package com.zt.common.utils;
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import java.io.UnsupportedEncodingException;
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import java.net.URLDecoder;
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import java.net.URLEncoder;
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import java.util.*;
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import java.util.regex.Matcher;
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import java.util.regex.Pattern;
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public class DiffMatch {
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/**
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* Number of seconds to map a diff before giving up (0 for infinity).
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*/
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public float Diff_Timeout = 1.0f;
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/**
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* Cost of an empty edit operation in terms of edit characters.
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*/
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public short Diff_EditCost = 4;
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/**
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* The size beyond which the double-ended diff activates.
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* Double-ending is twice as fast, but less accurate.
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*/
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public short Diff_DualThreshold = 32;
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/**
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* At what point is no match declared (0.0 = perfection, 1.0 = very loose).
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*/
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public float Match_Threshold = 0.5f;
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/**
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* How far to search for a match (0 = exact location, 1000+ = broad match).
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* A match this many characters away from the expected location will add
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* 1.0 to the score (0.0 is a perfect match).
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*/
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public int Match_Distance = 1000;
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/**
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* When deleting a large block of text (over ~64 characters), how close does
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* the contents have to match the expected contents. (0.0 = perfection,
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* 1.0 = very loose). Note that Match_Threshold controls how closely the
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* end points of a delete need to match.
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*/
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public float Patch_DeleteThreshold = 0.5f;
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/**
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* Chunk size for context length.
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*/
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public short Patch_Margin = 4;
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/**
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* The number of bits in an int.
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*/
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private int Match_MaxBits = 32;
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/**
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* Internal class for returning results from diff_linesToChars().
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* Other less paranoid languages just use a three-element array.
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*/
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protected static class LinesToCharsResult {
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protected String chars1;
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protected String chars2;
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protected List<String> lineArray;
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protected LinesToCharsResult(String chars1, String chars2,
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List<String> lineArray) {
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this.chars1 = chars1;
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this.chars2 = chars2;
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this.lineArray = lineArray;
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}
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}
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// DIFF FUNCTIONS
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/**
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* The data structure representing a diff is a Linked list of Diff objects:
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* {Diff(Operation.DELETE, "Hello"), Diff(Operation.INSERT, "Goodbye"),
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* Diff(Operation.EQUAL, " world.")}
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* which means: delete "Hello", add "Goodbye" and keep " world."
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*/
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public enum Operation {
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DELETE, INSERT, EQUAL
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}
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/**
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* Find the differences between two texts.
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* Run a faster slightly less optimal diff
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* This method allows the 'checklines' of diff_main() to be optional.
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* Most of the time checklines is wanted, so default to true.
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* @param text1 Old string to be diffed.
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* @param text2 New string to be diffed.
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* @return Linked List of Diff objects.
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*/
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public LinkedList<Diff> diff_main(String text1, String text2) {
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return diff_main(text1, text2, true);
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}
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/**
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* Find the differences between two texts. Simplifies the problem by
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* stripping any common prefix or suffix off the texts before diffing.
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* @param text1 Old string to be diffed.
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* @param text2 New string to be diffed.
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* @param checklines Speedup flag. If false, then don't run a
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* line-level diff first to identify the changed areas.
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* If true, then run a faster slightly less optimal diff
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* @return Linked List of Diff objects.
