overleaf/services/document-updater/app/lib/diff_match_patch.js

2341 lines
75 KiB
JavaScript

/* eslint-disable */
/**
* 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.
*/
/**
* @fileoverview Computes the difference between two texts to create a patch.
* Applies the patch onto another text, allowing for errors.
* @author fraser@google.com (Neil Fraser)
*/
/**
* Class containing the diff, match and patch methods.
* @constructor
*/
function diff_match_patch() {
// Defaults.
// Redefine these in your program to override the defaults.
// Number of seconds to map a diff before giving up (0 for infinity).
this.Diff_Timeout = 1.0
// Cost of an empty edit operation in terms of edit characters.
this.Diff_EditCost = 4
// At what point is no match declared (0.0 = perfection, 1.0 = very loose).
this.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).
this.Match_Distance = 1000
// When deleting a large block of text (over ~64 characters), how close do
// the contents have to be to match the expected contents. (0.0 = perfection,
// 1.0 = very loose). Note that Match_Threshold controls how closely the
// end points of a delete need to match.
this.Patch_DeleteThreshold = 0.5
// Chunk size for context length.
this.Patch_Margin = 4
// The number of bits in an int.
this.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.'
*/
var DIFF_DELETE = -1
var DIFF_INSERT = 1
var DIFF_EQUAL = 0
/** @typedef {{0: number, 1: string}} */
diff_match_patch.Diff
/**
* Find the differences between two texts. Simplifies the problem by stripping
* any common prefix or suffix off the texts before diffing.
* @param {string} text1 Old string to be diffed.
* @param {string} text2 New string to be diffed.
* @param {boolean=} opt_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.
* @param {number} opt_deadline Optional time when the diff should be complete
* by. Used internally for recursive calls. Users should set DiffTimeout
* instead.
* @return {!Array.<!diff_match_patch.Diff>} Array of diff tuples.
*/
diff_match_patch.prototype.diff_main = function (
text1,
text2,
opt_checklines,
opt_deadline
) {
// Set a deadline by which time the diff must be complete.
if (typeof opt_deadline == 'undefined') {
if (this.Diff_Timeout <= 0) {
opt_deadline = Number.MAX_VALUE
} else {
opt_deadline = new Date().getTime() + this.Diff_Timeout * 1000
}
}
var deadline = opt_deadline
// Check for null inputs.
if (text1 == null || text2 == null) {
throw new Error('Null input. (diff_main)')
}
// Check for equality (speedup).
if (text1 == text2) {
if (text1) {
return [[DIFF_EQUAL, text1]]
}
return []
}
if (typeof opt_checklines == 'undefined') {
opt_checklines = true
}
var checklines = opt_checklines
// Trim off common prefix (speedup).
var commonlength = this.diff_commonPrefix(text1, text2)
var commonprefix = text1.substring(0, commonlength)
text1 = text1.substring(commonlength)
text2 = text2.substring(commonlength)
// Trim off common suffix (speedup).
commonlength = this.diff_commonSuffix(text1, text2)
var commonsuffix = text1.substring(text1.length - commonlength)
text1 = text1.substring(0, text1.length - commonlength)
text2 = text2.substring(0, text2.length - commonlength)
// Compute the diff on the middle block.
var diffs = this.diff_compute_(text1, text2, checklines, deadline)
// Restore the prefix and suffix.
if (commonprefix) {
diffs.unshift([DIFF_EQUAL, commonprefix])
}
if (commonsuffix) {
diffs.push([DIFF_EQUAL, commonsuffix])
}
this.diff_cleanupMerge(diffs)
return diffs
}
/**
* Find the differences between two texts. Assumes that the texts do not
* have any common prefix or suffix.
* @param {string} text1 Old string to be diffed.
* @param {string} text2 New string to be diffed.
* @param {boolean} checklines Speedup flag. If false, then don't run a
* line-level diff first to identify the changed areas.
* If true, then run a faster, slightly less optimal diff.
* @param {number} deadline Time when the diff should be complete by.
* @return {!Array.<!diff_match_patch.Diff>} Array of diff tuples.
* @private
*/
diff_match_patch.prototype.diff_compute_ = function (
text1,
text2,
checklines,
deadline
) {
var diffs
if (!text1) {
// Just add some text (speedup).
return [[DIFF_INSERT, text2]]
}
if (!text2) {
// Just delete some text (speedup).
return [[DIFF_DELETE, text1]]
}
var longtext = text1.length > text2.length ? text1 : text2
var shorttext = text1.length > text2.length ? text2 : text1
var i = longtext.indexOf(shorttext)
if (i != -1) {
// Shorter text is inside the longer text (speedup).
diffs = [
[DIFF_INSERT, longtext.substring(0, i)],
[DIFF_EQUAL, shorttext],
[DIFF_INSERT, longtext.substring(i + shorttext.length)]
]
// Swap insertions for deletions if diff is reversed.
if (text1.length > text2.length) {
diffs[0][0] = diffs[2][0] = DIFF_DELETE
}
return diffs
}
if (shorttext.length == 1) {
// Single character string.
// After the previous speedup, the character can't be an equality.
return [
[DIFF_DELETE, text1],
[DIFF_INSERT, text2]
]
}
// Check to see if the problem can be split in two.
var hm = this.diff_halfMatch_(text1, text2)
if (hm) {
// A half-match was found, sort out the return data.
var text1_a = hm[0]
var text1_b = hm[1]
var text2_a = hm[2]
var text2_b = hm[3]
var mid_common = hm[4]
// Send both pairs off for separate processing.
var diffs_a = this.diff_main(text1_a, text2_a, checklines, deadline)
var diffs_b = this.diff_main(text1_b, text2_b, checklines, deadline)
// Merge the results.
return diffs_a.concat([[DIFF_EQUAL, mid_common]], diffs_b)
}
if (checklines && text1.length > 100 && text2.length > 100) {
return this.diff_lineMode_(text1, text2, deadline)
}
return this.diff_bisect_(text1, text2, deadline)
}
/**
* Do a quick line-level diff on both strings, then rediff the parts for
* greater accuracy.
* This speedup can produce non-minimal diffs.
* @param {string} text1 Old string to be diffed.
* @param {string} text2 New string to be diffed.
* @param {number} deadline Time when the diff should be complete by.
* @return {!Array.<!diff_match_patch.Diff>} Array of diff tuples.
* @private
*/
diff_match_patch.prototype.diff_lineMode_ = function (text1, text2, deadline) {
// Scan the text on a line-by-line basis first.
var a = this.diff_linesToChars_(text1, text2)
text1 = a.chars1
text2 = a.chars2
var linearray = a.lineArray
var diffs = this.diff_main(text1, text2, false, deadline)
// Convert the diff back to original text.
this.diff_charsToLines_(diffs, linearray)
// Eliminate freak matches (e.g. blank lines)
this.diff_cleanupSemantic(diffs)
// Rediff any replacement blocks, this time character-by-character.
// Add a dummy entry at the end.
diffs.push([DIFF_EQUAL, ''])
var pointer = 0
var count_delete = 0
var count_insert = 0
var text_delete = ''
var text_insert = ''
while (pointer < diffs.length) {
switch (diffs[pointer][0]) {
case DIFF_INSERT:
count_insert++
text_insert += diffs[pointer][1]
break
case DIFF_DELETE:
count_delete++
text_delete += diffs[pointer][1]
break
case DIFF_EQUAL:
// Upon reaching an equality, check for prior redundancies.
if (count_delete >= 1 && count_insert >= 1) {
// Delete the offending records and add the merged ones.
diffs.splice(
pointer - count_delete - count_insert,
count_delete + count_insert
)
pointer = pointer - count_delete - count_insert
var a = this.diff_main(text_delete, text_insert, false, deadline)
for (var j = a.length - 1; j >= 0; j--) {
diffs.splice(pointer, 0, a[j])
}
pointer = pointer + a.length
}
count_insert = 0
count_delete = 0
text_delete = ''
text_insert = ''
break
}
pointer++
}
diffs.pop() // Remove the dummy entry at the end.
return diffs
}
/**
* Find the 'middle snake' of a diff, split the problem in two
* and return the recursively constructed diff.
