2634 lines
107 KiB
C#
2634 lines
107 KiB
C#
using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Text;
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using System.Text.RegularExpressions;
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//using System.Web;
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namespace BismNormalizer.TabularCompare.UI
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{
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/* Diff Match and Patch
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* http://code.google.com/p/google-diff-match-patch/
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*/
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internal static class CompatibilityExtensions
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{
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// JScript splice function
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public static List<T> Splice<T>(this List<T> input, int start, int count,
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params T[] objects)
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{
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List<T> deletedRange = input.GetRange(start, count);
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input.RemoveRange(start, count);
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input.InsertRange(start, objects);
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return deletedRange;
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}
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// Java substring function
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public static string JavaSubstring(this string s, int begin, int end) => s.Substring(begin, end - begin);
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}
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/**-
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* The data structure representing a diff is a 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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{
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DELETE, INSERT, EQUAL
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}
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/**
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* Class representing one diff operation.
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*/
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public class Diff
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{
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public Operation operation;
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// One of: INSERT, DELETE or EQUAL.
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public string text;
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// The text associated with this diff operation.
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/**
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* Constructor. Initializes the diff with the provided values.
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* @param operation One of INSERT, DELETE or EQUAL.
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* @param text The text being applied.
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*/
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public Diff(Operation operation, string text)
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{
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// Construct a diff with the specified operation and text.
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this.operation = operation;
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this.text = text;
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}
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/**
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* Display a human-readable version of this Diff.
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* @return text version.
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*/
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public override string ToString()
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{
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string prettyText = this.text.Replace('\n', '\u00b6');
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return "Diff(" + this.operation + ",\"" + prettyText + "\")";
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}
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/**
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* Is this Diff equivalent to another Diff?
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* @param d Another Diff to compare against.
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* @return true or false.
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*/
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public override bool Equals(Object obj)
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{
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// If parameter is null return false.
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if (obj == null)
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{
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return false;
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}
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// If parameter cannot be cast to Diff return false.
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Diff p = obj as Diff;
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if ((System.Object)p == null)
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{
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return false;
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}
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// Return true if the fields match.
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return p.operation == this.operation && p.text == this.text;
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}
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public bool Equals(Diff obj)
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{
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// If parameter is null return false.
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if (obj == null)
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{
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return false;
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}
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// Return true if the fields match.
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return obj.operation == this.operation && obj.text == this.text;
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}
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public override int GetHashCode() => text.GetHashCode() ^ operation.GetHashCode();
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}
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/**
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* Class representing one patch operation.
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*/
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public class Patch
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{
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public List<Diff> diffs = new List<Diff>();
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public int start1;
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public int start2;
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public int length1;
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public int length2;
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/**
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* Emmulate GNU diff's format.
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* Header: @@ -382,8 +481,9 @@
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* Indicies are printed as 1-based, not 0-based.
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* @return The GNU diff string.
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*/
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public override string ToString()
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{
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string coords1, coords2;
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if (this.length1 == 0)
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{
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coords1 = this.start1 + ",0";
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}
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else if (this.length1 == 1)
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{
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coords1 = Convert.ToString(this.start1 + 1);
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}
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else {
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coords1 = (this.start1 + 1) + "," + this.length1;
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}
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if (this.length2 == 0)
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{
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coords2 = this.start2 + ",0";
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}
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else if (this.length2 == 1)
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{
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coords2 = Convert.ToString(this.start2 + 1);
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}
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else {
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coords2 = (this.start2 + 1) + "," + this.length2;
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}
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StringBuilder text = new StringBuilder();
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text.Append("@@ -").Append(coords1).Append(" +").Append(coords2)
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.Append(" @@\n");
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// Escape the body of the patch with %xx notation.
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foreach (Diff aDiff in this.diffs)
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{
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switch (aDiff.operation)
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{
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case Operation.INSERT:
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text.Append('+');
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break;
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case Operation.DELETE:
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text.Append('-');
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break;
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case Operation.EQUAL:
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text.Append(' ');
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break;
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}
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#region Commented out to avoid reference to System.Web
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//text.Append(HttpUtility.UrlEncode(aDiff.text, new UTF8Encoding()).Replace('+', ' ')).Append("\n");
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text.Append(aDiff.text.Replace('+', ' ')).Append("\n");
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#endregion
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}
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return DiffMatchPatch.unescapeForEncodeUriCompatability(
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text.ToString());
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}
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}
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/**
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* Class containing the diff, match and patch methods.
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* Also Contains the behaviour settings.
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*/
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public class DiffMatchPatch
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{
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// Defaults.
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// Set these on your diff_match_patch instance to override the defaults.
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// Number of seconds to map a diff before giving up (0 for infinity).
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public float Diff_Timeout = 1.0f;
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// Cost of an empty edit operation in terms of edit characters.
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public short Diff_EditCost = 4;
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// At what point is no match declared (0.0 = perfection, 1.0 = very loose).
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public float Match_Threshold = 0.5f;
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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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public int Match_Distance = 1000;
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// When deleting a large block of text (over ~64 characters), how close
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// do the contents have to be to match the expected contents. (0.0 =
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// perfection, 1.0 = very loose). Note that Match_Threshold controls
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// how closely the end points of a delete need to match.
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public float Patch_DeleteThreshold = 0.5f;
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// Chunk size for context length.
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public short Patch_Margin = 4;
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// The number of bits in an int.
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private short Match_MaxBits = 32;
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// DIFF FUNCTIONS
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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 List of Diff objects.
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*/
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public List<Diff> diff_main(string text1, string text2) => diff_main(text1, text2, true);
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/**
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* Find the differences between 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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* @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 List of Diff objects.
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*/
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public List<Diff> diff_main(string text1, string text2, bool checklines)
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{
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// Set a deadline by which time the diff must be complete.
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DateTime deadline;
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if (this.Diff_Timeout <= 0)
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{
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deadline = DateTime.MaxValue;
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}
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else {
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deadline = DateTime.Now +
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new TimeSpan(((long)(Diff_Timeout * 1000)) * 10000);
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}
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return diff_main(text1, text2, checklines, deadline);
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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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* @param deadline Time when the diff should be complete by. Used
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* internally for recursive calls. Users should set DiffTimeout
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* instead.
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* @return List of Diff objects.
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*/
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private List<Diff> diff_main(string text1, string text2, bool checklines,
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DateTime deadline)
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{
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// Check for null inputs not needed since null can't be passed in C#.
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// Check for equality (speedup).
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List<Diff> diffs;
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if (text1 == text2)
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{
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diffs = new List<Diff>();
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if (text1.Length != 0)
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{
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diffs.Add(new Diff(Operation.EQUAL, text1));
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}
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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, deadline);
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// Restore the prefix and suffix.
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if (commonprefix.Length != 0)
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{
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diffs.Insert(0, (new Diff(Operation.EQUAL, commonprefix)));
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}
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if (commonsuffix.Length != 0)
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{
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diffs.Add(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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* @param deadline Time when the diff should be complete by.
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* @return List of Diff objects.
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*/
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private List<Diff> diff_compute(string text1, string text2,
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bool checklines, DateTime deadline)
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{
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List<Diff> diffs = new List<Diff>();
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if (text1.Length == 0)
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{
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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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{
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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, StringComparison.Ordinal);
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if (i != -1)
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{
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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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if (shorttext.Length == 1)
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{
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// Single character string.
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// After the previous speedup, the character can't be an equality.
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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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return diffs;
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}
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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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{
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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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List<Diff> diffs_a = diff_main(text1_a, text2_a, checklines, deadline);
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List<Diff> diffs_b = diff_main(text1_b, text2_b, checklines, deadline);
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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.AddRange(diffs_b);
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return diffs;
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}
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if (checklines && text1.Length > 100 && text2.Length > 100)
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{
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return diff_lineMode(text1, text2, deadline);
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}
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return diff_bisect(text1, text2, deadline);
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}
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/**
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* Do a quick line-level diff on both strings, then rediff the parts for
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* greater accuracy.
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* This speedup can produce non-minimal diffs.
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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 deadline Time when the diff should be complete by.
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* @return List of Diff objects.
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*/
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private List<Diff> diff_lineMode(string text1, string text2,
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DateTime deadline)
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{
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// Scan the text on a line-by-line basis first.
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Object[] b = diff_linesToChars(text1, text2);
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text1 = (string)b[0];
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text2 = (string)b[1];
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List<string> linearray = (List<string>)b[2];
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List<Diff> diffs = diff_main(text1, text2, false, deadline);
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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, string.Empty));
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int pointer = 0;
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int count_delete = 0;
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int count_insert = 0;
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string text_delete = string.Empty;
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string text_insert = string.Empty;
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while (pointer < diffs.Count)
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{
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switch (diffs[pointer].operation)
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{
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case Operation.INSERT:
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count_insert++;
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text_insert += diffs[pointer].text;
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break;
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case Operation.DELETE:
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count_delete++;
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text_delete += diffs[pointer].text;
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break;
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case Operation.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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{
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// Delete the offending records and add the merged ones.
