package alma.logoot.logootengine.utils;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.ListIterator;
import java.util.Map;
import java.util.Stack;
/*
* 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)
*/
/**
* Class containing the diff, match and patch methods. Also contains the
* behaviour settings.
*/
public class diff_match_patch {
// Defaults.
// Set these on your diff_match_patch instance to override the defaults.
/**
* Number of seconds to map a diff before giving up (0 for infinity).
*/
public float Diff_Timeout = 1.0f;
/**
* Cost of an empty edit operation in terms of edit characters.
*/
public short Diff_EditCost = 4;
/**
* At what point is no match declared (0.0 = perfection, 1.0 = very loose).
*/
public float Match_Threshold = 0.5f;
/**
* 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).
*/
public int 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.
*/
public float Patch_DeleteThreshold = 0.5f;
/**
* Chunk size for context length.
*/
public short Patch_Margin = 4;
/**
* The number of bits in an int.
*/
private short Match_MaxBits = 32;
/**
* Internal class for returning results from diff_linesToChars(). Other less
* paranoid languages just use a three-element array.
*/
protected static class LinesToCharsResult {
protected String chars1;
protected String chars2;
protected List<String> lineArray;
protected LinesToCharsResult(String chars1, String chars2,
List<String> lineArray) {
this.chars1 = chars1;
this.chars2 = chars2;
this.lineArray = lineArray;
}
}
// DIFF FUNCTIONS
/**
* The data structure representing a diff is a Linked list of Diff objects:
* {Diff(Operation.DELETE, "Hello"), Diff(Operation.INSERT, "Goodbye"),
* Diff(Operation.EQUAL, " world.")} which means: delete "Hello", add
* "Goodbye" and keep " world."
*/
public enum Operation {
DELETE, INSERT, EQUAL
}
/**
* Find the differences between two texts. Run a faster, slightly less optimal
* diff. This method allows the 'checklines' of diff_main() to be optional.
* Most of the time checklines is wanted, so default to true.
*
* @param text1
* Old string to be diffed.
* @param text2
* New string to be diffed.
* @return Linked List of Diff objects.
*/
public LinkedList<Diff> diff_main(String text1, String text2) {
return diff_main(text1, text2, true);
}
/**
* Find the differences between two texts.
*
* @param text1
* Old string to be diffed.
* @param text2
* New string to be diffed.
* @param 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.
* @return Linked List of Diff objects.
*/
public LinkedList<Diff> diff_main(String text1, String text2,
boolean checklines) {
// Set a deadline by which time the diff must be complete.
long deadline;
if (Diff_Timeout <= 0) {
deadline = Long.MAX_VALUE;
} else {
deadline = System.currentTimeMillis() + (long) (Diff_Timeout * 1000);
}
return diff_main(text1, text2, checklines, deadline);
}
/**
* Find the differences between two texts. Simplifies the problem by stripping
* any common prefix or suffix off the texts before diffing.
*
* @param text1
* Old string to be diffed.
* @param text2
* New string to be diffed.
* @param 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 deadline
* Time when the diff should be complete by. Used internally for
* recursive calls. Users should set DiffTimeout instead.
* @return Linked List of Diff objects.
*/
private LinkedList<Diff> diff_main(String text1, String text2,
boolean checklines, long deadline) {
// Check for null inputs.
if (text1 == null || text2 == null) {
throw new IllegalArgumentException("Null inputs. (diff_main)");
}
// Check for equality (speedup).
LinkedList<Diff> diffs;
if (text1.equals(text2)) {
diffs = new LinkedList<Diff>();
if (text1.length() != 0) {
diffs.add(new Diff(Operation.EQUAL, text1));
}
return diffs;
}
// Trim off common prefix (speedup).
int commonlength = diff_commonPrefix(text1, text2);
String commonprefix = text1.substring(0, commonlength);
text1 = text1.substring(commonlength);
text2 = text2.substring(commonlength);
// Trim off common suffix (speedup).
commonlength = diff_commonSuffix(text1, text2);
String 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.
diffs = diff_compute(text1, text2, checklines, deadline);
// Restore the prefix and suffix.
if (commonprefix.length() != 0) {
diffs.addFirst(new Diff(Operation.EQUAL, commonprefix));
}
if (commonsuffix.length() != 0) {
diffs.addLast(new Diff(Operation.EQUAL, commonsuffix));
}
diff_cleanupMerge(diffs);
return diffs;
}
/**
* Find the differences between two texts. Assumes that the texts do not have
* any common prefix or suffix.
