// if (text2.length() == 0) {
// // Just delete some text (speedup).
// diffs.add(new Diff(Operation.DELETE, text1));
// return diffs;
// }
//
// {
// // New scope so as to garbage collect longtext and shorttext.
// String longtext = text1.length() > text2.length() ? text1 : text2;
// String shorttext = text1.length() > text2.length() ? text2 : text1;
// int i = longtext.indexOf(shorttext);
// if (i != -1) {
// // Shorter text is inside the longer text (speedup).
// Operation op = (text1.length() > text2.length())
// ? Operation.DELETE : Operation.INSERT;
// diffs.add(new Diff(op, longtext.substring(0, i)));
// diffs.add(new Diff(Operation.EQUAL, shorttext));
// diffs.add(new Diff(op, longtext.substring(i + shorttext.length())));
// return diffs;
// }
//
// if (shorttext.length() == 1) {
// // Single character string.
// // After the previous speedup, the character can't be an equality.
// diffs.add(new Diff(Operation.DELETE, text1));
// diffs.add(new Diff(Operation.INSERT, text2));
// return diffs;
// }
// }
//
// // Check to see if the problem can be split in two.
// String[] hm = diff_halfMatch(text1, text2);
// if (hm != null) {
// // A half-match was found, sort out the return data.
// String text1_a = hm[0];
// String text1_b = hm[1];
// String text2_a = hm[2];
// String text2_b = hm[3];
// String mid_common = hm[4];
// // Send both pairs off for separate processing.
// LinkedList diffs_a = diff_main(text1_a, text2_a,
// checklines, deadline);
// LinkedList diffs_b = diff_main(text1_b, text2_b,
// checklines, deadline);
// // Merge the results.
// diffs = diffs_a;
// diffs.add(new Diff(Operation.EQUAL, mid_common));
// diffs.addAll(diffs_b);
// return diffs;
// }
//
// if (checklines && text1.length() > 100 && text2.length() > 100) {
// return diff_lineMode(text1, text2, deadline);
// }
//
// return diff_bisect(text1, text2, deadline);
// }
//
// /**
// * Do a quick line-level diff on both strings, then rediff the parts for
// * greater accuracy. This speedup can produce non-minimal diffs.
// *
// * @param text1 Old string to be diffed.
// * @param text2 New string to be diffed.
// * @param deadline Time when the diff should be complete by.
// * @return Linked List of Diff objects.
// */
// private LinkedList diff_lineMode(String text1, String text2,
// long deadline) {
// // Scan the text on a line-by-line basis first.
// LinesToCharsResult b = diff_linesToChars(text1, text2);
// text1 = b.chars1;
// text2 = b.chars2;
// List linearray = b.lineArray;
//
// LinkedList diffs = diff_main(text1, text2, false, deadline);
//
// // Convert the diff back to original text.
// diff_charsToLines(diffs, linearray);
// // Eliminate freak matches (e.g. blank lines)
// diff_cleanupSemantic(diffs);
//
// // Rediff any replacement blocks, this time character-by-character.
// // Add a dummy entry at the end.
// diffs.add(new Diff(Operation.EQUAL, ""));
// int count_delete = 0;
// int count_insert = 0;
// String text_delete = "";
// String text_insert = "";
// ListIterator pointer = diffs.listIterator();
// Diff thisDiff = pointer.next();
// while (thisDiff != null) {
// switch (thisDiff.operation) {
// case INSERT:
// count_insert++;
// text_insert += thisDiff.text;
// break;
// case DELETE:
// count_delete++;
// text_delete += thisDiff.text;
// break;
// case EQUAL:
// // Upon reaching an equality, check for prior redundancies.
// if (count_delete >= 1 && count_insert >= 1) {
// // Delete the offending records and add the merged ones.
// pointer.previous();
// for (int j = 0; j < count_delete + count_insert; j++) {
// pointer.previous();
// pointer.remove();
// }
// for (Diff newDiff : diff_main(text_delete, text_insert, false,
// deadline)) {
// pointer.add(newDiff);
// }
// }
// count_insert = 0;
// count_delete = 0;
// text_delete = "";
// text_insert = "";
// break;
// }
// thisDiff = pointer.hasNext() ? pointer.next() : null;
// }
// diffs.removeLast(); // Remove the dummy entry at the end.
//
// return diffs;
// }
//
// /**
// * Find the 'middle snake' of a diff, split the problem in two and return
// * the recursively constructed diff. See Myers 1986 paper: An O(ND)
// * Difference Algorithm and Its Variations.
// *
// * @param text1 Old string to be diffed.
// * @param text2 New string to be diffed.
// * @param deadline Time at which to bail if not yet complete.
// * @return LinkedList of Diff objects.
// */
// protected LinkedList diff_bisect(String text1, String text2,
// long deadline) {
// // Cache the text lengths to prevent multiple calls.
// int text1_length = text1.length();
// int text2_length = text2.length();
// int max_d = (text1_length + text2_length + 1) / 2;
// int v_offset = max_d;
// int v_length = 2 * max_d;
// int[] v1 = new int[v_length];
// int[] v2 = new int[v_length];
// for (int x = 0; x < v_length; x++) {
// v1[x] = -1;
// v2[x] = -1;
// }
// v1[v_offset + 1] = 0;
// v2[v_offset + 1] = 0;
// int delta = text1_length - text2_length;
// // If the total number of characters is odd, then the front path will
// // collide with the reverse path.
// boolean front = (delta % 2 != 0);
// // Offsets for start and end of k loop.
// // Prevents mapping of space beyond the grid.
// int k1start = 0;
// int k1end = 0;
// int k2start = 0;
// int k2end = 0;
// for (int d = 0; d < max_d; d++) {
// // Bail out if deadline is reached.
// if (System.currentTimeMillis() > deadline) {
// break;
// }
//
// // Walk the front path one step.
// for (int k1 = -d + k1start; k1 <= d - k1end; k1 += 2) {
// int k1_offset = v_offset + k1;
// int x1;
// if (k1 == -d || (k1 != d && v1[k1_offset - 1] < v1[k1_offset + 1])) {
// x1 = v1[k1_offset + 1];
// } else {
// x1 = v1[k1_offset - 1] + 1;
// }
// int y1 = x1 - k1;
// while (x1 < text1_length && y1 < text2_length
// && text1.charAt(x1) == text2.charAt(y1)) {
// x1++;
// y1++;
// }
// v1[k1_offset] = x1;
// if (x1 > text1_length) {
// // Ran off the right of the graph.
// k1end += 2;
// } else if (y1 > text2_length) {
// // Ran off the bottom of the graph.
// k1start += 2;
// } else if (front) {
// int k2_offset = v_offset + delta - k1;
// if (k2_offset >= 0 && k2_offset < v_length && v2[k2_offset] != -1) {
// // Mirror x2 onto top-left coordinate system.
// int x2 = text1_length - v2[k2_offset];
// if (x1 >= x2) {
// // Overlap detected.
// return diff_bisectSplit(text1, text2, x1, y1, deadline);
// }
// }
// }
// }
//
// // Walk the reverse path one step.
// for (int k2 = -d + k2start; k2 <= d - k2end; k2 += 2) {
// int k2_offset = v_offset + k2;
// int x2;
// if (k2 == -d || (k2 != d && v2[k2_offset - 1] < v2[k2_offset + 1])) {
// x2 = v2[k2_offset + 1];
// } else {
// x2 = v2[k2_offset - 1] + 1;
// }
// int y2 = x2 - k2;
// while (x2 < text1_length && y2 < text2_length
// && text1.charAt(text1_length - x2 - 1)
// == text2.charAt(text2_length - y2 - 1)) {
// x2++;
// y2++;
// }
// v2[k2_offset] = x2;
// if (x2 > text1_length) {
// // Ran off the left of the graph.
// k2end += 2;
// } else if (y2 > text2_length) {
// // Ran off the top of the graph.
// k2start += 2;
// } else if (!front) {
// int k1_offset = v_offset + delta - k2;
// if (k1_offset >= 0 && k1_offset < v_length && v1[k1_offset] != -1) {
// int x1 = v1[k1_offset];
// int y1 = v_offset + x1 - k1_offset;
// // Mirror x2 onto top-left coordinate system.
// x2 = text1_length - x2;
// if (x1 >= x2) {
// // Overlap detected.
// return diff_bisectSplit(text1, text2, x1, y1, deadline);
// }
// }
// }
// }
// }
// // Diff took too long and hit the deadline or
// // number of diffs equals number of characters, no commonality at all.
// LinkedList diffs = new LinkedList();
// diffs.add(new Diff(Operation.DELETE, text1));
// diffs.add(new Diff(Operation.INSERT, text2));
// return diffs;
// }
//
// /**
// * Given the location of the 'middle snake', split the diff in two parts and
// * recurse.
// *
// * @param text1 Old string to be diffed.
// * @param text2 New string to be diffed.
// * @param x Index of split point in text1.
// * @param y Index of split point in text2.
// * @param deadline Time at which to bail if not yet complete.
// * @return LinkedList of Diff objects.
// */
// private LinkedList diff_bisectSplit(String text1, String text2,
// int x, int y, long deadline) {
// String text1a = text1.substring(0, x);
// String text2a = text2.substring(0, y);
// String text1b = text1.substring(x);
// String text2b = text2.substring(y);
//
// // Compute both diffs serially.
// LinkedList diffs = diff_main(text1a, text2a, false, deadline);
// LinkedList diffsb = diff_main(text1b, text2b, false, deadline);
//
// diffs.addAll(diffsb);
// return diffs;
// }
//
// /**
// * Split two texts into a list of strings. Reduce the texts to a string of
// * hashes where each Unicode character represents one line.
// *
// * @param text1 First string.
// * @param text2 Second string.