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diffs.RemoveRange(pointer - count_delete - count_insert,
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count_delete + count_insert);
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pointer = pointer - count_delete - count_insert;
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List<Diff> a =
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this.diff_main(text_delete, text_insert, false, deadline);
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diffs.InsertRange(pointer, a);
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pointer = pointer + a.Count;
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}
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count_insert = 0;
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count_delete = 0;
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text_delete = string.Empty;
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text_insert = string.Empty;
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break;
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}
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pointer++;
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}
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diffs.RemoveAt(diffs.Count - 1); // Remove the dummy entry at the end.
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return diffs;
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}
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/**
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* Find the 'middle snake' of a diff, split the problem in two
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* and return the recursively constructed diff.
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* See Myers 1986 paper: An O(ND) Difference Algorithm and Its Variations.
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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 deadline Time at which to bail if not yet complete.
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* @return List of Diff objects.
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*/
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protected List<Diff> diff_bisect(string text1, string text2,
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DateTime deadline)
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{
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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) / 2;
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int v_offset = max_d;
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int v_length = 2 * max_d;
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int[] v1 = new int[v_length];
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int[] v2 = new int[v_length];
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for (int x = 0; x < v_length; x++)
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{
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v1[x] = -1;
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v2[x] = -1;
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}
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v1[v_offset + 1] = 0;
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v2[v_offset + 1] = 0;
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int delta = text1_length - text2_length;
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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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bool front = (delta % 2 != 0);
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// Offsets for start and end of k loop.
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// Prevents mapping of space beyond the grid.
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int k1start = 0;
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int k1end = 0;
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int k2start = 0;
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int k2end = 0;
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for (int d = 0; d < max_d; d++)
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{
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// Bail out if deadline is reached.
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if (DateTime.Now > deadline)
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{
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break;
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}
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// Walk the front path one step.
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for (int k1 = -d + k1start; k1 <= d - k1end; k1 += 2)
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{
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int k1_offset = v_offset + k1;
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int x1;
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if (k1 == -d || k1 != d && v1[k1_offset - 1] < v1[k1_offset + 1])
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{
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x1 = v1[k1_offset + 1];
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}
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else {
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x1 = v1[k1_offset - 1] + 1;
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}
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int y1 = x1 - k1;
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while (x1 < text1_length && y1 < text2_length
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&& text1[x1] == text2[y1])
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{
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x1++;
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|
y1++;
|
|
}
|
|
v1[k1_offset] = x1;
|
|
if (x1 > text1_length)
|
|
{
|
|
// Ran off the right of the graph.
|
|
k1end += 2;
|
|
}
|
|
else if (y1 > text2_length)
|
|
{
|
|
// Ran off the bottom of the graph.
|
|
k1start += 2;
|
|
}
|
|
else if (front)
|
|
{
|
|
int k2_offset = v_offset + delta - k1;
|
|
if (k2_offset >= 0 && k2_offset < v_length && v2[k2_offset] != -1)
|
|
{
|
|
// Mirror x2 onto top-left coordinate system.
|
|
int x2 = text1_length - v2[k2_offset];
|
|
if (x1 >= x2)
|
|
{
|
|
// Overlap detected.
|
|
return diff_bisectSplit(text1, text2, x1, y1, deadline);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// Walk the reverse path one step.
|
|
for (int k2 = -d + k2start; k2 <= d - k2end; k2 += 2)
|
|
{
|
|
int k2_offset = v_offset + k2;
|
|
int x2;
|
|
if (k2 == -d || k2 != d && v2[k2_offset - 1] < v2[k2_offset + 1])
|
|
{
|
|
x2 = v2[k2_offset + 1];
|
|
}
|
|
else {
|
|
x2 = v2[k2_offset - 1] + 1;
|
|
}
|
|
int y2 = x2 - k2;
|
|
while (x2 < text1_length && y2 < text2_length
|
|
&& text1[text1_length - x2 - 1]
|
|
== text2[text2_length - y2 - 1])
|
|
{
|
|
x2++;
|
|
y2++;
|
|
}
|
|
v2[k2_offset] = x2;
|
|
if (x2 > text1_length)
|
|
{
|
|
// Ran off the left of the graph.
|
|
k2end += 2;
|
|
}
|
|
else if (y2 > text2_length)
|
|
{
|
|
// Ran off the top of the graph.
|
|
k2start += 2;
|
|
}
|
|
else if (!front)
|
|
{
|
|
int k1_offset = v_offset + delta - k2;
|
|
if (k1_offset >= 0 && k1_offset < v_length && v1[k1_offset] != -1)
|
|
{
|
|
int x1 = v1[k1_offset];
|
|
int y1 = v_offset + x1 - k1_offset;
|
|
// Mirror x2 onto top-left coordinate system.
|
|
x2 = text1_length - v2[k2_offset];
|
|
if (x1 >= x2)
|
|
{
|
|
// Overlap detected.
|
|
return diff_bisectSplit(text1, text2, x1, y1, deadline);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
// Diff took too long and hit the deadline or
|
|
// number of diffs equals number of characters, no commonality at all.
|
|
List<Diff> diffs = new List<Diff>();
|
|
diffs.Add(new Diff(Operation.DELETE, text1));
|
|
diffs.Add(new Diff(Operation.INSERT, text2));
|
|
return diffs;
|
|
}
|
|
|
|
/**
|
|
* Given the location of the 'middle snake', split the diff in two parts
|
|
* and recurse.
|
|
* @param text1 Old string to be diffed.
|
|
* @param text2 New string to be diffed.
|
|
* @param x Index of split point in text1.
|
|
* @param y Index of split point in text2.
|
|
* @param deadline Time at which to bail if not yet complete.
|
|
* @return LinkedList of Diff objects.
|
|
*/
|
|
private List<Diff> diff_bisectSplit(string text1, string text2,
|
|
int x, int y, DateTime deadline)
|
|
{
|
|
string text1a = text1.Substring(0, x);
|
|
string text2a = text2.Substring(0, y);
|
|
string text1b = text1.Substring(x);
|
|
string text2b = text2.Substring(y);
|
|
|
|
// Compute both diffs serially.
|
|
List<Diff> diffs = diff_main(text1a, text2a, false, deadline);
|
|
List<Diff> diffsb = diff_main(text1b, text2b, false, deadline);
|
|
|
|
diffs.AddRange(diffsb);
|
|
return diffs;
|
|
}
|
|
|
|
/**
|
|
* Split two texts into a list of strings. Reduce the texts to a string of
|
|
* hashes where each Unicode character represents one line.
|
|
* @param text1 First string.
|
|
* @param text2 Second string.
|
|
* @return Three element Object array, containing the encoded text1, the
|
|
* encoded text2 and the List of unique strings. The zeroth element
|
|
* of the List of unique strings is intentionally blank.
|
|
*/
|
|
protected Object[] diff_linesToChars(string text1, string text2)
|
|
{
|
|
List<string> lineArray = new List<string>();
|
|
Dictionary<string, int> lineHash = new Dictionary<string, int>();
|
|
// e.g. linearray[4] == "Hello\n"
|
|
// e.g. linehash.get("Hello\n") == 4
|
|
|
|
// "\x00" is a valid character, but various debuggers don't like it.
|
|
// So we'll insert a junk entry to avoid generating a null character.
|
|
lineArray.Add(string.Empty);
|
|
|
|
string chars1 = diff_linesToCharsMunge(text1, lineArray, lineHash);
|
|
string chars2 = diff_linesToCharsMunge(text2, lineArray, lineHash);
|
|
return new Object[] { chars1, chars2, lineArray };
|
|
}
|
|
|
|
/**
|
|
* Split a text into a list of strings. Reduce the texts to a string of
|
|
* hashes where each Unicode character represents one line.
|
|
* @param text String to encode.
|
|
* @param lineArray List of unique strings.
|
|
* @param lineHash Map of strings to indices.
|
|
* @return Encoded string.
|
|
*/
|
|
private string diff_linesToCharsMunge(string text, List<string> lineArray,
|
|
Dictionary<string, int> lineHash)
|
|
{
|
|
int lineStart = 0;
|
|
int lineEnd = -1;
|
|
string line;
|
|
StringBuilder chars = new StringBuilder();
|
|
// Walk the text, pulling out a Substring for each line.
|
|
// text.split('\n') would would temporarily double our memory footprint.
