Package at.letto.tools

Class diff_match_patch

java.lang.Object
at.letto.tools.diff_match_patch
public class diff_match_patch extends Object
Class containing the diff, match and patch methods. Also contains the behaviour settings.

  • Field Details

    • Diff_Timeout

      public float Diff_Timeout
      Number of seconds to map a diff before giving up (0 for infinity).

    • Diff_EditCost

      public short Diff_EditCost
      Cost of an empty edit operation in terms of edit characters.

    • Match_Threshold

      public float Match_Threshold
      At what point is no match declared (0.0 = perfection, 1.0 = very loose).

    • Match_Distance

      public int Match_Distance
      How far to search for a match (0 = exact location, 1000+ = broad match). A match this many characters away from the expected location will add 1.0 to the score (0.0 is a perfect match).

    • Patch_DeleteThreshold

      public float Patch_DeleteThreshold
      When deleting a large block of text (over ~64 characters), how close do the contents have to be to match the expected contents. (0.0 = perfection, 1.0 = very loose). Note that Match_Threshold controls how closely the end points of a delete need to match.

    • Patch_Margin

      public short Patch_Margin
      Chunk size for context length.

    • Match_MaxBits

      private short Match_MaxBits
      The number of bits in an int.

    • BLANKLINEEND

      private Pattern BLANKLINEEND

    • BLANKLINESTART

      private Pattern BLANKLINESTART

  • Constructor Details

    • diff_match_patch

      public diff_match_patch()

  • Method Details

    • diff_main

      public LinkedList<diff_match_patch.Diff> diff_main(String text1, String text2)
      Find the differences between two texts. Run a faster, slightly less optimal diff. This method allows the 'checklines' of diff_main() to be optional. Most of the time checklines is wanted, so default to true.
      Parameters:
      text1 - Old string to be diffed.
      text2 - New string to be diffed.
      Returns:
      Linked List of Diff objects.

    • diff_main

      public LinkedList<diff_match_patch.Diff> diff_main(String text1, String text2, boolean checklines)
      Find the differences between two texts.
      Parameters:
      text1 - Old string to be diffed.
      text2 - New string to be diffed.
      checklines - Speedup flag. If false, then don't run a line-level diff first to identify the changed areas. If true, then run a faster slightly less optimal diff.
      Returns:
      Linked List of Diff objects.

    • diff_main

      private LinkedList<diff_match_patch.Diff> diff_main(String text1, String text2, boolean checklines, long deadline)
      Find the differences between two texts. Simplifies the problem by stripping any common prefix or suffix off the texts before diffing.
      Parameters:
      text1 - Old string to be diffed.
      text2 - New string to be diffed.
      checklines - Speedup flag. If false, then don't run a line-level diff first to identify the changed areas. If true, then run a faster slightly less optimal diff.
      deadline - Time when the diff should be complete by. Used internally for recursive calls. Users should set DiffTimeout instead.
      Returns:
      Linked List of Diff objects.

    • diff_compute

      private LinkedList<diff_match_patch.Diff> diff_compute(String text1, String text2, boolean checklines, long deadline)
      Find the differences between two texts. Assumes that the texts do not have any common prefix or suffix.
      Parameters:
      text1 - Old string to be diffed.
      text2 - New string to be diffed.
      checklines - Speedup flag. If false, then don't run a line-level diff first to identify the changed areas. If true, then run a faster slightly less optimal diff.
      deadline - Time when the diff should be complete by.
      Returns:
      Linked List of Diff objects.

    • diff_lineMode

      private LinkedList<diff_match_patch.Diff> diff_lineMode(String text1, String text2, long deadline)
      Do a quick line-level diff on both strings, then rediff the parts for greater accuracy. This speedup can produce non-minimal diffs.
      Parameters:
      text1 - Old string to be diffed.
      text2 - New string to be diffed.
      deadline - Time when the diff should be complete by.
      Returns:
      Linked List of Diff objects.