// * @return An object containing the encoded text1, the encoded text2 and the
// * List of unique strings. The zeroth element of the List of unique strings
// * is intentionally blank.
// */
// protected LinesToCharsResult diff_linesToChars(String text1, String text2) {
// List lineArray = new ArrayList();
// Map lineHash = new HashMap();
// // e.g. linearray[4] == "Hello\n"
// // e.g. linehash.get("Hello\n") == 4
//
// // "\x00" is a valid character, but various debuggers don't like it.
// // So we'll insert a junk entry to avoid generating a null character.
// lineArray.add("");
//
// String chars1 = diff_linesToCharsMunge(text1, lineArray, lineHash);
// String chars2 = diff_linesToCharsMunge(text2, lineArray, lineHash);
// return new LinesToCharsResult(chars1, chars2, lineArray);
// }
//
// /**
// * Split a text into a list of strings. Reduce the texts to a string of
// * hashes where each Unicode character represents one line.
// *
// * @param text String to encode.
// * @param lineArray List of unique strings.
// * @param lineHash Map of strings to indices.
// * @return Encoded string.
// */
// private String diff_linesToCharsMunge(String text, List lineArray,
// Map lineHash) {
// int lineStart = 0;
// int lineEnd = -1;
// String line;
// StringBuilder chars = new StringBuilder();
// // Walk the text, pulling out a substring for each line.
// // text.split('\n') would would temporarily double our memory footprint.
// // Modifying text would create many large strings to garbage collect.
// while (lineEnd < text.length() - 1) {
// lineEnd = text.indexOf('\n', lineStart);
// if (lineEnd == -1) {
// lineEnd = text.length() - 1;
// }
// line = text.substring(lineStart, lineEnd + 1);
// lineStart = lineEnd + 1;
//
// if (lineHash.containsKey(line)) {
// chars.append(String.valueOf((char) (int) lineHash.get(line)));
// } else {
// lineArray.add(line);
// lineHash.put(line, lineArray.size() - 1);
// chars.append(String.valueOf((char) (lineArray.size() - 1)));
// }
// }
// return chars.toString();
// }
//
// /**
// * Rehydrate the text in a diff from a string of line hashes to real lines
// * of text.
// *
// * @param diffs LinkedList of Diff objects.
// * @param lineArray List of unique strings.
// */
// protected void diff_charsToLines(LinkedList diffs,
// List lineArray) {
// StringBuilder text;
// for (Diff diff : diffs) {
// text = new StringBuilder();
// for (int y = 0; y < diff.text.length(); y++) {
// text.append(lineArray.get(diff.text.charAt(y)));
// }
// diff.text = text.toString();
// }
// }
//
// /**
// * Determine the common prefix of two strings
// *
// * @param text1 First string.
// * @param text2 Second string.
// * @return The number of characters common to the start of each string.
// */
// public int diff_commonPrefix(String text1, String text2) {
// // Performance analysis: http://neil.fraser.name/news/2007/10/09/
// int n = Math.min(text1.length(), text2.length());
// for (int i = 0; i < n; i++) {
// if (text1.charAt(i) != text2.charAt(i)) {
// return i;
// }
// }
// return n;
// }
//
// /**
// * Determine the common suffix of two strings
// *
// * @param text1 First string.
// * @param text2 Second string.
// * @return The number of characters common to the end of each string.
// */
// public int diff_commonSuffix(String text1, String text2) {
// // Performance analysis: http://neil.fraser.name/news/2007/10/09/
// int text1_length = text1.length();
// int text2_length = text2.length();
// int n = Math.min(text1_length, text2_length);
// for (int i = 1; i <= n; i++) {
// if (text1.charAt(text1_length - i) != text2.charAt(text2_length - i)) {
// return i - 1;
// }
// }
// return n;
// }
//
// /**
// * Determine if the suffix of one string is the prefix of another.
// *
// * @param text1 First string.
// * @param text2 Second string.
// * @return The number of characters common to the end of the first string
// * and the start of the second string.
// */
// protected int diff_commonOverlap(String text1, String text2) {
// // Cache the text lengths to prevent multiple calls.
// int text1_length = text1.length();
// int text2_length = text2.length();
// // Eliminate the null case.
// if (text1_length == 0 || text2_length == 0) {
// return 0;
// }
// // Truncate the longer string.
// if (text1_length > text2_length) {
// text1 = text1.substring(text1_length - text2_length);
// } else if (text1_length < text2_length) {
// text2 = text2.substring(0, text1_length);
// }
// int text_length = Math.min(text1_length, text2_length);
// // Quick check for the worst case.
// if (text1.equals(text2)) {
// return text_length;
// }
//
// // Start by looking for a single character match
// // and increase length until no match is found.
// // Performance analysis: http://neil.fraser.name/news/2010/11/04/
// int best = 0;
// int length = 1;
// while (true) {
// String pattern = text1.substring(text_length - length);
// int found = text2.indexOf(pattern);
// if (found == -1) {
// return best;
// }
// length += found;
// if (found == 0 || text1.substring(text_length - length).equals(
// text2.substring(0, length))) {
// best = length;
// length++;
// }
// }
// }
//
// /**
// * Do the two texts share a substring which is at least half the length of
// * the longer text? This speedup can produce non-minimal diffs.
// *
// * @param text1 First string.
// * @param text2 Second string.
// * @return Five element String array, containing the prefix of text1, the
// * suffix of text1, the prefix of text2, the suffix of text2 and the common
// * middle. Or null if there was no match.
// */
// protected String[] diff_halfMatch(String text1, String text2) {
// if (Diff_Timeout <= 0) {
// // Don't risk returning a non-optimal diff if we have unlimited time.
// return null;
// }
// String longtext = text1.length() > text2.length() ? text1 : text2;
// String shorttext = text1.length() > text2.length() ? text2 : text1;
// if (longtext.length() < 4 || shorttext.length() * 2 < longtext.length()) {
// return null; // Pointless.
// }
//
// // First check if the second quarter is the seed for a half-match.
// String[] hm1 = diff_halfMatchI(longtext, shorttext,
// (longtext.length() + 3) / 4);
// // Check again based on the third quarter.
// String[] hm2 = diff_halfMatchI(longtext, shorttext,
// (longtext.length() + 1) / 2);
// String[] hm;
// if (hm1 == null && hm2 == null) {
// return null;
// } else if (hm2 == null) {
// hm = hm1;
// } else if (hm1 == null) {
// hm = hm2;
// } else {
// // Both matched. Select the longest.
// hm = hm1[4].length() > hm2[4].length() ? hm1 : hm2;
// }
//
// // A half-match was found, sort out the return data.
// if (text1.length() > text2.length()) {
// return hm;
// //return new String[]{hm[0], hm[1], hm[2], hm[3], hm[4]};
// } else {
// return new String[]{hm[2], hm[3], hm[0], hm[1], hm[4]};
// }
// }
//
// /**
// * Does a substring of shorttext exist within longtext such that the
// * substring is at least half the length of longtext?
// *
// * @param longtext Longer string.
// * @param shorttext Shorter string.
// * @param i Start index of quarter length substring within longtext.
// * @return Five element String array, containing the prefix of longtext, the
// * suffix of longtext, the prefix of shorttext, the suffix of shorttext and
// * the common middle. Or null if there was no match.
// */
// private String[] diff_halfMatchI(String longtext, String shorttext, int i) {
// // Start with a 1/4 length substring at position i as a seed.
// String seed = longtext.substring(i, i + longtext.length() / 4);
// int j = -1;
// String best_common = "";
// String best_longtext_a = "", best_longtext_b = "";
// String best_shorttext_a = "", best_shorttext_b = "";
// while ((j = shorttext.indexOf(seed, j + 1)) != -1) {
// int prefixLength = diff_commonPrefix(longtext.substring(i),
// shorttext.substring(j));
// int suffixLength = diff_commonSuffix(longtext.substring(0, i),
// shorttext.substring(0, j));
// if (best_common.length() < suffixLength + prefixLength) {
// best_common = shorttext.substring(j - suffixLength, j)
// + shorttext.substring(j, j + prefixLength);
// best_longtext_a = longtext.substring(0, i - suffixLength);
// best_longtext_b = longtext.substring(i + prefixLength);
// best_shorttext_a = shorttext.substring(0, j - suffixLength);
// best_shorttext_b = shorttext.substring(j + prefixLength);
// }
// }
// if (best_common.length() * 2 >= longtext.length()) {
// return new String[]{best_longtext_a, best_longtext_b,
// best_shorttext_a, best_shorttext_b, best_common};
// } else {
// return null;
// }
// }
//
// /**
// * Reduce the number of edits by eliminating semantically trivial
// * equalities.
// *
// * @param diffs LinkedList of Diff objects.
// */
// public void diff_cleanupSemantic(LinkedList diffs) {
// if (diffs.isEmpty()) {
// return;
// }
// boolean changes = false;
// Stack equalities = new Stack(); // Stack of qualities.
// String lastequality = null; // Always equal to equalities.lastElement().text
// ListIterator pointer = diffs.listIterator();
// // Number of characters that changed prior to the equality.
// int length_insertions1 = 0;
// int length_deletions1 = 0;
// // Number of characters that changed after the equality.
// int length_insertions2 = 0;
// int length_deletions2 = 0;
// Diff thisDiff = pointer.next();
// while (thisDiff != null) {
// if (thisDiff.operation == Operation.EQUAL) {
// // Equality found.
// equalities.push(thisDiff);
// length_insertions1 = length_insertions2;
// length_deletions1 = length_deletions2;
// length_insertions2 = 0;
// length_deletions2 = 0;
// lastequality = thisDiff.text;
// } else {
// // An insertion or deletion.