|
|
// Modifying text would create many large strings to garbage collect.
|
|
while (lineEnd < text.Length - 1)
|
|
{
|
|
lineEnd = text.IndexOf('\n', lineStart);
|
|
if (lineEnd == -1)
|
|
{
|
|
lineEnd = text.Length - 1;
|
|
}
|
|
line = text.JavaSubstring(lineStart, lineEnd + 1);
|
|
lineStart = lineEnd + 1;
|
|
|
|
if (lineHash.ContainsKey(line))
|
|
{
|
|
chars.Append(((char)(int)lineHash[line]));
|
|
}
|
|
else {
|
|
lineArray.Add(line);
|
|
lineHash.Add(line, lineArray.Count - 1);
|
|
chars.Append(((char)(lineArray.Count - 1)));
|
|
}
|
|
}
|
|
return chars.ToString();
|
|
}
|
|
|
|
/**
|
|
* Rehydrate the text in a diff from a string of line hashes to real lines
|
|
* of text.
|
|
* @param diffs List of Diff objects.
|
|
* @param lineArray List of unique strings.
|
|
*/
|
|
protected void diff_charsToLines(ICollection<Diff> diffs,
|
|
List<string> lineArray)
|
|
{
|
|
StringBuilder text;
|
|
foreach (Diff diff in diffs)
|
|
{
|
|
text = new StringBuilder();
|
|
for (int y = 0; y < diff.text.Length; y++)
|
|
{
|
|
text.Append(lineArray[diff.text[y]]);
|
|
}
|
|
diff.text = text.ToString();
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Determine the common prefix of two strings.
|
|
* @param text1 First string.
|
|
* @param text2 Second string.
|
|
* @return The number of characters common to the start of each string.
|
|
*/
|
|
public int diff_commonPrefix(string text1, string text2)
|
|
{
|
|
// Performance analysis: http://neil.fraser.name/news/2007/10/09/
|
|
int n = Math.Min(text1.Length, text2.Length);
|
|
for (int i = 0; i < n; i++)
|
|
{
|
|
if (text1[i] != text2[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[text1_length - i] != text2[text2_length - i])
|
|
{
|
|
return i - 1;
|
|
}
|
|
}
|
|
return n;
|
|
}
|
|
|
|
/**
|
|
* Determine if the suffix of one string is the prefix of another.
|
|
* @param text1 First string.
|
|
* @param text2 Second string.
|
|
* @return The number of characters common to the end of the first
|
|
* string and the start of the second string.
|
|
*/
|
|
protected int diff_commonOverlap(string text1, string text2)
|
|
{
|
|
// Cache the text lengths to prevent multiple calls.
|
|
int text1_length = text1.Length;
|
|
int text2_length = text2.Length;
|
|
// Eliminate the null case.
|
|
if (text1_length == 0 || text2_length == 0)
|
|
{
|
|
return 0;
|
|
}
|
|
// Truncate the longer string.
|
|
if (text1_length > text2_length)
|
|
{
|
|
text1 = text1.Substring(text1_length - text2_length);
|
|
}
|
|
else if (text1_length < text2_length)
|
|
{
|
|
text2 = text2.Substring(0, text1_length);
|
|
}
|
|
int text_length = Math.Min(text1_length, text2_length);
|
|
// Quick check for the worst case.
|
|
if (text1 == text2)
|
|
{
|
|
return text_length;
|
|
}
|
|
|
|
// Start by looking for a single character match
|
|
// and increase length until no match is found.
|
|
// Performance analysis: http://neil.fraser.name/news/2010/11/04/
|
|
int best = 0;
|
|
int length = 1;
|
|
while (true)
|
|
{
|
|
string pattern = text1.Substring(text_length - length);
|
|
int found = text2.IndexOf(pattern, StringComparison.Ordinal);
|
|
if (found == -1)
|
|
{
|
|
return best;
|
|
}
|
|
length += found;
|
|
if (found == 0 || text1.Substring(text_length - length) ==
|
|
text2.Substring(0, length))
|
|
{
|
|
best = length;
|
|
length++;
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Do the two texts share a Substring which is at least half the length of
|
|
* the longer text?
|
|
* This speedup can produce non-minimal diffs.
|
|
* @param text1 First string.
|
|
* @param text2 Second string.
|
|
* @return Five element String array, containing the prefix of text1, the
|
|
* suffix of text1, the prefix of text2, the suffix of text2 and the
|
|
* common middle. Or null if there was no match.
|
|
*/
|
|
|
|
protected string[] diff_halfMatch(string text1, string text2)
|
|
{
|
|
if (this.Diff_Timeout <= 0)
|
|
{
|
|
// Don't risk returning a non-optimal diff if we have unlimited time.
|
|
return null;
|
|
}
|
|
string longtext = text1.Length > text2.Length ? text1 : text2;
|
|
string shorttext = text1.Length > text2.Length ? text2 : text1;
|
|
if (longtext.Length < 4 || shorttext.Length * 2 < longtext.Length)
|
|
{
|
|
return null; // Pointless.
|
|
}
|
|
|
|
// First check if the second quarter is the seed for a half-match.
|
|
string[] hm1 = diff_halfMatchI(longtext, shorttext,
|
|
(longtext.Length + 3) / 4);
|
|
// Check again based on the third quarter.
|
|
string[] hm2 = diff_halfMatchI(longtext, shorttext,
|
|
(longtext.Length + 1) / 2);
|
|
string[] hm;
|
|
if (hm1 == null && hm2 == null)
|
|
{
|
|
return null;
|
|
}
|
|
else if (hm2 == null)
|
|
{
|
|
hm = hm1;
|
|
}
|
|
else if (hm1 == null)
|
|
{
|
|
hm = hm2;
|
|
}
|
|
else {
|
|
// Both matched. Select the longest.
|
|
hm = hm1[4].Length > hm2[4].Length ? hm1 : hm2;
|
|
}
|
|
|
|
// A half-match was found, sort out the return data.
|
|
if (text1.Length > text2.Length)
|
|
{
|
|
return hm;
|
|
//return new string[]{hm[0], hm[1], hm[2], hm[3], hm[4]};
|
|
}
|
|
else {
|
|
return new string[] { hm[2], hm[3], hm[0], hm[1], hm[4] };
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Does a Substring of shorttext exist within longtext such that the
|
|
* Substring is at least half the length of longtext?
|
|
* @param longtext Longer string.
|
|
* @param shorttext Shorter string.
|
|
* @param i Start index of quarter length Substring within longtext.
|
|
* @return Five element string array, containing the prefix of longtext, the
|
|
* suffix of longtext, the prefix of shorttext, the suffix of shorttext
|
|
* and the common middle. Or null if there was no match.
|
|
*/
|
|
private string[] diff_halfMatchI(string longtext, string shorttext, int i)
|
|
{
|
|
// Start with a 1/4 length Substring at position i as a seed.
|
|
string seed = longtext.Substring(i, longtext.Length / 4);
|
|
int j = -1;
|
|
string best_common = string.Empty;
|
|
string best_longtext_a = string.Empty, best_longtext_b = string.Empty;
|
|
string best_shorttext_a = string.Empty, best_shorttext_b = string.Empty;
|
|
while (j < shorttext.Length && (j = shorttext.IndexOf(seed, j + 1,
|
|
StringComparison.Ordinal)) != -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, suffixLength)
|
|
+ shorttext.Substring(j, prefixLength);
|
|
best_longtext_a = longtext.Substring(0, i - suffixLength);
|
|
best_longtext_b = longtext.Substring(i + prefixLength);
|
|
best_shorttext_a = shorttext.Substring(0, j - suffixLength);
|
|
best_shorttext_b = shorttext.Substring(j + prefixLength);
|
|
}
|
|
}
|
|
if (best_common.Length * 2 >= longtext.Length)
|
|
{
|
|
return new string[]{best_longtext_a, best_longtext_b,
|
|
best_shorttext_a, best_shorttext_b, best_common};
|
|
}
|
|
else {
|
|
return null;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Reduce the number of edits by eliminating semantically trivial
|
|
* equalities.
|
|
* @param diffs List of Diff objects.
|
|
*/
|
|
public void diff_cleanupSemantic(List<Diff> diffs)
|
|
{
|
|
bool changes = false;
|
|
// Stack of indices where equalities are found.
|
|
Stack<int> equalities = new Stack<int>();
|
|
// Always equal to equalities[equalitiesLength-1][1]
|
|
string lastequality = null;
|
|
int pointer = 0; // Index of current position.
|
|
// Number of characters that changed prior to the equality.
|
|
int length_insertions1 = 0;
|
|
int length_deletions1 = 0;
|
|
// Number of characters that changed after the equality.
