--- /dev/null
+#!/usr/bin/python2.4
+
+"""Diff Match and Patch
+
+Copyright 2006 Google Inc.
+http://code.google.com/p/google-diff-match-patch/
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+"""
+
+"""Functions for diff, match and patch.
+
+Computes the difference between two texts to create a patch.
+Applies the patch onto another text, allowing for errors.
+"""
+
+__author__ = 'fraser@google.com (Neil Fraser)'
+
+import math
+import time
+import urllib
+import re
+
+class diff_match_patch:
+ """Class containing the diff, match and patch methods.
+
+ Also contains the behaviour settings.
+ """
+
+ def __init__(self):
+ """Inits a diff_match_patch object with default settings.
+ Redefine these in your program to override the defaults.
+ """
+
+ # Number of seconds to map a diff before giving up (0 for infinity).
+ self.Diff_Timeout = 1.0
+ # Cost of an empty edit operation in terms of edit characters.
+ self.Diff_EditCost = 4
+ # The size beyond which the double-ended diff activates.
+ # Double-ending is twice as fast, but less accurate.
+ self.Diff_DualThreshold = 32
+ # At what point is no match declared (0.0 = perfection, 1.0 = very loose).
+ self.Match_Threshold = 0.5
+ # 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).
+ self.Match_Distance = 1000
+ # When deleting a large block of text (over ~64 characters), how close does
+ # the contents have 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.
+ self.Patch_DeleteThreshold = 0.5
+ # Chunk size for context length.
+ self.Patch_Margin = 4
+
+ # How many bits in a number?
+ # Python has no maximum, thus to disable patch splitting set to 0.
+ # However to avoid long patches in certain pathological cases, use 32.
+ # Multiple short patches (using native ints) are much faster than long ones.
+ self.Match_MaxBits = 32
+
+ # DIFF FUNCTIONS
+
+ # The data structure representing a diff is an array of tuples:
+ # [(DIFF_DELETE, "Hello"), (DIFF_INSERT, "Goodbye"), (DIFF_EQUAL, " world.")]
+ # which means: delete "Hello", add "Goodbye" and keep " world."
+ DIFF_DELETE = -1
+ DIFF_INSERT = 1
+ DIFF_EQUAL = 0
+
+ def diff_main(self, text1, text2, checklines=True):
+ """Find the differences between two texts. Simplifies the problem by
+ stripping any common prefix or suffix off the texts before diffing.
+
+ Args:
+ text1: Old string to be diffed.
+ text2: New string to be diffed.
+ checklines: Optional speedup flag. If present and false, then don't run
+ a line-level diff first to identify the changed areas.
+ Defaults to true, which does a faster, slightly less optimal diff.
+
+ Returns:
+ Array of changes.
+ """
+
+ # Check for null inputs.
+ if text1 == None or text2 == None:
+ raise ValueError("Null inputs. (diff_main)")
+
+ # Check for equality (speedup).
+ if text1 == text2:
+ return [(self.DIFF_EQUAL, text1)]
+
+ # Trim off common prefix (speedup).
+ commonlength = self.diff_commonPrefix(text1, text2)
+ commonprefix = text1[:commonlength]
+ text1 = text1[commonlength:]
+ text2 = text2[commonlength:]
+
+ # Trim off common suffix (speedup).
+ commonlength = self.diff_commonSuffix(text1, text2)
+ if commonlength == 0:
+ commonsuffix = ''
+ else:
+ commonsuffix = text1[-commonlength:]
+ text1 = text1[:-commonlength]
+ text2 = text2[:-commonlength]
+
+ # Compute the diff on the middle block.
+ diffs = self.diff_compute(text1, text2, checklines)
+
+ # Restore the prefix and suffix.
+ if commonprefix:
+ diffs[:0] = [(self.DIFF_EQUAL, commonprefix)]
+ if commonsuffix:
+ diffs.append((self.DIFF_EQUAL, commonsuffix))
+ self.diff_cleanupMerge(diffs)
+ return diffs
+
+ def diff_compute(self, text1, text2, checklines):
+ """Find the differences between two texts. Assumes that the texts do not
+ have any common prefix or suffix.
+
+ Args:
+ 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:
+ Array of changes.
+ """
+ if not text1:
+ # Just add some text (speedup).
+ return [(self.DIFF_INSERT, text2)]
+
+ if not text2:
+ # Just delete some text (speedup).
+ return [(self.DIFF_DELETE, text1)]
+
+ if len(text1) > len(text2):
+ (longtext, shorttext) = (text1, text2)
+ else:
+ (shorttext, longtext) = (text1, text2)
+ i = longtext.find(shorttext)
+ if i != -1:
+ # Shorter text is inside the longer text (speedup).
+ diffs = [(self.DIFF_INSERT, longtext[:i]), (self.DIFF_EQUAL, shorttext),
+ (self.DIFF_INSERT, longtext[i + len(shorttext):])]
+ # Swap insertions for deletions if diff is reversed.
+ if len(text1) > len(text2):
+ diffs[0] = (self.DIFF_DELETE, diffs[0][1])
+ diffs[2] = (self.DIFF_DELETE, diffs[2][1])
+ return diffs
+ longtext = shorttext = None # Garbage collect.
+
+ # Check to see if the problem can be split in two.
+ hm = self.diff_halfMatch(text1, text2)
+ if hm:
+ # A half-match was found, sort out the return data.
+ (text1_a, text1_b, text2_a, text2_b, mid_common) = hm
+ # Send both pairs off for separate processing.
+ diffs_a = self.diff_main(text1_a, text2_a, checklines)
+ diffs_b = self.diff_main(text1_b, text2_b, checklines)
+ # Merge the results.
+ return diffs_a + [(self.DIFF_EQUAL, mid_common)] + diffs_b
+
+ # Perform a real diff.
+ if checklines and (len(text1) < 100 or len(text2) < 100):
+ checklines = False # Too trivial for the overhead.
+ if checklines:
+ # Scan the text on a line-by-line basis first.
+ (text1, text2, linearray) = self.diff_linesToChars(text1, text2)
+
+ diffs = self.diff_map(text1, text2)
+ if not diffs: # No acceptable result.
+ diffs = [(self.DIFF_DELETE, text1), (self.DIFF_INSERT, text2)]
+ if checklines:
+ # Convert the diff back to original text.
+ self.diff_charsToLines(diffs, linearray)
+ # Eliminate freak matches (e.g. blank lines)
+ self.diff_cleanupSemantic(diffs)
+
+ # Rediff any replacement blocks, this time character-by-character.
+ # Add a dummy entry at the end.
+ diffs.append((self.DIFF_EQUAL, ''))
+ pointer = 0
+ count_delete = 0
+ count_insert = 0
+ text_delete = ''
+ text_insert = ''
+ while pointer < len(diffs):
+ if diffs[pointer][0] == self.DIFF_INSERT:
+ count_insert += 1
+ text_insert += diffs[pointer][1]
+ elif diffs[pointer][0] == self.DIFF_DELETE:
+ count_delete += 1
+ text_delete += diffs[pointer][1]
+ elif diffs[pointer][0] == self.DIFF_EQUAL:
+ # Upon reaching an equality, check for prior redundancies.
+ if count_delete >= 1 and count_insert >= 1:
+ # Delete the offending records and add the merged ones.
+ a = self.diff_main(text_delete, text_insert, False)
+ diffs[pointer - count_delete - count_insert : pointer] = a
+ pointer = pointer - count_delete - count_insert + len(a)
+ count_insert = 0
+ count_delete = 0
+ text_delete = ''
+ text_insert = ''
+
+ pointer += 1
+
+ diffs.pop() # Remove the dummy entry at the end.
+ return diffs
+
+ def diff_linesToChars(self, text1, text2):
+ """Split two texts into an array of strings. Reduce the texts to a string
+ of hashes where each Unicode character represents one line.
+
+ Args:
+ text1: First string.
+ text2: Second string.
+
+ Returns:
+ Three element tuple, containing the encoded text1, the encoded text2 and
+ the array of unique strings. The zeroth element of the array of unique
+ strings is intentionally blank.