*
* @param text1
* Old string to be diffed.
* @param text2
* New string to be diffed.
* @param 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 deadline
* Time when the diff should be complete by.
* @return Linked List of Diff objects.
*/
private LinkedList<Diff> diff_compute(String text1, String text2,
boolean checklines, long deadline) {
LinkedList<Diff> diffs = new LinkedList<Diff>();
if (text1.length() == 0) {
// Just add some text (speedup).
diffs.add(new Diff(Operation.INSERT, text2));
return diffs;
}
if (text2.length() == 0) {
// Just delete some text (speedup).
diffs.add(new Diff(Operation.DELETE, text1));
return diffs;
}
String longtext = text1.length() > text2.length() ? text1 : text2;
String shorttext = text1.length() > text2.length() ? text2 : text1;
int i = longtext.indexOf(shorttext);
if (i != -1) {
// Shorter text is inside the longer text (speedup).
Operation op = (text1.length() > text2.length()) ? Operation.DELETE
: Operation.INSERT;
diffs.add(new Diff(op, longtext.substring(0, i)));
diffs.add(new Diff(Operation.EQUAL, shorttext));
diffs.add(new Diff(op, longtext.substring(i + shorttext.length())));
return diffs;
}
if (shorttext.length() == 1) {
// Single character string.
// After the previous speedup, the character can't be an equality.
diffs.add(new Diff(Operation.DELETE, text1));
diffs.add(new Diff(Operation.INSERT, text2));
return diffs;
}
// Check to see if the problem can be split in two.
String[] hm = diff_halfMatch(text1, text2);
if (hm != null) {
// A half-match was found, sort out the return data.
String text1_a = hm[0];
String text1_b = hm[1];
String text2_a = hm[2];
String text2_b = hm[3];
String mid_common = hm[4];
// Send both pairs off for separate processing.
LinkedList<Diff> diffs_a = diff_main(text1_a, text2_a, checklines,
deadline);
LinkedList<Diff> diffs_b = diff_main(text1_b, text2_b, checklines,
deadline);
// Merge the results.
diffs = diffs_a;
diffs.add(new Diff(Operation.EQUAL, mid_common));
diffs.addAll(diffs_b);
return diffs;
}
if (checklines && text1.length() > 100 && text2.length() > 100) {
return diff_lineMode(text1, text2, deadline);
}
return 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 text1
* Old string to be diffed.
* @param text2
* New string to be diffed.
* @param deadline
* Time when the diff should be complete by.
* @return Linked List of Diff objects.
*/
private LinkedList<Diff> diff_lineMode(String text1, String text2,
long deadline) {
// Scan the text on a line-by-line basis first.
LinesToCharsResult b = diff_linesToChars(text1, text2);
text1 = b.chars1;
text2 = b.chars2;
List<String> linearray = b.lineArray;
LinkedList<Diff> diffs = diff_main(text1, text2, false, deadline);
// Convert the diff back to original text.
diff_charsToLines(diffs, linearray);
// Eliminate freak matches (e.g. blank lines)
diff_cleanupSemantic(diffs);
// Rediff any replacement blocks, this time character-by-character.
// Add a dummy entry at the end.
diffs.add(new Diff(Operation.EQUAL, ""));
int count_delete = 0;
int count_insert = 0;
String text_delete = "";
String text_insert = "";
ListIterator<Diff> pointer = diffs.listIterator();
Diff thisDiff = pointer.next();
while (thisDiff != null) {
switch (thisDiff.operation) {
case INSERT:
count_insert++;
text_insert += thisDiff.text;
break;
case DELETE:
count_delete++;
text_delete += thisDiff.text;
break;
case 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.
pointer.previous();
for (int j = 0; j < count_delete + count_insert; j++) {
pointer.previous();
pointer.remove();
}
for (Diff newDiff : diff_main(text_delete, text_insert, false,
deadline)) {
pointer.add(newDiff);
}
}
count_insert = 0;
count_delete = 0;
text_delete = "";
text_insert = "";
break;
}
thisDiff = pointer.hasNext() ? pointer.next() : null;
}
diffs.removeLast(); // 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 text1
* Old string to be diffed.