* See Myers 1986 paper: An O(ND) Difference Algorithm and Its Variations.
* @param {string} text1 Old string to be diffed.
* @param {string} text2 New string to be diffed.
* @param {number} deadline Time at which to bail if not yet complete.
* @return {!Array.<!diff_match_patch.Diff>} Array of diff tuples.
* @private
*/
diff_match_patch.prototype.diff_bisect_ = function (text1, text2, deadline) {
// Cache the text lengths to prevent multiple calls.
var text1_length = text1.length
var text2_length = text2.length
var max_d = Math.ceil((text1_length + text2_length) / 2)
var v_offset = max_d
var v_length = 2 * max_d
var v1 = new Array(v_length)
var v2 = new Array(v_length)
// Setting all elements to -1 is faster in Chrome & Firefox than mixing
// integers and undefined.
for (var x = 0; x < v_length; x++) {
v1[x] = -1
v2[x] = -1
}
v1[v_offset + 1] = 0
v2[v_offset + 1] = 0
var delta = text1_length - text2_length
// If the total number of characters is odd, then the front path will collide
// with the reverse path.
var front = delta % 2 != 0
// Offsets for start and end of k loop.
// Prevents mapping of space beyond the grid.
var k1start = 0
var k1end = 0
var k2start = 0
var k2end = 0
for (var d = 0; d < max_d; d++) {
// Bail out if deadline is reached.
if (new Date().getTime() > deadline) {
break
}
// Walk the front path one step.
for (var k1 = -d + k1start; k1 <= d - k1end; k1 += 2) {
var k1_offset = v_offset + k1
var x1
if (k1 == -d || (k1 != d && v1[k1_offset - 1] < v1[k1_offset + 1])) {
x1 = v1[k1_offset + 1]
} else {
x1 = v1[k1_offset - 1] + 1
}
var y1 = x1 - k1
while (
x1 < text1_length &&
y1 < text2_length &&
text1.charAt(x1) == text2.charAt(y1)
) {
x1++
y1++
}
v1[k1_offset] = x1
if (x1 > text1_length) {
// Ran off the right of the graph.
k1end += 2
} else if (y1 > text2_length) {
// Ran off the bottom of the graph.
k1start += 2
} else if (front) {
var 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.
var x2 = text1_length - v2[k2_offset]
if (x1 >= x2) {
// Overlap detected.
return this.diff_bisectSplit_(text1, text2, x1, y1, deadline)
}
}
}
}
// Walk the reverse path one step.
for (var k2 = -d + k2start; k2 <= d - k2end; k2 += 2) {
var k2_offset = v_offset + k2
var 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
}
var y2 = x2 - k2
while (
x2 < text1_length &&
y2 < text2_length &&
text1.charAt(text1_length - x2 - 1) ==
text2.charAt(text2_length - y2 - 1)
) {
x2++
y2++
}
v2[k2_offset] = x2
if (x2 > text1_length) {
// Ran off the left of the graph.
k2end += 2
} else if (y2 > text2_length) {
// Ran off the top of the graph.
k2start += 2
} else if (!front) {
var k1_offset = v_offset + delta - k2
if (k1_offset >= 0 && k1_offset < v_length && v1[k1_offset] != -1) {
var x1 = v1[k1_offset]
var y1 = v_offset + x1 - k1_offset
// Mirror x2 onto top-left coordinate system.
x2 = text1_length - x2
if (x1 >= x2) {
// Overlap detected.
return this.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.
return [
[DIFF_DELETE, text1],
[DIFF_INSERT, text2]
]
}
/**
* Given the location of the 'middle snake', split the diff in two parts
* and recurse.
* @param {string} text1 Old string to be diffed.
* @param {string} text2 New string to be diffed.
* @param {number} x Index of split point in text1.
* @param {number} y Index of split point in text2.
* @param {number} deadline Time at which to bail if not yet complete.
* @return {!Array.<!diff_match_patch.Diff>} Array of diff tuples.
* @private
*/
diff_match_patch.prototype.diff_bisectSplit_ = function (
text1,
text2,
x,
y,
deadline
) {
var text1a = text1.substring(0, x)
var text2a = text2.substring(0, y)
var text1b = text1.substring(x)
var text2b = text2.substring(y)
// Compute both diffs serially.
var diffs = this.diff_main(text1a, text2a, false, deadline)
var diffsb = this.diff_main(text1b, text2b, false, deadline)
return diffs.concat(diffsb)
}
/**
* Split two texts into an array of strings. Reduce the texts to a string of
* hashes where each Unicode character represents one line.
* @param {string} text1 First string.
* @param {string} text2 Second string.
* @return {{chars1: string, chars2: string, lineArray: !Array.<string>}}
* An object 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.
* @private
*/
diff_match_patch.prototype.diff_linesToChars_ = function (text1, text2) {
var lineArray = [] // e.g. lineArray[4] == 'Hello\n'
var 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[0] = ''
/**
* 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.
* @param {string} text String to encode.
* @return {string} Encoded string.
* @private
*/
function diff_linesToCharsMunge_(text) {
var 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.
var lineStart = 0
var lineEnd = -1
// Keeping our own length variable is faster than looking it up.
var lineArrayLength = lineArray.length
while (lineEnd < text.length - 1) {
lineEnd = text.indexOf('\n', lineStart)
if (lineEnd == -1) {
lineEnd = text.length - 1
}
var line = text.substring(lineStart, lineEnd + 1)
lineStart = lineEnd + 1
if (
lineHash.hasOwnProperty
? lineHash.hasOwnProperty(line)
: lineHash[line] !== undefined
) {
chars += String.fromCharCode(lineHash[line])
} else {
chars += String.fromCharCode(lineArrayLength)
lineHash[line] = lineArrayLength
lineArray[lineArrayLength++] = line
}
}
return chars
}
var chars1 = diff_linesToCharsMunge_(text1)
var chars2 = diff_linesToCharsMunge_(text2)
return { chars1: chars1, chars2: chars2, lineArray: lineArray }
}
/**
* Rehydrate the text in a diff from a string of line hashes to real lines of
* text.
* @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples.
* @param {!Array.<string>} lineArray Array of unique strings.
* @private
*/
diff_match_patch.prototype.diff_charsToLines_ = function (diffs, lineArray) {
for (var x = 0; x < diffs.length; x++) {
var chars = diffs[x][1]
var text = []
for (var y = 0; y < chars.length; y++) {
text[y] = lineArray[chars.charCodeAt(y)]
}
diffs[x][1] = text.join('')
}
}
/**
* Determine the common prefix of two strings.
* @param {string} text1 First string.
* @param {string} text2 Second string.
* @return {number} The number of characters common to the start of each
* string.
*/
diff_match_patch.prototype.diff_commonPrefix = function (text1, text2) {
// Quick check for common null cases.
if (!text1 || !text2 || text1.charAt(0) != text2.charAt(0)) {
return 0
}
// Binary search.