// if (thisDiff.operation == Operation.INSERT) {
// length_insertions2 += thisDiff.text.length();
// } else {
// length_deletions2 += thisDiff.text.length();
// }
// // Eliminate an equality that is smaller or equal to the edits on both
// // sides of it.
// if (lastequality != null && (lastequality.length()
// <= Math.max(length_insertions1, length_deletions1))
// && (lastequality.length()
// <= Math.max(length_insertions2, length_deletions2))) {
// //System.out.println("Splitting: '" + lastequality + "'");
// // Walk back to offending equality.
// while (thisDiff != equalities.lastElement()) {
// thisDiff = pointer.previous();
// }
// pointer.next();
//
// // Replace equality with a delete.
// pointer.set(new Diff(Operation.DELETE, lastequality));
// // Insert a corresponding an insert.
// pointer.add(new Diff(Operation.INSERT, lastequality));
//
// equalities.pop(); // Throw away the equality we just deleted.
// if (!equalities.empty()) {
// // Throw away the previous equality (it needs to be reevaluated).
// equalities.pop();
// }
// if (equalities.empty()) {
// // There are no previous equalities, walk back to the start.
// while (pointer.hasPrevious()) {
// pointer.previous();
// }
// } else {
// // There is a safe equality we can fall back to.
// thisDiff = equalities.lastElement();
// while (thisDiff != pointer.previous()) {
// // Intentionally empty loop.
// }
// }
//
// length_insertions1 = 0; // Reset the counters.
// length_insertions2 = 0;
// length_deletions1 = 0;
// length_deletions2 = 0;
// lastequality = null;
// changes = true;
// }
// }
// thisDiff = pointer.hasNext() ? pointer.next() : null;
// }
//
// // Normalize the diff.
// if (changes) {
// diff_cleanupMerge(diffs);
// }
// diff_cleanupSemanticLossless(diffs);
//
// // Find any overlaps between deletions and insertions.
// // e.g: abcxxxxxxdef
// // -> abcxxxdef
// // e.g: xxxabcdefxxx
// // -> def xxxabc
// // Only extract an overlap if it is as big as the edit ahead or behind it.
// pointer = diffs.listIterator();
// Diff prevDiff = null;
// thisDiff = null;
// if (pointer.hasNext()) {
// prevDiff = pointer.next();
// if (pointer.hasNext()) {
// thisDiff = pointer.next();
// }
// }
// while (thisDiff != null) {
// if (prevDiff.operation == Operation.DELETE
// && thisDiff.operation == Operation.INSERT) {
// String deletion = prevDiff.text;
// String insertion = thisDiff.text;
// int overlap_length1 = this.diff_commonOverlap(deletion, insertion);
// int overlap_length2 = this.diff_commonOverlap(insertion, deletion);
// if (overlap_length1 >= overlap_length2) {
// if (overlap_length1 >= deletion.length() / 2.0
// || overlap_length1 >= insertion.length() / 2.0) {
// // Overlap found. Insert an equality and trim the surrounding edits.
// pointer.previous();
// pointer.add(new Diff(Operation.EQUAL,
// insertion.substring(0, overlap_length1)));
// prevDiff.text =
// deletion.substring(0, deletion.length() - overlap_length1);
// thisDiff.text = insertion.substring(overlap_length1);
// // pointer.add inserts the element before the cursor, so there is
// // no need to step past the new element.
// }
// } else {
// if (overlap_length2 >= deletion.length() / 2.0
// || overlap_length2 >= insertion.length() / 2.0) {
// // Reverse overlap found.
// // Insert an equality and swap and trim the surrounding edits.
// pointer.previous();
// pointer.add(new Diff(Operation.EQUAL,
// deletion.substring(0, overlap_length2)));
// prevDiff.operation = Operation.INSERT;
// prevDiff.text =
// insertion.substring(0, insertion.length() - overlap_length2);
// thisDiff.operation = Operation.DELETE;
// thisDiff.text = deletion.substring(overlap_length2);
// // pointer.add inserts the element before the cursor, so there is
// // no need to step past the new element.
// }
// }
// thisDiff = pointer.hasNext() ? pointer.next() : null;
// }
// prevDiff = thisDiff;
// thisDiff = pointer.hasNext() ? pointer.next() : null;
// }
// }
//
// /**
// * Look for single edits surrounded on both sides by equalities which can be
// * shifted sideways to align the edit to a word boundary. e.g: The cat
// * c ame. -> The cat came.
// *
// * @param diffs LinkedList of Diff objects.
// */
// public void diff_cleanupSemanticLossless(LinkedList diffs) {
// String equality1, edit, equality2;
// String commonString;
// int commonOffset;
// int score, bestScore;
// String bestEquality1, bestEdit, bestEquality2;
// // Create a new iterator at the start.
// ListIterator pointer = diffs.listIterator();
// Diff prevDiff = pointer.hasNext() ? pointer.next() : null;
// Diff thisDiff = pointer.hasNext() ? pointer.next() : null;
// Diff nextDiff = pointer.hasNext() ? pointer.next() : null;
// // Intentionally ignore the first and last element (don't need checking).
// while (nextDiff != null) {
// if (prevDiff.operation == Operation.EQUAL
// && nextDiff.operation == Operation.EQUAL) {
// // This is a single edit surrounded by equalities.
// equality1 = prevDiff.text;
// edit = thisDiff.text;
// equality2 = nextDiff.text;
//
// // First, shift the edit as far left as possible.
// commonOffset = diff_commonSuffix(equality1, edit);
// if (commonOffset != 0) {
// commonString = edit.substring(edit.length() - commonOffset);
// equality1 = equality1.substring(0, equality1.length() - commonOffset);
// edit = commonString + edit.substring(0, edit.length() - commonOffset);
// equality2 = commonString + equality2;
// }
//
// // Second, step character by character right, looking for the best fit.
// bestEquality1 = equality1;
// bestEdit = edit;
// bestEquality2 = equality2;
// bestScore = diff_cleanupSemanticScore(equality1, edit)
// + diff_cleanupSemanticScore(edit, equality2);
// while (edit.length() != 0 && equality2.length() != 0
// && edit.charAt(0) == equality2.charAt(0)) {
// equality1 += edit.charAt(0);
// edit = edit.substring(1) + equality2.charAt(0);
// equality2 = equality2.substring(1);
// score = diff_cleanupSemanticScore(equality1, edit)
// + diff_cleanupSemanticScore(edit, equality2);
// // The >= encourages trailing rather than leading whitespace on edits.
// if (score >= bestScore) {
// bestScore = score;
// bestEquality1 = equality1;
// bestEdit = edit;
// bestEquality2 = equality2;
// }
// }
//
// if (!prevDiff.text.equals(bestEquality1)) {
// // We have an improvement, save it back to the diff.
// if (bestEquality1.length() != 0) {
// prevDiff.text = bestEquality1;
// } else {
// pointer.previous(); // Walk past nextDiff.
// pointer.previous(); // Walk past thisDiff.
// pointer.previous(); // Walk past prevDiff.
// pointer.remove(); // Delete prevDiff.
// pointer.next(); // Walk past thisDiff.
// pointer.next(); // Walk past nextDiff.
// }
// thisDiff.text = bestEdit;
// if (bestEquality2.length() != 0) {
// nextDiff.text = bestEquality2;
// } else {
// pointer.remove(); // Delete nextDiff.
// nextDiff = thisDiff;
// thisDiff = prevDiff;
// }
// }
// }
// prevDiff = thisDiff;
// thisDiff = nextDiff;
// nextDiff = pointer.hasNext() ? pointer.next() : null;
// }
// }
//
// /**
// * Given two strings, compute a score representing whether the internal
// * boundary falls on logical boundaries. Scores range from 6 (best) to 0
// * (worst).
// *
// * @param one First string.
// * @param two Second string.
// * @return The score.
// */
// private int diff_cleanupSemanticScore(String one, String two) {
// if (one.length() == 0 || two.length() == 0) {
// // Edges are the best.
// return 6;
// }
//
// // Each port of this function behaves slightly differently due to
// // subtle differences in each language's definition of things like
// // 'whitespace'. Since this function's purpose is largely cosmetic,
// // the choice has been made to use each language's native features
// // rather than force total conformity.
// char char1 = one.charAt(one.length() - 1);
// char char2 = two.charAt(0);
// boolean nonAlphaNumeric1 = !Character.isLetterOrDigit(char1);
// boolean nonAlphaNumeric2 = !Character.isLetterOrDigit(char2);
// boolean whitespace1 = nonAlphaNumeric1 && Character.isWhitespace(char1);
// boolean whitespace2 = nonAlphaNumeric2 && Character.isWhitespace(char2);
// boolean lineBreak1 = whitespace1
// && Character.getType(char1) == Character.CONTROL;
// boolean lineBreak2 = whitespace2
// && Character.getType(char2) == Character.CONTROL;
// boolean blankLine1 = lineBreak1 && BLANKLINEEND.matcher(one).find();
// boolean blankLine2 = lineBreak2 && BLANKLINESTART.matcher(two).find();
//
// if (blankLine1 || blankLine2) {
// // Five points for blank lines.
// return 5;
// } else if (lineBreak1 || lineBreak2) {
// // Four points for line breaks.
// return 4;
// } else if (nonAlphaNumeric1 && !whitespace1 && whitespace2) {
// // Three points for end of sentences.
// return 3;
// } else if (whitespace1 || whitespace2) {
// // Two points for whitespace.
// return 2;
// } else if (nonAlphaNumeric1 || nonAlphaNumeric2) {
// // One point for non-alphanumeric.
// return 1;
// }
// return 0;
// }
// // Define some regex patterns for matching boundaries.
// private Pattern BLANKLINEEND = Pattern.compile("\\n\\r?\\n\\Z", Pattern.DOTALL);
// private Pattern BLANKLINESTART = Pattern.compile("\\A\\r?\\n\\r?\\n", Pattern.DOTALL);
//
// /**
// * Reduce the number of edits by eliminating operationally trivial
// * equalities.