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*/
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public LinkedList<Diff> diff_main(String text1, String text2, boolean checklines) {
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// Check for equality (speedup)
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LinkedList<Diff> diffs;
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if (text1.equals(text2)) {
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diffs = new LinkedList<Diff>();
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diffs.add(new Diff(Operation.EQUAL, text1));
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return diffs;
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}
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// Trim off common prefix (speedup)
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int commonlength = diff_commonPrefix(text1, text2);
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String commonprefix = text1.substring(0, commonlength);
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text1 = text1.substring(commonlength);
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text2 = text2.substring(commonlength);
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// Trim off common suffix (speedup)
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commonlength = diff_commonSuffix(text1, text2);
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String commonsuffix = text1.substring(text1.length() - commonlength);
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text1 = text1.substring(0, text1.length() - commonlength);
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text2 = text2.substring(0, text2.length() - commonlength);
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// Compute the diff on the middle block
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diffs = diff_compute(text1, text2, checklines);
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// Restore the prefix and suffix
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if (commonprefix.length() != 0) {
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diffs.addFirst(new Diff(Operation.EQUAL, commonprefix));
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}
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if (commonsuffix.length() != 0) {
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diffs.addLast(new Diff(Operation.EQUAL, commonsuffix));
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}
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diff_cleanupMerge(diffs);
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return diffs;
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}
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/**
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* Find the differences between two texts. Assumes that the texts do not
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* have any common prefix or suffix.
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* @param text1 Old string to be diffed.
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* @param text2 New string to be diffed.
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* @param checklines Speedup flag. If false, then don't run a
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* line-level diff first to identify the changed areas.
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* If true, then run a faster slightly less optimal diff
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* @return Linked List of Diff objects.
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*/
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protected LinkedList<Diff> diff_compute(String text1, String text2,boolean checklines) {
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LinkedList<Diff> diffs = new LinkedList<Diff>();
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if (text1.length() == 0) {
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// Just add some text (speedup)
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diffs.add(new Diff(Operation.INSERT, text2));
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return diffs;
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}
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if (text2.length() == 0) {
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// Just delete some text (speedup)
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diffs.add(new Diff(Operation.DELETE, text1));
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return diffs;
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}
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String longtext = text1.length() > text2.length() ? text1 : text2;
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String shorttext = text1.length() > text2.length() ? text2 : text1;
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int i = longtext.indexOf(shorttext);
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if (i != -1) {
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// Shorter text is inside the longer text (speedup)
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Operation op = (text1.length() > text2.length()) ?
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Operation.DELETE : Operation.INSERT;
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diffs.add(new Diff(op, longtext.substring(0, i)));
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diffs.add(new Diff(Operation.EQUAL, shorttext));
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diffs.add(new Diff(op, longtext.substring(i + shorttext.length())));
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return diffs;
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}
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longtext = shorttext = null; // Garbage collect.
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// Check to see if the problem can be split in two.
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String[] hm = diff_halfMatch(text1, text2);
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if (hm != null) {
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// A half-match was found, sort out the return data.
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String text1_a = hm[0];
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String text1_b = hm[1];
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String text2_a = hm[2];
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String text2_b = hm[3];
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String mid_common = hm[4];
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// Send both pairs off for separate processing.
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LinkedList<Diff> diffs_a = diff_main(text1_a, text2_a, checklines);
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LinkedList<Diff> diffs_b = diff_main(text1_b, text2_b, checklines);
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// Merge the results.
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diffs = diffs_a;
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diffs.add(new Diff(Operation.EQUAL, mid_common));
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diffs.addAll(diffs_b);
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return diffs;
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}
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// Perform a real diff.
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if (checklines && (text1.length() < 100 || text2.length() < 100)) {
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checklines = false; // Too trivial for the overhead.
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}
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List<String> linearray = null;
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if (checklines) {
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// Scan the text on a line-by-line basis first.
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LinesToCharsResult b = diff_linesToChars(text1, text2);
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text1 = b.chars1;
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text2 = b.chars2;
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linearray = b.lineArray;
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}
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diffs = diff_map(text1, text2);
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if (diffs == null) {
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// No acceptable result.
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diffs = new LinkedList<Diff>();
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diffs.add(new Diff(Operation.DELETE, text1));
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diffs.add(new Diff(Operation.INSERT, text2));
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}
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if (checklines) {
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// Convert the diff back to original text.
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diff_charsToLines(diffs, linearray);
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// Eliminate freak matches (e.g. blank lines)
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diff_cleanupSemantic(diffs);
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// Rediff any replacement blocks, this time character-by-character.
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// Add a dummy entry at the end.