// Performance analysis: http://neil.fraser.name/news/2007/10/09/
var pointermin = 0
var pointermax = Math.min(text1.length, text2.length)
var pointermid = pointermax
var pointerstart = 0
while (pointermin < pointermid) {
if (
text1.substring(pointerstart, pointermid) ==
text2.substring(pointerstart, pointermid)
) {
pointermin = pointermid
pointerstart = pointermin
} else {
pointermax = pointermid
}
pointermid = Math.floor((pointermax - pointermin) / 2 + pointermin)
}
return pointermid
}
/**
* Determine the common suffix of two strings.
* @param {string} text1 First string.
* @param {string} text2 Second string.
* @return {number} The number of characters common to the end of each string.
*/
diff_match_patch.prototype.diff_commonSuffix = function (text1, text2) {
// Quick check for common null cases.
if (
!text1 ||
!text2 ||
text1.charAt(text1.length - 1) != text2.charAt(text2.length - 1)
) {
return 0
}
// Binary search.
// Performance analysis: http://neil.fraser.name/news/2007/10/09/
var pointermin = 0
var pointermax = Math.min(text1.length, text2.length)
var pointermid = pointermax
var pointerend = 0
while (pointermin < pointermid) {
if (
text1.substring(text1.length - pointermid, text1.length - pointerend) ==
text2.substring(text2.length - pointermid, text2.length - pointerend)
) {
pointermin = pointermid
pointerend = pointermin
} else {
pointermax = pointermid
}
pointermid = Math.floor((pointermax - pointermin) / 2 + pointermin)
}
return pointermid
}
/**
* Determine if the suffix of one string is the prefix of another.
* @param {string} text1 First string.
* @param {string} text2 Second string.
* @return {number} The number of characters common to the end of the first
* string and the start of the second string.
* @private
*/
diff_match_patch.prototype.diff_commonOverlap_ = function (text1, text2) {
// Cache the text lengths to prevent multiple calls.
var text1_length = text1.length
var 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)
}
var 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/
var best = 0
var length = 1
while (true) {
var pattern = text1.substring(text_length - length)
var found = text2.indexOf(pattern)
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 {string} text1 First string.
* @param {string} text2 Second string.
* @return {Array.<string>} 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 null if there was no match.
* @private
*/
diff_match_patch.prototype.diff_halfMatch_ = function (text1, text2) {
if (this.Diff_Timeout <= 0) {
// Don't risk returning a non-optimal diff if we have unlimited time.
return null
}
var longtext = text1.length > text2.length ? text1 : text2
var shorttext = text1.length > text2.length ? text2 : text1
if (longtext.length < 4 || shorttext.length * 2 < longtext.length) {
return null // Pointless.
}
var dmp = this // 'this' becomes 'window' in a closure.
/**
* 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.
* @param {string} longtext Longer string.
* @param {string} shorttext Shorter string.
* @param {number} i Start index of quarter length substring within longtext.
* @return {Array.<string>} 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 null if there was no match.
* @private
*/
function diff_halfMatchI_(longtext, shorttext, i) {
// Start with a 1/4 length substring at position i as a seed.
var seed = longtext.substring(i, i + Math.floor(longtext.length / 4))
var j = -1
var best_common = ''
var best_longtext_a, best_longtext_b, best_shorttext_a, best_shorttext_b
while ((j = shorttext.indexOf(seed, j + 1)) != -1) {
var prefixLength = dmp.diff_commonPrefix(
longtext.substring(i),
shorttext.substring(j)
)
var suffixLength = dmp.diff_commonSuffix(
longtext.substring(0, i),
shorttext.substring(0, j)
)
if (best_common.length < suffixLength + prefixLength) {
best_common =
shorttext.substring(j - suffixLength, j) +
shorttext.substring(j, j + prefixLength)
best_longtext_a = longtext.substring(0, i - suffixLength)
best_longtext_b = longtext.substring(i + prefixLength)
best_shorttext_a = shorttext.substring(0, j - suffixLength)
best_shorttext_b = shorttext.substring(j + prefixLength)
}
}
if (best_common.length * 2 >= longtext.length) {
return [
best_longtext_a,
best_longtext_b,
best_shorttext_a,
best_shorttext_b,
best_common
]
} else {
return null
}
}
// First check if the second quarter is the seed for a half-match.
var hm1 = diff_halfMatchI_(
longtext,
shorttext,
Math.ceil(longtext.length / 4)
)
// Check again based on the third quarter.
var hm2 = diff_halfMatchI_(
longtext,
shorttext,
Math.ceil(longtext.length / 2)
)
var hm
if (!hm1 && !hm2) {
return null
} else if (!hm2) {
hm = hm1
} else if (!hm1) {
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.
var text1_a, text1_b, text2_a, text2_b
if (text1.length > text2.length) {
text1_a = hm[0]
text1_b = hm[1]
text2_a = hm[2]
text2_b = hm[3]
} else {
text2_a = hm[0]
text2_b = hm[1]
text1_a = hm[2]
text1_b = hm[3]
}
var mid_common = hm[4]
return [text1_a, text1_b, text2_a, text2_b, mid_common]
}
/**
* Reduce the number of edits by eliminating semantically trivial equalities.
* @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples.
*/
diff_match_patch.prototype.diff_cleanupSemantic = function (diffs) {
var changes = false
var equalities = [] // Stack of indices where equalities are found.
var equalitiesLength = 0 // Keeping our own length var is faster in JS.
/** @type {?string} */
var lastequality = null
// Always equal to diffs[equalities[equalitiesLength - 1]][1]
var pointer = 0 // Index of current position.
// Number of characters that changed prior to the equality.
var length_insertions1 = 0
var length_deletions1 = 0
// Number of characters that changed after the equality.
var length_insertions2 = 0
var length_deletions2 = 0
while (pointer < diffs.length) {
if (diffs[pointer][0] == DIFF_EQUAL) {
// Equality found.
equalities[equalitiesLength++] = pointer
length_insertions1 = length_insertions2
length_deletions1 = length_deletions2
length_insertions2 = 0
length_deletions2 = 0
lastequality = diffs[pointer][1]
} else {
// An insertion or deletion.
if (diffs[pointer][0] == DIFF_INSERT) {
length_insertions2 += diffs[pointer][1].length
} else {
length_deletions2 += diffs[pointer][1].length
}
// Eliminate an equality that is smaller or equal to the edits on both
// sides of it.
if (
lastequality &&
lastequality.length <=
Math.max(length_insertions1, length_deletions1) &&
lastequality.length <= Math.max(length_insertions2, length_deletions2)
) {
// Duplicate record.
diffs.splice(equalities[equalitiesLength - 1], 0, [
DIFF_DELETE,
lastequality
])
// Change second copy to insert.
diffs[equalities[equalitiesLength - 1] + 1][0] = DIFF_INSERT
// Throw away the equality we just deleted.
equalitiesLength--
// Throw away the previous equality (it needs to be reevaluated).
equalitiesLength--
pointer = equalitiesLength > 0 ? equalities[equalitiesLength - 1] : -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) {
this.diff_cleanupMerge(diffs)
}
this.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.length) {
if (
diffs[pointer - 1][0] == DIFF_DELETE &&
diffs[pointer][0] == DIFF_INSERT
) {
var deletion = diffs[pointer - 1][1]
var insertion = diffs[pointer][1]
var overlap_length1 = this.diff_commonOverlap_(deletion, insertion)
var overlap_length2 = this.diff_commonOverlap_(insertion, deletion)
if (overlap_length1 >= overlap_length2) {
if (
overlap_length1 >= deletion.length / 2 ||
overlap_length1 >= insertion.length / 2
) {
// Overlap found. Insert an equality and trim the surrounding edits.
diffs.splice(pointer, 0, [
DIFF_EQUAL,
insertion.substring(0, overlap_length1)
])
diffs[pointer - 1][1] = deletion.substring(
0,
deletion.length - overlap_length1
)
diffs[pointer + 1][1] = insertion.substring(overlap_length1)
pointer++
}
} else {
if (
overlap_length2 >= deletion.length / 2 ||
overlap_length2 >= insertion.length / 2
) {
// Reverse overlap found.