// *
// * @param diffs LinkedList of Diff objects.
// */
// public void diff_cleanupEfficiency(LinkedList diffs) {
// if (diffs.isEmpty()) {
// return;
// }
// boolean changes = false;
// Stack equalities = new Stack(); // Stack of equalities.
// String lastequality = null; // Always equal to equalities.lastElement().text
// ListIterator pointer = diffs.listIterator();
// // Is there an insertion operation before the last equality.
// boolean pre_ins = false;
// // Is there a deletion operation before the last equality.
// boolean pre_del = false;
// // Is there an insertion operation after the last equality.
// boolean post_ins = false;
// // Is there a deletion operation after the last equality.
// boolean post_del = false;
// Diff thisDiff = pointer.next();
// Diff safeDiff = thisDiff; // The last Diff that is known to be unsplitable.
// while (thisDiff != null) {
// if (thisDiff.operation == Operation.EQUAL) {
// // Equality found.
// if (thisDiff.text.length() < Diff_EditCost && (post_ins || post_del)) {
// // Candidate found.
// equalities.push(thisDiff);
// pre_ins = post_ins;
// pre_del = post_del;
// lastequality = thisDiff.text;
// } else {
// // Not a candidate, and can never become one.
// equalities.clear();
// lastequality = null;
// safeDiff = thisDiff;
// }
// post_ins = post_del = false;
// } else {
// // An insertion or deletion.
// if (thisDiff.operation == Operation.DELETE) {
// post_del = true;
// } else {
// post_ins = true;
// }
// /*
// * Five types to be split:
// * A BXYC D
// * A XC D
// * A BXC
// * AXC D
// * A BXC
// */
// if (lastequality != null
// && ((pre_ins && pre_del && post_ins && post_del)
// || ((lastequality.length() < Diff_EditCost / 2)
// && ((pre_ins ? 1 : 0) + (pre_del ? 1 : 0)
// + (post_ins ? 1 : 0) + (post_del ? 1 : 0)) == 3))) {
// //System.out.println("Splitting: '" + lastequality + "'");
// // Walk back to offending equality.
// while (thisDiff != equalities.lastElement()) {
// thisDiff = pointer.previous();
// }
// pointer.next();
//
// // Replace equality with a delete.
// pointer.set(new Diff(Operation.DELETE, lastequality));
// // Insert a corresponding an insert.
// pointer.add(thisDiff = new Diff(Operation.INSERT, lastequality));
//
// equalities.pop(); // Throw away the equality we just deleted.
// lastequality = null;
// if (pre_ins && pre_del) {
// // No changes made which could affect previous entry, keep going.
// post_ins = post_del = true;
// equalities.clear();
// safeDiff = thisDiff;
// } else {
// if (!equalities.empty()) {
// // Throw away the previous equality (it needs to be reevaluated).
// equalities.pop();
// }
// if (equalities.empty()) {
// // There are no previous questionable equalities,
// // walk back to the last known safe diff.
// thisDiff = safeDiff;
// } else {
// // There is an equality we can fall back to.
// thisDiff = equalities.lastElement();
// }
// while (thisDiff != pointer.previous()) {
// // Intentionally empty loop.
// }
// post_ins = post_del = false;
// }
//
// changes = true;
// }
// }
// thisDiff = pointer.hasNext() ? pointer.next() : null;
// }
//
// if (changes) {
// diff_cleanupMerge(diffs);
// }
// }
//
// /**
// * Reorder and merge like edit sections. Merge equalities. Any edit section
// * can move as long as it doesn't cross an equality.
// *
// * @param diffs LinkedList of Diff objects.
// */
// public void diff_cleanupMerge(LinkedList diffs) {
// diffs.add(new Diff(Operation.EQUAL, "")); // Add a dummy entry at the end.
// ListIterator pointer = diffs.listIterator();
// int count_delete = 0;
// int count_insert = 0;
// String text_delete = "";
// String text_insert = "";
// Diff thisDiff = pointer.next();
// Diff prevEqual = null;
// int commonlength;
// while (thisDiff != null) {
// switch (thisDiff.operation) {
// case INSERT:
// count_insert++;
// text_insert += thisDiff.text;
// prevEqual = null;
// break;
// case DELETE:
// count_delete++;
// text_delete += thisDiff.text;
// prevEqual = null;
// break;
// case EQUAL:
// if (count_delete + count_insert > 1) {
// boolean both_types = count_delete != 0 && count_insert != 0;
// // Delete the offending records.
// pointer.previous(); // Reverse direction.
// while (count_delete-- > 0) {
// pointer.previous();
// pointer.remove();
// }
// while (count_insert-- > 0) {
// pointer.previous();
// pointer.remove();
// }
// if (both_types) {
// // Factor out any common prefixies.
// commonlength = diff_commonPrefix(text_insert, text_delete);
// if (commonlength != 0) {
// if (pointer.hasPrevious()) {
// thisDiff = pointer.previous();
// assert thisDiff.operation == Operation.EQUAL : "Previous diff should have been an equality.";
// thisDiff.text += text_insert.substring(0, commonlength);
// pointer.next();
// } else {
// pointer.add(new Diff(Operation.EQUAL,
// text_insert.substring(0, commonlength)));
// }
// text_insert = text_insert.substring(commonlength);
// text_delete = text_delete.substring(commonlength);
// }
// // Factor out any common suffixies.
// commonlength = diff_commonSuffix(text_insert, text_delete);
// if (commonlength != 0) {
// thisDiff = pointer.next();
// thisDiff.text = text_insert.substring(text_insert.length()
// - commonlength) + thisDiff.text;
// text_insert = text_insert.substring(0, text_insert.length()
// - commonlength);
// text_delete = text_delete.substring(0, text_delete.length()
// - commonlength);
// pointer.previous();
// }
// }
// // Insert the merged records.
// if (text_delete.length() != 0) {
// pointer.add(new Diff(Operation.DELETE, text_delete));
// }
// if (text_insert.length() != 0) {
// pointer.add(new Diff(Operation.INSERT, text_insert));
// }
// // Step forward to the equality.
// thisDiff = pointer.hasNext() ? pointer.next() : null;
// } else if (prevEqual != null) {
// // Merge this equality with the previous one.
// prevEqual.text += thisDiff.text;
// pointer.remove();
// thisDiff = pointer.previous();
// pointer.next(); // Forward direction
// }
// count_insert = 0;
// count_delete = 0;
// text_delete = "";
// text_insert = "";
// prevEqual = thisDiff;
// break;
// }
// thisDiff = pointer.hasNext() ? pointer.next() : null;
// }
// if (diffs.getLast().text.length() == 0) {
// diffs.removeLast(); // Remove the dummy entry at the end.
// }
//
// /*
// * Second pass: look for single edits surrounded on both sides by equalities
// * which can be shifted sideways to eliminate an equality.
// * e.g: ABA C -> AB AC
// */
// boolean changes = false;
// // Create a new iterator at the start.
// // (As opposed to walking the current one back.)
// pointer = diffs.listIterator();
// Diff prevDiff = pointer.hasNext() ? pointer.next() : null;
// thisDiff = pointer.hasNext() ? pointer.next() : null;
// Diff nextDiff = pointer.hasNext() ? pointer.next() : null;
// // Intentionally ignore the first and last element (don't need checking).
// while (nextDiff != null) {
// if (prevDiff.operation == Operation.EQUAL
// && nextDiff.operation == Operation.EQUAL) {
// // This is a single edit surrounded by equalities.
// if (thisDiff.text.endsWith(prevDiff.text)) {
// // Shift the edit over the previous equality.
// thisDiff.text = prevDiff.text
// + thisDiff.text.substring(0, thisDiff.text.length()
// - prevDiff.text.length());
// nextDiff.text = prevDiff.text + nextDiff.text;
// pointer.previous(); // Walk past nextDiff.
// pointer.previous(); // Walk past thisDiff.
// pointer.previous(); // Walk past prevDiff.
// pointer.remove(); // Delete prevDiff.
// pointer.next(); // Walk past thisDiff.
// thisDiff = pointer.next(); // Walk past nextDiff.
// nextDiff = pointer.hasNext() ? pointer.next() : null;
// changes = true;
// } else if (thisDiff.text.startsWith(nextDiff.text)) {
// // Shift the edit over the next equality.
// prevDiff.text += nextDiff.text;
// thisDiff.text = thisDiff.text.substring(nextDiff.text.length())
// + nextDiff.text;
// pointer.remove(); // Delete nextDiff.
// nextDiff = pointer.hasNext() ? pointer.next() : null;
// changes = true;
// }
// }
// prevDiff = thisDiff;
// thisDiff = nextDiff;
// nextDiff = pointer.hasNext() ? pointer.next() : null;
// }
// // If shifts were made, the diff needs reordering and another shift sweep.
// if (changes) {
// diff_cleanupMerge(diffs);
// }
// }
//
// /**
// * loc is a location in text1, compute and return the equivalent location in
// * text2. e.g. "The cat" vs "The big cat", 1->1, 5->8
// *
// * @param diffs LinkedList of Diff objects.
// * @param loc Location within text1.
// * @return Location within text2.
// */
// public int diff_xIndex(LinkedList diffs, int loc) {
// int chars1 = 0;
// int chars2 = 0;
// int last_chars1 = 0;
// int last_chars2 = 0;
// Diff lastDiff = null;
// for (Diff aDiff : diffs) {
// if (aDiff.operation != Operation.INSERT) {
// // Equality or deletion.
// chars1 += aDiff.text.length();
// }
// if (aDiff.operation != Operation.DELETE) {
// // Equality or insertion.
// chars2 += aDiff.text.length();
// }
// if (chars1 > loc) {
// // Overshot the location.