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diffs.add(new Diff(Operation.EQUAL, ""));
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int count_delete = 0;
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int count_insert = 0;
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String text_delete = "";
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String text_insert = "";
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ListIterator<Diff> pointer = diffs.listIterator();
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Diff thisDiff = pointer.next();
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while (thisDiff != null) {
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switch (thisDiff.operation) {
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case INSERT:
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count_insert++;
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text_insert += thisDiff.text;
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break;
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case DELETE:
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count_delete++;
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text_delete += thisDiff.text;
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break;
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case EQUAL:
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// Upon reaching an equality, check for prior redundancies.
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if (count_delete >= 1 && count_insert >= 1) {
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// Delete the offending records and add the merged ones.
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pointer.previous();
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for (int j = 0; j < count_delete + count_insert; j++) {
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pointer.previous();
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pointer.remove();
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}
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for (Diff newDiff : diff_main(text_delete, text_insert, false)) {
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pointer.add(newDiff);
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}
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}
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count_insert = 0;
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count_delete = 0;
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text_delete = "";
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text_insert = "";
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break;
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}
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thisDiff = pointer.hasNext() ? pointer.next() : null;
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}
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diffs.removeLast(); // Remove the dummy entry at the end.
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}
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return diffs;
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}
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/**
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* Split two texts into a list of strings. Reduce the texts to a string of
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* hashes where each Unicode character represents one line.
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* @param text1 First string.
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* @param text2 Second string.
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* @return An object containing the encoded text1, the encoded text2 and
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* the List of unique strings. The zeroth element of the List of
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* unique strings is intentionally blank.
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*/
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protected LinesToCharsResult diff_linesToChars(String text1, String text2) {
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List<String> lineArray = new ArrayList<String>();
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Map<String, Integer> lineHash = new HashMap<String, Integer>();
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// e.g. linearray[4] == "Hello\n"
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// e.g. linehash.get("Hello\n") == 4
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// "\x00" is a valid character, but various debuggers don't like it.
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// So we'll insert a junk entry to avoid generating a null character.
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lineArray.add("");
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String chars1 = diff_linesToCharsMunge(text1, lineArray, lineHash);
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String chars2 = diff_linesToCharsMunge(text2, lineArray, lineHash);
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return new LinesToCharsResult(chars1, chars2, lineArray);
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}
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/**
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* Split a text into a list of strings. Reduce the texts to a string of
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* hashes where each Unicode character represents one line.
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* @param text String to encode.
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* @param lineArray List of unique strings.
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* @param lineHash Map of strings to indices.
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* @return Encoded string.
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*/
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private String diff_linesToCharsMunge(String text, List<String> lineArray,
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Map<String, Integer> lineHash) {
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int lineStart = 0;
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int lineEnd = -1;
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String line;
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StringBuilder chars = new StringBuilder();
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// Walk the text, pulling out a substring for each line.
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// text.split('\n') would would temporarily double our memory footprint.
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// Modifying text would create many large strings to garbage collect.
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while (lineEnd < text.length() - 1) {
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lineEnd = text.indexOf('\n', lineStart);
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if (lineEnd == -1) {
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lineEnd = text.length() - 1;
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}
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line = text.substring(lineStart, lineEnd + 1);
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lineStart = lineEnd + 1;
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if (lineHash.containsKey(line)) {
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chars.append(String.valueOf((char) (int) lineHash.get(line)));
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} else {
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lineArray.add(line);
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lineHash.put(line, lineArray.size() - 1);
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chars.append(String.valueOf((char) (lineArray.size() - 1)));
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}
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}
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return chars.toString();
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}
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/**
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* Rehydrate the text in a diff from a string of line hashes to real lines of
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* text.
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* @param diffs LinkedList of Diff objects.
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* @param lineArray List of unique strings.
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*/
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protected void diff_charsToLines(LinkedList<Diff> diffs,
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List<String> lineArray) {
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StringBuilder text;
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for (Diff diff : diffs) {
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text = new StringBuilder();
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for (int y = 0; y < diff.text.length(); y++) {
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text.append(lineArray.get(diff.text.charAt(y)));
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}
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diff.text = text.toString();
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}
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}
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/**
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* Explore the intersection points between the two texts.