// Insert an equality and swap and trim the surrounding edits.
diffs.splice(pointer, 0, [
DIFF_EQUAL,
deletion.substring(0, overlap_length2)
])
diffs[pointer - 1][0] = DIFF_INSERT
diffs[pointer - 1][1] = insertion.substring(
0,
insertion.length - overlap_length2
)
diffs[pointer + 1][0] = DIFF_DELETE
diffs[pointer + 1][1] = 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 {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples.
*/
diff_match_patch.prototype.diff_cleanupSemanticLossless = function (diffs) {
/**
* Given two strings, compute a score representing whether the internal
* boundary falls on logical boundaries.
* Scores range from 6 (best) to 0 (worst).
* Closure, but does not reference any external variables.
* @param {string} one First string.
* @param {string} two Second string.
* @return {number} The score.
* @private
*/
function diff_cleanupSemanticScore_(one, two) {
if (!one || !two) {
// 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.
var char1 = one.charAt(one.length - 1)
var char2 = two.charAt(0)
var nonAlphaNumeric1 = char1.match(diff_match_patch.nonAlphaNumericRegex_)
var nonAlphaNumeric2 = char2.match(diff_match_patch.nonAlphaNumericRegex_)
var whitespace1 =
nonAlphaNumeric1 && char1.match(diff_match_patch.whitespaceRegex_)
var whitespace2 =
nonAlphaNumeric2 && char2.match(diff_match_patch.whitespaceRegex_)
var lineBreak1 =
whitespace1 && char1.match(diff_match_patch.linebreakRegex_)
var lineBreak2 =
whitespace2 && char2.match(diff_match_patch.linebreakRegex_)
var blankLine1 =
lineBreak1 && one.match(diff_match_patch.blanklineEndRegex_)
var blankLine2 =
lineBreak2 && two.match(diff_match_patch.blanklineStartRegex_)
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
}
var pointer = 1
// Intentionally ignore the first and last element (don't need checking).
while (pointer < diffs.length - 1) {
if (
diffs[pointer - 1][0] == DIFF_EQUAL &&
diffs[pointer + 1][0] == DIFF_EQUAL
) {
// This is a single edit surrounded by equalities.
var equality1 = diffs[pointer - 1][1]
var edit = diffs[pointer][1]
var equality2 = diffs[pointer + 1][1]
// First, shift the edit as far left as possible.
var commonOffset = this.diff_commonSuffix(equality1, edit)
if (commonOffset) {
var 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.
var bestEquality1 = equality1
var bestEdit = edit
var bestEquality2 = equality2
var bestScore =
diff_cleanupSemanticScore_(equality1, edit) +
diff_cleanupSemanticScore_(edit, equality2)
while (edit.charAt(0) === equality2.charAt(0)) {
equality1 += edit.charAt(0)
edit = edit.substring(1) + equality2.charAt(0)
equality2 = equality2.substring(1)
var 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][1] = bestEquality1
} else {
diffs.splice(pointer - 1, 1)
pointer--
}
diffs[pointer][1] = bestEdit
if (bestEquality2) {
diffs[pointer + 1][1] = bestEquality2
} else {
diffs.splice(pointer + 1, 1)
pointer--
}
}
}
pointer++
}
}
// Define some regex patterns for matching boundaries.
diff_match_patch.nonAlphaNumericRegex_ = /[^a-zA-Z0-9]/
diff_match_patch.whitespaceRegex_ = /\s/
diff_match_patch.linebreakRegex_ = /[\r\n]/
diff_match_patch.blanklineEndRegex_ = /\n\r?\n$/
diff_match_patch.blanklineStartRegex_ = /^\r?\n\r?\n/
/**
* Reduce the number of edits by eliminating operationally trivial equalities.
* @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples.
*/
diff_match_patch.prototype.diff_cleanupEfficiency = function (diffs) {
var changes = false
var equalities = [] // Stack of indices where equalities are found.
var equalitiesLength = 0 // Keeping our own length var is faster in JS.
/** @type {?string} */
var lastequality = null
// Always equal to diffs[equalities[equalitiesLength - 1]][1]
var pointer = 0 // Index of current position.
// Is there an insertion operation before the last equality.
var pre_ins = false
// Is there a deletion operation before the last equality.
var pre_del = false
// Is there an insertion operation after the last equality.
var post_ins = false
// Is there a deletion operation after the last equality.
var post_del = false
while (pointer < diffs.length) {
if (diffs[pointer][0] == DIFF_EQUAL) {
// Equality found.
if (
diffs[pointer][1].length < this.Diff_EditCost &&
(post_ins || post_del)
) {
// Candidate found.
equalities[equalitiesLength++] = pointer
pre_ins = post_ins
pre_del = post_del
lastequality = diffs[pointer][1]
} else {
// Not a candidate, and can never become one.
equalitiesLength = 0
lastequality = null
}
post_ins = post_del = false
} else {
// An insertion or deletion.
if (diffs[pointer][0] == 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 &&
((pre_ins && pre_del && post_ins && post_del) ||
(lastequality.length < this.Diff_EditCost / 2 &&
pre_ins + pre_del + post_ins + post_del == 3))
) {
// Duplicate record.
diffs.splice(equalities[equalitiesLength - 1], 0, [
DIFF_DELETE,
lastequality
])
// Change second copy to insert.
diffs[equalities[equalitiesLength - 1] + 1][0] = DIFF_INSERT
equalitiesLength-- // Throw away the equality we just deleted;
lastequality = null
if (pre_ins && pre_del) {
// No changes made which could affect previous entry, keep going.
post_ins = post_del = true
equalitiesLength = 0
} else {
equalitiesLength-- // Throw away the previous equality.
pointer = equalitiesLength > 0 ? equalities[equalitiesLength - 1] : -1
post_ins = post_del = false
}
changes = true
}
}
pointer++
}
if (changes) {
this.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 {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples.
*/
diff_match_patch.prototype.diff_cleanupMerge = function (diffs) {
diffs.push([DIFF_EQUAL, '']) // Add a dummy entry at the end.
var pointer = 0
var count_delete = 0
var count_insert = 0
var text_delete = ''
var text_insert = ''
var commonlength
while (pointer < diffs.length) {
switch (diffs[pointer][0]) {
case DIFF_INSERT:
count_insert++
text_insert += diffs[pointer][1]
pointer++
break
case DIFF_DELETE:
count_delete++
text_delete += diffs[pointer][1]
pointer++
break
case DIFF_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][0] ==
DIFF_EQUAL
) {
diffs[
pointer - count_delete - count_insert - 1
][1] += text_insert.substring(0, commonlength)
} else {
diffs.splice(0, 0, [
DIFF_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][1] =
text_insert.substring(text_insert.length - commonlength) +
diffs[pointer][1]
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, [
DIFF_INSERT,
text_insert
])
} else if (count_insert === 0) {
diffs.splice(pointer - count_delete, count_delete + count_insert, [
DIFF_DELETE,
text_delete
])
} else {
diffs.splice(
pointer - count_delete - count_insert,
count_delete + count_insert,
[DIFF_DELETE, text_delete],
[DIFF_INSERT, text_insert]
)
}
pointer =
pointer -
count_delete -
count_insert +
(count_delete ? 1 : 0) +
(count_insert ? 1 : 0) +
1
} else if (pointer !== 0 && diffs[pointer - 1][0] == DIFF_EQUAL) {
// Merge this equality with the previous one.
