--- /dev/null
+/*
+ * Diff Match and Patch
+ * Copyright 2018 The diff-match-patch Authors.
+ * https://github.com/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 user.commons.strings;
+
+import java.io.UnsupportedEncodingException;
+import java.net.URLDecoder;
+import java.net.URLEncoder;
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Deque;
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.ListIterator;
+import java.util.Map;
+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 fraser@google.com (Neil Fraser)
+ */
+
+/**
+ * Class containing the diff, match and patch methods.
+ * Also contains the behaviour settings.
+ */
+public class DiffMatch {
+
+ // 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<String> lineArray;
+
+ protected LinesToCharsResult(String chars1, String chars2, List<String> 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> 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> 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> 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<Diff> diffs;
+ if (text1.equals(text2)) {
+ diffs = new LinkedList<Diff>();
+ 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> diff_compute(String text1, String text2, boolean checklines, long deadline) {
+ LinkedList<Diff> diffs = new LinkedList<Diff>();
+
+ 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;
+ }
+
+ 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<Diff> diffs_a = diff_main(text1_a, text2_a, checklines, deadline);
+ LinkedList<Diff> 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> diff_lineMode(String text1, String text2, long deadline) {
+ // Scan the text on a line-by-line basis first.
+ LinesToCharsResult a = diff_linesToChars(text1, text2);
+ text1 = a.chars1;
+ text2 = a.chars2;
+ List<String> linearray = a.lineArray;
+
+ LinkedList<Diff> 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<Diff> 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 subDiff : diff_main(text_delete, text_insert, false, deadline)) {
+ pointer.add(subDiff);
+ }
+ }
+ 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> 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<Diff> diffs = new LinkedList<Diff>();
+ 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> 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<Diff> diffs = diff_main(text1a, text2a, false, deadline);
+ LinkedList<Diff> 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<String> lineArray = new ArrayList<String>();
+ Map<String, Integer> lineHash = new HashMap<String, Integer>();
+ // 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("");
+
+ // Allocate 2/3rds of the space for text1, the rest for text2.
+ String chars1 = diff_linesToCharsMunge(text1, lineArray, lineHash, 40000);
+ String chars2 = diff_linesToCharsMunge(text2, lineArray, lineHash, 65535);
+ 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.
+ * @param maxLines Maximum length of lineArray.
+ * @return Encoded string.
+ */
+ private String diff_linesToCharsMunge(String text, List<String> lineArray, Map<String, Integer> lineHash,
+ int maxLines) {
+ 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);
+
+ if (lineHash.containsKey(line)) {
+ chars.append(String.valueOf((char) (int) lineHash.get(line)));
+ } else {
+ if (lineArray.size() == maxLines) {
+ // Bail out at 65535 because
+ // String.valueOf((char) 65536).equals(String.valueOf(((char) 0)))
+ line = text.substring(lineStart);
+ lineEnd = text.length();
+ }
+ lineArray.add(line);
+ lineHash.put(line, lineArray.size() - 1);
+ chars.append(String.valueOf((char) (lineArray.size() - 1)));
+ }
+ lineStart = lineEnd + 1;
+ }
+ return chars.toString();
+ }
+
+ /**
+ * Rehydrate the text in a diff from a string of line hashes to real lines of
+ * text.
+ * @param diffs List of Diff objects.
+ * @param lineArray List of unique strings.
+ */
+ protected void diff_charsToLines(List<Diff> diffs, List<String> lineArray) {
+ StringBuilder text;
+ for (Diff diff : diffs) {
+ text = new StringBuilder();
+ for (int j = 0; j < diff.text.length(); j++) {
+ text.append(lineArray.get(diff.text.charAt(j)));
+ }
+ 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: https://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: https://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: https://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<Diff> diffs) {
+ if (diffs.isEmpty()) {
+ return;
+ }
+ boolean changes = false;
+ Deque<Diff> equalities = new ArrayDeque<Diff>(); // Double-ended queue of qualities.
+ String lastEquality = null; // Always equal to equalities.peek().text
+ ListIterator<Diff> 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.peek()) {
+ 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.isEmpty()) {
+ // Throw away the previous equality (it needs to be reevaluated).
+ equalities.pop();
+ }
+ if (equalities.isEmpty()) {
+ // 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.peek();
+ 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: <del>abcxxx</del><ins>xxxdef</ins>
+ // -> <del>abc</del>xxx<ins>def</ins>
+ // e.g: <del>xxxabc</del><ins>defxxx</ins>
+ // -> <ins>def</ins>xxx<del>abc</del>
+ // 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 c<ins>at c</ins>ame. -> The <ins>cat </ins>came.
+ * @param diffs LinkedList of Diff objects.
+ */
+ public void diff_cleanupSemanticLossless(LinkedList<Diff> diffs) {
+ String equality1, edit, equality2;
+ String commonString;
+ int commonOffset;
+ int score, bestScore;
+ String bestEquality1, bestEdit, bestEquality2;
+ // Create a new iterator at the start.
+ ListIterator<Diff> 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<Diff> diffs) {
+ if (diffs.isEmpty()) {
+ return;
+ }
+ boolean changes = false;
+ Deque<Diff> equalities = new ArrayDeque<Diff>(); // Double-ended queue of equalities.
+ String lastEquality = null; // Always equal to equalities.peek().text
+ ListIterator<Diff> 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 unsplittable.