    • diff_bisect

      protected LinkedList<diff_match_patch.Diff> diff_bisect(String text1, String text2, long deadline)
      Find the 'middle snake' of a diff, split the problem in two and return the recursively constructed diff. See Myers 1986 paper: An O(ND) Difference Algorithm and Its Variations.
      Parameters:
      text1 - Old string to be diffed.
      text2 - New string to be diffed.
      deadline - Time at which to bail if not yet complete.
      Returns:
      LinkedList of Diff objects.

    • diff_bisectSplit

      private LinkedList<diff_match_patch.Diff> diff_bisectSplit(String text1, String text2, int x, int y, long deadline)
      Given the location of the 'middle snake', split the diff in two parts and recurse.
      Parameters:
      text1 - Old string to be diffed.
      text2 - New string to be diffed.
      x - Index of split point in text1.
      y - Index of split point in text2.
      deadline - Time at which to bail if not yet complete.
      Returns:
      LinkedList of Diff objects.

    • diff_linesToChars

      protected diff_match_patch.LinesToCharsResult diff_linesToChars(String text1, String text2)
      Split two texts into a list of strings. Reduce the texts to a string of hashes where each Unicode character represents one line.
      Parameters:
      text1 - First string.
      text2 - Second string.
      Returns:
      An object containing the encoded text1, the encoded text2 and the List of unique strings. The zeroth element of the List of unique strings is intentionally blank.

    • diff_linesToCharsMunge

      private String diff_linesToCharsMunge(String text, List<String> lineArray, Map<String,Integer> lineHash)
      Split a text into a list of strings. Reduce the texts to a string of hashes where each Unicode character represents one line.
      Parameters:
      text - String to encode.
      lineArray - List of unique strings.
      lineHash - Map of strings to indices.
      Returns:
      Encoded string.

    • diff_charsToLines

      protected void diff_charsToLines(LinkedList<diff_match_patch.Diff> diffs, List<String> lineArray)
      Rehydrate the text in a diff from a string of line hashes to real lines of text.
      Parameters:
      diffs - LinkedList of Diff objects.
      lineArray - List of unique strings.

    • diff_commonPrefix

      public int diff_commonPrefix(String text1, String text2)
      Determine the common prefix of two strings
      Parameters:
      text1 - First string.
      text2 - Second string.
      Returns:
      The number of characters common to the start of each string.

    • diff_commonSuffix

      public int diff_commonSuffix(String text1, String text2)
      Determine the common suffix of two strings
      Parameters:
      text1 - First string.
      text2 - Second string.
      Returns:
      The number of characters common to the end of each string.

    • diff_commonOverlap

      protected int diff_commonOverlap(String text1, String text2)
      Determine if the suffix of one string is the prefix of another.
      Parameters:
      text1 - First string.
      text2 - Second string.
      Returns:
      The number of characters common to the end of the first string and the start of the second string.

    • diff_halfMatch

      protected String[] diff_halfMatch(String text1, String text2)
      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.
      Parameters:
      text1 - First string.
      text2 - Second string.
      Returns:
      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.

    • diff_halfMatchI

      private String[] diff_halfMatchI(String longtext, String shorttext, int i)
      Does a substring of shorttext exist within longtext such that the substring is at least half the length of longtext?
      Parameters:
      longtext - Longer string.
      shorttext - Shorter string.
      i - Start index of quarter length substring within longtext.
      Returns:
      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.

    • diff_cleanupSemantic

      public void diff_cleanupSemantic(LinkedList<diff_match_patch.Diff> diffs)
      Reduce the number of edits by eliminating semantically trivial equalities.
      Parameters:
      diffs - LinkedList of Diff objects.

    • diff_cleanupSemanticLossless

      public void diff_cleanupSemanticLossless(LinkedList<diff_match_patch.Diff> diffs)
      Look for single edits surrounded on both sides by equalities which can be shifted sideways to align the edit to a word boundary.
      Parameters:
      diffs - LinkedList of Diff objects.