// lastDiff = aDiff;
// break;
// }
// last_chars1 = chars1;
// last_chars2 = chars2;
// }
// if (lastDiff != null && lastDiff.operation == Operation.DELETE) {
// // The location was deleted.
// return last_chars2;
// }
// // Add the remaining character length.
// return last_chars2 + (loc - last_chars1);
// }
//
// /**
// * Convert a Diff list into a pretty HTML report.
// *
// * @param diffs LinkedList of Diff objects.
// * @return HTML representation.
// */
// public String diff_prettyHtml(LinkedList diffs) {
// StringBuilder html = new StringBuilder();
// for (Diff aDiff : diffs) {
// String text = aDiff.text.replace("&", "&").replace("<", "<")
// .replace(">", ">").replace("\n", "¶").append(text)
// .append(" ");
// break;
// case DELETE:
// html.append("").append(text)
// .append("");
// break;
// case EQUAL:
// html.append("").append(text).append(" ");
// break;
// }
// }
// return html.toString();
// }
//
// /**
// * Compute and return the source text (all equalities and deletions).
// *
// * @param diffs LinkedList of Diff objects.
// * @return Source text.
// */
// public String diff_text1(LinkedList diffs) {
// StringBuilder text = new StringBuilder();
// for (Diff aDiff : diffs) {
// if (aDiff.operation != Operation.INSERT) {
// text.append(aDiff.text);
// }
// }
// return text.toString();
// }
//
// /**
// *
// * @param diffs
// * @return
// */
// public String diff_text1Custom(LinkedList diffs) {
// StringBuilder text = new StringBuilder();
// for (Diff aDiff : diffs) {
// if (aDiff.operation == Operation.DELETE) {
// if (aDiff.text.matches(" *")) {
// text.append("").append(aDiff.text).append(" ").append(aDiff.text).append(" ");
//
// }
// }
// if (aDiff.operation == Operation.EQUAL) {
// text.append(aDiff.text);
// }
// }
// return text.toString();
// }
//
// /**
// * Compute and return the destination text (all equalities and insertions).
// *
// * @param diffs LinkedList of Diff objects.
// * @return Destination text.
// */
// public String diff_text2(LinkedList diffs) {
// StringBuilder text = new StringBuilder();
// for (Diff aDiff : diffs) {
// if (aDiff.operation != Operation.DELETE) {
// text.append(aDiff.text);
// }
// }
// return text.toString();
// }
//
// /**
// *
// * @param diffs
// * @return
// */
// public String diff_text2Custom(LinkedList diffs) {
// StringBuilder text = new StringBuilder();
// for (Diff aDiff : diffs) {
//
// if (aDiff.operation == Operation.INSERT) {
// if (aDiff.text.matches(" *")) {
// text.append("").append(aDiff.text).append(" ").append(aDiff.text).append(" ");
//
// }
// }
// if (aDiff.operation == Operation.EQUAL) {
// text.append(aDiff.text);
// }
// }
// return text.toString();
// }
//
// /**
// * Compute the Levenshtein distance; the number of inserted, deleted or
// * substituted characters.
// *
// * @param diffs LinkedList of Diff objects.
// * @return Number of changes.
// */
// public int diff_levenshtein(LinkedList diffs) {
// int levenshtein = 0;
// int insertions = 0;
// int deletions = 0;
// for (Diff aDiff : diffs) {
// switch (aDiff.operation) {
// case INSERT:
// insertions += aDiff.text.length();
// break;
// case DELETE:
// deletions += aDiff.text.length();
// break;
// case EQUAL:
// // A deletion and an insertion is one substitution.
// levenshtein += Math.max(insertions, deletions);
// insertions = 0;
// deletions = 0;
// break;
// }
// }
// levenshtein += Math.max(insertions, deletions);
// return levenshtein;
// }
//
// /**
// * Crush the diff into an encoded string which describes the operations
// * required to transform text1 into text2. E.g. =3\t-2\t+ing -> Keep 3
// * chars, delete 2 chars, insert 'ing'. Operations are tab-separated.
// * Inserted text is escaped using %xx notation.
// *
// * @param diffs Array of Diff objects.
// * @return Delta text.
// */
// public String diff_toDelta(LinkedList diffs) {
// StringBuilder text = new StringBuilder();
// for (Diff aDiff : diffs) {
// switch (aDiff.operation) {
// case INSERT:
// try {
// text.append("+").append(URLEncoder.encode(aDiff.text, "UTF-8")
// .replace('+', ' ')).append("\t");
// } catch (UnsupportedEncodingException e) {
// // Not likely on modern system.
// throw new Error("This system does not support UTF-8.", e);
// }
// break;
// case DELETE:
// text.append("-").append(aDiff.text.length()).append("\t");
// break;
// case EQUAL:
// text.append("=").append(aDiff.text.length()).append("\t");
// break;
// }
// }
// String delta = text.toString();
// if (delta.length() != 0) {
// // Strip off trailing tab character.
// delta = delta.substring(0, delta.length() - 1);
// delta = unescapeForEncodeUriCompatability(delta);
// }
// return delta;
// }
//
// /**
// * Given the original text1, and an encoded string which describes the
// * operations required to transform text1 into text2, compute the full diff.
// *
// * @param text1 Source string for the diff.
// * @param delta Delta text.
// * @return Array of Diff objects or null if invalid.
// * @throws IllegalArgumentException If invalid input.
// */
// public LinkedList diff_fromDelta(String text1, String delta)
// throws IllegalArgumentException {
// LinkedList diffs = new LinkedList();
// int pointer = 0; // Cursor in text1
// String[] tokens = delta.split("\t");
// for (String token : tokens) {
// if (token.length() == 0) {
// // Blank tokens are ok (from a trailing \t).
// continue;
// }
// // Each token begins with a one character parameter which specifies the
// // operation of this token (delete, insert, equality).
// String param = token.substring(1);
// switch (token.charAt(0)) {
// case '+':
// // decode would change all "+" to " "
// param = param.replace("+", "%2B");
// try {
// param = URLDecoder.decode(param, "UTF-8");
// } catch (UnsupportedEncodingException e) {
// // Not likely on modern system.
// throw new Error("This system does not support UTF-8.", e);
// } catch (IllegalArgumentException e) {
// // Malformed URI sequence.
// throw new IllegalArgumentException(
// "Illegal escape in diff_fromDelta: " + param, e);
// }
// diffs.add(new Diff(Operation.INSERT, param));
// break;
// case '-':
// // Fall through.
// case '=':
// int n;
// try {
// n = Integer.parseInt(param);
// } catch (NumberFormatException e) {
// throw new IllegalArgumentException(
// "Invalid number in diff_fromDelta: " + param, e);
// }
// if (n < 0) {
// throw new IllegalArgumentException(
// "Negative number in diff_fromDelta: " + param);
// }
// String text;
// try {
// text = text1.substring(pointer, pointer += n);
// } catch (StringIndexOutOfBoundsException e) {
// throw new IllegalArgumentException("Delta length (" + pointer
// + ") larger than source text length (" + text1.length()
// + ").", e);
// }
// if (token.charAt(0) == '=') {
// diffs.add(new Diff(Operation.EQUAL, text));
// } else {
// diffs.add(new Diff(Operation.DELETE, text));
// }
// break;
// default:
// // Anything else is an error.
// throw new IllegalArgumentException(
// "Invalid diff operation in diff_fromDelta: " + token.charAt(0));
// }
// }
// if (pointer != text1.length()) {
// throw new IllegalArgumentException("Delta length (" + pointer
// + ") smaller than source text length (" + text1.length() + ").");
// }
// return diffs;
// }
//
// // MATCH FUNCTIONS
// /**
// * Locate the best instance of 'pattern' in 'text' near 'loc'. Returns -1 if
// * no match found.
// *
// * @param text The text to search.
// * @param pattern The pattern to search for.
// * @param loc The location to search around.
// * @return Best match index or -1.
// */
// public int match_main(String text, String pattern, int loc) {
// // Check for null inputs.
// if (text == null || pattern == null) {
// throw new IllegalArgumentException("Null inputs. (match_main)");
// }
//
// loc = Math.max(0, Math.min(loc, text.length()));
// if (text.equals(pattern)) {
// // Shortcut (potentially not guaranteed by the algorithm)
// return 0;
// } else if (text.length() == 0) {
// // Nothing to match.
// return -1;
// } else if (loc + pattern.length() <= text.length()
// && text.substring(loc, loc + pattern.length()).equals(pattern)) {
// // Perfect match at the perfect spot! (Includes case of null pattern)
// return loc;
// } else {
// // Do a fuzzy compare.
// return match_bitap(text, pattern, loc);
// }
// }
//
// /**
// * Locate the best instance of 'pattern' in 'text' near 'loc' using the
// * Bitap algorithm. Returns -1 if no match found.
// *
// * @param text The text to search.
// * @param pattern The pattern to search for.
// * @param loc The location to search around.
// * @return Best match index or -1.
// */
// protected int match_bitap(String text, String pattern, int loc) {
// assert (Match_MaxBits == 0 || pattern.length() <= Match_MaxBits) : "Pattern too long for this application.";
//
// // Initialise the alphabet.
// Map s = match_alphabet(pattern);
//
// // Highest score beyond which we give up.
// double score_threshold = Match_Threshold;
// // Is there a nearby exact match? (speedup)
// int best_loc = text.indexOf(pattern, loc);
// if (best_loc != -1) {
// score_threshold = Math.min(match_bitapScore(0, best_loc, loc, pattern),
// score_threshold);
// // What about in the other direction? (speedup)
// best_loc = text.lastIndexOf(pattern, loc + pattern.length());
// if (best_loc != -1) {
// score_threshold = Math.min(match_bitapScore(0, best_loc, loc, pattern),
// score_threshold);
// }
// }
//
// // Initialise the bit arrays.