* @param text2
* New string to be diffed.
* @param deadline
* Time at which to bail if not yet complete.
* @return LinkedList of Diff objects.
*/
protected LinkedList<Diff> diff_bisect(String text1, String text2,
long deadline) {
// Cache the text lengths to prevent multiple calls.
int text1_length = text1.length();
int text2_length = text2.length();
int max_d = (text1_length + text2_length + 1) / 2;
int v_offset = max_d;
int v_length = 2 * max_d;
int[] v1 = new int[v_length];
int[] v2 = new int[v_length];
for (int x = 0; x < v_length; x++) {
v1[x] = -1;
v2[x] = -1;
}
v1[v_offset + 1] = 0;
v2[v_offset + 1] = 0;
int delta = text1_length - text2_length;
// If the total number of characters is odd, then the front path will
// collide with the reverse path.
boolean front = (delta % 2 != 0);
// Offsets for start and end of k loop.
// Prevents mapping of space beyond the grid.
int k1start = 0;
int k1end = 0;
int k2start = 0;
int k2end = 0;
for (int d = 0; d < max_d; d++) {
// Bail out if deadline is reached.
if (System.currentTimeMillis() > deadline) {
break;
}
// Walk the front path one step.
for (int k1 = -d + k1start; k1 <= d - k1end; k1 += 2) {
int k1_offset = v_offset + k1;
int 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;
}
int 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) {
int k2_offset = v_offset + delta - k1;
if (k2_offset >= 0 && k2_offset < v_length && v2[k2_offset] != -1) {
// Mirror x2 onto top-left coordinate system.
int x2 = text1_length - v2[k2_offset];
if (x1 >= x2) {
// Overlap detected.
return diff_bisectSplit(text1, text2, x1, y1, deadline);
}
}
}
}
// Walk the reverse path one step.
for (int k2 = -d + k2start; k2 <= d - k2end; k2 += 2) {
int k2_offset = v_offset + k2;
int x2;
if (k2 == -d || (k2 != d && v2[k2_offset - 1] < v2[k2_offset + 1])) {
x2 = v2[k2_offset + 1];
} else {
x2 = v2[k2_offset - 1] + 1;
}
int y2 = x2 - k2;
while (x2 < text1_length
&& y2 < text2_length
&& text1.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) {
int k1_offset = v_offset + delta - k2;
if (k1_offset >= 0 && k1_offset < v_length && v1[k1_offset] != -1) {
int x1 = v1[k1_offset];
int y1 = v_offset + x1 - k1_offset;
// Mirror x2 onto top-left coordinate system.
x2 = text1_length - x2;
if (x1 >= x2) {
// Overlap detected.
return diff_bisectSplit(text1, text2, x1, y1, deadline);
}
}
}
}
}
// Diff took too long and hit the deadline or
// number of diffs equals number of characters, no commonality at all.
LinkedList<Diff> diffs = new LinkedList<Diff>();
diffs.add(new Diff(Operation.DELETE, text1));
diffs.add(new Diff(Operation.INSERT, text2));
return diffs;
}
/**
* Given the location of the 'middle snake', split the diff in two parts and
* recurse.
*
* @param text1
* Old string to be diffed.
* @param text2
* New string to be diffed.
* @param x
* Index of split point in text1.
* @param y
* Index of split point in text2.
* @param deadline
* Time at which to bail if not yet complete.
* @return LinkedList of Diff objects.
*/
private LinkedList<Diff> diff_bisectSplit(String text1, String text2, int x,
int y, long deadline) {
String text1a = text1.substring(0, x);
String text2a = text2.substring(0, y);
String text1b = text1.substring(x);
String text2b = text2.substring(y);
// Compute both diffs serially.
LinkedList<Diff> diffs = diff_main(text1a, text2a, false, deadline);
LinkedList<Diff> diffsb = diff_main(text1b, text2b, false, deadline);
diffs.addAll(diffsb);
return diffs;
}
/**
* Split two texts into a list of strings. Reduce the texts to a string of
* hashes where each Unicode character represents one line.