    • diff_cleanupSemanticScore

      private int diff_cleanupSemanticScore(String one, String two)
      Given two strings, compute a score representing whether the internal boundary falls on logical boundaries. Scores range from 6 (best) to 0 (worst).
      Parameters:
      one - First string.
      two - Second string.
      Returns:
      The score.

    • diff_cleanupEfficiency

      public void diff_cleanupEfficiency(LinkedList<diff_match_patch.Diff> diffs)
      Reduce the number of edits by eliminating operationally trivial equalities.
      Parameters:
      diffs - LinkedList of Diff objects.

    • diff_cleanupMerge

      public void diff_cleanupMerge(LinkedList<diff_match_patch.Diff> diffs)
      Reorder and merge like edit sections. Merge equalities. Any edit section can move as long as it doesn't cross an equality.
      Parameters:
      diffs - LinkedList of Diff objects.

    • diff_xIndex

      public int diff_xIndex(LinkedList<diff_match_patch.Diff> diffs, int loc)
      loc is a location in text1, compute and return the equivalent location in text2. e.g. "The cat" vs "The big cat", 1->1, 5->8
      Parameters:
      diffs - LinkedList of Diff objects.
      loc - Location within text1.
      Returns:
      Location within text2.

    • diff_prettyHtml

      public String diff_prettyHtml(LinkedList<diff_match_patch.Diff> diffs)
      Convert a Diff list into a pretty HTML report.
      Parameters:
      diffs - LinkedList of Diff objects.
      Returns:
      HTML representation.

    • diff_text1

      public String diff_text1(LinkedList<diff_match_patch.Diff> diffs)
      Compute and return the source text (all equalities and deletions).
      Parameters:
      diffs - LinkedList of Diff objects.
      Returns:
      Source text.

    • diff_text2

      public String diff_text2(LinkedList<diff_match_patch.Diff> diffs)
      Compute and return the destination text (all equalities and insertions).
      Parameters:
      diffs - LinkedList of Diff objects.
      Returns:
      Destination text.

    • diff_levenshtein

      public int diff_levenshtein(LinkedList<diff_match_patch.Diff> diffs)
      Compute the Levenshtein distance; the number of inserted, deleted or substituted characters.
      Parameters:
      diffs - LinkedList of Diff objects.
      Returns:
      Number of changes.

    • diff_toDelta

      public String diff_toDelta(LinkedList<diff_match_patch.Diff> diffs)
      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.
      Parameters:
      diffs - Array of Diff objects.
      Returns:
      Delta text.

    • diff_fromDelta

      public LinkedList<diff_match_patch.Diff> diff_fromDelta(String text1, String delta) throws IllegalArgumentException
      Given the original text1, and an encoded string which describes the operations required to transform text1 into text2, compute the full diff.
      Parameters:
      text1 - Source string for the diff.
      delta - Delta text.
      Returns:
      Array of Diff objects or null if invalid.
      Throws:
      IllegalArgumentException - If invalid input.

    • match_main

      public int match_main(String text, String pattern, int loc)
      Locate the best instance of 'pattern' in 'text' near 'loc'. Returns -1 if no match found.
      Parameters:
      text - The text to search.
      pattern - The pattern to search for.
      loc - The location to search around.
      Returns:
      Best match index or -1.

    • match_bitap

      protected int match_bitap(String text, String pattern, int loc)
      Locate the best instance of 'pattern' in 'text' near 'loc' using the Bitap algorithm. Returns -1 if no match found.
      Parameters:
      text - The text to search.
      pattern - The pattern to search for.
      loc - The location to search around.
      Returns:
      Best match index or -1.

    • match_bitapScore

      private double match_bitapScore(int e, int x, int loc, String pattern)
      Compute and return the score for a match with e errors and x location.
      Parameters:
      e - Number of errors in match.
      x - Location of match.
      loc - Expected location of match.
      pattern - Pattern being sought.
      Returns:
      Overall score for match (0.0 = good, 1.0 = bad).

    • match_alphabet

      protected Map<Character,Integer> match_alphabet(String pattern)
      Initialise the alphabet for the Bitap algorithm.
      Parameters:
      pattern - The text to encode.
      Returns:
      Hash of character locations.