|
|
int length_insertions2 = 0;
|
|
int length_deletions2 = 0;
|
|
while (pointer < diffs.Count)
|
|
{
|
|
if (diffs[pointer].operation == Operation.EQUAL)
|
|
{ // Equality found.
|
|
equalities.Push(pointer);
|
|
length_insertions1 = length_insertions2;
|
|
length_deletions1 = length_deletions2;
|
|
length_insertions2 = 0;
|
|
length_deletions2 = 0;
|
|
lastequality = diffs[pointer].text;
|
|
}
|
|
else { // an insertion or deletion
|
|
if (diffs[pointer].operation == Operation.INSERT)
|
|
{
|
|
length_insertions2 += diffs[pointer].text.Length;
|
|
}
|
|
else {
|
|
length_deletions2 += diffs[pointer].text.Length;
|
|
}
|
|
// Eliminate an equality that is smaller or equal to the edits on both
|
|
// sides of it.
|
|
if (lastequality != null && (lastequality.Length
|
|
<= Math.Max(length_insertions1, length_deletions1))
|
|
&& (lastequality.Length
|
|
<= Math.Max(length_insertions2, length_deletions2)))
|
|
{
|
|
// Duplicate record.
|
|
diffs.Insert(equalities.Peek(),
|
|
new Diff(Operation.DELETE, lastequality));
|
|
// Change second copy to insert.
|
|
diffs[equalities.Peek() + 1].operation = Operation.INSERT;
|
|
// Throw away the equality we just deleted.
|
|
equalities.Pop();
|
|
if (equalities.Count > 0)
|
|
{
|
|
equalities.Pop();
|
|
}
|
|
pointer = equalities.Count > 0 ? equalities.Peek() : -1;
|
|
length_insertions1 = 0; // Reset the counters.
|
|
length_deletions1 = 0;
|
|
length_insertions2 = 0;
|
|
length_deletions2 = 0;
|
|
lastequality = null;
|
|
changes = true;
|
|
}
|
|
}
|
|
pointer++;
|
|
}
|
|
|
|
// Normalize the diff.
|
|
if (changes)
|
|
{
|
|
diff_cleanupMerge(diffs);
|
|
}
|
|
diff_cleanupSemanticLossless(diffs);
|
|
|
|
// Find any overlaps between deletions and insertions.
|
|
// e.g: <del>abcxxx</del><ins>xxxdef</ins>
|
|
// -> <del>abc</del>xxx<ins>def</ins>
|
|
// e.g: <del>xxxabc</del><ins>defxxx</ins>
|
|
// -> <ins>def</ins>xxx<del>abc</del>
|
|
// Only extract an overlap if it is as big as the edit ahead or behind it.
|
|
pointer = 1;
|
|
while (pointer < diffs.Count)
|
|
{
|
|
if (diffs[pointer - 1].operation == Operation.DELETE &&
|
|
diffs[pointer].operation == Operation.INSERT)
|
|
{
|
|
string deletion = diffs[pointer - 1].text;
|
|
string insertion = diffs[pointer].text;
|
|
int overlap_length1 = diff_commonOverlap(deletion, insertion);
|
|
int overlap_length2 = diff_commonOverlap(insertion, deletion);
|
|
if (overlap_length1 >= overlap_length2)
|
|
{
|
|
if (overlap_length1 >= deletion.Length / 2.0 ||
|
|
overlap_length1 >= insertion.Length / 2.0)
|
|
{
|
|
// Overlap found.
|
|
// Insert an equality and trim the surrounding edits.
|
|
diffs.Insert(pointer, new Diff(Operation.EQUAL,
|
|
insertion.Substring(0, overlap_length1)));
|
|
diffs[pointer - 1].text =
|
|
deletion.Substring(0, deletion.Length - overlap_length1);
|
|
diffs[pointer + 1].text = insertion.Substring(overlap_length1);
|
|
pointer++;
|
|
}
|
|
}
|
|
else {
|
|
if (overlap_length2 >= deletion.Length / 2.0 ||
|
|
overlap_length2 >= insertion.Length / 2.0)
|
|
{
|
|
// Reverse overlap found.
|
|
// Insert an equality and swap and trim the surrounding edits.
|
|
diffs.Insert(pointer, new Diff(Operation.EQUAL,
|
|
deletion.Substring(0, overlap_length2)));
|
|
diffs[pointer - 1].operation = Operation.INSERT;
|
|
diffs[pointer - 1].text =
|
|
insertion.Substring(0, insertion.Length - overlap_length2);
|
|
diffs[pointer + 1].operation = Operation.DELETE;
|
|
diffs[pointer + 1].text = deletion.Substring(overlap_length2);
|
|
pointer++;
|
|
}
|
|
}
|
|
pointer++;
|
|
}
|
|
pointer++;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* 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 List of Diff objects.
|
|
*/
|
|
public void diff_cleanupSemanticLossless(List<Diff> diffs)
|
|
{
|
|
int pointer = 1;
|
|
// Intentionally ignore the first and last element (don't need checking).
|
|
while (pointer < diffs.Count - 1)
|
|
{
|
|
if (diffs[pointer - 1].operation == Operation.EQUAL &&
|
|
diffs[pointer + 1].operation == Operation.EQUAL)
|
|
{
|
|
// This is a single edit surrounded by equalities.
|
|
string equality1 = diffs[pointer - 1].text;
|
|
string edit = diffs[pointer].text;
|
|
string equality2 = diffs[pointer + 1].text;
|
|
|
|
// First, shift the edit as far left as possible.
|
|
int commonOffset = this.diff_commonSuffix(equality1, edit);
|
|
if (commonOffset > 0)
|
|
{
|
|
string 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.
|
|
string bestEquality1 = equality1;
|
|
string bestEdit = edit;
|
|
string bestEquality2 = equality2;
|
|
int bestScore = diff_cleanupSemanticScore(equality1, edit) +
|
|
diff_cleanupSemanticScore(edit, equality2);
|
|
while (edit.Length != 0 && equality2.Length != 0
|
|
&& edit[0] == equality2[0])
|
|
{
|
|
equality1 += edit[0];
|
|
edit = edit.Substring(1) + equality2[0];
|
|
equality2 = equality2.Substring(1);
|
|
int 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 (diffs[pointer - 1].text != bestEquality1)
|
|
{
|
|
// We have an improvement, save it back to the diff.
|
|
if (bestEquality1.Length != 0)
|
|
{
|
|
diffs[pointer - 1].text = bestEquality1;
|
|
}
|
|
else {
|
|
diffs.RemoveAt(pointer - 1);
|
|
pointer--;
|
|
}
|
|
diffs[pointer].text = bestEdit;
|
|
if (bestEquality2.Length != 0)
|
|
{
|
|
diffs[pointer + 1].text = bestEquality2;
|
|
}
|
|
else {
|
|
diffs.RemoveAt(pointer + 1);
|
|
pointer--;
|
|
}
|
|
}
|
|
}
|
|
pointer++;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Given two strings, comAdde a score representing whether the internal
|
|
* boundary falls on logical boundaries.
|
|
* Scores range from 6 (best) to 0 (worst).
|
|
* @param one First string.
|
|
* @param two Second string.
|
|
* @return The score.
|
|
*/
|
|
private int diff_cleanupSemanticScore(string one, string two)
|
|
{
|
|
if (one.Length == 0 || two.Length == 0)
|
|
{
|
|
// Edges are the best.
|
|
return 6;
|
|
}
|
|
|
|
// Each port of this function behaves slightly differently due to
|
|
// subtle differences in each language's definition of things like
|
|
// 'whitespace'. Since this function's purpose is largely cosmetic,
|
|
// the choice has been made to use each language's native features
|
|
// rather than force total conformity.
|
|
char char1 = one[one.Length - 1];
|
|
char char2 = two[0];
|
|
bool nonAlphaNumeric1 = !Char.IsLetterOrDigit(char1);
|
|
bool nonAlphaNumeric2 = !Char.IsLetterOrDigit(char2);
|
|
bool whitespace1 = nonAlphaNumeric1 && Char.IsWhiteSpace(char1);
|
|
bool whitespace2 = nonAlphaNumeric2 && Char.IsWhiteSpace(char2);
|
|
bool lineBreak1 = whitespace1 && Char.IsControl(char1);
|
|
bool lineBreak2 = whitespace2 && Char.IsControl(char2);
|
|
bool blankLine1 = lineBreak1 && BLANKLINEEND.IsMatch(one);
|
|
bool blankLine2 = lineBreak2 && BLANKLINESTART.IsMatch(two);
|
|
|
|
if (blankLine1 || blankLine2)
|
|
{
|
|
// Five points for blank lines.
|
|
return 5;
|
|
}
|
|
else if (lineBreak1 || lineBreak2)
|
|
{
|
|
// Four points for line breaks.
|
|
return 4;
|
|
}
|
|
else if (nonAlphaNumeric1 && !whitespace1 && whitespace2)
|
|
{
|
|
// Three points for end of sentences.
|
|
return 3;
|
|
}
|
|
else if (whitespace1 || whitespace2)
|
|
{
|
|
// Two points for whitespace.
|
|
return 2;
|
|
}
|
|
else if (nonAlphaNumeric1 || nonAlphaNumeric2)
|
|
{
|
|
// One point for non-alphanumeric.