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* @param text1 Old string to be diffed.
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* @param text2 New string to be diffed.
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* @return LinkedList of Diff objects or null if no diff available.
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*/
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protected LinkedList<Diff> diff_map(String text1, String text2) {
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long ms_end = System.currentTimeMillis() + (long) (Diff_Timeout * 1000);
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// Cache the text lengths to prevent multiple calls.
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int text1_length = text1.length();
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int text2_length = text2.length();
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int max_d = text1_length + text2_length - 1;
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boolean doubleEnd = Diff_DualThreshold * 2 < max_d;
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List<Set<Long>> v_map1 = new ArrayList<Set<Long>>();
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List<Set<Long>> v_map2 = new ArrayList<Set<Long>>();
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Map<Integer, Integer> v1 = new HashMap<Integer, Integer>();
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Map<Integer, Integer> v2 = new HashMap<Integer, Integer>();
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v1.put(1, 0);
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v2.put(1, 0);
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int x, y;
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Long footstep = 0L; // Used to track overlapping paths.
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Map<Long, Integer> footsteps = new HashMap<Long, Integer>();
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boolean done = false;
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// If the total number of characters is odd, then the front path will
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// collide with the reverse path.
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boolean front = ((text1_length + text2_length) % 2 == 1);
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for (int d = 0; d < max_d; d++) {
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// Bail out if timeout reached.
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if (Diff_Timeout > 0 && System.currentTimeMillis() > ms_end) {
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return null;
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}
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// Walk the front path one step.
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v_map1.add(new HashSet<Long>()); // Adds at index 'd'.
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for (int k = -d; k <= d; k += 2) {
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if (k == -d || k != d && v1.get(k - 1) < v1.get(k + 1)) {
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x = v1.get(k + 1);
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} else {
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x = v1.get(k - 1) + 1;
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}
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y = x - k;
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if (doubleEnd) {
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footstep = diff_footprint(x, y);
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if (front && (footsteps.containsKey(footstep))) {
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done = true;
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}
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if (!front) {
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footsteps.put(footstep, d);
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}
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}
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while (!done && x < text1_length && y < text2_length
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&& text1.charAt(x) == text2.charAt(y)) {
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x++;
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y++;
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if (doubleEnd) {
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footstep = diff_footprint(x, y);
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if (front && (footsteps.containsKey(footstep))) {
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done = true;
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}
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if (!front) {
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footsteps.put(footstep, d);
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}
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}
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}
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v1.put(k, x);
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v_map1.get(d).add(diff_footprint(x, y));
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if (x == text1_length && y == text2_length) {
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// Reached the end in single-path mode.
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return diff_path1(v_map1, text1, text2);
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} else if (done) {
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// Front path ran over reverse path.
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v_map2 = v_map2.subList(0, footsteps.get(footstep) + 1);
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LinkedList<Diff> a = diff_path1(v_map1, text1.substring(0, x),
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text2.substring(0, y));
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a.addAll(diff_path2(v_map2, text1.substring(x), text2.substring(y)));
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return a;
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}
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}
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if (doubleEnd) {
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// Walk the reverse path one step.
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v_map2.add(new HashSet<Long>()); // Adds at index 'd'.
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for (int k = -d; k <= d; k += 2) {
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if (k == -d || k != d && v2.get(k - 1) < v2.get(k + 1)) {
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x = v2.get(k + 1);
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} else {
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x = v2.get(k - 1) + 1;
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}
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y = x - k;
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footstep = diff_footprint(text1_length - x, text2_length - y);
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if (!front && (footsteps.containsKey(footstep))) {
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done = true;
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}
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if (front) {
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footsteps.put(footstep, d);
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}
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while (!done && x < text1_length && y < text2_length
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&& text1.charAt(text1_length - x - 1)
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== text2.charAt(text2_length - y - 1)) {
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x++;
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y++;
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footstep = diff_footprint(text1_length - x, text2_length - y);
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if (!front && (footsteps.containsKey(footstep))) {
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done = true;
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}
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if (front) {
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footsteps.put(footstep, d);
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}
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}
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v2.put(k, x);
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v_map2.get(d).add(diff_footprint(x, y));
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if (done) {
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// Reverse path ran over front path.