    • patch_addContext

      protected void patch_addContext(diff_match_patch.Patch patch, String text)
      Increase the context until it is unique, but don't let the pattern expand beyond Match_MaxBits.
      Parameters:
      patch - The patch to grow.
      text - Source text.

    • patch_make

      public LinkedList<diff_match_patch.Patch> patch_make(String text1, String text2)
      Compute a list of patches to turn text1 into text2. A set of diffs will be computed.
      Parameters:
      text1 - Old text.
      text2 - New text.
      Returns:
      LinkedList of Patch objects.

    • patch_make

      public LinkedList<diff_match_patch.Patch> patch_make(LinkedList<diff_match_patch.Diff> diffs)
      Compute a list of patches to turn text1 into text2. text1 will be derived from the provided diffs.
      Parameters:
      diffs - Array of Diff objects for text1 to text2.
      Returns:
      LinkedList of Patch objects.

    • patch_make

      public LinkedList<diff_match_patch.Patch> patch_make(String text1, String text2, LinkedList<diff_match_patch.Diff> diffs)
      Deprecated.
      Prefer patch_make(String text1, LinkedList<Diff> diffs).
      Compute a list of patches to turn text1 into text2. text2 is ignored, diffs are the delta between text1 and text2.
      Parameters:
      text1 - Old text
      text2 - Ignored.
      diffs - Array of Diff objects for text1 to text2.
      Returns:
      LinkedList of Patch objects.

    • patch_make

      public LinkedList<diff_match_patch.Patch> patch_make(String text1, LinkedList<diff_match_patch.Diff> diffs)
      Compute a list of patches to turn text1 into text2. text2 is not provided, diffs are the delta between text1 and text2.
      Parameters:
      text1 - Old text.
      diffs - Array of Diff objects for text1 to text2.
      Returns:
      LinkedList of Patch objects.

    • patch_deepCopy

      public LinkedList<diff_match_patch.Patch> patch_deepCopy(LinkedList<diff_match_patch.Patch> patches)
      Given an array of patches, return another array that is identical.
      Parameters:
      patches - Array of Patch objects.
      Returns:
      Array of Patch objects.

    • patch_apply

      public Object[] patch_apply(LinkedList<diff_match_patch.Patch> patches, String text)
      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.
      Parameters:
      patches - Array of Patch objects
      text - Old text.
      Returns:
      Two element Object array, containing the new text and an array of boolean values.

    • patch_addPadding

      public String patch_addPadding(LinkedList<diff_match_patch.Patch> patches)
      Add some padding on text start and end so that edges can match something. Intended to be called only from within patch_apply.
      Parameters:
      patches - Array of Patch objects.
      Returns:
      The padding string added to each side.

    • patch_splitMax

      public void patch_splitMax(LinkedList<diff_match_patch.Patch> patches)
      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.
      Parameters:
      patches - LinkedList of Patch objects.

    • patch_toText

      public String patch_toText(List<diff_match_patch.Patch> patches)
      Take a list of patches and return a textual representation.
      Parameters:
      patches - List of Patch objects.
      Returns:
      Text representation of patches.

    • patch_fromText

      public List<diff_match_patch.Patch> patch_fromText(String textline) throws IllegalArgumentException
      Parse a textual representation of patches and return a List of Patch objects.
      Parameters:
      textline - Text representation of patches.
      Returns:
      List of Patch objects.
      Throws:
      IllegalArgumentException - If invalid input.

    • unescapeForEncodeUriCompatability

      private static String unescapeForEncodeUriCompatability(String str)
      Unescape selected chars for compatability with JavaScript's encodeURI. In speed critical applications this could be dropped since the receiving application will certainly decode these fine. Note that this function is case-sensitive. Thus "%3f" would not be unescaped. But this is ok because it is only called with the output of URLEncoder.encode which returns uppercase hex. Example: "%3F" -> "?", "%24" -> "$", etc.
      Parameters:
      str - The string to escape.
      Returns:
      The escaped string.