// int matchmask = 1 << (pattern.length() - 1);
// best_loc = -1;
//
// int bin_min, bin_mid;
// int bin_max = pattern.length() + text.length();
// // Empty initialization added to appease Java compiler.
// int[] last_rd = new int[0];
// for (int d = 0; d < pattern.length(); d++) {
// // Scan for the best match; each iteration allows for one more error.
// // Run a binary search to determine how far from 'loc' we can stray at
// // this error level.
// bin_min = 0;
// bin_mid = bin_max;
// while (bin_min < bin_mid) {
// if (match_bitapScore(d, loc + bin_mid, loc, pattern)
// <= score_threshold) {
// bin_min = bin_mid;
// } else {
// bin_max = bin_mid;
// }
// bin_mid = (bin_max - bin_min) / 2 + bin_min;
// }
// // Use the result from this iteration as the maximum for the next.
// bin_max = bin_mid;
// int start = Math.max(1, loc - bin_mid + 1);
// int finish = Math.min(loc + bin_mid, text.length()) + pattern.length();
//
// int[] rd = new int[finish + 2];
// rd[finish + 1] = (1 << d) - 1;
// for (int j = finish; j >= start; j--) {
// int charMatch;
// if (text.length() <= j - 1 || !s.containsKey(text.charAt(j - 1))) {
// // Out of range.
// charMatch = 0;
// } else {
// charMatch = s.get(text.charAt(j - 1));
// }
// if (d == 0) {
// // First pass: exact match.
// rd[j] = ((rd[j + 1] << 1) | 1) & charMatch;
// } else {
// // Subsequent passes: fuzzy match.
// rd[j] = (((rd[j + 1] << 1) | 1) & charMatch)
// | (((last_rd[j + 1] | last_rd[j]) << 1) | 1) | last_rd[j + 1];
// }
// if ((rd[j] & matchmask) != 0) {
// double score = match_bitapScore(d, j - 1, loc, pattern);
// // This match will almost certainly be better than any existing
// // match. But check anyway.
// if (score <= score_threshold) {
// // Told you so.
// score_threshold = score;
// best_loc = j - 1;
// if (best_loc > loc) {
// // When passing loc, don't exceed our current distance from loc.
// start = Math.max(1, 2 * loc - best_loc);
// } else {
// // Already passed loc, downhill from here on in.
// break;
// }
// }
// }
// }
// if (match_bitapScore(d + 1, loc, loc, pattern) > score_threshold) {
// // No hope for a (better) match at greater error levels.
// break;
// }
// last_rd = rd;
// }
// return best_loc;
// }
//
// /**
// * Compute and return the score for a match with e errors and x location.
// *
// * @param e Number of errors in match.
// * @param x Location of match.
// * @param loc Expected location of match.
// * @param pattern Pattern being sought.
// * @return Overall score for match (0.0 = good, 1.0 = bad).
// */
// private double match_bitapScore(int e, int x, int loc, String pattern) {
// float accuracy = (float) e / pattern.length();
// int proximity = Math.abs(loc - x);
// if (Match_Distance == 0) {
// // Dodge divide by zero error.
// return proximity == 0 ? accuracy : 1.0;
// }
// return accuracy + (proximity / (float) Match_Distance);
// }
//
// /**
// * Initialise the alphabet for the Bitap algorithm.
// *
// * @param pattern The text to encode.
// * @return Hash of character locations.
// */
// protected Map match_alphabet(String pattern) {
// Map s = new HashMap();
// char[] char_pattern = pattern.toCharArray();
// for (char c : char_pattern) {
// s.put(c, 0);
// }
// int i = 0;
// for (char c : char_pattern) {
// s.put(c, s.get(c) | (1 << (pattern.length() - i - 1)));
// i++;
// }
// return s;
// }
//
// // PATCH FUNCTIONS
// /**
// * Increase the context until it is unique, but don't let the pattern expand
// * beyond Match_MaxBits.
// *
// * @param patch The patch to grow.
// * @param text Source text.
// */
// protected void patch_addContext(Patch patch, String text) {
// if (text.length() == 0) {
// return;
// }
// String pattern = text.substring(patch.start2, patch.start2 + patch.length1);
// int padding = 0;
//
// // Look for the first and last matches of pattern in text. If two different
// // matches are found, increase the pattern length.
// while (text.indexOf(pattern) != text.lastIndexOf(pattern)
// && pattern.length() < Match_MaxBits - Patch_Margin - Patch_Margin) {
// padding += Patch_Margin;
// pattern = text.substring(Math.max(0, patch.start2 - padding),
// Math.min(text.length(), patch.start2 + patch.length1 + padding));
// }
// // Add one chunk for good luck.
// padding += Patch_Margin;
//
// // Add the prefix.
// String prefix = text.substring(Math.max(0, patch.start2 - padding),
// patch.start2);
// if (prefix.length() != 0) {
// patch.diffs.addFirst(new Diff(Operation.EQUAL, prefix));
// }
// // Add the suffix.
// String suffix = text.substring(patch.start2 + patch.length1,
// Math.min(text.length(), patch.start2 + patch.length1 + padding));
// if (suffix.length() != 0) {
// patch.diffs.addLast(new Diff(Operation.EQUAL, suffix));
// }
//
// // Roll back the start points.
// patch.start1 -= prefix.length();
// patch.start2 -= prefix.length();
// // Extend the lengths.
// patch.length1 += prefix.length() + suffix.length();
// patch.length2 += prefix.length() + suffix.length();
// }
//
// /**
// * Compute a list of patches to turn text1 into text2. A set of diffs will
// * be computed.
// *
// * @param text1 Old text.
// * @param text2 New text.
// * @return LinkedList of Patch objects.
// */
// public LinkedList patch_make(String text1, String text2) {
// if (text1 == null || text2 == null) {
// return null;
// }
// // No diffs provided, compute our own.
// LinkedList diffs = diff_main(text1, text2, true);
// if (diffs.size() > 2) {
// diff_cleanupSemantic(diffs);
// diff_cleanupEfficiency(diffs);
// }
// return patch_make(text1, diffs);
// }
//
// /**
// * Compute a list of patches to turn text1 into text2. text1 will be derived
// * from the provided diffs.
// *
// * @param diffs Array of Diff objects for text1 to text2.
// * @return LinkedList of Patch objects.
// */
// public LinkedList patch_make(LinkedList diffs) {
// if (diffs == null) {
// throw new IllegalArgumentException("Null inputs. (patch_make)");
// }
// // No origin string provided, compute our own.
// String text1 = diff_text1(diffs);
// return patch_make(text1, diffs);
// }
//
// /**
// * Compute a list of patches to turn text1 into text2. text2 is ignored,
// * diffs are the delta between text1 and text2.
// *
// * @param text1 Old text
// * @param text2 Ignored.
// * @param diffs Array of Diff objects for text1 to text2.
// * @return LinkedList of Patch objects.
// * @deprecated Prefer patch_make(String text1, LinkedList diffs).
// */
// public LinkedList patch_make(String text1, String text2,
// LinkedList diffs) {
// return patch_make(text1, diffs);
// }
//
// /**
// * Compute a list of patches to turn text1 into text2. text2 is not
// * provided, diffs are the delta between text1 and text2.
// *
// * @param text1 Old text.
// * @param diffs Array of Diff objects for text1 to text2.
// * @return LinkedList of Patch objects.
// */
// public LinkedList patch_make(String text1, LinkedList diffs) {
// if (text1 == null || diffs == null) {
// throw new IllegalArgumentException("Null inputs. (patch_make)");
// }
//
// LinkedList patches = new LinkedList();
// if (diffs.isEmpty()) {
// return patches; // Get rid of the null case.
// }
// Patch patch = new Patch();
// int char_count1 = 0; // Number of characters into the text1 string.
// int char_count2 = 0; // Number of characters into the text2 string.
// // Start with text1 (prepatch_text) and apply the diffs until we arrive at
// // text2 (postpatch_text). We recreate the patches one by one to determine
// // context info.
// String prepatch_text = text1;
// String postpatch_text = text1;
// for (Diff aDiff : diffs) {
// if (patch.diffs.isEmpty() && aDiff.operation != Operation.EQUAL) {
// // A new patch starts here.
// patch.start1 = char_count1;
// patch.start2 = char_count2;
// }
//
// switch (aDiff.operation) {
// case INSERT:
// patch.diffs.add(aDiff);
// patch.length2 += aDiff.text.length();
// postpatch_text = postpatch_text.substring(0, char_count2)
// + aDiff.text + postpatch_text.substring(char_count2);
// break;
// case DELETE:
// patch.length1 += aDiff.text.length();
// patch.diffs.add(aDiff);
// postpatch_text = postpatch_text.substring(0, char_count2)
// + postpatch_text.substring(char_count2 + aDiff.text.length());
// break;
// case EQUAL:
// if (aDiff.text.length() <= 2 * Patch_Margin
// && !patch.diffs.isEmpty() && aDiff != diffs.getLast()) {
// // Small equality inside a patch.
// patch.diffs.add(aDiff);
// patch.length1 += aDiff.text.length();
// patch.length2 += aDiff.text.length();
// }
//
// if (aDiff.text.length() >= 2 * Patch_Margin) {
// // Time for a new patch.
// if (!patch.diffs.isEmpty()) {
// patch_addContext(patch, prepatch_text);
// patches.add(patch);
// patch = new Patch();
// // Unlike Unidiff, our patch lists have a rolling context.
// // http://code.google.com/p/google-diff-match-patch/wiki/Unidiff
// // Update prepatch text & pos to reflect the application of the
// // just completed patch.
// prepatch_text = postpatch_text;
// char_count1 = char_count2;
// }
// }
// break;
// }
//
// // Update the current character count.