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
// Define some regex patterns for matching boundaries.
|
|
private Regex BLANKLINEEND = new Regex("\\n\\r?\\n\\Z");
|
|
private Regex BLANKLINESTART = new Regex("\\A\\r?\\n\\r?\\n");
|
|
|
|
/**
|
|
* Reduce the number of edits by eliminating operationally trivial
|
|
* equalities.
|
|
* @param diffs List of Diff objects.
|
|
*/
|
|
public void diff_cleanupEfficiency(List<Diff> diffs)
|
|
{
|
|
bool changes = false;
|
|
// Stack of indices where equalities are found.
|
|
Stack<int> equalities = new Stack<int>();
|
|
// Always equal to equalities[equalitiesLength-1][1]
|
|
string lastequality = string.Empty;
|
|
int pointer = 0; // Index of current position.
|
|
// Is there an insertion operation before the last equality.
|
|
bool pre_ins = false;
|
|
// Is there a deletion operation before the last equality.
|
|
bool pre_del = false;
|
|
// Is there an insertion operation after the last equality.
|
|
bool post_ins = false;
|
|
// Is there a deletion operation after the last equality.
|
|
bool post_del = false;
|
|
while (pointer < diffs.Count)
|
|
{
|
|
if (diffs[pointer].operation == Operation.EQUAL)
|
|
{ // Equality found.
|
|
if (diffs[pointer].text.Length < this.Diff_EditCost
|
|
&& (post_ins || post_del))
|
|
{
|
|
// Candidate found.
|
|
equalities.Push(pointer);
|
|
pre_ins = post_ins;
|
|
pre_del = post_del;
|
|
lastequality = diffs[pointer].text;
|
|
}
|
|
else {
|
|
// Not a candidate, and can never become one.
|
|
equalities.Clear();
|
|
lastequality = string.Empty;
|
|
}
|
|
post_ins = post_del = false;
|
|
}
|
|
else { // An insertion or deletion.
|
|
if (diffs[pointer].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.Length != 0)
|
|
&& ((pre_ins && pre_del && post_ins && post_del)
|
|
|| ((lastequality.Length < this.Diff_EditCost / 2)
|
|
&& ((pre_ins ? 1 : 0) + (pre_del ? 1 : 0) + (post_ins ? 1 : 0)
|
|
+ (post_del ? 1 : 0)) == 3)))
|
|
{
|
|
// Duplicate record.
|
|
diffs.Insert(equalities.Peek(),
|
|
new Diff(Operation.DELETE, lastequality));
|
|
// Change second copy to insert.
|
|
diffs[equalities.Peek() + 1].operation = Operation.INSERT;
|
|
equalities.Pop(); // Throw away the equality we just deleted.
|
|
lastequality = string.Empty;
|
|
if (pre_ins && pre_del)
|
|
{
|
|
// No changes made which could affect previous entry, keep going.
|
|
post_ins = post_del = true;
|
|
equalities.Clear();
|
|
}
|
|
else {
|
|
if (equalities.Count > 0)
|
|
{
|
|
equalities.Pop();
|
|
}
|
|
|
|
pointer = equalities.Count > 0 ? equalities.Peek() : -1;
|
|
post_ins = post_del = false;
|
|
}
|
|
changes = true;
|
|
}
|
|
}
|
|
pointer++;
|
|
}
|
|
|
|
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 List of Diff objects.
|
|
*/
|
|
public void diff_cleanupMerge(List<Diff> diffs)
|
|
{
|
|
// Add a dummy entry at the end.
|
|
diffs.Add(new Diff(Operation.EQUAL, string.Empty));
|
|
int pointer = 0;
|
|
int count_delete = 0;
|
|
int count_insert = 0;
|
|
string text_delete = string.Empty;
|
|
string text_insert = string.Empty;
|
|
int commonlength;
|
|
while (pointer < diffs.Count)
|
|
{
|
|
switch (diffs[pointer].operation)
|
|
{
|
|
case Operation.INSERT:
|
|
count_insert++;
|
|
text_insert += diffs[pointer].text;
|
|
pointer++;
|
|
break;
|
|
case Operation.DELETE:
|
|
count_delete++;
|
|
text_delete += diffs[pointer].text;
|
|
pointer++;
|
|
break;
|
|
case Operation.EQUAL:
|
|
// Upon reaching an equality, check for prior redundancies.
|
|
if (count_delete + count_insert > 1)
|
|
{
|
|
if (count_delete != 0 && count_insert != 0)
|
|
{
|
|
// Factor out any common prefixies.
|
|
commonlength = this.diff_commonPrefix(text_insert, text_delete);
|
|
if (commonlength != 0)
|
|
{
|
|
if ((pointer - count_delete - count_insert) > 0 &&
|
|
diffs[pointer - count_delete - count_insert - 1].operation
|
|
== Operation.EQUAL)
|
|
{
|
|
diffs[pointer - count_delete - count_insert - 1].text
|
|
+= text_insert.Substring(0, commonlength);
|
|
}
|
|
else {
|
|
diffs.Insert(0, new Diff(Operation.EQUAL,
|
|
text_insert.Substring(0, commonlength)));
|
|
pointer++;
|
|
}
|
|
text_insert = text_insert.Substring(commonlength);
|
|
text_delete = text_delete.Substring(commonlength);
|
|
}
|
|
// Factor out any common suffixies.
|
|
commonlength = this.diff_commonSuffix(text_insert, text_delete);
|
|
if (commonlength != 0)
|
|
{
|
|
diffs[pointer].text = text_insert.Substring(text_insert.Length
|
|
- commonlength) + diffs[pointer].text;
|
|
text_insert = text_insert.Substring(0, text_insert.Length
|
|
- commonlength);
|
|
text_delete = text_delete.Substring(0, text_delete.Length
|
|
- commonlength);
|
|
}
|
|
}
|
|
// Delete the offending records and add the merged ones.
|
|
if (count_delete == 0)
|
|
{
|
|
diffs.Splice(pointer - count_insert,
|
|
count_delete + count_insert,
|
|
new Diff(Operation.INSERT, text_insert));
|
|
}
|
|
else if (count_insert == 0)
|
|
{
|
|
diffs.Splice(pointer - count_delete,
|
|
count_delete + count_insert,
|
|
new Diff(Operation.DELETE, text_delete));
|
|
}
|
|
else {
|
|
diffs.Splice(pointer - count_delete - count_insert,
|
|
count_delete + count_insert,
|
|
new Diff(Operation.DELETE, text_delete),
|
|
new Diff(Operation.INSERT, text_insert));
|
|
}
|
|
pointer = pointer - count_delete - count_insert +
|
|
(count_delete != 0 ? 1 : 0) + (count_insert != 0 ? 1 : 0) + 1;
|
|
}
|
|
else if (pointer != 0
|
|
&& diffs[pointer - 1].operation == Operation.EQUAL)
|
|
{
|
|
// Merge this equality with the previous one.
|
|
diffs[pointer - 1].text += diffs[pointer].text;
|
|
diffs.RemoveAt(pointer);
|
|
}
|
|
else {
|
|
pointer++;
|
|
}
|
|
count_insert = 0;
|
|
count_delete = 0;
|
|
text_delete = string.Empty;
|
|
text_insert = string.Empty;
|
|
break;
|
|
}
|
|
}
|
|
if (diffs[diffs.Count - 1].text.Length == 0)
|
|
{
|
|
diffs.RemoveAt(diffs.Count - 1); // 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
|
|
bool changes = false;
|
|
pointer = 1;
|
|
// Intentionally ignore the first and last element (don't need checking).
|
|
while (pointer < (diffs.Count - 1))
|
|
{
|
|
if (diffs[pointer - 1].operation == Operation.EQUAL &&
|
|
diffs[pointer + 1].operation == Operation.EQUAL)
|
|
{
|
|
// This is a single edit surrounded by equalities.
|
|
if (diffs[pointer].text.EndsWith(diffs[pointer - 1].text,
|
|
StringComparison.Ordinal))
|
|
{
|
|
// Shift the edit over the previous equality.