+ """
+ lineArray = [] # e.g. lineArray[4] == "Hello\n"
+ lineHash = {} # e.g. lineHash["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.append('')
+
+ def diff_linesToCharsMunge(text):
+ """Split a text into an array of strings. Reduce the texts to a string
+ of hashes where each Unicode character represents one line.
+ Modifies linearray and linehash through being a closure.
+
+ Args:
+ text: String to encode.
+
+ Returns:
+ Encoded string.
+ """
+ chars = []
+ # 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.
+ lineStart = 0
+ lineEnd = -1
+ while lineEnd < len(text) - 1:
+ lineEnd = text.find('\n', lineStart)
+ if lineEnd == -1:
+ lineEnd = len(text) - 1
+ line = text[lineStart:lineEnd + 1]
+ lineStart = lineEnd + 1
+
+ if line in lineHash:
+ chars.append(unichr(lineHash[line]))
+ else:
+ lineArray.append(line)
+ lineHash[line] = len(lineArray) - 1
+ chars.append(unichr(len(lineArray) - 1))
+ return "".join(chars)
+
+ chars1 = diff_linesToCharsMunge(text1)
+ chars2 = diff_linesToCharsMunge(text2)
+ return (chars1, chars2, lineArray)
+
+ def diff_charsToLines(self, diffs, lineArray):
+ """Rehydrate the text in a diff from a string of line hashes to real lines
+ of text.
+
+ Args:
+ diffs: Array of diff tuples.
+ lineArray: Array of unique strings.
+ """
+ for x in xrange(len(diffs)):
+ text = []
+ for char in diffs[x][1]:
+ text.append(lineArray[ord(char)])
+ diffs[x] = (diffs[x][0], "".join(text))
+
+ def diff_map(self, text1, text2):
+ """Explore the intersection points between the two texts.
+
+ Args:
+ text1: Old string to be diffed.
+ text2: New string to be diffed.
+
+ Returns:
+ Array of diff tuples or None if no diff available.
+ """
+
+ # Unlike in most languages, Python counts time in seconds.
+ s_end = time.time() + self.Diff_Timeout # Don't run for too long.
+ # Cache the text lengths to prevent multiple calls.
+ text1_length = len(text1)
+ text2_length = len(text2)
+ max_d = text1_length + text2_length - 1
+ doubleEnd = self.Diff_DualThreshold * 2 < max_d
+ # Python efficiency note: (x << 32) + y is the fastest way to combine
+ # x and y into a single hashable value. Tested in Python 2.5.
+ # It is unclear why it is faster for v_map[d] to be indexed with an
+ # integer whereas footsteps is indexed with a string.
+ v_map1 = []
+ v_map2 = []
+ v1 = {}
+ v2 = {}
+ v1[1] = 0
+ v2[1] = 0
+ footsteps = {}
+ done = False
+ # If the total number of characters is odd, then the front path will
+ # collide with the reverse path.
+ front = (text1_length + text2_length) % 2
+ for d in xrange(max_d):
+ # Bail out if timeout reached.
+ if self.Diff_Timeout > 0 and time.time() > s_end:
+ return None
+
+ # Walk the front path one step.
+ v_map1.append({})
+ for k in xrange(-d, d + 1, 2):
+ if k == -d or k != d and v1[k - 1] < v1[k + 1]:
+ x = v1[k + 1]
+ else:
+ x = v1[k - 1] + 1
+ y = x - k
+ if doubleEnd:
+ footstep = str((x << 32) + y)
+ if front and footstep in footsteps:
+ done = True
+ if not front:
+ footsteps[footstep] = d
+
+ while (not done and x < text1_length and y < text2_length and
+ text1[x] == text2[y]):
+ x += 1
+ y += 1
+ if doubleEnd:
+ footstep = str((x << 32) + y)
+ if front and footstep in footsteps:
+ done = True
+ if not front:
+ footsteps[footstep] = d
+
+ v1[k] = x
+ v_map1[d][(x << 32) + y] = True
+ if x == text1_length and y == text2_length:
+ # Reached the end in single-path mode.
+ return self.diff_path1(v_map1, text1, text2)
+ elif done:
+ # Front path ran over reverse path.
+ v_map2 = v_map2[:footsteps[footstep] + 1]
+ a = self.diff_path1(v_map1, text1[:x], text2[:y])
+ b = self.diff_path2(v_map2, text1[x:], text2[y:])
+ return a + b
+
+ if doubleEnd:
+ # Walk the reverse path one step.
+ v_map2.append({})
+ for k in xrange(-d, d + 1, 2):
+ if k == -d or k != d and v2[k - 1] < v2[k + 1]:
+ x = v2[k + 1]
+ else:
+ x = v2[k - 1] + 1
+ y = x - k
+ footstep = str((text1_length - x << 32) + text2_length - y)
+ if not front and footstep in footsteps:
+ done = True
+ if front:
+ footsteps[footstep] = d
+ while (not done and x < text1_length and y < text2_length and
+ text1[-x - 1] == text2[-y - 1]):
+ x += 1
+ y += 1
+ footstep = str((text1_length - x << 32) + text2_length - y)
+ if not front and footstep in footsteps:
+ done = True
+ if front:
+ footsteps[footstep] = d
+
+ v2[k] = x
+ v_map2[d][(x << 32) + y] = True
+ if done:
+ # Reverse path ran over front path.
+ v_map1 = v_map1[:footsteps[footstep] + 1]
+ a = self.diff_path1(v_map1, text1[:text1_length - x],
+ text2[:text2_length - y])
+ b = self.diff_path2(v_map2, text1[text1_length - x:],
+ text2[text2_length - y:])
+ return a + b
+
+ # Number of diffs equals number of characters, no commonality at all.
+ return None
+
+ def diff_path1(self, v_map, text1, text2):
+ """Work from the middle back to the start to determine the path.
+
+ Args:
+ v_map: Array of paths.
+ text1: Old string fragment to be diffed.
+ text2: New string fragment to be diffed.
+
+ Returns:
+ Array of diff tuples.
+ """
+ path = []
+ x = len(text1)
+ y = len(text2)
+ last_op = None
+ for d in xrange(len(v_map) - 2, -1, -1):
+ while True:
+ if (x - 1 << 32) + y in v_map[d]:
+ x -= 1
+ if last_op == self.DIFF_DELETE:
+ path[0] = (self.DIFF_DELETE, text1[x] + path[0][1])
+ else:
+ path[:0] = [(self.DIFF_DELETE, text1[x])]
+ last_op = self.DIFF_DELETE
+ break
+ elif (x << 32) + y - 1 in v_map[d]:
+ y -= 1
+ if last_op == self.DIFF_INSERT:
+ path[0] = (self.DIFF_INSERT, text2[y] + path[0][1])
+ else:
+ path[:0] = [(self.DIFF_INSERT, text2[y])]
+ last_op = self.DIFF_INSERT
+ break
+ else:
+ x -= 1
+ y -= 1
+ assert text1[x] == text2[y], ("No diagonal. " +
+ "Can't happen. (diff_path1)")
+ if last_op == self.DIFF_EQUAL:
+ path[0] = (self.DIFF_EQUAL, text1[x] + path[0][1])
+ else:
+ path[:0] = [(self.DIFF_EQUAL, text1[x])]
+ last_op = self.DIFF_EQUAL
+ return path
+
+ def diff_path2(self, v_map, text1, text2):
+ """Work from the middle back to the end to determine the path.
+
+ Args:
+ v_map: Array of paths.
+ text1: Old string fragment to be diffed.
+ text2: New string fragment to be diffed.
+
+ Returns:
+ Array of diff tuples.