*
* @param text1
* First string.
* @param text2
* Second string.
* @return An object containing the encoded text1, the encoded text2 and the
* List of unique strings. The zeroth element of the List of unique
* strings is intentionally blank.
*/
protected LinesToCharsResult diff_linesToChars(String text1, String text2) {
List<String> lineArray = new ArrayList<String>();
Map<String, Integer> lineHash = new HashMap<String, Integer>();
// e.g. linearray[4] == "Hello\n"
// e.g. linehash.get("Hello\n") == 4
// "\x00" is a valid character, but various debuggers don't like it.
// So we'll insert a junk entry to avoid generating a null character.
lineArray.add("");
String chars1 = diff_linesToCharsMunge(text1, lineArray, lineHash);
String chars2 = diff_linesToCharsMunge(text2, lineArray, lineHash);
return new LinesToCharsResult(chars1, chars2, lineArray);
}
/**
* Split a text into a list of strings. Reduce the texts to a string of hashes
* where each Unicode character represents one line.
*
* @param text
* String to encode.
* @param lineArray
* List of unique strings.
* @param lineHash
* Map of strings to indices.
* @return Encoded string.
*/
private String diff_linesToCharsMunge(String text, List<String> lineArray,
Map<String, Integer> lineHash) {
int lineStart = 0;
int lineEnd = -1;
String line;
StringBuilder chars = new StringBuilder();
// Walk the text, pulling out a substring for each line.
// text.split('\n') would would temporarily double our memory footprint.
// Modifying text would create many large strings to garbage collect.
while (lineEnd < text.length() - 1) {
lineEnd = text.indexOf('\n', lineStart);
if (lineEnd == -1) {
lineEnd = text.length() - 1;
}
line = text.substring(lineStart, lineEnd + 1);
lineStart = lineEnd + 1;
if (lineHash.containsKey(line)) {
chars.append(String.valueOf((char) (int) lineHash.get(line)));
} else {
lineArray.add(line);
lineHash.put(line, lineArray.size() - 1);
chars.append(String.valueOf((char) (lineArray.size() - 1)));
}
}
return chars.toString();
}
/**
* Rehydrate the text in a diff from a string of line hashes to real lines of
* text.
*
* @param diffs
* LinkedList of Diff objects.
* @param lineArray
* List of unique strings.
*/
protected void diff_charsToLines(LinkedList<Diff> diffs,
List<String> lineArray) {
StringBuilder text;
for (Diff diff : diffs) {
text = new StringBuilder();
for (int y = 0; y < diff.text.length(); y++) {
text.append(lineArray.get(diff.text.charAt(y)));
}
diff.text = text.toString();
}
}
/**
* Determine the common prefix of two strings
*
* @param text1
* First string.
* @param text2
* Second string.
* @return The number of characters common to the start of each string.
*/
public int diff_commonPrefix(String text1, String text2) {
// Performance analysis: http://neil.fraser.name/news/2007/10/09/
int n = Math.min(text1.length(), text2.length());
for (int i = 0; i < n; i++) {
if (text1.charAt(i) != text2.charAt(i)) {
return i;
}
}
return n;
}
/**
* Determine the common suffix of two strings
*
* @param text1
* First string.
* @param text2
* Second string.
* @return The number of characters common to the end of each string.
*/
public int diff_commonSuffix(String text1, String text2) {
// Performance analysis: http://neil.fraser.name/news/2007/10/09/
int text1_length = text1.length();
int text2_length = text2.length();
int n = Math.min(text1_length, text2_length);
for (int i = 1; i <= n; i++) {
if (text1.charAt(text1_length - i) != text2.charAt(text2_length - i)) {
return i - 1;
}
}
return n;
}
/**
* Determine if the suffix of one string is the prefix of another.
*
* @param text1
* First string.
* @param text2
* Second string.
* @return The number of characters common to the end of the first string and
* the start of the second string.