|
|
diffs[pointer].text = diffs[pointer - 1].text +
|
|
diffs[pointer].text.Substring(0, diffs[pointer].text.Length -
|
|
diffs[pointer - 1].text.Length);
|
|
diffs[pointer + 1].text = diffs[pointer - 1].text
|
|
+ diffs[pointer + 1].text;
|
|
diffs.Splice(pointer - 1, 1);
|
|
changes = true;
|
|
}
|
|
else if (diffs[pointer].text.StartsWith(diffs[pointer + 1].text,
|
|
StringComparison.Ordinal))
|
|
{
|
|
// Shift the edit over the next equality.
|
|
diffs[pointer - 1].text += diffs[pointer + 1].text;
|
|
diffs[pointer].text =
|
|
diffs[pointer].text.Substring(diffs[pointer + 1].text.Length)
|
|
+ diffs[pointer + 1].text;
|
|
diffs.Splice(pointer + 1, 1);
|
|
changes = true;
|
|
}
|
|
}
|
|
pointer++;
|
|
}
|
|
// If shifts were made, the diff needs reordering and another shift sweep.
|
|
if (changes)
|
|
{
|
|
this.diff_cleanupMerge(diffs);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* loc is a location in text1, comAdde and return the equivalent location in
|
|
* text2.
|
|
* e.g. "The cat" vs "The big cat", 1->1, 5->8
|
|
* @param diffs List of Diff objects.
|
|
* @param loc Location within text1.
|
|
* @return Location within text2.
|
|
*/
|
|
public int diff_xIndex(List<Diff> diffs, int loc)
|
|
{
|
|
int chars1 = 0;
|
|
int chars2 = 0;
|
|
int last_chars1 = 0;
|
|
int last_chars2 = 0;
|
|
Diff lastDiff = null;
|
|
foreach (Diff aDiff in diffs)
|
|
{
|
|
if (aDiff.operation != Operation.INSERT)
|
|
{
|
|
// Equality or deletion.
|
|
chars1 += aDiff.text.Length;
|
|
}
|
|
if (aDiff.operation != Operation.DELETE)
|
|
{
|
|
// Equality or insertion.
|
|
chars2 += aDiff.text.Length;
|
|
}
|
|
if (chars1 > loc)
|
|
{
|
|
// Overshot the location.
|
|
lastDiff = aDiff;
|
|
break;
|
|
}
|
|
last_chars1 = chars1;
|
|
last_chars2 = chars2;
|
|
}
|
|
if (lastDiff != null && lastDiff.operation == Operation.DELETE)
|
|
{
|
|
// The location was deleted.
|
|
return last_chars2;
|
|
}
|
|
// Add the remaining character length.
|
|
return last_chars2 + (loc - last_chars1);
|
|
}
|
|
|
|
/**
|
|
* Convert a Diff list into a pretty HTML report.
|
|
* @param diffs List of Diff objects.
|
|
* @return HTML representation.
|
|
*/
|
|
public string diff_prettyHtml(List<Diff> diffs)
|
|
{
|
|
StringBuilder html = new StringBuilder();
|
|
foreach (Diff aDiff in diffs)
|
|
{
|
|
string text = aDiff.text.Replace("&", "&").Replace("<", "<")
|
|
.Replace(">", ">").Replace("\n", "¶<br>");
|
|
switch (aDiff.operation)
|
|
{
|
|
case Operation.INSERT:
|
|
html.Append("<ins style=\"background:#e6ffe6;\">").Append(text)
|
|
.Append("</ins>");
|
|
break;
|
|
case Operation.DELETE:
|
|
html.Append("<del style=\"background:#ffe6e6;\">").Append(text)
|
|
.Append("</del>");
|
|
break;
|
|
case Operation.EQUAL:
|
|
html.Append("<span>").Append(text).Append("</span>");
|
|
break;
|
|
}
|
|
}
|
|
return html.ToString();
|
|
}
|
|
|
|
/**
|
|
* Compute and return the source text (all equalities and deletions).
|
|
* @param diffs List of Diff objects.
|
|
* @return Source text.
|
|
*/
|
|
public string diff_text1(List<Diff> diffs)
|
|
{
|
|
StringBuilder text = new StringBuilder();
|
|
foreach (Diff aDiff in diffs)
|
|
{
|
|
if (aDiff.operation != Operation.INSERT)
|
|
{
|
|
text.Append(aDiff.text);
|
|
}
|
|
}
|
|
return text.ToString();
|
|
}
|
|
|
|
/**
|
|
* Compute and return the destination text (all equalities and insertions).
|
|
* @param diffs List of Diff objects.
|
|
* @return Destination text.
|
|
*/
|
|
public string diff_text2(List<Diff> diffs)
|
|
{
|
|
StringBuilder text = new StringBuilder();
|
|
foreach (Diff aDiff in diffs)
|
|
{
|
|
if (aDiff.operation != Operation.DELETE)
|
|
{
|
|
text.Append(aDiff.text);
|
|
}
|
|
}
|
|
return text.ToString();
|
|
}
|
|
|
|
/**
|
|
* Compute the Levenshtein distance; the number of inserted, deleted or
|
|
* substituted characters.
|
|
* @param diffs List of Diff objects.
|
|
* @return Number of changes.
|
|
*/
|
|
public int diff_levenshtein(List<Diff> diffs)
|
|
{
|
|
int levenshtein = 0;
|
|
int insertions = 0;
|
|
int deletions = 0;
|
|
foreach (Diff aDiff in diffs)
|
|
{
|
|
switch (aDiff.operation)
|
|
{
|
|
case Operation.INSERT:
|
|
insertions += aDiff.text.Length;
|
|
break;
|
|
case Operation.DELETE:
|
|
deletions += aDiff.text.Length;
|
|
break;
|
|
case Operation.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;
|
|
}
|
|
|
|
#region Commented out to avoid reference to System.Web
|
|
|
|
///**
|
|
// * Crush the diff into an encoded string which describes the operations
|
|
// * required to transform text1 into text2.
|
|
// * E.g. =3\t-2\t+ing -> Keep 3 chars, delete 2 chars, insert 'ing'.
|
|
// * Operations are tab-separated. Inserted text is escaped using %xx
|
|
// * notation.
|
|
// * @param diffs Array of Diff objects.
|
|
// * @return Delta text.
|
|
// */
|
|
//public string diff_toDelta(List<Diff> diffs)
|
|
//{
|
|
// StringBuilder text = new StringBuilder();
|
|
// foreach (Diff aDiff in diffs)
|
|
// {
|
|
// switch (aDiff.operation)
|
|
// {
|
|
// case Operation.INSERT:
|
|
// text.Append("+").Append(HttpUtility.UrlEncode(aDiff.text,
|
|
// new UTF8Encoding()).Replace('+', ' ')).Append("\t");
|
|
// break;
|
|
// case Operation.DELETE:
|
|
// text.Append("-").Append(aDiff.text.Length).Append("\t");
|
|
// break;
|
|
// case Operation.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, comAdde the full diff.
|
|
// * @param text1 Source string for the diff.
|
|
// * @param delta Delta text.
|
|
// * @return Array of Diff objects or null if invalid.
|
|
// * @throws ArgumentException If invalid input.
|
|
// */
|
|
//public List<Diff> diff_fromDelta(string text1, string delta)
|
|
//{
|
|
// List<Diff> diffs = new List<Diff>();
|
|
// int pointer = 0; // Cursor in text1
|
|
// string[] tokens = delta.Split(new string[] { "\t" },
|
|
// StringSplitOptions.None);
|
|
// foreach (string token in 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[0])
|
|
// {
|
|
// case '+':
|
|
// // decode would change all "+" to " "
|
|
// param = param.Replace("+", "%2b");
|
|
|
|
// param = HttpUtility.UrlDecode(param, new UTF8Encoding(false, true));
|
|
// //} 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 = Convert.ToInt32(param);
|
|
// }
|
|
// catch (FormatException e)
|
|
// {
|
|
// throw new ArgumentException(
|
|
// "Invalid number in diff_fromDelta: " + param, e);
|
|
// }
|
|
// if (n < 0)
|
|
// {
|
|
// throw new ArgumentException(
|
|
// "Negative number in diff_fromDelta: " + param);
|
|
// }
|
|
// string text;
|
|
// try
|
|
// {
|
|
// text = text1.Substring(pointer, n);
|
|
// pointer += n;
|
|
// }
|
|
// catch (ArgumentOutOfRangeException e)
|
|
// {
|
|
// throw new ArgumentException("Delta length (" + pointer
|
|
// + ") larger than source text length (" + text1.Length
|
|
// + ").", e);
|
|
// }
|
|
// if (token[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 ArgumentException(
|
|
// "Invalid diff operation in diff_fromDelta: " + token[0]);
|
|
// }
|
|
// }
|
|
// if (pointer != text1.Length)
|
|
// {
|
|
// throw new ArgumentException("Delta length (" + pointer
|
|
// + ") smaller than source text length (" + text1.Length + ").");
|
|
// }
|
|
// return diffs;
|
|
//}
|
|
|
|
#endregion
|
|
|
|
// MATCH FUNCTIONS
|
|
|
|
|
|
/**
|
|
* Locate the best instance of 'pattern' in 'text' near 'loc'.