+ """
+ path = []
+ x = len(text1)
+ y = len(text2)
+ last_op = None
+ for d in xrange(len(v_map) - 2, -1, -1):
+ while True:
+ if (x - 1 << 32) + y in v_map[d]:
+ x -= 1
+ if last_op == self.DIFF_DELETE:
+ path[-1] = (self.DIFF_DELETE, path[-1][1] + text1[-x - 1])
+ else:
+ path.append((self.DIFF_DELETE, text1[-x - 1]))
+ last_op = self.DIFF_DELETE
+ break
+ elif (x << 32) + y - 1 in v_map[d]:
+ y -= 1
+ if last_op == self.DIFF_INSERT:
+ path[-1] = (self.DIFF_INSERT, path[-1][1] + text2[-y - 1])
+ else:
+ path.append((self.DIFF_INSERT, text2[-y - 1]))
+ last_op = self.DIFF_INSERT
+ break
+ else:
+ x -= 1
+ y -= 1
+ assert text1[-x - 1] == text2[-y - 1], ("No diagonal. " +
+ "Can't happen. (diff_path2)")
+ if last_op == self.DIFF_EQUAL:
+ path[-1] = (self.DIFF_EQUAL, path[-1][1] + text1[-x - 1])
+ else:
+ path.append((self.DIFF_EQUAL, text1[-x - 1]))
+ last_op = self.DIFF_EQUAL
+ return path
+
+ def diff_commonPrefix(self, text1, text2):
+ """Determine the common prefix of two strings.
+
+ Args:
+ text1: First string.
+ text2: Second string.
+
+ Returns:
+ The number of characters common to the start of each string.
+ """
+ # Quick check for common null cases.
+ if not text1 or not text2 or text1[0] != text2[0]:
+ return 0
+ # Binary search.
+ # Performance analysis: http://neil.fraser.name/news/2007/10/09/
+ pointermin = 0
+ pointermax = min(len(text1), len(text2))
+ pointermid = pointermax
+ pointerstart = 0
+ while pointermin < pointermid:
+ if text1[pointerstart:pointermid] == text2[pointerstart:pointermid]:
+ pointermin = pointermid
+ pointerstart = pointermin
+ else:
+ pointermax = pointermid
+ pointermid = int((pointermax - pointermin) / 2 + pointermin)
+ return pointermid
+
+ def diff_commonSuffix(self, text1, text2):
+ """Determine the common suffix of two strings.
+
+ Args:
+ text1: First string.
+ text2: Second string.
+
+ Returns:
+ The number of characters common to the end of each string.
+ """
+ # Quick check for common null cases.
+ if not text1 or not text2 or text1[-1] != text2[-1]:
+ return 0
+ # Binary search.
+ # Performance analysis: http://neil.fraser.name/news/2007/10/09/
+ pointermin = 0
+ pointermax = min(len(text1), len(text2))
+ pointermid = pointermax
+ pointerend = 0
+ while pointermin < pointermid:
+ if (text1[-pointermid:len(text1) - pointerend] ==
+ text2[-pointermid:len(text2) - pointerend]):
+ pointermin = pointermid
+ pointerend = pointermin
+ else:
+ pointermax = pointermid
+ pointermid = int((pointermax - pointermin) / 2 + pointermin)
+ return pointermid
+
+ def diff_halfMatch(self, text1, text2):
+ """Do the two texts share a substring which is at least half the length of
+ the longer text?
+
+ Args:
+ text1: First string.
+ text2: Second string.
+
+ Returns:
+ Five element Array, containing the prefix of text1, the suffix of text1,
+ the prefix of text2, the suffix of text2 and the common middle. Or None
+ if there was no match.
+ """
+ if len(text1) > len(text2):
+ (longtext, shorttext) = (text1, text2)
+ else:
+ (shorttext, longtext) = (text1, text2)
+ if len(longtext) < 10 or len(shorttext) < 1:
+ return None # Pointless.
+
+ def diff_halfMatchI(longtext, shorttext, i):
+ """Does a substring of shorttext exist within longtext such that the
+ substring is at least half the length of longtext?
+ Closure, but does not reference any external variables.
+
+ Args:
+ longtext: Longer string.
+ shorttext: Shorter string.
+ i: Start index of quarter length substring within longtext.
+
+ Returns:
+ Five element Array, containing the prefix of longtext, the suffix of
+ longtext, the prefix of shorttext, the suffix of shorttext and the
+ common middle. Or None if there was no match.
+ """
+ seed = longtext[i:i + len(longtext) / 4]
+ best_common = ''
+ j = shorttext.find(seed)
+ while j != -1:
+ prefixLength = self.diff_commonPrefix(longtext[i:], shorttext[j:])
+ suffixLength = self.diff_commonSuffix(longtext[:i], shorttext[:j])
+ if len(best_common) < suffixLength + prefixLength:
+ best_common = (shorttext[j - suffixLength:j] +
+ shorttext[j:j + prefixLength])
+ best_longtext_a = longtext[:i - suffixLength]
+ best_longtext_b = longtext[i + prefixLength:]
+ best_shorttext_a = shorttext[:j - suffixLength]
+ best_shorttext_b = shorttext[j + prefixLength:]
+ j = shorttext.find(seed, j + 1)
+
+ if len(best_common) >= len(longtext) / 2:
+ return (best_longtext_a, best_longtext_b,
+ best_shorttext_a, best_shorttext_b, best_common)
+ else:
+ return None
+
+ # First check if the second quarter is the seed for a half-match.
+ hm1 = diff_halfMatchI(longtext, shorttext, (len(longtext) + 3) / 4)
+ # Check again based on the third quarter.
+ hm2 = diff_halfMatchI(longtext, shorttext, (len(longtext) + 1) / 2)
+ if not hm1 and not hm2:
+ return None
+ elif not hm2:
+ hm = hm1
+ elif not hm1:
+ hm = hm2
+ else:
+ # Both matched. Select the longest.
+ if len(hm1[4]) > len(hm2[4]):
+ hm = hm1
+ else:
+ hm = hm2
+
+ # A half-match was found, sort out the return data.
+ if len(text1) > len(text2):
+ (text1_a, text1_b, text2_a, text2_b, mid_common) = hm
+ else:
+ (text2_a, text2_b, text1_a, text1_b, mid_common) = hm
+ return (text1_a, text1_b, text2_a, text2_b, mid_common)
+
+ def diff_cleanupSemantic(self, diffs):
+ """Reduce the number of edits by eliminating semantically trivial
+ equalities.
+
+ Args:
+ diffs: Array of diff tuples.
+ """
+ changes = False
+ equalities = [] # Stack of indices where equalities are found.
+ lastequality = None # Always equal to equalities[-1][1]
+ pointer = 0 # Index of current position.
+ length_changes1 = 0 # Number of chars that changed prior to the equality.
+ length_changes2 = 0 # Number of chars that changed after the equality.
+ while pointer < len(diffs):
+ if diffs[pointer][0] == self.DIFF_EQUAL: # equality found
+ equalities.append(pointer)
+ length_changes1 = length_changes2
+ length_changes2 = 0
+ lastequality = diffs[pointer][1]
+ else: # an insertion or deletion
+ length_changes2 += len(diffs[pointer][1])
+ if (lastequality != None and (len(lastequality) <= length_changes1) and
+ (len(lastequality) <= length_changes2)):
+ # Duplicate record
+ diffs.insert(equalities[-1], (self.DIFF_DELETE, lastequality))
+ # Change second copy to insert.
+ diffs[equalities[-1] + 1] = (self.DIFF_INSERT,
+ diffs[equalities[-1] + 1][1])
+ # Throw away the equality we just deleted.
+ equalities.pop()
+ # Throw away the previous equality (it needs to be reevaluated).
+ if len(equalities) != 0:
+ equalities.pop()
+ if len(equalities):
+ pointer = equalities[-1]
+ else:
+ pointer = -1
+ length_changes1 = 0 # Reset the counters.
+ length_changes2 = 0
+ lastequality = None
+ changes = True
+ pointer += 1
+
+ if changes:
+ self.diff_cleanupMerge(diffs)
+
+ self.diff_cleanupSemanticLossless(diffs)
+
+ def diff_cleanupSemanticLossless(self, diffs):
+ """Look for single edits surrounded on both sides by equalities
+ which can be shifted sideways to align the edit to a word boundary.
+ e.g: The c<ins>at c</ins>ame. -> The <ins>cat </ins>came.