diffs[pointer - 1][1] += diffs[pointer][1]
diffs.splice(pointer, 1)
} else {
pointer++
}
count_insert = 0
count_delete = 0
text_delete = ''
text_insert = ''
break
}
}
if (diffs[diffs.length - 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
var changes = false
pointer = 1
// Intentionally ignore the first and last element (don't need checking).
while (pointer < diffs.length - 1) {
if (
diffs[pointer - 1][0] == DIFF_EQUAL &&
diffs[pointer + 1][0] == DIFF_EQUAL
) {
// This is a single edit surrounded by equalities.
if (
diffs[pointer][1].substring(
diffs[pointer][1].length - diffs[pointer - 1][1].length
) == diffs[pointer - 1][1]
) {
// Shift the edit over the previous equality.
diffs[pointer][1] =
diffs[pointer - 1][1] +
diffs[pointer][1].substring(
0,
diffs[pointer][1].length - diffs[pointer - 1][1].length
)
diffs[pointer + 1][1] = diffs[pointer - 1][1] + diffs[pointer + 1][1]
diffs.splice(pointer - 1, 1)
changes = true
} else if (
diffs[pointer][1].substring(0, diffs[pointer + 1][1].length) ==
diffs[pointer + 1][1]
) {
// Shift the edit over the next equality.
diffs[pointer - 1][1] += diffs[pointer + 1][1]
diffs[pointer][1] =
diffs[pointer][1].substring(diffs[pointer + 1][1].length) +
diffs[pointer + 1][1]
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, compute and return the equivalent location in
* text2.
* e.g. 'The cat' vs 'The big cat', 1->1, 5->8
* @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples.
* @param {number} loc Location within text1.
* @return {number} Location within text2.
*/
diff_match_patch.prototype.diff_xIndex = function (diffs, loc) {
var chars1 = 0
var chars2 = 0
var last_chars1 = 0
var last_chars2 = 0
var x
for (x = 0; x < diffs.length; x++) {
if (diffs[x][0] !== DIFF_INSERT) {
// Equality or deletion.
chars1 += diffs[x][1].length
}
if (diffs[x][0] !== DIFF_DELETE) {
// Equality or insertion.
chars2 += diffs[x][1].length
}
if (chars1 > loc) {
// Overshot the location.
break
}
last_chars1 = chars1
last_chars2 = chars2
}
// Was the location was deleted?
if (diffs.length != x && diffs[x][0] === DIFF_DELETE) {
return last_chars2
}
// Add the remaining character length.
return last_chars2 + (loc - last_chars1)
}
/**
* Convert a diff array into a pretty HTML report.
* @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples.
* @return {string} HTML representation.
*/
diff_match_patch.prototype.diff_prettyHtml = function (diffs) {
var html = []
var pattern_amp = /&/g
var pattern_lt = /</g
var pattern_gt = />/g
var pattern_para = /\n/g
for (var x = 0; x < diffs.length; x++) {
var op = diffs[x][0] // Operation (insert, delete, equal)
var data = diffs[x][1] // Text of change.
var text = data
.replace(pattern_amp, '&amp;')
.replace(pattern_lt, '&lt;')
.replace(pattern_gt, '&gt;')
.replace(pattern_para, '&para;<br>')
switch (op) {
case DIFF_INSERT:
html[x] = '<ins style="background:#e6ffe6;">' + text + '</ins>'
break
case DIFF_DELETE:
html[x] = '<del style="background:#ffe6e6;">' + text + '</del>'
break
case DIFF_EQUAL:
html[x] = '<span>' + text + '</span>'
break
}
}
return html.join('')
}
/**
* Compute and return the source text (all equalities and deletions).
* @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples.
* @return {string} Source text.
*/
diff_match_patch.prototype.diff_text1 = function (diffs) {
var text = []
for (var x = 0; x < diffs.length; x++) {
if (diffs[x][0] !== DIFF_INSERT) {
text[x] = diffs[x][1]
}
}
return text.join('')
}
/**
* Compute and return the destination text (all equalities and insertions).
* @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples.
* @return {string} Destination text.
*/
diff_match_patch.prototype.diff_text2 = function (diffs) {
var text = []
for (var x = 0; x < diffs.length; x++) {
if (diffs[x][0] !== DIFF_DELETE) {
text[x] = diffs[x][1]
}
}
return text.join('')
}
/**
* Compute the Levenshtein distance; the number of inserted, deleted or
* substituted characters.
* @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples.
* @return {number} Number of changes.
*/
diff_match_patch.prototype.diff_levenshtein = function (diffs) {
var levenshtein = 0
var insertions = 0
var deletions = 0
for (var x = 0; x < diffs.length; x++) {
var op = diffs[x][0]
var data = diffs[x][1]
switch (op) {
case DIFF_INSERT:
insertions += data.length
break
case DIFF_DELETE:
deletions += data.length
break
case DIFF_EQUAL:
// A deletion and an insertion is one substitution.
levenshtein += Math.max(insertions, deletions)
insertions = 0
deletions = 0
break
}
}
levenshtein += Math.max(insertions, deletions)
return levenshtein
}
/**
* Crush the diff into an encoded string which describes the operations
* required to transform text1 into text2.
* E.g. =3\t-2\t+ing -> Keep 3 chars, delete 2 chars, insert 'ing'.
* Operations are tab-separated. Inserted text is escaped using %xx notation.
* @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples.
* @return {string} Delta text.
*/
diff_match_patch.prototype.diff_toDelta = function (diffs) {
var text = []
for (var x = 0; x < diffs.length; x++) {
switch (diffs[x][0]) {
case DIFF_INSERT:
text[x] = '+' + encodeURI(diffs[x][1])
break
case DIFF_DELETE:
text[x] = '-' + diffs[x][1].length
break
case DIFF_EQUAL:
text[x] = '=' + diffs[x][1].length
break
}
}
return text.join('\t').replace(/%20/g, ' ')
}
/**
* Given the original text1, and an encoded string which describes the
* operations required to transform text1 into text2, compute the full diff.
* @param {string} text1 Source string for the diff.
* @param {string} delta Delta text.
* @return {!Array.<!diff_match_patch.Diff>} Array of diff tuples.
* @throws {!Error} If invalid input.
*/
diff_match_patch.prototype.diff_fromDelta = function (text1, delta) {
var diffs = []
var diffsLength = 0 // Keeping our own length var is faster in JS.
var pointer = 0 // Cursor in text1
var tokens = delta.split(/\t/g)
for (var x = 0; x < tokens.length; x++) {
// Each token begins with a one character parameter which specifies the
// operation of this token (delete, insert, equality).
var param = tokens[x].substring(1)
switch (tokens[x].charAt(0)) {
case '+':
try {
diffs[diffsLength++] = [DIFF_INSERT, decodeURI(param)]
} catch (ex) {
// Malformed URI sequence.
throw new Error('Illegal escape in diff_fromDelta: ' + param)
}
break
case '-':
// Fall through.
case '=':
var n = parseInt(param, 10)
if (isNaN(n) || n < 0) {
throw new Error('Invalid number in diff_fromDelta: ' + param)
}
var text = text1.substring(pointer, (pointer += n))
if (tokens[x].charAt(0) == '=') {
diffs[diffsLength++] = [DIFF_EQUAL, text]
} else {
diffs[diffsLength++] = [DIFF_DELETE, text]
}
break
default:
// Blank tokens are ok (from a trailing \t).
// Anything else is an error.
if (tokens[x]) {
throw new Error(
'Invalid diff operation in diff_fromDelta: ' + tokens[x]
)
}
}
}
if (pointer != text1.length) {
throw new Error(
'Delta length (' +
pointer +
') does not equal source text length (' +
text1.length +
').'