// if (aDiff.operation != Operation.INSERT) {
// char_count1 += aDiff.text.length();
// }
// if (aDiff.operation != Operation.DELETE) {
// char_count2 += aDiff.text.length();
// }
// }
// // Pick up the leftover patch if not empty.
// if (!patch.diffs.isEmpty()) {
// patch_addContext(patch, prepatch_text);
// patches.add(patch);
// }
//
// return patches;
// }
//
// /**
// * Given an array of patches, return another array that is identical.
// *
// * @param patches Array of Patch objects.
// * @return Array of Patch objects.
// */
// public LinkedList patch_deepCopy(LinkedList patches) {
// LinkedList patchesCopy = new LinkedList();
// for (Patch aPatch : patches) {
// Patch patchCopy = new Patch();
// for (Diff aDiff : aPatch.diffs) {
// Diff diffCopy = new Diff(aDiff.operation, aDiff.text);
// patchCopy.diffs.add(diffCopy);
// }
// patchCopy.start1 = aPatch.start1;
// patchCopy.start2 = aPatch.start2;
// patchCopy.length1 = aPatch.length1;
// patchCopy.length2 = aPatch.length2;
// patchesCopy.add(patchCopy);
// }
// return patchesCopy;
// }
//
// /**
// * Merge a set of patches onto the text. Return a patched text, as well as
// * an array of true/false values indicating which patches were applied.
// *
// * @param patches Array of Patch objects
// * @param text Old text.
// * @return Two element Object array, containing the new text and an array of
// * boolean values.
// */
// public Object[] patch_apply(LinkedList patches, String text) {
// if (patches.isEmpty()) {
// return new Object[]{text, new boolean[0]};
// }
//
// // Deep copy the patches so that no changes are made to originals.
// patches = patch_deepCopy(patches);
//
// String nullPadding = patch_addPadding(patches);
// text = nullPadding + text + nullPadding;
// patch_splitMax(patches);
//
// int x = 0;
// // delta keeps track of the offset between the expected and actual location
// // of the previous patch. If there are patches expected at positions 10 and
// // 20, but the first patch was found at 12, delta is 2 and the second patch
// // has an effective expected position of 22.
// int delta = 0;
// boolean[] results = new boolean[patches.size()];
// for (Patch aPatch : patches) {
// int expected_loc = aPatch.start2 + delta;
// String text1 = diff_text1(aPatch.diffs);
// int start_loc;
// int end_loc = -1;
// if (text1.length() > this.Match_MaxBits) {
// // patch_splitMax will only provide an oversized pattern in the case of
// // a monster delete.
// start_loc = match_main(text,
// text1.substring(0, this.Match_MaxBits), expected_loc);
// if (start_loc != -1) {
// end_loc = match_main(text,
// text1.substring(text1.length() - this.Match_MaxBits),
// expected_loc + text1.length() - this.Match_MaxBits);
// if (end_loc == -1 || start_loc >= end_loc) {
// // Can't find valid trailing context. Drop this patch.
// start_loc = -1;
// }
// }
// } else {
// start_loc = match_main(text, text1, expected_loc);
// }
// if (start_loc == -1) {
// // No match found. :(
// results[x] = false;
// // Subtract the delta for this failed patch from subsequent patches.
// delta -= aPatch.length2 - aPatch.length1;
// } else {
// // Found a match. :)
// results[x] = true;
// delta = start_loc - expected_loc;
// String text2;
// if (end_loc == -1) {
// text2 = text.substring(start_loc,
// Math.min(start_loc + text1.length(), text.length()));
// } else {
// text2 = text.substring(start_loc,
// Math.min(end_loc + this.Match_MaxBits, text.length()));
// }
// if (text1.equals(text2)) {
// // Perfect match, just shove the replacement text in.
// text = text.substring(0, start_loc) + diff_text2(aPatch.diffs)
// + text.substring(start_loc + text1.length());
// } else {
// // Imperfect match. Run a diff to get a framework of equivalent
// // indices.
// LinkedList diffs = diff_main(text1, text2, false);
// if (text1.length() > this.Match_MaxBits
// && diff_levenshtein(diffs) / (float) text1.length()
// > this.Patch_DeleteThreshold) {
// // The end points match, but the content is unacceptably bad.
// results[x] = false;
// } else {
// diff_cleanupSemanticLossless(diffs);
// int index1 = 0;
// for (Diff aDiff : aPatch.diffs) {
// if (aDiff.operation != Operation.EQUAL) {
// int index2 = diff_xIndex(diffs, index1);
// if (aDiff.operation == Operation.INSERT) {
// // Insertion
// text = text.substring(0, start_loc + index2) + aDiff.text
// + text.substring(start_loc + index2);
// } else if (aDiff.operation == Operation.DELETE) {
// // Deletion
// text = text.substring(0, start_loc + index2)
// + text.substring(start_loc + diff_xIndex(diffs,
// index1 + aDiff.text.length()));
// }
// }
// if (aDiff.operation != Operation.DELETE) {
// index1 += aDiff.text.length();
// }
// }
// }
// }
// }
// x++;
// }
// // Strip the padding off.
// text = text.substring(nullPadding.length(), text.length()
// - nullPadding.length());
// return new Object[]{text, results};
// }
//
// /**
// * Add some padding on text start and end so that edges can match something.
// * Intended to be called only from within patch_apply.
// *
// * @param patches Array of Patch objects.
// * @return The padding string added to each side.
// */
// public String patch_addPadding(LinkedList patches) {
// short paddingLength = this.Patch_Margin;
// String nullPadding = "";
// for (short x = 1; x <= paddingLength; x++) {
// nullPadding += String.valueOf((char) x);
// }
//
// // Bump all the patches forward.
// for (Patch aPatch : patches) {
// aPatch.start1 += paddingLength;
// aPatch.start2 += paddingLength;
// }
//
// // Add some padding on start of first diff.
// Patch patch = patches.getFirst();
// LinkedList diffs = patch.diffs;
// if (diffs.isEmpty() || diffs.getFirst().operation != Operation.EQUAL) {
// // Add nullPadding equality.
// diffs.addFirst(new Diff(Operation.EQUAL, nullPadding));
// patch.start1 -= paddingLength; // Should be 0.
// patch.start2 -= paddingLength; // Should be 0.
// patch.length1 += paddingLength;
// patch.length2 += paddingLength;
// } else if (paddingLength > diffs.getFirst().text.length()) {
// // Grow first equality.
// Diff firstDiff = diffs.getFirst();
// int extraLength = paddingLength - firstDiff.text.length();
// firstDiff.text = nullPadding.substring(firstDiff.text.length())
// + firstDiff.text;
// patch.start1 -= extraLength;
// patch.start2 -= extraLength;
// patch.length1 += extraLength;
// patch.length2 += extraLength;
// }
//
// // Add some padding on end of last diff.
// patch = patches.getLast();
// diffs = patch.diffs;
// if (diffs.isEmpty() || diffs.getLast().operation != Operation.EQUAL) {
// // Add nullPadding equality.
// diffs.addLast(new Diff(Operation.EQUAL, nullPadding));
// patch.length1 += paddingLength;
// patch.length2 += paddingLength;
// } else if (paddingLength > diffs.getLast().text.length()) {
// // Grow last equality.
// Diff lastDiff = diffs.getLast();
// int extraLength = paddingLength - lastDiff.text.length();
// lastDiff.text += nullPadding.substring(0, extraLength);
// patch.length1 += extraLength;
// patch.length2 += extraLength;
// }
//
// return nullPadding;
// }
//
// /**
// * Look through the patches and break up any which are longer than the
// * maximum limit of the match algorithm. Intended to be called only from
// * within patch_apply.
// *
// * @param patches LinkedList of Patch objects.
// */
// public void patch_splitMax(LinkedList patches) {
// short patch_size = Match_MaxBits;
// String precontext, postcontext;
// Patch patch;
// int start1, start2;
// boolean empty;
// Operation diff_type;
// String diff_text;
// ListIterator pointer = patches.listIterator();
// Patch bigpatch = pointer.hasNext() ? pointer.next() : null;
// while (bigpatch != null) {
// if (bigpatch.length1 <= Match_MaxBits) {
// bigpatch = pointer.hasNext() ? pointer.next() : null;
// continue;
// }
// // Remove the big old patch.
// pointer.remove();
// start1 = bigpatch.start1;
// start2 = bigpatch.start2;
// precontext = "";
// while (!bigpatch.diffs.isEmpty()) {
// // Create one of several smaller patches.
// patch = new Patch();
// empty = true;
// patch.start1 = start1 - precontext.length();
// patch.start2 = start2 - precontext.length();
// if (precontext.length() != 0) {
// patch.length1 = patch.length2 = precontext.length();
// patch.diffs.add(new Diff(Operation.EQUAL, precontext));
// }
// while (!bigpatch.diffs.isEmpty()
// && patch.length1 < patch_size - Patch_Margin) {
// diff_type = bigpatch.diffs.getFirst().operation;
// diff_text = bigpatch.diffs.getFirst().text;
// if (diff_type == Operation.INSERT) {
// // Insertions are harmless.
// patch.length2 += diff_text.length();
// start2 += diff_text.length();
// patch.diffs.addLast(bigpatch.diffs.removeFirst());
// empty = false;
// } else if (diff_type == Operation.DELETE && patch.diffs.size() == 1
// && patch.diffs.getFirst().operation == Operation.EQUAL
// && diff_text.length() > 2 * patch_size) {
// // This is a large deletion. Let it pass in one chunk.
// patch.length1 += diff_text.length();
// start1 += diff_text.length();
// empty = false;
// patch.diffs.add(new Diff(diff_type, diff_text));
// bigpatch.diffs.removeFirst();
// } else {
// // Deletion or equality. Only take as much as we can stomach.