+
+ Args:
+ diffs: Array of diff tuples.
+ """
+
+ def diff_cleanupSemanticScore(one, two):
+ """Given two strings, compute a score representing whether the
+ internal boundary falls on logical boundaries.
+ Scores range from 5 (best) to 0 (worst).
+ Closure, but does not reference any external variables.
+
+ Args:
+ one: First string.
+ two: Second string.
+
+ Returns:
+ The score.
+ """
+ if not one or not two:
+ # Edges are the best.
+ return 5
+
+ # Each port of this function behaves slightly differently due to
+ # subtle differences in each language's definition of things like
+ # 'whitespace'. Since this function's purpose is largely cosmetic,
+ # the choice has been made to use each language's native features
+ # rather than force total conformity.
+ score = 0
+ # One point for non-alphanumeric.
+ if not one[-1].isalnum() or not two[0].isalnum():
+ score += 1
+ # Two points for whitespace.
+ if one[-1].isspace() or two[0].isspace():
+ score += 1
+ # Three points for line breaks.
+ if (one[-1] == "\r" or one[-1] == "\n" or
+ two[0] == "\r" or two[0] == "\n"):
+ score += 1
+ # Four points for blank lines.
+ if (re.search("\\n\\r?\\n$", one) or
+ re.match("^\\r?\\n\\r?\\n", two)):
+ score += 1
+ return score
+
+ pointer = 1
+ # Intentionally ignore the first and last element (don't need checking).
+ while pointer < len(diffs) - 1:
+ if (diffs[pointer - 1][0] == self.DIFF_EQUAL and
+ diffs[pointer + 1][0] == self.DIFF_EQUAL):
+ # This is a single edit surrounded by equalities.
+ equality1 = diffs[pointer - 1][1]
+ edit = diffs[pointer][1]
+ equality2 = diffs[pointer + 1][1]
+
+ # First, shift the edit as far left as possible.
+ commonOffset = self.diff_commonSuffix(equality1, edit)
+ if commonOffset:
+ commonString = edit[-commonOffset:]
+ equality1 = equality1[:-commonOffset]
+ edit = commonString + edit[:-commonOffset]
+ equality2 = commonString + equality2
+
+ # Second, step character by character right, looking for the best fit.
+ bestEquality1 = equality1
+ bestEdit = edit
+ bestEquality2 = equality2
+ bestScore = (diff_cleanupSemanticScore(equality1, edit) +
+ diff_cleanupSemanticScore(edit, equality2))
+ while edit and equality2 and edit[0] == equality2[0]:
+ equality1 += edit[0]
+ edit = edit[1:] + equality2[0]
+ equality2 = equality2[1:]
+ score = (diff_cleanupSemanticScore(equality1, edit) +
+ diff_cleanupSemanticScore(edit, equality2))
+ # The >= encourages trailing rather than leading whitespace on edits.
+ if score >= bestScore:
+ bestScore = score
+ bestEquality1 = equality1
+ bestEdit = edit
+ bestEquality2 = equality2
+
+ if diffs[pointer - 1][1] != bestEquality1:
+ # We have an improvement, save it back to the diff.
+ if bestEquality1:
+ diffs[pointer - 1] = (diffs[pointer - 1][0], bestEquality1)
+ else:
+ del diffs[pointer - 1]
+ pointer -= 1
+ diffs[pointer] = (diffs[pointer][0], bestEdit)
+ if bestEquality2:
+ diffs[pointer + 1] = (diffs[pointer + 1][0], bestEquality2)
+ else:
+ del diffs[pointer + 1]
+ pointer -= 1
+ pointer += 1
+
+ def diff_cleanupEfficiency(self, diffs):
+ """Reduce the number of edits by eliminating operationally trivial
+ equalities.
+
+ Args:
+ diffs: Array of diff tuples.
+ """
+ changes = False
+ equalities = [] # Stack of indices where equalities are found.
+ lastequality = '' # Always equal to equalities[-1][1]
+ pointer = 0 # Index of current position.
+ pre_ins = False # Is there an insertion operation before the last equality.
+ pre_del = False # Is there a deletion operation before the last equality.
+ post_ins = False # Is there an insertion operation after the last equality.
+ post_del = False # Is there a deletion operation after the last equality.
+ while pointer < len(diffs):
+ if diffs[pointer][0] == self.DIFF_EQUAL: # equality found
+ if (len(diffs[pointer][1]) < self.Diff_EditCost and
+ (post_ins or post_del)):
+ # Candidate found.
+ equalities.append(pointer)
+ pre_ins = post_ins
+ pre_del = post_del
+ lastequality = diffs[pointer][1]
+ else:
+ # Not a candidate, and can never become one.
+ equalities = []
+ lastequality = ''
+
+ post_ins = post_del = False
+ else: # an insertion or deletion
+ if diffs[pointer][0] == self.DIFF_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 and ((pre_ins and pre_del and post_ins and post_del) or
+ ((len(lastequality) < self.Diff_EditCost / 2) and
+ (pre_ins + pre_del + post_ins + post_del) == 3)):
+ # Duplicate record
+ diffs.insert(equalities[-1], (self.DIFF_DELETE, lastequality))
+ # Change second copy to insert.
+ diffs[equalities[-1] + 1] = (self.DIFF_INSERT,
+ diffs[equalities[-1] + 1][1])
+ equalities.pop() # Throw away the equality we just deleted
+ lastequality = ''
+ if pre_ins and pre_del:
+ # No changes made which could affect previous entry, keep going.
+ post_ins = post_del = True
+ equalities = []
+ else:
+ if len(equalities):
+ equalities.pop() # Throw away the previous equality
+ if len(equalities):
+ pointer = equalities[-1]
+ else:
+ pointer = -1
+ post_ins = post_del = False
+ changes = True
+ pointer += 1
+
+ if changes:
+ self.diff_cleanupMerge(diffs)
+
+ def diff_cleanupMerge(self, diffs):
+ """Reorder and merge like edit sections. Merge equalities.
+ Any edit section can move as long as it doesn't cross an equality.
+
+ Args:
+ diffs: Array of diff tuples.
+ """
+ diffs.append((self.DIFF_EQUAL, '')) # Add a dummy entry at the end.
+ pointer = 0
+ count_delete = 0
+ count_insert = 0
+ text_delete = ''
+ text_insert = ''
+ while pointer < len(diffs):
+ if diffs[pointer][0] == self.DIFF_INSERT:
+ count_insert += 1
+ text_insert += diffs[pointer][1]
+ pointer += 1
+ elif diffs[pointer][0] == self.DIFF_DELETE:
+ count_delete += 1
+ text_delete += diffs[pointer][1]
+ pointer += 1
+ elif diffs[pointer][0] == self.DIFF_EQUAL:
+ # Upon reaching an equality, check for prior redundancies.
+ if count_delete != 0 or count_insert != 0:
+ if count_delete != 0 and count_insert != 0:
+ # Factor out any common prefixies.
+ commonlength = self.diff_commonPrefix(text_insert, text_delete)
+ if commonlength != 0:
+ x = pointer - count_delete - count_insert - 1
+ if x >= 0 and diffs[x][0] == self.DIFF_EQUAL:
+ diffs[x] = (diffs[x][0], diffs[x][1] +
+ text_insert[:commonlength])
+ else:
+ diffs.insert(0, (self.DIFF_EQUAL, text_insert[:commonlength]))
+ pointer += 1
+ text_insert = text_insert[commonlength:]
+ text_delete = text_delete[commonlength:]
+ # Factor out any common suffixies.
+ commonlength = self.diff_commonSuffix(text_insert, text_delete)
+ if commonlength != 0:
+ diffs[pointer] = (diffs[pointer][0], text_insert[-commonlength:] +
+ diffs[pointer][1])
+ text_insert = text_insert[:-commonlength]
+ text_delete = text_delete[:-commonlength]
+ # Delete the offending records and add the merged ones.