)
}
return diffs
}
// MATCH FUNCTIONS
/**
* Locate the best instance of 'pattern' in 'text' near 'loc'.
* @param {string} text The text to search.
* @param {string} pattern The pattern to search for.
* @param {number} loc The location to search around.
* @return {number} Best match index or -1.
*/
diff_match_patch.prototype.match_main = function (text, pattern, loc) {
// Check for null inputs.
if (text == null || pattern == null || loc == null) {
throw new Error('Null input. (match_main)')
}
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) {
// Nothing to match.
return -1
} else if (text.substring(loc, loc + pattern.length) == pattern) {
// Perfect match at the perfect spot! (Includes case of null pattern)
return loc
} else {
// Do a fuzzy compare.
return this.match_bitap_(text, pattern, loc)
}
}
/**
* Locate the best instance of 'pattern' in 'text' near 'loc' using the
* Bitap algorithm.
* @param {string} text The text to search.
* @param {string} pattern The pattern to search for.
* @param {number} loc The location to search around.
* @return {number} Best match index or -1.
* @private
*/
diff_match_patch.prototype.match_bitap_ = function (text, pattern, loc) {
if (pattern.length > this.Match_MaxBits) {
throw new Error('Pattern too long for this browser.')
}
// Initialise the alphabet.
var s = this.match_alphabet_(pattern)
var dmp = this // 'this' becomes 'window' in a closure.
/**
* Compute and return the score for a match with e errors and x location.
* Accesses loc and pattern through being a closure.
* @param {number} e Number of errors in match.
* @param {number} x Location of match.
* @return {number} Overall score for match (0.0 = good, 1.0 = bad).
* @private
*/
function match_bitapScore_(e, x) {
var accuracy = e / pattern.length
var proximity = Math.abs(loc - x)
if (!dmp.Match_Distance) {
// Dodge divide by zero error.
return proximity ? 1.0 : accuracy
}
return accuracy + proximity / dmp.Match_Distance
}
// Highest score beyond which we give up.
var score_threshold = this.Match_Threshold
// Is there a nearby exact match? (speedup)
var best_loc = text.indexOf(pattern, loc)
if (best_loc != -1) {
score_threshold = Math.min(match_bitapScore_(0, best_loc), score_threshold)
// What about in the other direction? (speedup)
best_loc = text.lastIndexOf(pattern, loc + pattern.length)
if (best_loc != -1) {
score_threshold = Math.min(
match_bitapScore_(0, best_loc),
score_threshold
)
}
}
// Initialise the bit arrays.
var matchmask = 1 << (pattern.length - 1)
best_loc = -1
var bin_min, bin_mid
var bin_max = pattern.length + text.length
var last_rd
for (var 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) <= score_threshold) {
bin_min = bin_mid
} else {
bin_max = bin_mid
}
bin_mid = Math.floor((bin_max - bin_min) / 2 + bin_min)
}
// Use the result from this iteration as the maximum for the next.
bin_max = bin_mid
var start = Math.max(1, loc - bin_mid + 1)
var finish = Math.min(loc + bin_mid, text.length) + pattern.length
var rd = Array(finish + 2)
rd[finish + 1] = (1 << d) - 1
for (var j = finish; j >= start; j--) {
// The alphabet (s) is a sparse hash, so the following line generates
// warnings.
var charMatch = s[text.charAt(j - 1)]
if (d === 0) {
// First pass: exact match.
rd[j] = ((rd[j + 1] << 1) | 1) & charMatch
} else {
// Subsequent passes: fuzzy match.
rd[j] =
(((rd[j + 1] << 1) | 1) & charMatch) |
(((last_rd[j + 1] | last_rd[j]) << 1) | 1) |
last_rd[j + 1]
}
if (rd[j] & matchmask) {
var 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 = Math.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
}
/**
* Initialise the alphabet for the Bitap algorithm.
* @param {string} pattern The text to encode.
* @return {!Object} Hash of character locations.
* @private
*/
diff_match_patch.prototype.match_alphabet_ = function (pattern) {
var s = {}
for (var i = 0; i < pattern.length; i++) {
s[pattern.charAt(i)] = 0
}
for (var i = 0; i < pattern.length; i++) {
s[pattern.charAt(i)] |= 1 << (pattern.length - i - 1)
}
return s
}
// PATCH FUNCTIONS
/**
* Increase the context until it is unique,
* but don't let the pattern expand beyond Match_MaxBits.
* @param {!diff_match_patch.patch_obj} patch The patch to grow.
* @param {string} text Source text.
* @private
*/
diff_match_patch.prototype.patch_addContext_ = function (patch, text) {
if (text.length == 0) {
return
}
var pattern = text.substring(patch.start2, patch.start2 + patch.length1)
var padding = 0
// Look for the first and last matches of pattern in text. If two different
// matches are found, increase the pattern length.
while (
text.indexOf(pattern) != text.lastIndexOf(pattern) &&
pattern.length < this.Match_MaxBits - this.Patch_Margin - this.Patch_Margin
) {
padding += this.Patch_Margin
pattern = text.substring(
patch.start2 - padding,
patch.start2 + patch.length1 + padding
)
}
// Add one chunk for good luck.
padding += this.Patch_Margin
// Add the prefix.
var prefix = text.substring(patch.start2 - padding, patch.start2)
if (prefix) {
patch.diffs.unshift([DIFF_EQUAL, prefix])
}
// Add the suffix.
var suffix = text.substring(
patch.start2 + patch.length1,
patch.start2 + patch.length1 + padding
)
if (suffix) {
patch.diffs.push([DIFF_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.
* 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
*
* @param {string|!Array.<!diff_match_patch.Diff>} a text1 (methods 1,3,4) or
* Array of diff tuples for text1 to text2 (method 2).
* @param {string|!Array.<!diff_match_patch.Diff>} opt_b text2 (methods 1,4) or
* Array of diff tuples for text1 to text2 (method 3) or undefined (method 2).
* @param {string|!Array.<!diff_match_patch.Diff>} opt_c Array of diff tuples
* for text1 to text2 (method 4) or undefined (methods 1,2,3).
* @return {!Array.<!diff_match_patch.patch_obj>} Array of Patch objects.
*/
diff_match_patch.prototype.patch_make = function (a, opt_b, opt_c) {
var text1, diffs
if (
typeof a == 'string' &&
typeof opt_b == 'string' &&
typeof opt_c == 'undefined'
) {
// Method 1: text1, text2
// Compute diffs from text1 and text2.
text1 = /** @type {string} */ (a)
diffs = this.diff_main(text1, /** @type {string} */ (opt_b), true)
if (diffs.length > 2) {
this.diff_cleanupSemantic(diffs)
this.diff_cleanupEfficiency(diffs)
}
} else if (
a &&
typeof a == 'object' &&
typeof opt_b == 'undefined' &&
typeof opt_c == 'undefined'
) {
// Method 2: diffs
// Compute text1 from diffs.
diffs = /** @type {!Array.<!diff_match_patch.Diff>} */ (a)
text1 = this.diff_text1(diffs)
} else if (
typeof a == 'string' &&
opt_b &&
typeof opt_b == 'object' &&
typeof opt_c == 'undefined'
) {
// Method 3: text1, diffs
text1 = /** @type {string} */ (a)
diffs = /** @type {!Array.<!diff_match_patch.Diff>} */ (opt_b)
} else if (
typeof a == 'string' &&
typeof opt_b == 'string' &&
opt_c &&
typeof opt_c == 'object'
) {
// Method 4: text1, text2, diffs
// text2 is not used.
text1 = /** @type {string} */ (a)
diffs = /** @type {!Array.<!diff_match_patch.Diff>} */ (opt_c)
} else {
throw new Error('Unknown call format to patch_make.')