*/
protected int diff_commonOverlap(String text1, String text2) {
// Cache the text lengths to prevent multiple calls.
int text1_length = text1.length();
int text2_length = text2.length();
// Eliminate the null case.
if (text1_length == 0 || text2_length == 0) {
return 0;
}
// Truncate the longer string.
if (text1_length > text2_length) {
text1 = text1.substring(text1_length - text2_length);
} else if (text1_length < text2_length) {
text2 = text2.substring(0, text1_length);
}
int text_length = Math.min(text1_length, text2_length);
// Quick check for the worst case.
if (text1.equals(text2)) {
return text_length;
}
// Start by looking for a single character match
// and increase length until no match is found.
// Performance analysis: http://neil.fraser.name/news/2010/11/04/
int best = 0;
int length = 1;
while (true) {
String pattern = text1.substring(text_length - length);
int found = text2.indexOf(pattern);
if (found == -1) {
return best;
}
length += found;
if (found == 0
|| text1.substring(text_length - length).equals(
text2.substring(0, length))) {
best = length;
length++;
}
}
}
/**
* Do the two texts share a substring which is at least half the length of the
* longer text? This speedup can produce non-minimal diffs.
*
* @param text1
* First string.
* @param text2
* Second string.
* @return Five element String array, containing the prefix of text1, the
* suffix of text1, the prefix of text2, the suffix of text2 and the
* common middle. Or null if there was no match.
*/
protected String[] diff_halfMatch(String text1, String text2) {
if (Diff_Timeout <= 0) {
// Don't risk returning a non-optimal diff if we have unlimited
// time.
return null;
}
String longtext = text1.length() > text2.length() ? text1 : text2;
String shorttext = text1.length() > text2.length() ? text2 : text1;
if (longtext.length() < 4 || shorttext.length() * 2 < longtext.length()) {
return null; // Pointless.
}
// First check if the second quarter is the seed for a half-match.
String[] hm1 = diff_halfMatchI(longtext, shorttext,
(longtext.length() + 3) / 4);
// Check again based on the third quarter.
String[] hm2 = diff_halfMatchI(longtext, shorttext,
(longtext.length() + 1) / 2);
String[] hm;
if (hm1 == null && hm2 == null) {
return null;
} else if (hm2 == null) {
hm = hm1;
} else if (hm1 == null) {
hm = hm2;
} else {
// Both matched. Select the longest.
hm = hm1[4].length() > hm2[4].length() ? hm1 : hm2;
}
// A half-match was found, sort out the return data.
if (text1.length() > text2.length()) {
return hm;
// return new String[]{hm[0], hm[1], hm[2], hm[3], hm[4]};
} else {
return new String[] { hm[2], hm[3], hm[0], hm[1], hm[4] };
}
}
/**
* Does a substring of shorttext exist within longtext such that the substring
* is at least half the length of longtext?
*
* @param longtext
* Longer string.
* @param shorttext
* Shorter string.
* @param i
* Start index of quarter length substring within longtext.
* @return Five element String array, containing the prefix of longtext, the
* suffix of longtext, the prefix of shorttext, the suffix of
* shorttext and the common middle. Or null if there was no match.
*/
private String[] diff_halfMatchI(String longtext, String shorttext, int i) {
// Start with a 1/4 length substring at position i as a seed.
String seed = longtext.substring(i, i + longtext.length() / 4);
int j = -1;
String best_common = "";
String best_longtext_a = "", best_longtext_b = "";
String best_shorttext_a = "", best_shorttext_b = "";
while ((j = shorttext.indexOf(seed, j + 1)) != -1) {
int prefixLength = diff_commonPrefix(longtext.substring(i),
shorttext.substring(j));
int suffixLength = diff_commonSuffix(longtext.substring(0, i),
shorttext.substring(0, j));
if (best_common.length() < suffixLength + prefixLength) {
best_common = shorttext.substring(j - suffixLength, j)
+ shorttext.substring(j, j + prefixLength);
best_longtext_a = longtext.substring(0, i - suffixLength);
best_longtext_b = longtext.substring(i + prefixLength);
best_shorttext_a = shorttext.substring(0, j - suffixLength);
best_shorttext_b = shorttext.substring(j + prefixLength);
}
}
if (best_common.length() * 2 >= longtext.length()) {
return new String[] { best_longtext_a, best_longtext_b, best_shorttext_a,
best_shorttext_b, best_common };
} else {
return null;
}
}
/**
* Reduce the number of edits by eliminating semantically trivial equalities.