+ if count_delete == 0:
+ diffs[pointer - count_insert : pointer] = [
+ (self.DIFF_INSERT, text_insert)]
+ elif count_insert == 0:
+ diffs[pointer - count_delete : pointer] = [
+ (self.DIFF_DELETE, text_delete)]
+ else:
+ diffs[pointer - count_delete - count_insert : pointer] = [
+ (self.DIFF_DELETE, text_delete),
+ (self.DIFF_INSERT, text_insert)]
+ pointer = pointer - count_delete - count_insert + 1
+ if count_delete != 0:
+ pointer += 1
+ if count_insert != 0:
+ pointer += 1
+ elif pointer != 0 and diffs[pointer - 1][0] == self.DIFF_EQUAL:
+ # Merge this equality with the previous one.
+ diffs[pointer - 1] = (diffs[pointer - 1][0],
+ diffs[pointer - 1][1] + diffs[pointer][1])
+ del diffs[pointer]
+ else:
+ pointer += 1
+
+ count_insert = 0
+ count_delete = 0
+ text_delete = ''
+ text_insert = ''
+
+ if diffs[-1][1] == '':
+ diffs.pop() # 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
+ changes = False
+ pointer = 1
+ # Intentionally ignore the first and last element (don't need checking).
+ while pointer < len(diffs) - 1:
+ if (diffs[pointer - 1][0] == self.DIFF_EQUAL and
+ diffs[pointer + 1][0] == self.DIFF_EQUAL):
+ # This is a single edit surrounded by equalities.
+ if diffs[pointer][1].endswith(diffs[pointer - 1][1]):
+ # Shift the edit over the previous equality.
+ diffs[pointer] = (diffs[pointer][0],
+ diffs[pointer - 1][1] +
+ diffs[pointer][1][:-len(diffs[pointer - 1][1])])
+ diffs[pointer + 1] = (diffs[pointer + 1][0],
+ diffs[pointer - 1][1] + diffs[pointer + 1][1])
+ del diffs[pointer - 1]
+ changes = True
+ elif diffs[pointer][1].startswith(diffs[pointer + 1][1]):
+ # Shift the edit over the next equality.
+ diffs[pointer - 1] = (diffs[pointer - 1][0],
+ diffs[pointer - 1][1] + diffs[pointer + 1][1])
+ diffs[pointer] = (diffs[pointer][0],
+ diffs[pointer][1][len(diffs[pointer + 1][1]):] +
+ diffs[pointer + 1][1])
+ del diffs[pointer + 1]
+ changes = True
+ pointer += 1
+
+ # If shifts were made, the diff needs reordering and another shift sweep.
+ if changes:
+ self.diff_cleanupMerge(diffs)
+
+ def diff_xIndex(self, diffs, 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
+
+ Args:
+ diffs: Array of diff tuples.
+ loc: Location within text1.
+
+ Returns:
+ Location within text2.
+ """
+ chars1 = 0
+ chars2 = 0
+ last_chars1 = 0
+ last_chars2 = 0
+ for x in xrange(len(diffs)):
+ (op, text) = diffs[x]
+ if op != self.DIFF_INSERT: # Equality or deletion.
+ chars1 += len(text)
+ if op != self.DIFF_DELETE: # Equality or insertion.
+ chars2 += len(text)
+ if chars1 > loc: # Overshot the location.
+ break
+ last_chars1 = chars1
+ last_chars2 = chars2
+
+ if len(diffs) != x and diffs[x][0] == self.DIFF_DELETE:
+ # The location was deleted.
+ return last_chars2
+ # Add the remaining len(character).
+ return last_chars2 + (loc - last_chars1)
+
+ def diff_prettyHtml(self, diffs):
+ """Convert a diff array into a pretty HTML report.
+
+ Args:
+ diffs: Array of diff tuples.
+
+ Returns:
+ HTML representation.
+ """
+ html = []
+ i = 0
+ for (op, data) in diffs:
+ text = (data.replace("&", "&").replace("<", "<")
+ .replace(">", ">").replace("\n", "¶<BR>"))
+ if op == self.DIFF_INSERT:
+ html.append("<INS STYLE=\"background:#E6FFE6;\" TITLE=\"i=%i\">%s</INS>"
+ % (i, text))
+ elif op == self.DIFF_DELETE:
+ html.append("<DEL STYLE=\"background:#FFE6E6;\" TITLE=\"i=%i\">%s</DEL>"
+ % (i, text))
+ elif op == self.DIFF_EQUAL:
+ html.append("<SPAN TITLE=\"i=%i\">%s</SPAN>" % (i, text))
+ if op != self.DIFF_DELETE:
+ i += len(data)
+ return "".join(html)
+
+ def diff_text1(self, diffs):
+ """Compute and return the source text (all equalities and deletions).
+
+ Args:
+ diffs: Array of diff tuples.
+
+ Returns:
+ Source text.
+ """
+ text = []
+ for (op, data) in diffs:
+ if op != self.DIFF_INSERT:
+ text.append(data)
+ return "".join(text)
+
+ def diff_text2(self, diffs):
+ """Compute and return the destination text (all equalities and insertions).
+
+ Args:
+ diffs: Array of diff tuples.
+
+ Returns:
+ Destination text.
+ """
+ text = []
+ for (op, data) in diffs:
+ if op != self.DIFF_DELETE:
+ text.append(data)
+ return "".join(text)
+
+ def diff_levenshtein(self, diffs):
+ """Compute the Levenshtein distance; the number of inserted, deleted or
+ substituted characters.
+
+ Args:
+ diffs: Array of diff tuples.
+
+ Returns:
+ Number of changes.
+ """
+ levenshtein = 0
+ insertions = 0
+ deletions = 0
+ for (op, data) in diffs:
+ if op == self.DIFF_INSERT:
+ insertions += len(data)
+ elif op == self.DIFF_DELETE:
+ deletions += len(data)
+ elif op == self.DIFF_EQUAL:
+ # A deletion and an insertion is one substitution.
+ levenshtein += max(insertions, deletions)
+ insertions = 0
+ deletions = 0
+ levenshtein += max(insertions, deletions)
+ return levenshtein
+
+ def diff_toDelta(self, 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.
+
+ Args:
+ diffs: Array of diff tuples.
+
+ Returns:
+ Delta text.
+ """
+ text = []
+ for (op, data) in diffs:
+ if op == self.DIFF_INSERT:
+ # High ascii will raise UnicodeDecodeError. Use Unicode instead.
+ data = data.encode("utf-8")
+ text.append("+" + urllib.quote(data, "!~*'();/?:@&=+$,# "))
+ elif op == self.DIFF_DELETE:
+ text.append("-%d" % len(data))
+ elif op == self.DIFF_EQUAL:
+ text.append("=%d" % len(data))
+ return "\t".join(text)
+
+ def diff_fromDelta(self, text1, delta):
+ """Given the original text1, and an encoded string which describes the
+ operations required to transform text1 into text2, compute the full diff.
+
+ Args:
+ text1: Source string for the diff.
+ delta: Delta text.
+
+ Returns:
+ Array of diff tuples.
+
+ Raises:
+ ValueError: If invalid input.
+ """
+ if type(delta) == unicode:
+ # Deltas should be composed of a subset of ascii chars, Unicode not
+ # required. If this encode raises UnicodeEncodeError, delta is invalid.
+ delta = delta.encode("ascii")
+ diffs = []
+ pointer = 0 # Cursor in text1
+ tokens = delta.split("\t")
+ for token in tokens:
+ if token == "":
+ # 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).
+ param = token[1:]
+ if token[0] == "+":
+ param = urllib.unquote(param).decode("utf-8")
+ diffs.append((self.DIFF_INSERT, param))
+ elif token[0] == "-" or token[0] == "=":
+ try:
+ n = int(param)
+ except ValueError:
+ raise ValueError("Invalid number in diff_fromDelta: " + param)
+ if n < 0:
+ raise ValueError("Negative number in diff_fromDelta: " + param)
+ text = text1[pointer : pointer + n]
+ pointer += n
+ if token[0] == "=":
+ diffs.append((self.DIFF_EQUAL, text))
+ else:
+ diffs.append((self.DIFF_DELETE, text))
+ else:
+ # Anything else is an error.