}
if (diffs.length === 0) {
return [] // Get rid of the null case.
}
var patches = []
var patch = new diff_match_patch.patch_obj()
var patchDiffLength = 0 // Keeping our own length var is faster in JS.
var char_count1 = 0 // Number of characters into the text1 string.
var 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.
var prepatch_text = text1
var postpatch_text = text1
for (var x = 0; x < diffs.length; x++) {
var diff_type = diffs[x][0]
var diff_text = diffs[x][1]
if (!patchDiffLength && diff_type !== DIFF_EQUAL) {
// A new patch starts here.
patch.start1 = char_count1
patch.start2 = char_count2
}
switch (diff_type) {
case DIFF_INSERT:
patch.diffs[patchDiffLength++] = diffs[x]
patch.length2 += diff_text.length
postpatch_text =
postpatch_text.substring(0, char_count2) +
diff_text +
postpatch_text.substring(char_count2)
break
case DIFF_DELETE:
patch.length1 += diff_text.length
patch.diffs[patchDiffLength++] = diffs[x]
postpatch_text =
postpatch_text.substring(0, char_count2) +
postpatch_text.substring(char_count2 + diff_text.length)
break
case DIFF_EQUAL:
if (
diff_text.length <= 2 * this.Patch_Margin &&
patchDiffLength &&
diffs.length != x + 1
) {
// Small equality inside a patch.
patch.diffs[patchDiffLength++] = diffs[x]
patch.length1 += diff_text.length
patch.length2 += diff_text.length
} else if (diff_text.length >= 2 * this.Patch_Margin) {
// Time for a new patch.
if (patchDiffLength) {
this.patch_addContext_(patch, prepatch_text)
patches.push(patch)
patch = new diff_match_patch.patch_obj()
patchDiffLength = 0
// 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 (diff_type !== DIFF_INSERT) {
char_count1 += diff_text.length
}
if (diff_type !== DIFF_DELETE) {
char_count2 += diff_text.length
}
}
// Pick up the leftover patch if not empty.
if (patchDiffLength) {
this.patch_addContext_(patch, prepatch_text)
patches.push(patch)
}
return patches
}
/**
* Given an array of patches, return another array that is identical.
* @param {!Array.<!diff_match_patch.patch_obj>} patches Array of Patch objects.
* @return {!Array.<!diff_match_patch.patch_obj>} Array of Patch objects.
*/
diff_match_patch.prototype.patch_deepCopy = function (patches) {
// Making deep copies is hard in JavaScript.
var patchesCopy = []
for (var x = 0; x < patches.length; x++) {
var patch = patches[x]
var patchCopy = new diff_match_patch.patch_obj()
patchCopy.diffs = []
for (var y = 0; y < patch.diffs.length; y++) {
patchCopy.diffs[y] = patch.diffs[y].slice()
}
patchCopy.start1 = patch.start1
patchCopy.start2 = patch.start2
patchCopy.length1 = patch.length1
patchCopy.length2 = patch.length2
patchesCopy[x] = patchCopy
}
return patchesCopy
}
/**
* 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.
* @param {!Array.<!diff_match_patch.patch_obj>} patches Array of Patch objects.
* @param {string} text Old text.
* @return {!Array.<string|!Array.<boolean>>} Two element Array, containing the
* new text and an array of boolean values.
*/
diff_match_patch.prototype.patch_apply = function (patches, text) {
if (patches.length == 0) {
return [text, []]
}
// Deep copy the patches so that no changes are made to originals.
patches = this.patch_deepCopy(patches)
var nullPadding = this.patch_addPadding(patches)
text = nullPadding + text + nullPadding
this.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.
var delta = 0
var results = []
for (var x = 0; x < patches.length; x++) {
var expected_loc = patches[x].start2 + delta
var text1 = this.diff_text1(patches[x].diffs)
var start_loc
var 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 = this.match_main(
text,
text1.substring(0, this.Match_MaxBits),
expected_loc
)
if (start_loc != -1) {
end_loc = this.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 -= patches[x].length2 - patches[x].length1
} else {
// Found a match. :)
results[x] = true
delta = start_loc - expected_loc
var text2
if (end_loc == -1) {
text2 = text.substring(start_loc, start_loc + text1.length)
} else {
text2 = text.substring(start_loc, end_loc + this.Match_MaxBits)
}
if (text1 == text2) {
// Perfect match, just shove the replacement text in.
text =
text.substring(0, start_loc) +
this.diff_text2(patches[x].diffs) +
text.substring(start_loc + text1.length)
} else {
// Imperfect match. Run a diff to get a framework of equivalent
// indices.
var diffs = this.diff_main(text1, text2, false)
if (
text1.length > this.Match_MaxBits &&
this.diff_levenshtein(diffs) / text1.length >
this.Patch_DeleteThreshold
) {
// The end points match, but the content is unacceptably bad.
results[x] = false
} else {
this.diff_cleanupSemanticLossless(diffs)
var index1 = 0
var index2
for (var y = 0; y < patches[x].diffs.length; y++) {
var mod = patches[x].diffs[y]
if (mod[0] !== DIFF_EQUAL) {
index2 = this.diff_xIndex(diffs, index1)
}
if (mod[0] === DIFF_INSERT) {
// Insertion
text =
text.substring(0, start_loc + index2) +
mod[1] +
text.substring(start_loc + index2)
} else if (mod[0] === DIFF_DELETE) {
// Deletion
text =
text.substring(0, start_loc + index2) +
text.substring(
start_loc + this.diff_xIndex(diffs, index1 + mod[1].length)
)
}
if (mod[0] !== DIFF_DELETE) {
index1 += mod[1].length
}
}
}
}
}
}
// Strip the padding off.
text = text.substring(nullPadding.length, text.length - nullPadding.length)
return [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 {!Array.<!diff_match_patch.patch_obj>} patches Array of Patch objects.
* @return {string} The padding string added to each side.
*/
diff_match_patch.prototype.patch_addPadding = function (patches) {
var paddingLength = this.Patch_Margin
var nullPadding = ''
for (var x = 1; x <= paddingLength; x++) {
nullPadding += String.fromCharCode(x)
}
// Bump all the patches forward.
for (var x = 0; x < patches.length; x++) {
patches[x].start1 += paddingLength
patches[x].start2 += paddingLength
}
// Add some padding on start of first diff.
var patch = patches[0]
var diffs = patch.diffs
if (diffs.length == 0 || diffs[0][0] != DIFF_EQUAL) {
// Add nullPadding equality.
diffs.unshift([DIFF_EQUAL, nullPadding])
patch.start1 -= paddingLength // Should be 0.
patch.start2 -= paddingLength // Should be 0.
patch.length1 += paddingLength
patch.length2 += paddingLength
} else if (paddingLength > diffs[0][1].length) {
// Grow first equality.
var extraLength = paddingLength - diffs[0][1].length
diffs[0][1] = nullPadding.substring(diffs[0][1].length) + diffs[0][1]
patch.start1 -= extraLength
patch.start2 -= extraLength
patch.length1 += extraLength
patch.length2 += extraLength
}
// Add some padding on end of last diff.
patch = patches[patches.length - 1]
diffs = patch.diffs
if (diffs.length == 0 || diffs[diffs.length - 1][0] != DIFF_EQUAL) {
// Add nullPadding equality.
diffs.push([DIFF_EQUAL, nullPadding])
patch.length1 += paddingLength
patch.length2 += paddingLength
} else if (paddingLength > diffs[diffs.length - 1][1].length) {
// Grow last equality.
var extraLength = paddingLength - diffs[diffs.length - 1][1].length
diffs[diffs.length - 1][1] += 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 {!Array.<!diff_match_patch.patch_obj>} patches Array of Patch objects.