*
* @param diffs
* LinkedList of Diff objects.
*/
public void diff_cleanupSemantic(LinkedList<Diff> diffs) {
if (diffs.isEmpty()) {
return;
}
boolean changes = false;
Stack<Diff> equalities = new Stack<Diff>(); // Stack of qualities.
String lastequality = null; // Always equal to
// equalities.lastElement().text
ListIterator<Diff> pointer = diffs.listIterator();
// Number of characters that changed prior to the equality.
int length_insertions1 = 0;
int length_deletions1 = 0;
// Number of characters that changed after the equality.
int length_insertions2 = 0;
int length_deletions2 = 0;
Diff thisDiff = pointer.next();
while (thisDiff != null) {
if (thisDiff.operation == Operation.EQUAL) {
// Equality found.
equalities.push(thisDiff);
length_insertions1 = length_insertions2;
length_deletions1 = length_deletions2;
length_insertions2 = 0;
length_deletions2 = 0;
lastequality = thisDiff.text;
} else {
// An insertion or deletion.
if (thisDiff.operation == Operation.INSERT) {
length_insertions2 += thisDiff.text.length();
} else {
length_deletions2 += thisDiff.text.length();
}
// Eliminate an equality that is smaller or equal to the edits
// on both
// sides of it.
if (lastequality != null
&& (lastequality.length() <= Math.max(length_insertions1,
length_deletions1))
&& (lastequality.length() <= Math.max(length_insertions2,
length_deletions2))) {
// System.out.println("Splitting: '" + lastequality + "'");
// Walk back to offending equality.
while (thisDiff != equalities.lastElement()) {
thisDiff = pointer.previous();
}
pointer.next();
// Replace equality with a delete.
pointer.set(new Diff(Operation.DELETE, lastequality));
// Insert a corresponding an insert.
pointer.add(new Diff(Operation.INSERT, lastequality));
equalities.pop(); // Throw away the equality we just
// deleted.
if (!equalities.empty()) {
// Throw away the previous equality (it needs to be
// reevaluated).
equalities.pop();
}
if (equalities.empty()) {
// There are no previous equalities, walk back to the
// start.
while (pointer.hasPrevious()) {
pointer.previous();
}
} else {
// There is a safe equality we can fall back to.
thisDiff = equalities.lastElement();
while (thisDiff != pointer.previous()) {
// Intentionally empty loop.
}
}
length_insertions1 = 0; // Reset the counters.
length_insertions2 = 0;
length_deletions1 = 0;
length_deletions2 = 0;
lastequality = null;
changes = true;
}
}
thisDiff = pointer.hasNext() ? pointer.next() : null;
}
// Normalize the diff.
if (changes) {
diff_cleanupMerge(diffs);
}
diff_cleanupSemanticLossless(diffs);
// Find any overlaps between deletions and insertions.
// e.g: <del>abcxxx</del><ins>xxxdef</ins>
// -> <del>abc</del>xxx<ins>def</ins>
// e.g: <del>xxxabc</del><ins>defxxx</ins>
// -> <ins>def</ins>xxx<del>abc</del>
// Only extract an overlap if it is as big as the edit ahead or behind
// it.
pointer = diffs.listIterator();
Diff prevDiff = null;
thisDiff = null;
if (pointer.hasNext()) {
prevDiff = pointer.next();
if (pointer.hasNext()) {
thisDiff = pointer.next();
}
}
while (thisDiff != null) {
if (prevDiff.operation == Operation.DELETE
&& thisDiff.operation == Operation.INSERT) {
String deletion = prevDiff.text;
String insertion = thisDiff.text;
int overlap_length1 = this.diff_commonOverlap(deletion, insertion);
int overlap_length2 = this.diff_commonOverlap(insertion, deletion);
if (overlap_length1 >= overlap_length2) {
if (overlap_length1 >= deletion.length() / 2.0
|| overlap_length1 >= insertion.length() / 2.0) {
// Overlap found. Insert an equality and trim the
// surrounding edits.
pointer.previous();
pointer.add(new Diff(Operation.EQUAL, insertion.substring(0,
overlap_length1)));
prevDiff.text = deletion.substring(0, deletion.length()
- overlap_length1);
thisDiff.text = insertion.substring(overlap_length1);
// pointer.add inserts the element before the cursor, so
// there is
// no need to step past the new element.