+ raise ValueError("Invalid diff operation in diff_fromDelta: " +
+ token[0])
+ if pointer != len(text1):
+ raise ValueError(
+ "Delta length (%d) does not equal source text length (%d)." %
+ (pointer, len(text1)))
+ return diffs
+
+ # MATCH FUNCTIONS
+
+ def match_main(self, text, pattern, loc):
+ """Locate the best instance of 'pattern' in 'text' near 'loc'.
+
+ Args:
+ text: The text to search.
+ pattern: The pattern to search for.
+ loc: The location to search around.
+
+ Returns:
+ Best match index or -1.
+ """
+ # Check for null inputs.
+ if text == None or pattern == None:
+ raise ValueError("Null inputs. (match_main)")
+
+ loc = max(0, min(loc, len(text)))
+ if text == pattern:
+ # Shortcut (potentially not guaranteed by the algorithm)
+ return 0
+ elif not text:
+ # Nothing to match.
+ return -1
+ elif text[loc:loc + len(pattern)] == pattern:
+ # Perfect match at the perfect spot! (Includes case of null pattern)
+ return loc
+ else:
+ # Do a fuzzy compare.
+ match = self.match_bitap(text, pattern, loc)
+ return match
+
+ def match_bitap(self, text, pattern, loc):
+ """Locate the best instance of 'pattern' in 'text' near 'loc' using the
+ Bitap algorithm.
+
+ Args:
+ text: The text to search.
+ pattern: The pattern to search for.
+ loc: The location to search around.
+
+ Returns:
+ Best match index or -1.
+ """
+ # Python doesn't have a maxint limit, so ignore this check.
+ #if self.Match_MaxBits != 0 and len(pattern) > self.Match_MaxBits:
+ # raise ValueError("Pattern too long for this application.")
+
+ # Initialise the alphabet.
+ s = self.match_alphabet(pattern)
+
+ def match_bitapScore(e, x):
+ """Compute and return the score for a match with e errors and x location.
+ Accesses loc and pattern through being a closure.
+
+ Args:
+ e: Number of errors in match.
+ x: Location of match.
+
+ Returns:
+ Overall score for match (0.0 = good, 1.0 = bad).
+ """
+ accuracy = float(e) / len(pattern)
+ proximity = abs(loc - x)
+ if not self.Match_Distance:
+ # Dodge divide by zero error.
+ return proximity and 1.0 or accuracy
+ return accuracy + (proximity / float(self.Match_Distance))
+
+ # Highest score beyond which we give up.
+ score_threshold = self.Match_Threshold
+ # Is there a nearby exact match? (speedup)
+ best_loc = text.find(pattern, loc)
+ if best_loc != -1:
+ score_threshold = min(match_bitapScore(0, best_loc), score_threshold)
+ # What about in the other direction? (speedup)
+ best_loc = text.rfind(pattern, loc + len(pattern))
+ if best_loc != -1:
+ score_threshold = min(match_bitapScore(0, best_loc), score_threshold)
+
+ # Initialise the bit arrays.
+ matchmask = 1 << (len(pattern) - 1)
+ best_loc = -1
+
+ bin_max = len(pattern) + len(text)
+ # Empty initialization added to appease pychecker.
+ last_rd = None
+ for d in xrange(len(pattern)):
+ # 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) <= 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
+ start = max(1, loc - bin_mid + 1)
+ finish = min(loc + bin_mid, len(text)) + len(pattern)
+
+ rd = range(finish + 1)
+ rd.append((1 << d) - 1)
+ for j in xrange(finish, start - 1, -1):
+ if len(text) <= j - 1:
+ # Out of range.
+ charMatch = 0
+ else:
+ charMatch = s.get(text[j - 1], 0)
+ 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:
+ score = match_bitapScore(d, j - 1)
+ # 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 = max(1, 2 * loc - best_loc)
+ else:
+ # Already passed loc, downhill from here on in.
+ break
+ # No hope for a (better) match at greater error levels.
+ if match_bitapScore(d + 1, loc) > score_threshold:
+ break
+ last_rd = rd
+ return best_loc
+
+ def match_alphabet(self, pattern):
+ """Initialise the alphabet for the Bitap algorithm.
+
+ Args:
+ pattern: The text to encode.
+
+ Returns:
+ Hash of character locations.
+ """
+ s = {}
+ for char in pattern:
+ s[char] = 0
+ for i in xrange(len(pattern)):
+ s[pattern[i]] |= 1 << (len(pattern) - i - 1)
+ return s
+
+ # PATCH FUNCTIONS
+
+ def patch_addContext(self, patch, text):
+ """Increase the context until it is unique,
+ but don't let the pattern expand beyond Match_MaxBits.
+
+ Args:
+ patch: The patch to grow.
+ text: Source text.
+ """
+ if len(text) == 0:
+ return
+ pattern = text[patch.start2 : patch.start2 + patch.length1]
+ 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.find(pattern) != text.rfind(pattern) and (self.Match_MaxBits ==
+ 0 or len(pattern) < self.Match_MaxBits - self.Patch_Margin -
+ self.Patch_Margin)):
+ padding += self.Patch_Margin
+ pattern = text[max(0, patch.start2 - padding) :
+ patch.start2 + patch.length1 + padding]
+ # Add one chunk for good luck.
+ padding += self.Patch_Margin
+
+ # Add the prefix.
+ prefix = text[max(0, patch.start2 - padding) : patch.start2]
+ if prefix:
+ patch.diffs[:0] = [(self.DIFF_EQUAL, prefix)]
+ # Add the suffix.
+ suffix = text[patch.start2 + patch.length1 :
+ patch.start2 + patch.length1 + padding]
+ if suffix:
+ patch.diffs.append((self.DIFF_EQUAL, suffix))
+
+ # Roll back the start points.
+ patch.start1 -= len(prefix)
+ patch.start2 -= len(prefix)
+ # Extend lengths.
+ patch.length1 += len(prefix) + len(suffix)
+ patch.length2 += len(prefix) + len(suffix)
+
+ def patch_make(self, a, b=None, c=None):
+ """Compute a list of patches to turn text1 into text2.
+ Use diffs if provided, otherwise compute it ourselves.
+ There are four ways to call this function, depending on what data is
+ available to the caller:
+ Method 1:
+ a = text1, b = text2
+ Method 2:
+ a = diffs
+ Method 3 (optimal):
+ a = text1, b = diffs
+ Method 4 (deprecated, use method 3):
+ a = text1, b = text2, c = diffs
+
+ Args:
+ a: text1 (methods 1,3,4) or Array of diff tuples for text1 to
+ text2 (method 2).
+ b: text2 (methods 1,4) or Array of diff tuples for text1 to
+ text2 (method 3) or undefined (method 2).
+ c: Array of diff tuples for text1 to text2 (method 4) or
+ undefined (methods 1,2,3).
+
+ Returns:
+ Array of patch objects.
+ """
+ text1 = None
+ diffs = None
+ # Note that texts may arrive as 'str' or 'unicode'.
+ if isinstance(a, basestring) and isinstance(b, basestring) and c is None:
+ # Method 1: text1, text2
+ # Compute diffs from text1 and text2.
+ text1 = a
+ diffs = self.diff_main(text1, b, True)
+ if len(diffs) > 2:
+ self.diff_cleanupSemantic(diffs)
+ self.diff_cleanupEfficiency(diffs)
+ elif isinstance(a, list) and b is None and c is None:
+ # Method 2: diffs
+ # Compute text1 from diffs.
+ diffs = a
+ text1 = self.diff_text1(diffs)
+ elif isinstance(a, basestring) and isinstance(b, list) and c is None:
+ # Method 3: text1, diffs
+ text1 = a
+ diffs = b
+ elif (isinstance(a, basestring) and isinstance(b, basestring) and
+ isinstance(c, list)):
+ # Method 4: text1, text2, diffs
+ # text2 is not used.
+ text1 = a
+ diffs = c
+ else:
+ raise ValueError("Unknown call format to patch_make.")
+
+ if not diffs:
+ return [] # Get rid of the None case.