|
|
* Returns -1 if no match found.
|
|
* @param text The text to search.
|
|
* @param pattern The pattern to search for.
|
|
* @param loc The location to search around.
|
|
* @return Best match index or -1.
|
|
*/
|
|
public int match_main(string text, string pattern, int loc)
|
|
{
|
|
// Check for null inputs not needed since null can't be passed in C#.
|
|
|
|
loc = Math.Max(0, Math.Min(loc, text.Length));
|
|
if (text == 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, pattern.Length) == 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.
|
|
Dictionary<char, int> 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, StringComparison.Ordinal);
|
|
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,
|
|
Math.Min(loc + pattern.Length, text.Length),
|
|
StringComparison.Ordinal);
|
|
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 C# 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[j - 1]))
|
|
{
|
|
// Out of range.
|
|
charMatch = 0;
|
|
}
|
|
else {
|
|
charMatch = s[text[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 Dictionary<char, int> match_alphabet(string pattern)
|
|
{
|
|
Dictionary<char, int> s = new Dictionary<char, int>();
|
|
char[] char_pattern = pattern.ToCharArray();
|
|
foreach (char c in char_pattern)
|
|
{
|
|
if (!s.ContainsKey(c))
|
|
{
|
|
s.Add(c, 0);
|
|
}
|
|
}
|
|
int i = 0;
|
|
foreach (char c in char_pattern)
|
|
{
|
|
int value = s[c] | (1 << (pattern.Length - i - 1));
|
|
s[c] = value;
|
|
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.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, StringComparison.Ordinal)
|
|
!= text.LastIndexOf(pattern, StringComparison.Ordinal)
|
|
&& pattern.Length < Match_MaxBits - Patch_Margin - Patch_Margin)
|
|
{
|
|
padding += Patch_Margin;
|
|
pattern = text.JavaSubstring(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.JavaSubstring(Math.Max(0, patch.start2 - padding),
|
|
patch.start2);
|
|
if (prefix.Length != 0)
|
|
{
|
|
patch.diffs.Insert(0, new Diff(Operation.EQUAL, prefix));
|
|
}
|
|
// Add the suffix.
|
|
string suffix = text.JavaSubstring(patch.start2 + patch.length1,
|
|
Math.Min(text.Length, patch.start2 + patch.length1 + padding));
|
|
if (suffix.Length != 0)
|
|
{
|
|
patch.diffs.Add(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 List of Patch objects.
|
|
*/
|
|
public List<Patch> patch_make(string text1, string text2)
|
|
{
|
|
// Check for null inputs not needed since null can't be passed in C#.
|
|
// No diffs provided, comAdde our own.
|
|
List<Diff> diffs = diff_main(text1, text2, true);
|
|
if (diffs.Count > 2)
|
|
{
|
|
diff_cleanupSemantic(diffs);
|
|
diff_cleanupEfficiency(diffs);
|
|
}
|
|
return patch_make(text1, diffs);
|
|
}
|
|
|
|
/**
|
|
* Compute a list of patches to turn text1 into text2.
|
|
* text1 will be derived from the provided diffs.
|
|
* @param diffs Array of Diff objects for text1 to text2.
|
|
* @return List of Patch objects.
|
|
*/
|
|
public List<Patch> patch_make(List<Diff> diffs)
|
|
{
|
|
// Check for null inputs not needed since null can't be passed in C#.
|
|
// No origin string provided, comAdde our own.
|
|
string text1 = diff_text1(diffs);
|
|
return patch_make(text1, diffs);
|
|
}
|
|
|
|
/**
|
|
* Compute a list of patches to turn text1 into text2.
|
|
* text2 is ignored, diffs are the delta between text1 and text2.
|
|
* @param text1 Old text
|
|
* @param text2 Ignored.
|
|
* @param diffs Array of Diff objects for text1 to text2.
|
|
* @return List of Patch objects.
|
|
* @deprecated Prefer patch_make(string text1, List<Diff> diffs).
|
|
*/
|
|
public List<Patch> patch_make(string text1, string text2, List<Diff> diffs)
|
|
=> patch_make(text1, diffs);
|
|
|
|
/**
|
|
* Compute a list of patches to turn text1 into text2.
|
|
* text2 is not provided, diffs are the delta between text1 and text2.
|
|
* @param text1 Old text.
|
|
* @param diffs Array of Diff objects for text1 to text2.
|
|
* @return List of Patch objects.
|
|
*/
|
|
public List<Patch> patch_make(string text1, List<Diff> diffs)
|
|
{
|
|
// Check for null inputs not needed since null can't be passed in C#.
|
|
List<Patch> patches = new List<Patch>();
|
|
if (diffs.Count == 0)
|
|
{
|
|
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;
|
|
foreach (Diff aDiff in diffs)
|
|
{
|
|
if (patch.diffs.Count == 0 && aDiff.operation != Operation.EQUAL)
|
|
{
|
|
// A new patch starts here.
|
|
patch.start1 = char_count1;
|
|
patch.start2 = char_count2;
|
|
}
|
|
|
|
switch (aDiff.operation)
|
|
{
|
|
case Operation.INSERT:
|
|
patch.diffs.Add(aDiff);
|
|
patch.length2 += aDiff.text.Length;
|
|
postpatch_text = postpatch_text.Insert(char_count2, aDiff.text);
|
|
break;
|
|
case Operation.DELETE:
|
|
patch.length1 += aDiff.text.Length;
|
|
patch.diffs.Add(aDiff);
|
|
postpatch_text = postpatch_text.Remove(char_count2,
|
|
aDiff.text.Length);
|
|
break;
|
|
case Operation.EQUAL:
|
|
if (aDiff.text.Length <= 2 * Patch_Margin
|
|
&& patch.diffs.Count() != 0 && aDiff != diffs.Last())
|
|
{
|
|
// 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.Count != 0)
|
|
{
|
|
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.Count != 0)
|
|
{
|
|
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 List<Patch> patch_deepCopy(List<Patch> patches)
|
|
{
|
|
List<Patch> patchesCopy = new List<Patch>();
|
|
foreach (Patch aPatch in patches)
|
|
{
|
|
Patch patchCopy = new Patch();
|
|
foreach (Diff aDiff in 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
|
|
* bool values.
|
|
*/
|
|
public Object[] patch_apply(List<Patch> patches, string text)
|
|
{
|
|
if (patches.Count == 0)
|
|
{
|
|
return new Object[] { text, new bool[0] };
|
|
}
|
|
|
|
// Deep copy the patches so that no changes are made to originals.
|
|
patches = patch_deepCopy(patches);
|
|
|
|
string nullPadding = this.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;
|
|
bool[] results = new bool[patches.Count];
|
|
foreach (Patch aPatch in 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 = this.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.JavaSubstring(start_loc,
|
|
Math.Min(start_loc + text1.Length, text.Length));
|
|
}
|
|
else {
|
|
text2 = text.JavaSubstring(start_loc,
|
|
Math.Min(end_loc + this.Match_MaxBits, text.Length));
|
|
}
|
|
if (text1 == 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.
|
|
List<Diff> diffs = diff_main(text1, text2, false);
|
|
if (text1.Length > this.Match_MaxBits
|
|
&& this.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;
|
|
foreach (Diff aDiff in aPatch.diffs)
|
|
{
|
|
if (aDiff.operation != Operation.EQUAL)
|
|
{
|
|
int index2 = diff_xIndex(diffs, index1);
|
|
if (aDiff.operation == Operation.INSERT)
|
|
{
|
|
// Insertion
|
|
text = text.Insert(start_loc + index2, aDiff.text);
|
|
}
|
|
else if (aDiff.operation == Operation.DELETE)
|
|
{
|
|
// Deletion
|
|
text = text.Remove(start_loc + index2, diff_xIndex(diffs,
|
|
index1 + aDiff.text.Length) - index2);
|
|
}
|
|
}
|
|
if (aDiff.operation != Operation.DELETE)
|
|
{
|
|
index1 += aDiff.text.Length;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
x++;
|
|
}
|
|
// Strip the padding off.