}
} else {
if (overlap_length2 >= deletion.length() / 2.0
|| overlap_length2 >= insertion.length() / 2.0) {
// Reverse overlap found.
// Insert an equality and swap and trim the surrounding
// edits.
pointer.previous();
pointer.add(new Diff(Operation.EQUAL, deletion.substring(0,
overlap_length2)));
prevDiff.operation = Operation.INSERT;
prevDiff.text = insertion.substring(0, insertion.length()
- overlap_length2);
thisDiff.operation = Operation.DELETE;
thisDiff.text = deletion.substring(overlap_length2);
// pointer.add inserts the element before the cursor, so
// there is
// no need to step past the new element.
}
}
thisDiff = pointer.hasNext() ? pointer.next() : null;
}
prevDiff = thisDiff;
thisDiff = pointer.hasNext() ? pointer.next() : null;
}
}
/**
* Look for single edits surrounded on both sides by equalities which can be
* shifted sideways to align the edit to a word boundary. e.g: The c<ins>at
* c</ins>ame. -> The <ins>cat </ins>came.
*
* @param diffs
* LinkedList of Diff objects.
*/
public void diff_cleanupSemanticLossless(LinkedList<Diff> diffs) {
String equality1, edit, equality2;
String commonString;
int commonOffset;
int score, bestScore;
String bestEquality1, bestEdit, bestEquality2;
// Create a new iterator at the start.
ListIterator<Diff> pointer = diffs.listIterator();
Diff prevDiff = pointer.hasNext() ? pointer.next() : null;
Diff thisDiff = pointer.hasNext() ? pointer.next() : null;
Diff nextDiff = pointer.hasNext() ? pointer.next() : null;
// Intentionally ignore the first and last element (don't need
// checking).
while (nextDiff != null) {
if (prevDiff.operation == Operation.EQUAL
&& nextDiff.operation == Operation.EQUAL) {
// This is a single edit surrounded by equalities.
equality1 = prevDiff.text;
edit = thisDiff.text;
equality2 = nextDiff.text;
// First, shift the edit as far left as possible.
commonOffset = diff_commonSuffix(equality1, edit);
if (commonOffset != 0) {
commonString = edit.substring(edit.length() - commonOffset);
equality1 = equality1.substring(0, equality1.length() - commonOffset);
edit = commonString + edit.substring(0, edit.length() - commonOffset);
equality2 = commonString + equality2;
}
// Second, step character by character right, looking for the
// best fit.
bestEquality1 = equality1;
bestEdit = edit;
bestEquality2 = equality2;
bestScore = diff_cleanupSemanticScore(equality1, edit)
+ diff_cleanupSemanticScore(edit, equality2);
while (edit.length() != 0 && equality2.length() != 0
&& edit.charAt(0) == equality2.charAt(0)) {
equality1 += edit.charAt(0);
edit = edit.substring(1) + equality2.charAt(0);
equality2 = equality2.substring(1);
score = diff_cleanupSemanticScore(equality1, edit)
+ diff_cleanupSemanticScore(edit, equality2);
// The >= encourages trailing rather than leading whitespace
// on edits.
if (score >= bestScore) {
bestScore = score;
bestEquality1 = equality1;
bestEdit = edit;
bestEquality2 = equality2;
}
}
if (!prevDiff.text.equals(bestEquality1)) {
// We have an improvement, save it back to the diff.
if (bestEquality1.length() != 0) {
prevDiff.text = bestEquality1;
} else {
pointer.previous(); // Walk past nextDiff.
pointer.previous(); // Walk past thisDiff.
pointer.previous(); // Walk past prevDiff.
pointer.remove(); // Delete prevDiff.
pointer.next(); // Walk past thisDiff.
pointer.next(); // Walk past nextDiff.