+ patches = []
+ patch = patch_obj()
+ char_count1 = 0 # Number of characters into the text1 string.
+ char_count2 = 0 # Number of characters into the text2 string.
+ prepatch_text = text1 # Recreate the patches to determine context info.
+ postpatch_text = text1
+ for x in xrange(len(diffs)):
+ (diff_type, diff_text) = diffs[x]
+ if len(patch.diffs) == 0 and diff_type != self.DIFF_EQUAL:
+ # A new patch starts here.
+ patch.start1 = char_count1
+ patch.start2 = char_count2
+ if diff_type == self.DIFF_INSERT:
+ # Insertion
+ patch.diffs.append(diffs[x])
+ patch.length2 += len(diff_text)
+ postpatch_text = (postpatch_text[:char_count2] + diff_text +
+ postpatch_text[char_count2:])
+ elif diff_type == self.DIFF_DELETE:
+ # Deletion.
+ patch.length1 += len(diff_text)
+ patch.diffs.append(diffs[x])
+ postpatch_text = (postpatch_text[:char_count2] +
+ postpatch_text[char_count2 + len(diff_text):])
+ elif (diff_type == self.DIFF_EQUAL and
+ len(diff_text) <= 2 * self.Patch_Margin and
+ len(patch.diffs) != 0 and len(diffs) != x + 1):
+ # Small equality inside a patch.
+ patch.diffs.append(diffs[x])
+ patch.length1 += len(diff_text)
+ patch.length2 += len(diff_text)
+
+ if (diff_type == self.DIFF_EQUAL and
+ len(diff_text) >= 2 * self.Patch_Margin):
+ # Time for a new patch.
+ if len(patch.diffs) != 0:
+ self.patch_addContext(patch, prepatch_text)
+ patches.append(patch)
+ patch = patch_obj()
+ # 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
+
+ # Update the current character count.
+ if diff_type != self.DIFF_INSERT:
+ char_count1 += len(diff_text)
+ if diff_type != self.DIFF_DELETE:
+ char_count2 += len(diff_text)
+
+ # Pick up the leftover patch if not empty.
+ if len(patch.diffs) != 0:
+ self.patch_addContext(patch, prepatch_text)
+ patches.append(patch)
+ return patches
+
+ def patch_deepCopy(self, patches):
+ """Given an array of patches, return another array that is identical.
+
+ Args:
+ patches: Array of patch objects.
+
+ Returns:
+ Array of patch objects.
+ """
+ patchesCopy = []
+ for patch in patches:
+ patchCopy = patch_obj()
+ # No need to deep copy the tuples since they are immutable.
+ patchCopy.diffs = patch.diffs[:]
+ patchCopy.start1 = patch.start1
+ patchCopy.start2 = patch.start2
+ patchCopy.length1 = patch.length1
+ patchCopy.length2 = patch.length2
+ patchesCopy.append(patchCopy)
+ return patchesCopy
+
+ def patch_apply(self, patches, text):
+ """Merge a set of patches onto the text. Return a patched text, as well
+ as a list of true/false values indicating which patches were applied.
+
+ Args:
+ patches: Array of patch objects.
+ text: Old text.
+
+ Returns:
+ Two element Array, containing the new text and an array of boolean values.
+ """
+ if not patches:
+ return (text, [])
+
+ # Deep copy the patches so that no changes are made to originals.
+ patches = self.patch_deepCopy(patches)
+
+ nullPadding = self.patch_addPadding(patches)
+ text = nullPadding + text + nullPadding
+ self.patch_splitMax(patches)
+
+ # 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.
+ delta = 0
+ results = []
+ for patch in patches:
+ expected_loc = patch.start2 + delta
+ text1 = self.diff_text1(patch.diffs)
+ end_loc = -1
+ if len(text1) > self.Match_MaxBits:
+ # patch_splitMax will only provide an oversized pattern in the case of
+ # a monster delete.
+ start_loc = self.match_main(text, text1[:self.Match_MaxBits],
+ expected_loc)
+ if start_loc != -1:
+ end_loc = self.match_main(text, text1[-self.Match_MaxBits:],
+ expected_loc + len(text1) - self.Match_MaxBits)
+ if end_loc == -1 or start_loc >= end_loc:
+ # Can't find valid trailing context. Drop this patch.
+ start_loc = -1
+ else:
+ start_loc = self.match_main(text, text1, expected_loc)
+ if start_loc == -1:
+ # No match found. :(
+ results.append(False)
+ # Subtract the delta for this failed patch from subsequent patches.
+ delta -= patch.length2 - patch.length1
+ else:
+ # Found a match. :)
+ results.append(True)
+ delta = start_loc - expected_loc
+ if end_loc == -1:
+ text2 = text[start_loc : start_loc + len(text1)]
+ else:
+ text2 = text[start_loc : end_loc + self.Match_MaxBits]
+ if text1 == text2:
+ # Perfect match, just shove the replacement text in.
+ text = (text[:start_loc] + self.diff_text2(patch.diffs) +
+ text[start_loc + len(text1):])
+ else:
+ # Imperfect match.
+ # Run a diff to get a framework of equivalent indices.
+ diffs = self.diff_main(text1, text2, False)
+ if (len(text1) > self.Match_MaxBits and
+ self.diff_levenshtein(diffs) / float(len(text1)) >
+ self.Patch_DeleteThreshold):
+ # The end points match, but the content is unacceptably bad.
+ results[-1] = False
+ else:
+ self.diff_cleanupSemanticLossless(diffs)
+ index1 = 0
+ for (op, data) in patch.diffs:
+ if op != self.DIFF_EQUAL:
+ index2 = self.diff_xIndex(diffs, index1)
+ if op == self.DIFF_INSERT: # Insertion
+ text = text[:start_loc + index2] + data + text[start_loc +
+ index2:]
+ elif op == self.DIFF_DELETE: # Deletion
+ text = text[:start_loc + index2] + text[start_loc +
+ self.diff_xIndex(diffs, index1 + len(data)):]
+ if op != self.DIFF_DELETE:
+ index1 += len(data)
+ # Strip the padding off.
+ text = text[len(nullPadding):-len(nullPadding)]
+ return (text, results)
+
+ def patch_addPadding(self, patches):
+ """Add some padding on text start and end so that edges can match
+ something. Intended to be called only from within patch_apply.
+
+ Args:
+ patches: Array of patch objects.
+
+ Returns:
+ The padding string added to each side.
+ """
+ paddingLength = self.Patch_Margin
+ nullPadding = ""
+ for x in xrange(1, paddingLength + 1):
+ nullPadding += chr(x)
+
+ # Bump all the patches forward.
+ for patch in patches:
+ patch.start1 += paddingLength
+ patch.start2 += paddingLength
+
+ # Add some padding on start of first diff.
+ patch = patches[0]
+ diffs = patch.diffs
+ if not diffs or diffs[0][0] != self.DIFF_EQUAL:
+ # Add nullPadding equality.
+ diffs.insert(0, (self.DIFF_EQUAL, nullPadding))
+ patch.start1 -= paddingLength # Should be 0.
+ patch.start2 -= paddingLength # Should be 0.
+ patch.length1 += paddingLength
+ patch.length2 += paddingLength
+ elif paddingLength > len(diffs[0][1]):
+ # Grow first equality.
+ extraLength = paddingLength - len(diffs[0][1])
+ newText = nullPadding[len(diffs[0][1]):] + diffs[0][1]
+ diffs[0] = (diffs[0][0], newText)
+ patch.start1 -= extraLength
+ patch.start2 -= extraLength
+ patch.length1 += extraLength
+ patch.length2 += extraLength
+
+ # Add some padding on end of last diff.
+ patch = patches[-1]
+ diffs = patch.diffs
+ if not diffs or diffs[-1][0] != self.DIFF_EQUAL:
+ # Add nullPadding equality.
+ diffs.append((self.DIFF_EQUAL, nullPadding))
+ patch.length1 += paddingLength
+ patch.length2 += paddingLength
+ elif paddingLength > len(diffs[-1][1]):
+ # Grow last equality.