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v_map1 = v_map1.subList(0, footsteps.get(footstep) + 1);
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LinkedList<Diff> a
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= diff_path1(v_map1, text1.substring(0, text1_length - x),
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text2.substring(0, text2_length - y));
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a.addAll(diff_path2(v_map2, text1.substring(text1_length - x),
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text2.substring(text2_length - y)));
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return a;
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}
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}
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}
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}
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// Number of diffs equals number of characters, no commonality at all.
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return null;
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}
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/**
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* Work from the middle back to the start to determine the path.
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* @param v_map List of path sets.
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* @param text1 Old string fragment to be diffed.
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* @param text2 New string fragment to be diffed.
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* @return LinkedList of Diff objects.
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*/
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protected LinkedList<Diff> diff_path1(List<Set<Long>> v_map,
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String text1, String text2) {
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LinkedList<Diff> path = new LinkedList<Diff>();
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int x = text1.length();
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int y = text2.length();
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Operation last_op = null;
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for (int d = v_map.size() - 2; d >= 0; d--) {
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while (true) {
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if (v_map.get(d).contains(diff_footprint(x - 1, y))) {
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x--;
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if (last_op == Operation.DELETE) {
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path.getFirst().text = text1.charAt(x) + path.getFirst().text;
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} else {
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path.addFirst(new Diff(Operation.DELETE,
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text1.substring(x, x + 1)));
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}
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last_op = Operation.DELETE;
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break;
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} else if (v_map.get(d).contains(diff_footprint(x, y - 1))) {
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y--;
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if (last_op == Operation.INSERT) {
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path.getFirst().text = text2.charAt(y) + path.getFirst().text;
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} else {
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path.addFirst(new Diff(Operation.INSERT,
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text2.substring(y, y + 1)));
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}
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last_op = Operation.INSERT;
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break;
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} else {
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x--;
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y--;
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assert (text1.charAt(x) == text2.charAt(y))
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: "No diagonal. Can't happen. (diff_path1)";
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if (last_op == Operation.EQUAL) {
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path.getFirst().text = text1.charAt(x) + path.getFirst().text;
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} else {
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path.addFirst(new Diff(Operation.EQUAL, text1.substring(x, x + 1)));
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}
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last_op = Operation.EQUAL;
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}
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}
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}
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return path;
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}
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/**
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* Work from the middle back to the end to determine the path.
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* @param v_map List of path sets.
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* @param text1 Old string fragment to be diffed.
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* @param text2 New string fragment to be diffed.
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* @return LinkedList of Diff objects.
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*/
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protected LinkedList<Diff> diff_path2(List<Set<Long>> v_map,
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String text1, String text2) {
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LinkedList<Diff> path = new LinkedList<Diff>();
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int x = text1.length();
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int y = text2.length();
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Operation last_op = null;
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for (int d = v_map.size() - 2; d >= 0; d--) {
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while (true) {
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if (v_map.get(d).contains(diff_footprint(x - 1, y))) {
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x--;
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if (last_op == Operation.DELETE) {
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path.getLast().text += text1.charAt(text1.length() - x - 1);
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} else {
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path.addLast(new Diff(Operation.DELETE,
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text1.substring(text1.length() - x - 1, text1.length() - x)));
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}
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last_op = Operation.DELETE;
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break;
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} else if (v_map.get(d).contains(diff_footprint(x, y - 1))) {
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y--;
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if (last_op == Operation.INSERT) {
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path.getLast().text += text2.charAt(text2.length() - y - 1);
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} else {
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path.addLast(new Diff(Operation.INSERT,
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text2.substring(text2.length() - y - 1, text2.length() - y)));
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}
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last_op = Operation.INSERT;
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break;
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} else {
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x--;
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y--;
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assert (text1.charAt(text1.length() - x - 1)
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== text2.charAt(text2.length() - y - 1))
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: "No diagonal. Can't happen. (diff_path2)";
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if (last_op == Operation.EQUAL) {
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path.getLast().text += text1.charAt(text1.length() - x - 1);
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} else {
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path.addLast(new Diff(Operation.EQUAL,
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text1.substring(text1.length() - x - 1, text1.length() - x)));
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}
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last_op = Operation.EQUAL;
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}
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}
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}
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return path;
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}
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/**
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* Compute a good hash of two integers.