// diff_text = diff_text.substring(0, Math.min(diff_text.length(),
// patch_size - patch.length1 - Patch_Margin));
// patch.length1 += diff_text.length();
// start1 += diff_text.length();
// if (diff_type == Operation.EQUAL) {
// patch.length2 += diff_text.length();
// start2 += diff_text.length();
// } else {
// empty = false;
// }
// patch.diffs.add(new Diff(diff_type, diff_text));
// if (diff_text.equals(bigpatch.diffs.getFirst().text)) {
// bigpatch.diffs.removeFirst();
// } else {
// bigpatch.diffs.getFirst().text = bigpatch.diffs.getFirst().text
// .substring(diff_text.length());
// }
// }
// }
// // Compute the head context for the next patch.
// precontext = diff_text2(patch.diffs);
// precontext = precontext.substring(Math.max(0, precontext.length()
// - Patch_Margin));
// // Append the end context for this patch.
// if (diff_text1(bigpatch.diffs).length() > Patch_Margin) {
// postcontext = diff_text1(bigpatch.diffs).substring(0, Patch_Margin);
// } else {
// postcontext = diff_text1(bigpatch.diffs);
// }
// if (postcontext.length() != 0) {
// patch.length1 += postcontext.length();
// patch.length2 += postcontext.length();
// if (!patch.diffs.isEmpty()
// && patch.diffs.getLast().operation == Operation.EQUAL) {
// patch.diffs.getLast().text += postcontext;
// } else {
// patch.diffs.add(new Diff(Operation.EQUAL, postcontext));
// }
// }
// if (!empty) {
// pointer.add(patch);
// }
// }
// bigpatch = pointer.hasNext() ? pointer.next() : null;
// }
// }
//
// /**
// * Take a list of patches and return a textual representation.
// *
// * @param patches List of Patch objects.
// * @return Text representation of patches.
// */
// public String patch_toText(List patches) {
// StringBuilder text = new StringBuilder();
// for (Patch aPatch : patches) {
// text.append(aPatch);
// }
// return text.toString();
// }
//
// /**
// * Parse a textual representation of patches and return a List of Patch
// * objects.
// *
// * @param textline Text representation of patches.
// * @return List of Patch objects.
// * @throws IllegalArgumentException If invalid input.
// */
// public List patch_fromText(String textline)
// throws IllegalArgumentException {
// List patches = new LinkedList();
// if (textline.length() == 0) {
// return patches;
// }
// List textList = Arrays.asList(textline.split("\n"));
// LinkedList text = new LinkedList(textList);
// Patch patch;
// Pattern patchHeader = Pattern.compile("^@@ -(\\d+),?(\\d*) \\+(\\d+),?(\\d*) @@$");
// Matcher m;
// char sign;
// String line;
// while (!text.isEmpty()) {
// m = patchHeader.matcher(text.getFirst());
// if (!m.matches()) {
// throw new IllegalArgumentException(
// "Invalid patch string: " + text.getFirst());
// }
// patch = new Patch();
// patches.add(patch);
// patch.start1 = Integer.parseInt(m.group(1));
// if (m.group(2).length() == 0) {
// patch.start1--;
// patch.length1 = 1;
// } else if (m.group(2).equals("0")) {
// patch.length1 = 0;
// } else {
// patch.start1--;
// patch.length1 = Integer.parseInt(m.group(2));
// }
//
// patch.start2 = Integer.parseInt(m.group(3));
// if (m.group(4).length() == 0) {
// patch.start2--;
// patch.length2 = 1;
// } else if (m.group(4).equals("0")) {
// patch.length2 = 0;
// } else {
// patch.start2--;
// patch.length2 = Integer.parseInt(m.group(4));
// }
// text.removeFirst();
//
// while (!text.isEmpty()) {
// try {
// sign = text.getFirst().charAt(0);
// } catch (IndexOutOfBoundsException e) {
// // Blank line? Whatever.
// text.removeFirst();
// continue;
// }
// line = text.getFirst().substring(1);
// line = line.replace("+", "%2B"); // decode would change all "+" to " "
// try {
// line = URLDecoder.decode(line, "UTF-8");
// } catch (UnsupportedEncodingException e) {
// // Not likely on modern system.
// throw new Error("This system does not support UTF-8.", e);
// } catch (IllegalArgumentException e) {
// // Malformed URI sequence.
// throw new IllegalArgumentException(
// "Illegal escape in patch_fromText: " + line, e);
// }
// if (sign == '-') {
// // Deletion.
// patch.diffs.add(new Diff(Operation.DELETE, line));
// } else if (sign == '+') {
// // Insertion.
// patch.diffs.add(new Diff(Operation.INSERT, line));
// } else if (sign == ' ') {
// // Minor equality.
// patch.diffs.add(new Diff(Operation.EQUAL, line));
// } else if (sign == '@') {
// // Start of next patch.
// break;
// } else {
// // WTF?
// throw new IllegalArgumentException(
// "Invalid patch mode '" + sign + "' in: " + line);
// }
// text.removeFirst();
// }
// }
// return patches;
// }
//
// /**
// * Class representing one diff operation.
// */
// public static class Diff {
//
// /**
// * One of: INSERT, DELETE or EQUAL.
// */
// public Operation operation;
// /**
// * The text associated with this diff operation.
// */
// public String text;
//
// /**
// * Constructor. Initializes the diff with the provided values.
// *
// * @param operation One of INSERT, DELETE or EQUAL.
// * @param text The text being applied.
// */
// public Diff(Operation operation, String text) {
// // Construct a diff with the specified operation and text.
// this.operation = operation;
// this.text = text;
// }
//
// /**
// * Display a human-readable version of this Diff.
// *
// * @return text version.
// */
// public String toString() {
// String prettyText = this.text.replace('\n', '\u00b6');
// return "Diff(" + this.operation + ",\"" + prettyText + "\")";
// }
//
// /**
// * Create a numeric hash value for a Diff. This function is not used by
// * DMP.
// *
// * @return Hash value.
// */
// @Override
// public int hashCode() {
// final int prime = 31;
// int result = (operation == null) ? 0 : operation.hashCode();
// result += prime * ((text == null) ? 0 : text.hashCode());
// return result;
// }
//
// /**
// * Is this Diff equivalent to another Diff?
// *
// * @param obj Another Diff to compare against.
// * @return true or false.
// */
// @Override
// public boolean equals(Object obj) {
// if (this == obj) {
// return true;
// }
// if (obj == null) {
// return false;
// }
// if (getClass() != obj.getClass()) {
// return false;
// }
// Diff other = (Diff) obj;
// if (operation != other.operation) {
// return false;
// }
// if (text == null) {
// if (other.text != null) {
// return false;
// }
// } else if (!text.equals(other.text)) {
// return false;
// }
// return true;
// }
// }
//
// /**
// * Class representing one patch operation.
// */
// public static class Patch {
//
// /**
// *
// */
// public LinkedList diffs;
//
// /**
// *
// */
// public int start1;
//
// /**
// *
// */
// public int start2;
//
// /**
// *
// */
// public int length1;
//
// /**
// *
// */
// public int length2;
//
// /**
// * Constructor. Initializes with an empty list of diffs.
// */
// public Patch() {
// this.diffs = new LinkedList();
// }
//
// /**
// * Emmulate GNU diff's format. Header:
// *
// * @@ -382,8 +481,9
// * @@ Indicies are printed as 1-based, not 0-based.
// * @return The GNU diff string.
// */
// public String toString() {
// String coords1, coords2;
// if (this.length1 == 0) {
// coords1 = this.start1 + ",0";
// } else if (this.length1 == 1) {
// coords1 = Integer.toString(this.start1 + 1);
// } else {
// coords1 = (this.start1 + 1) + "," + this.length1;
// }
// if (this.length2 == 0) {
// coords2 = this.start2 + ",0";
// } else if (this.length2 == 1) {
// coords2 = Integer.toString(this.start2 + 1);
// } else {
// coords2 = (this.start2 + 1) + "," + this.length2;
// }
// StringBuilder text = new StringBuilder();
// text.append("@@ -").append(coords1).append(" +").append(coords2)
// .append(" @@\n");
// // Escape the body of the patch with %xx notation.
// for (Diff aDiff : this.diffs) {
// switch (aDiff.operation) {
// case INSERT:
// text.append('+');
// break;
// case DELETE:
// text.append('-');
// break;
// case EQUAL:
// text.append(' ');
// break;
// }
// try {
// text.append(URLEncoder.encode(aDiff.text, "UTF-8").replace('+', ' '))
// .append("\n");
// } catch (UnsupportedEncodingException e) {
// // Not likely on modern system.
// throw new Error("This system does not support UTF-8.", e);
// }
// }
// return unescapeForEncodeUriCompatability(text.toString());
// }
// }
//
// /**
// * Unescape selected chars for compatability with JavaScript's encodeURI. In
// * speed critical applications this could be dropped since the receiving
// * application will certainly decode these fine. Note that this function is
// * case-sensitive. Thus "%3f" would not be unescaped. But this is ok because
// * it is only called with the output of URLEncoder.encode which returns
// * uppercase hex.
// *
// * Example: "%3F" -> "?", "%24" -> "$", etc.
// *
// * @param str The string to escape.
// * @return The escaped string.
// */
// private static String unescapeForEncodeUriCompatability(String str) {
// return str.replace("%21", "!").replace("%7E", "~")
// .replace("%27", "'").replace("%28", "(").replace("%29", ")")
// .replace("%3B", ";").replace("%2F", "/").replace("%3F", "?")
// .replace("%3A", ":").replace("%40", "@").replace("%26", "&")
// .replace("%3D", "=").replace("%2B", "+").replace("%24", "$")
// .replace("%2C", ",").replace("%23", "#");
// }
//}