+ extraLength = paddingLength - len(diffs[-1][1])
+ newText = diffs[-1][1] + nullPadding[:extraLength]
+ diffs[-1] = (diffs[-1][0], newText)
+ patch.length1 += extraLength
+ patch.length2 += extraLength
+
+ return nullPadding
+
+ def patch_splitMax(self, patches):
+ """Look through the patches and break up any which are longer than the
+ maximum limit of the match algorithm.
+
+ Args:
+ patches: Array of patch objects.
+ """
+ if self.Match_MaxBits == 0:
+ return
+ for x in xrange(len(patches)):
+ if patches[x].length1 > self.Match_MaxBits:
+ bigpatch = patches[x]
+ # Remove the big old patch.
+ del patches[x]
+ x -= 1
+ patch_size = self.Match_MaxBits
+ start1 = bigpatch.start1
+ start2 = bigpatch.start2
+ precontext = ''
+ while len(bigpatch.diffs) != 0:
+ # Create one of several smaller patches.
+ patch = patch_obj()
+ empty = True
+ patch.start1 = start1 - len(precontext)
+ patch.start2 = start2 - len(precontext)
+ if precontext:
+ patch.length1 = patch.length2 = len(precontext)
+ patch.diffs.append((self.DIFF_EQUAL, precontext))
+
+ while (len(bigpatch.diffs) != 0 and
+ patch.length1 < patch_size - self.Patch_Margin):
+ (diff_type, diff_text) = bigpatch.diffs[0]
+ if diff_type == self.DIFF_INSERT:
+ # Insertions are harmless.
+ patch.length2 += len(diff_text)
+ start2 += len(diff_text)
+ patch.diffs.append(bigpatch.diffs.pop(0))
+ empty = False
+ elif (diff_type == self.DIFF_DELETE and len(patch.diffs) == 1 and
+ patch.diffs[0][0] == self.DIFF_EQUAL and
+ len(diff_text) > 2 * patch_size):
+ # This is a large deletion. Let it pass in one chunk.
+ patch.length1 += len(diff_text)
+ start1 += len(diff_text)
+ empty = False
+ patch.diffs.append((diff_type, diff_text))
+ del bigpatch.diffs[0]
+ else:
+ # Deletion or equality. Only take as much as we can stomach.
+ diff_text = diff_text[:patch_size - patch.length1 -
+ self.Patch_Margin]
+ patch.length1 += len(diff_text)
+ start1 += len(diff_text)
+ if diff_type == self.DIFF_EQUAL:
+ patch.length2 += len(diff_text)
+ start2 += len(diff_text)
+ else:
+ empty = False
+
+ patch.diffs.append((diff_type, diff_text))
+ if diff_text == bigpatch.diffs[0][1]:
+ del bigpatch.diffs[0]
+ else:
+ bigpatch.diffs[0] = (bigpatch.diffs[0][0],
+ bigpatch.diffs[0][1][len(diff_text):])
+
+ # Compute the head context for the next patch.
+ precontext = self.diff_text2(patch.diffs)
+ precontext = precontext[-self.Patch_Margin:]
+ # Append the end context for this patch.
+ postcontext = self.diff_text1(bigpatch.diffs)[:self.Patch_Margin]
+ if postcontext:
+ patch.length1 += len(postcontext)
+ patch.length2 += len(postcontext)
+ if len(patch.diffs) != 0 and patch.diffs[-1][0] == self.DIFF_EQUAL:
+ patch.diffs[-1] = (self.DIFF_EQUAL, patch.diffs[-1][1] +
+ postcontext)
+ else:
+ patch.diffs.append((self.DIFF_EQUAL, postcontext))
+
+ if not empty:
+ x += 1
+ patches.insert(x, patch)
+
+ def patch_toText(self, patches):
+ """Take a list of patches and return a textual representation.
+
+ Args:
+ patches: Array of patch objects.
+
+ Returns:
+ Text representation of patches.
+ """
+ text = []
+ for patch in patches:
+ text.append(str(patch))
+ return "".join(text)
+
+ def patch_fromText(self, textline):
+ """Parse a textual representation of patches and return a list of patch
+ objects.
+
+ Args:
+ textline: Text representation of patches.
+
+ Returns:
+ Array of patch objects.
+
+ Raises:
+ ValueError: If invalid input.
+ """
+ if type(textline) == unicode:
+ # Patches should be composed of a subset of ascii chars, Unicode not
+ # required. If this encode raises UnicodeEncodeError, patch is invalid.
+ textline = textline.encode("ascii")
+ patches = []
+ if not textline:
+ return patches
+ text = textline.split('\n')
+ while len(text) != 0:
+ m = re.match("^@@ -(\d+),?(\d*) \+(\d+),?(\d*) @@$", text[0])
+ if not m:
+ raise ValueError("Invalid patch string: " + text[0])
+ patch = patch_obj()
+ patches.append(patch)
+ patch.start1 = int(m.group(1))
+ if m.group(2) == '':
+ patch.start1 -= 1
+ patch.length1 = 1
+ elif m.group(2) == '0':
+ patch.length1 = 0
+ else:
+ patch.start1 -= 1
+ patch.length1 = int(m.group(2))
+
+ patch.start2 = int(m.group(3))
+ if m.group(4) == '':
+ patch.start2 -= 1
+ patch.length2 = 1
+ elif m.group(4) == '0':
+ patch.length2 = 0
+ else:
+ patch.start2 -= 1
+ patch.length2 = int(m.group(4))
+
+ del text[0]
+
+ while len(text) != 0:
+ if text[0]:
+ sign = text[0][0]
+ else:
+ sign = ''
+ line = urllib.unquote(text[0][1:])
+ line = line.decode("utf-8")
+ if sign == '+':
+ # Insertion.
+ patch.diffs.append((self.DIFF_INSERT, line))
+ elif sign == '-':
+ # Deletion.
+ patch.diffs.append((self.DIFF_DELETE, line))
+ elif sign == ' ':
+ # Minor equality.
+ patch.diffs.append((self.DIFF_EQUAL, line))
+ elif sign == '@':
+ # Start of next patch.
+ break
+ elif sign == '':
+ # Blank line? Whatever.
+ pass
+ else:
+ # WTF?
+ raise ValueError("Invalid patch mode: '%s'\n%s" % (sign, line))
+ del text[0]
+ return patches
+
+
+class patch_obj:
+ """Class representing one patch operation.
+ """
+
+ def __init__(self):
+ """Initializes with an empty list of diffs.
+ """
+ self.diffs = []
+ self.start1 = None
+ self.start2 = None
+ self.length1 = 0
+ self.length2 = 0
+
+ def __str__(self):
+ """Emmulate GNU diff's format.
+ Header: @@ -382,8 +481,9 @@
+ Indicies are printed as 1-based, not 0-based.
+
+ Returns:
+ The GNU diff string.
+ """
+ if self.length1 == 0:
+ coords1 = str(self.start1) + ",0"
+ elif self.length1 == 1:
+ coords1 = str(self.start1 + 1)
+ else:
+ coords1 = str(self.start1 + 1) + "," + str(self.length1)
+ if self.length2 == 0:
+ coords2 = str(self.start2) + ",0"
+ elif self.length2 == 1:
+ coords2 = str(self.start2 + 1)
+ else:
+ coords2 = str(self.start2 + 1) + "," + str(self.length2)
+ text = ["@@ -", coords1, " +", coords2, " @@\n"]
+ # Escape the body of the patch with %xx notation.
+ for (op, data) in self.diffs:
+ if op == diff_match_patch.DIFF_INSERT:
+ text.append("+")
+ elif op == diff_match_patch.DIFF_DELETE:
+ text.append("-")
+ elif op == diff_match_patch.DIFF_EQUAL:
+ text.append(" ")
+ # High ascii will raise UnicodeDecodeError. Use Unicode instead.
+ data = data.encode("utf-8")
+ text.append(urllib.quote(data, "!~*'();/?:@&=+$,# ") + "\n")
+ return "".join(text)
projects / bookreader.git / commitdiff