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* @param x First int.
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* @param y Second int.
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* @return A long made up of both ints.
|
*/
|
protected long diff_footprint(int x, int y) {
|
// The maximum size for a long is 9,223,372,036,854,775,807
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// The maximum size for an int is 2,147,483,647
|
// Two ints fit nicely in one long.
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long result = x;
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result = result << 32;
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result += y;
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return result;
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}
|
/**
|
* 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;
|
}
|
/**
|
* Do the two texts share a substring which is at least half the length of
|
* the longer text?
|
* @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) {
|
String longtext = text1.length() > text2.length() ? text1 : text2;
|
String shorttext = text1.length() > text2.length() ? text2 : text1;
|
if (longtext.length() < 10 || shorttext.length() < 1) {
|
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() >= longtext.length() / 2) {
|
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;
|
Stack<Diff> equalities = new Stack<Diff>(); // Stack of qualities.
|
String lastequality = null; // Always equal to equalities.lastElement().text
|
ListIterator<Diff> pointer = diffs.listIterator();
|
// Number of characters that changed prior to the equality.
|
int length_changes1 = 0;
|
// Number of characters that changed after the equality.
|
int length_changes2 = 0;
|
Diff thisDiff = pointer.next();
|
while (thisDiff != null) {
|
if (thisDiff.operation == Operation.EQUAL) {
|
// equality found
|
equalities.push(thisDiff);
|
length_changes1 = length_changes2;
|
length_changes2 = 0;
|
lastequality = thisDiff.text;
|
} else {
|
// an insertion or deletion
|
length_changes2 += thisDiff.text.length();
|
if (lastequality != null && (lastequality.length() <= length_changes1)
|
&& (lastequality.length() <= length_changes2)) {
|
//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_changes1 = 0; // Reset the counters.
|
length_changes2 = 0;
|
lastequality = null;
|
changes = true;
|
}
|
}
|
thisDiff = pointer.hasNext() ? pointer.next() : null;
|
}
|
if (changes) {
|
diff_cleanupMerge(diffs);
|
}
|
diff_cleanupSemanticLossless(diffs);
|
}
|
/**
|
* 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 5 (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 5;
|
}
|
// 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.
|
int score = 0;
|
// One point for non-alphanumeric.
|
if (!Character.isLetterOrDigit(one.charAt(one.length() - 1))
|
|| !Character.isLetterOrDigit(two.charAt(0))) {
|
score++;
|
// Two points for whitespace.
|
if (Character.isWhitespace(one.charAt(one.length() - 1))
|
|| Character.isWhitespace(two.charAt(0))) {
|
score++;
|
// Three points for line breaks.
|
if (Character.getType(one.charAt(one.length() - 1)) == Character.CONTROL
|
|| Character.getType(two.charAt(0)) == Character.CONTROL) {
|
score++;
|
// Four points for blank lines.
|
if (BLANKLINEEND.matcher(one).find()
|
|| BLANKLINESTART.matcher(two).find()) {
|
score++;
|
}
|
}
|
}
|
}
|
return score;
|
}
|
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;
|
Stack<Diff> equalities = new Stack<Diff>(); // Stack of equalities.
|
String lastequality = null; // Always equal to equalities.lastElement().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 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:
|
* <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.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<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 != 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 (count_delete != 0 && count_insert != 0) {
|
// 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;
|
}
|
// System.out.println(diff);
|
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 LinkedList of Diff objects.