+ 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:
+ * <ins>A</ins><del>B</del>XY<ins>C</ins><del>D</del>
+ * <ins>A</ins>X<ins>C</ins><del>D</del>
+ * <ins>A</ins><del>B</del>X<ins>C</ins>
+ * <ins>A</del>X<ins>C</ins><del>D</del>
+ * <ins>A</ins><del>B</del>X<del>C</del>
+ */
+ 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.peek()) {
+ 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.isEmpty()) {
+ // Throw away the previous equality (it needs to be reevaluated).
+ equalities.pop();
+ }
+ if (equalities.isEmpty()) {
+ // 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.peek();
+ }
+ 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<Diff> diffs) {
+ diffs.add(new Diff(Operation.EQUAL, "")); // Add a dummy entry at the end.
+ ListIterator<Diff> 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: A<ins>BA</ins>C -> <ins>AB</ins>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 List of Diff objects.
+ * @param loc Location within text1.
+ * @return Location within text2.
+ */
+ public int diff_xIndex(List<Diff> 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 List of Diff objects.
+ * @return HTML representation.
+ */
+ public String diff_prettyHtml(List<Diff> diffs) {
+ StringBuilder html = new StringBuilder();
+ for (Diff aDiff : diffs) {
+ String text = aDiff.text.replace("&", "&").replace("<", "<").replace(">", ">").replace("\n",
+ "¶<br>");
+ switch (aDiff.operation) {
+ case INSERT:
+ html.append("<ins style=\"background:#e6ffe6;\">").append(text).append("</ins>");
+ break;
+ case DELETE:
+ html.append("<del style=\"background:#ffe6e6;\">").append(text).append("</del>");
+ break;
+ case EQUAL:
+ html.append("<span>").append(text).append("</span>");
+ break;
+ }
+ }
+ return html.toString();
+ }
+
+ /**
+ * Compute and return the source text (all equalities and deletions).
+ * @param diffs List of Diff objects.
+ * @return Source text.
+ */
+ public String diff_text1(List<Diff> diffs) {
+ StringBuilder text = new StringBuilder();
+ for (Diff aDiff : diffs) {
+ if (aDiff.operation != Operation.INSERT) {
+ text.append(aDiff.text);
+ }
+ }
+ return text.toString();
+ }
+
+ /**
+ * Compute and return the destination text (all equalities and insertions).
+ * @param diffs List of Diff objects.
+ * @return Destination text.
+ */
+ public String diff_text2(List<Diff> diffs) {
+ StringBuilder text = new StringBuilder();
+ for (Diff aDiff : diffs) {
+ if (aDiff.operation != Operation.DELETE) {
+ text.append(aDiff.text);
+ }
+ }
+ return text.toString();
+ }
+
+ /**
+ * Compute the Levenshtein distance; the number of inserted, deleted or
+ * substituted characters.
+ * @param diffs List of Diff objects.
+ * @return Number of changes.
+ */
+ public int diff_levenshtein(List<Diff> 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 List of Diff objects.
+ * @return Delta text.
+ */
+ public String diff_toDelta(List<Diff> 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> diff_fromDelta(String text1, String delta) throws IllegalArgumentException {
+ LinkedList<Diff> diffs = new LinkedList<Diff>();
+ 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<Character, Integer> 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<Character, Integer> match_alphabet(String pattern) {
+ Map<Character, Integer> s = new HashMap<Character, Integer>();
+ 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> patch_make(String text1, String text2) {
+ if (text1 == null || text2 == null) {
+ throw new IllegalArgumentException("Null inputs. (patch_make)");
+ }
+ // No diffs provided, compute our own.
+ LinkedList<Diff> 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> patch_make(LinkedList<Diff> 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<Diff> diffs).
+ */
+ @Deprecated
+ public LinkedList<Patch> patch_make(String text1, String text2, LinkedList<Diff> 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> patch_make(String text1, LinkedList<Diff> diffs) {
+ if (text1 == null || diffs == null) {
+ throw new IllegalArgumentException("Null inputs. (patch_make)");
+ }
+
+ LinkedList<Patch> patches = new LinkedList<Patch>();
+ 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 && !patch.diffs.isEmpty()) {
+ // 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.
+ // https://github.com/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> patch_deepCopy(LinkedList<Patch> patches) {
+ LinkedList<Patch> patchesCopy = new LinkedList<Patch>();
+ 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<Patch> 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<Diff> 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<Patch> 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<Diff> 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<Patch> patches) {
+ short patch_size = Match_MaxBits;
+ String precontext, postcontext;
+ Patch patch;
+ int start1, start2;
+ boolean empty;
+ Operation diff_type;
+ String diff_text;
+ ListIterator<Patch> 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<Patch> 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> patch_fromText(String textline) throws IllegalArgumentException {
+ List<Patch> patches = new LinkedList<Patch>();
+ if (textline.length() == 0) {
+ return patches;
+ }
+ List<String> textList = Arrays.asList(textline.split("\n"));
+ LinkedList<String> text = new LinkedList<String>(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.
+ */
+ @Override
+ 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<Diff> 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<Diff>();
+ }
+
+ /**
+ * Emulate GNU diff's format.
+ * Header: @@ -382,8 +481,9 @@
+ * Indices are printed as 1-based, not 0-based.
+ * @return The GNU diff string.
+ */
+ @Override
+ 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", "#");
+ }
+}
https://git.useribm.hu / mediacube.git / commitdiff