*/
diff_match_patch.prototype.patch_splitMax = function (patches) {
var patch_size = this.Match_MaxBits
for (var x = 0; x < patches.length; x++) {
if (patches[x].length1 <= patch_size) {
continue
}
var bigpatch = patches[x]
// Remove the big old patch.
patches.splice(x--, 1)
var start1 = bigpatch.start1
var start2 = bigpatch.start2
var precontext = ''
while (bigpatch.diffs.length !== 0) {
// Create one of several smaller patches.
var patch = new diff_match_patch.patch_obj()
var empty = true
patch.start1 = start1 - precontext.length
patch.start2 = start2 - precontext.length
if (precontext !== '') {
patch.length1 = patch.length2 = precontext.length
patch.diffs.push([DIFF_EQUAL, precontext])
}
while (
bigpatch.diffs.length !== 0 &&
patch.length1 < patch_size - this.Patch_Margin
) {
var diff_type = bigpatch.diffs[0][0]
var diff_text = bigpatch.diffs[0][1]
if (diff_type === DIFF_INSERT) {
// Insertions are harmless.
patch.length2 += diff_text.length
start2 += diff_text.length
patch.diffs.push(bigpatch.diffs.shift())
empty = false
} else if (
diff_type === DIFF_DELETE &&
patch.diffs.length == 1 &&
patch.diffs[0][0] == DIFF_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.push([diff_type, diff_text])
bigpatch.diffs.shift()
} else {
// Deletion or equality. Only take as much as we can stomach.
diff_text = diff_text.substring(
0,
patch_size - patch.length1 - this.Patch_Margin
)
patch.length1 += diff_text.length
start1 += diff_text.length
if (diff_type === DIFF_EQUAL) {
patch.length2 += diff_text.length
start2 += diff_text.length
} else {
empty = false
}
patch.diffs.push([diff_type, diff_text])
if (diff_text == bigpatch.diffs[0][1]) {
bigpatch.diffs.shift()
} else {
bigpatch.diffs[0][1] = bigpatch.diffs[0][1].substring(
diff_text.length
)
}
}
}
// Compute the head context for the next patch.
precontext = this.diff_text2(patch.diffs)
precontext = precontext.substring(precontext.length - this.Patch_Margin)
// Append the end context for this patch.
var postcontext = this.diff_text1(bigpatch.diffs).substring(
0,
this.Patch_Margin
)
if (postcontext !== '') {
patch.length1 += postcontext.length
patch.length2 += postcontext.length
if (
patch.diffs.length !== 0 &&
patch.diffs[patch.diffs.length - 1][0] === DIFF_EQUAL
) {
patch.diffs[patch.diffs.length - 1][1] += postcontext
} else {
patch.diffs.push([DIFF_EQUAL, postcontext])
}
}
if (!empty) {
patches.splice(++x, 0, patch)
}
}
}
}
/**
* Take a list of patches and return a textual representation.
* @param {!Array.<!diff_match_patch.patch_obj>} patches Array of Patch objects.
* @return {string} Text representation of patches.
*/
diff_match_patch.prototype.patch_toText = function (patches) {
var text = []
for (var x = 0; x < patches.length; x++) {
text[x] = patches[x]
}
return text.join('')
}
/**
* Parse a textual representation of patches and return a list of Patch objects.
* @param {string} textline Text representation of patches.
* @return {!Array.<!diff_match_patch.patch_obj>} Array of Patch objects.
* @throws {!Error} If invalid input.
*/
diff_match_patch.prototype.patch_fromText = function (textline) {
var patches = []
if (!textline) {
return patches
}
var text = textline.split('\n')
var textPointer = 0
var patchHeader = /^@@ -(\d+),?(\d*) \+(\d+),?(\d*) @@$/
while (textPointer < text.length) {
var m = text[textPointer].match(patchHeader)
if (!m) {
throw new Error('Invalid patch string: ' + text[textPointer])
}
var patch = new diff_match_patch.patch_obj()
patches.push(patch)
patch.start1 = parseInt(m[1], 10)
if (m[2] === '') {
patch.start1--
patch.length1 = 1
} else if (m[2] == '0') {
patch.length1 = 0
} else {
patch.start1--
patch.length1 = parseInt(m[2], 10)
}
patch.start2 = parseInt(m[3], 10)
if (m[4] === '') {
patch.start2--
patch.length2 = 1
} else if (m[4] == '0') {
patch.length2 = 0
} else {
patch.start2--
patch.length2 = parseInt(m[4], 10)
}
textPointer++
while (textPointer < text.length) {
var sign = text[textPointer].charAt(0)
try {
var line = decodeURI(text[textPointer].substring(1))
} catch (ex) {
// Malformed URI sequence.
throw new Error('Illegal escape in patch_fromText: ' + line)
}
if (sign == '-') {
// Deletion.
patch.diffs.push([DIFF_DELETE, line])
} else if (sign == '+') {
// Insertion.
patch.diffs.push([DIFF_INSERT, line])
} else if (sign == ' ') {
// Minor equality.
patch.diffs.push([DIFF_EQUAL, line])
} else if (sign == '@') {
// Start of next patch.
break
} else if (sign === '') {
// Blank line? Whatever.
} else {
// WTF?
throw new Error('Invalid patch mode "' + sign + '" in: ' + line)
}
textPointer++
}
}
return patches
}
/**
* Class representing one patch operation.
* @constructor
*/
diff_match_patch.patch_obj = function () {
/** @type {!Array.<!diff_match_patch.Diff>} */
this.diffs = []
/** @type {?number} */
this.start1 = null
/** @type {?number} */
this.start2 = null
/** @type {number} */
this.length1 = 0
/** @type {number} */
this.length2 = 0
}
/**
* Emmulate GNU diff's format.
* Header: @@ -382,8 +481,9 @@
* Indicies are printed as 1-based, not 0-based.
* @return {string} The GNU diff string.
*/
diff_match_patch.patch_obj.prototype.toString = function () {
var coords1, coords2
if (this.length1 === 0) {
coords1 = this.start1 + ',0'
} else if (this.length1 == 1) {
coords1 = this.start1 + 1
} else {
coords1 = this.start1 + 1 + ',' + this.length1
}
if (this.length2 === 0) {
coords2 = this.start2 + ',0'
} else if (this.length2 == 1) {
coords2 = this.start2 + 1
} else {
coords2 = this.start2 + 1 + ',' + this.length2
}
var text = ['@@ -' + coords1 + ' +' + coords2 + ' @@\n']
var op
// Escape the body of the patch with %xx notation.
for (var x = 0; x < this.diffs.length; x++) {
switch (this.diffs[x][0]) {
case DIFF_INSERT:
op = '+'
break
case DIFF_DELETE:
op = '-'
break
case DIFF_EQUAL:
op = ' '
break
}
text[x + 1] = op + encodeURI(this.diffs[x][1]) + '\n'
}
return text.join('').replace(/%20/g, ' ')
}
// Export these global variables so that they survive Google's JS compiler.
// In a browser, 'this' will be 'window'.
// Users of node.js should 'require' the uncompressed version since Google's
// JS compiler may break the following exports for non-browser environments.
this['diff_match_patch'] = diff_match_patch
this['DIFF_DELETE'] = DIFF_DELETE
this['DIFF_INSERT'] = DIFF_INSERT
this['DIFF_EQUAL'] = DIFF_EQUAL