|
* @param loc Location within text1.
|
* @return Location within text2.
|
*/
|
public int diff_xIndex(LinkedList<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 LinkedList of Diff objects.
|
* @return HTML representation.
|
*/
|
public String diff_prettyHtml(LinkedList<Diff> diffs) {
|
StringBuilder html = new StringBuilder();
|
int i = 0;
|
for (Diff aDiff : diffs) {
|
String text = aDiff.text.replace("&", "&").replace("<", "<")
|
.replace(">", ">");// .replace("\n", "¶<BR>")
|
switch (aDiff.operation) {
|
case INSERT:
|
html.append("<INS STYLE=\"color:#0278E7;\"").append(i)
|
.append("\">").append(text).append("</INS>");
|
break;
|
case DELETE:
|
html.append("<DEL STYLE=\"color:#91262A;\" ").append(i)
|
.append("\">").append(text).append("</DEL>");
|
break;
|
case EQUAL:
|
html.append("<SPAN ").append(i).append("\">").append(text)
|
.append("</SPAN>");
|
break;
|
}
|
if (aDiff.operation != Operation.DELETE) {
|
i += aDiff.text.length();
|
}
|
}
|
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<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 LinkedList of Diff objects.
|
* @return Destination text.
|
*/
|
public String diff_text2(LinkedList<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 LinkedList of Diff objects.
|
* @return Number of changes.
|
*/
|
public int diff_levenshtein(LinkedList<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 Array of diff tuples.
|
* @return Delta text.
|
*/
|
public String diff_toDelta(LinkedList<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 tuples 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) {
|
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) {
|
// 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 tuples for text1 to text2.
|
* @return LinkedList of Patch objects.
|
*/
|
public LinkedList<Patch> patch_make(LinkedList<Diff> diffs) {
|
// 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 tuples for text1 to text2.
|
* @return LinkedList of Patch objects.
|
* @deprecated Prefer patch_make(String text1, LinkedList<Diff> diffs).
|
*/
|
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 tuples for text1 to text2.
|
* @return LinkedList of Patch objects.
|
*/
|
public LinkedList<Patch> patch_make(String text1, LinkedList<Diff> diffs) {
|
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) {
|
// 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> 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) {
|
int paddingLength = this.Patch_Margin;
|
String nullPadding = "";
|
for (int 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.
|
* @param patches LinkedList of Patch objects.
|
*/
|
public void patch_splitMax(LinkedList<Patch> patches) {
|
int patch_size;
|
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();
|
patch_size = Match_MaxBits;
|
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.
|
*/
|
public String toString() {
|
String prettyText = this.text.replace('\n', '\u00b6');
|
return "Diff(" + this.operation + ",\"" + prettyText + "\")";
|
}
|
|
|
/**
|
* Is this Diff equivalent to another Diff?
|
* @param d Another Diff to compare against.
|
* @return true or false.
|
*/
|
public boolean equals(Object d) {
|
try {
|
return (((Diff) d).operation == this.operation)
|
&& (((Diff) d).text.equals(this.text));
|
} catch (ClassCastException e) {
|
return false;
|
}
|
}
|
}
|
|
|
/**
|
* 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>();
|
}
|
|
|
/**
|
* 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", "#");
|
}
|
|
public String getDiffMatch(String oldString, String newString) {
|
if (newString != null) {
|
if (oldString == null) {
|
oldString = "";
|
}
|
return diff_prettyHtml(diff_main(oldString, newString));
|
} else {
|
return newString;
|
}
|
}
|
|
public String getShowHtml(Object oldObj, Object newObj){
|
String newStr ="";
|
if (newObj!=null)
|
newStr = newObj.toString();
|
if (oldObj!=null) {
|
newStr = diff_prettyHtml(diff_main(oldObj.toString(), newStr));
|
return newStr;
|
} else {
|
return newStr;
|
}
|
}
|
}
|