|
|
text = text.Substring(nullPadding.Length, text.Length
|
|
- 2 * 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(List<Patch> patches)
|
|
{
|
|
short paddingLength = this.Patch_Margin;
|
|
string nullPadding = string.Empty;
|
|
for (short x = 1; x <= paddingLength; x++)
|
|
{
|
|
nullPadding += (char)x;
|
|
}
|
|
|
|
// Bump all the patches forward.
|
|
foreach (Patch aPatch in patches)
|
|
{
|
|
aPatch.start1 += paddingLength;
|
|
aPatch.start2 += paddingLength;
|
|
}
|
|
|
|
// Add some padding on start of first diff.
|
|
Patch patch = patches.First();
|
|
List<Diff> diffs = patch.diffs;
|
|
if (diffs.Count == 0 || diffs.First().operation != Operation.EQUAL)
|
|
{
|
|
// Add nullPadding equality.
|
|
diffs.Insert(0, 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.First().text.Length)
|
|
{
|
|
// Grow first equality.
|
|
Diff firstDiff = diffs.First();
|
|
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.Last();
|
|
diffs = patch.diffs;
|
|
if (diffs.Count == 0 || diffs.Last().operation != Operation.EQUAL)
|
|
{
|
|
// Add nullPadding equality.
|
|
diffs.Add(new Diff(Operation.EQUAL, nullPadding));
|
|
patch.length1 += paddingLength;
|
|
patch.length2 += paddingLength;
|
|
}
|
|
else if (paddingLength > diffs.Last().text.Length)
|
|
{
|
|
// Grow last equality.
|
|
Diff lastDiff = diffs.Last();
|
|
int extraLength = paddingLength - lastDiff.text.Length;
|
|
lastDiff.text += nullPadding.Substring(0, extraLength);
|
|
patch.length1 += extraLength;
|
|
patch.length2 += extraLength;
|
|
}
|
|
|
|
return nullPadding;
|
|
}
|
|
|
|
/**
|
|
* Look through the patches and break up any which are longer than the
|
|
* maximum limit of the match algorithm.
|
|
* Intended to be called only from within patch_apply.
|
|
* @param patches List of Patch objects.
|
|
*/
|
|
public void patch_splitMax(List<Patch> patches)
|
|
{
|
|
short patch_size = this.Match_MaxBits;
|
|
for (int x = 0; x < patches.Count; x++)
|
|
{
|
|
if (patches[x].length1 <= patch_size)
|
|
{
|
|
continue;
|
|
}
|
|
Patch bigpatch = patches[x];
|
|
// Remove the big old patch.
|
|
patches.Splice(x--, 1);
|
|
int start1 = bigpatch.start1;
|
|
int start2 = bigpatch.start2;
|
|
string precontext = string.Empty;
|
|
while (bigpatch.diffs.Count != 0)
|
|
{
|
|
// Create one of several smaller patches.
|
|
Patch patch = new Patch();
|
|
bool 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.Count != 0
|
|
&& patch.length1 < patch_size - this.Patch_Margin)
|
|
{
|
|
Operation diff_type = bigpatch.diffs[0].operation;
|
|
string diff_text = bigpatch.diffs[0].text;
|
|
if (diff_type == Operation.INSERT)
|
|
{
|
|
// Insertions are harmless.
|
|
patch.length2 += diff_text.Length;
|
|
start2 += diff_text.Length;
|
|
patch.diffs.Add(bigpatch.diffs.First());
|
|
bigpatch.diffs.RemoveAt(0);
|
|
empty = false;
|
|
}
|
|
else if (diff_type == Operation.DELETE && patch.diffs.Count == 1
|
|
&& patch.diffs.First().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.RemoveAt(0);
|
|
}
|
|
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 == bigpatch.diffs[0].text)
|
|
{
|
|
bigpatch.diffs.RemoveAt(0);
|
|
}
|
|
else {
|
|
bigpatch.diffs[0].text =
|
|
bigpatch.diffs[0].text.Substring(diff_text.Length);
|
|
}
|
|
}
|
|
}
|
|
// Compute the head context for the next patch.
|
|
precontext = this.diff_text2(patch.diffs);
|
|
precontext = precontext.Substring(Math.Max(0,
|
|
precontext.Length - this.Patch_Margin));
|
|
|
|
string postcontext = null;
|
|
// 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.Count != 0
|
|
&& patch.diffs[patch.diffs.Count - 1].operation
|
|
== Operation.EQUAL)
|
|
{
|
|
patch.diffs[patch.diffs.Count - 1].text += postcontext;
|
|
}
|
|
else {
|
|
patch.diffs.Add(new Diff(Operation.EQUAL, postcontext));
|
|
}
|
|
}
|
|
if (!empty)
|
|
{
|
|
patches.Splice(++x, 0, patch);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* 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();
|
|
foreach (Patch aPatch in patches)
|
|
{
|
|
text.Append(aPatch);
|
|
}
|
|
return text.ToString();
|
|
}
|
|
|
|
#region Commented out to avoid reference to System.Web
|
|
|
|
///**
|
|
// * 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 ArgumentException If invalid input.
|
|
// */
|
|
//public List<Patch> patch_fromText(string textline)
|
|
//{
|
|
// List<Patch> patches = new List<Patch>();
|
|
// if (textline.Length == 0)
|
|
// {
|
|
// return patches;
|
|
// }
|
|
// string[] text = textline.Split('\n');
|
|
// int textPointer = 0;
|
|
// Patch patch;
|
|
// Regex patchHeader
|
|
// = new Regex("^@@ -(\\d+),?(\\d*) \\+(\\d+),?(\\d*) @@$");
|
|
// Match m;
|
|
// char sign;
|
|
// string line;
|
|
// while (textPointer < text.Length)
|
|
// {
|
|
// m = patchHeader.Match(text[textPointer]);
|
|
// if (!m.Success)
|
|
// {
|
|
// throw new ArgumentException("Invalid patch string: "
|
|
// + text[textPointer]);
|
|
// }
|
|
// patch = new Patch();
|
|
// patches.Add(patch);
|
|
// patch.start1 = Convert.ToInt32(m.Groups[1].Value);
|
|
// if (m.Groups[2].Length == 0)
|
|
// {
|
|
// patch.start1--;
|
|
// patch.length1 = 1;
|
|
// }
|
|
// else if (m.Groups[2].Value == "0")
|
|
// {
|
|
// patch.length1 = 0;
|
|
// }
|
|
// else {
|
|
// patch.start1--;
|
|
// patch.length1 = Convert.ToInt32(m.Groups[2].Value);
|
|
// }
|
|
|
|
// patch.start2 = Convert.ToInt32(m.Groups[3].Value);
|
|
// if (m.Groups[4].Length == 0)
|
|
// {
|
|
// patch.start2--;
|
|
// patch.length2 = 1;
|
|
// }
|
|
// else if (m.Groups[4].Value == "0")
|
|
// {
|
|
// patch.length2 = 0;
|
|
// }
|
|
// else {
|
|
// patch.start2--;
|
|
// patch.length2 = Convert.ToInt32(m.Groups[4].Value);
|
|
// }
|
|
// textPointer++;
|
|
|
|
// while (textPointer < text.Length)
|
|
// {
|
|
// try
|
|
// {
|
|
// sign = text[textPointer][0];
|
|
// }
|
|
// catch (IndexOutOfRangeException)
|
|
// {
|
|
// // Blank line? Whatever.
|
|
// textPointer++;
|
|
// continue;
|
|
// }
|
|
// line = text[textPointer].Substring(1);
|
|
// line = line.Replace("+", "%2b");
|
|
// line = HttpUtility.UrlDecode(line, new UTF8Encoding(false, true));
|
|
// 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 ArgumentException(
|
|
// "Invalid patch mode '" + sign + "' in: " + line);
|
|
// }
|
|
// textPointer++;
|
|
// }
|
|
// }
|
|
// return patches;
|
|
//}
|
|
|
|
#endregion
|
|
|
|
/**
|
|
* 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
|
|
* HttpUtility.UrlEncode which returns lowercase hex.
|
|
*
|
|
* Example: "%3f" -> "?", "%24" -> "$", etc.
|
|
*
|
|
* @param str The string to escape.
|
|
* @return The escaped string.
|
|
*/
|
|
public static string unescapeForEncodeUriCompatability(string str)
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=> str.Replace("%21", "!").Replace("%7e", "~")
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.Replace("%27", "'").Replace("%28", "(").Replace("%29", ")")
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.Replace("%3b", ";").Replace("%2f", "/").Replace("%3f", "?")
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.Replace("%3a", ":").Replace("%40", "@").Replace("%26", "&")
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.Replace("%3d", "=").Replace("%2b", "+").Replace("%24", "$")
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.Replace("%2c", ",").Replace("%23", "#");
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}
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}
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