}
thisDiff.text = bestEdit;
if (bestEquality2.length() != 0) {
nextDiff.text = bestEquality2;
} else {
pointer.remove(); // Delete nextDiff.
nextDiff = thisDiff;
thisDiff = prevDiff;
}
}
}
prevDiff = thisDiff;
thisDiff = nextDiff;
nextDiff = pointer.hasNext() ? pointer.next() : null;
}
}
/**
* Given two strings, compute a score representing whether the internal
* boundary falls on logical boundaries. Scores range from 6 (best) to 0
* (worst).
*
* @param one
* First string.
* @param two
* Second string.
* @return The score.
*/
private int diff_cleanupSemanticScore(String one, String two) {
if (one.length() == 0 || two.length() == 0) {
// Edges are the best.
return 6;
}
return 0;
// Each port of this function behaves slightly differently due to
// subtle differences in each language's definition of things like
// 'whitespace'. Since this function's purpose is largely cosmetic,
// the choice has been made to use each language's native features
// rather than force total conformity.
// char char1 = one.charAt(one.length() - 1);
// char char2 = two.charAt(0);
// boolean nonAlphaNumeric1 = !Character.isLetterOrDigit(char1);
// boolean nonAlphaNumeric2 = !Character.isLetterOrDigit(char2);
// boolean whitespace1 = nonAlphaNumeric1 && Character.isWhitespace(char1);
// boolean whitespace2 = nonAlphaNumeric2 && Character.isWhitespace(char2);
// boolean lineBreak1 = whitespace1
// && Character.getType(char1) == Character.CONTROL;
// boolean lineBreak2 = whitespace2
// && Character.getType(char2) == Character.CONTROL;
// boolean blankLine1 = lineBreak1 && BLANKLINEEND.matcher(one).find();
// boolean blankLine2 = lineBreak2 && BLANKLINESTART.matcher(two).find();
//
// if (blankLine1 || blankLine2) {
// // Five points for blank lines.
// return 5;
// } else if (lineBreak1 || lineBreak2) {
// // Four points for line breaks.
// return 4;
// } else if (nonAlphaNumeric1 && !whitespace1 && whitespace2) {
// // Three points for end of sentences.
// return 3;
// } else if (whitespace1 || whitespace2) {
// // Two points for whitespace.
// return 2;
// } else if (nonAlphaNumeric1 || nonAlphaNumeric2) {
// // One point for non-alphanumeric.
// return 1;
// }
// return 0;
}
// Define some regex patterns for matching boundaries.
// private Pattern BLANKLINEEND = Pattern.compile("\\n\\r?\\n\\Z",
// Pattern.DOTALL);
// private Pattern BLANKLINESTART = Pattern.compile("\\A\\r?\\n\\r?\\n",
// Pattern.DOTALL);
/**
* Reduce the number of edits by eliminating operationally trivial equalities.
*
* @param diffs
* LinkedList of Diff objects.
*/
public void diff_cleanupEfficiency(LinkedList<Diff> diffs) {
if (diffs.isEmpty()) {
return;
}
boolean changes = false;
Stack<Diff> equalities = new Stack<Diff>(); // Stack of equalities.
String lastequality = null; // Always equal to
// equalities.lastElement().text
ListIterator<Diff> pointer = diffs.listIterator();
// Is there an insertion operation before the last equality.
boolean pre_ins = false;
// Is there a deletion operation before the last equality.
boolean pre_del = false;
// Is there an insertion operation after the last equality.
boolean post_ins = false;
// Is there a deletion operation after the last equality.
boolean post_del = false;
Diff thisDiff = pointer.next();
Diff safeDiff = thisDiff; // The last Diff that is known to be
// unsplitable.
while (thisDiff != null) {
if (thisDiff.operation == Operation.EQUAL) {
// Equality found.
if (thisDiff.text.length() < Diff_EditCost && (post_ins || post_del)) {
// Candidate found.
equalities.push(thisDiff);
pre_ins = post_ins;
pre_del = post_del;
lastequality = thisDiff.text;
} else {
// Not a candidate, and can never become one.
equalities.clear();
lastequality = null;
safeDiff = thisDiff;
}
post_ins = post_del = false;
} else {
// An insertion or deletion.
if (thisDiff.operation == Operation.DELETE) {
post_del = true;
} else {
post_ins = true;
}
/*
* Five types to be split:
* <ins>A</ins><del>B</del>XY<ins>C</ins><del>D</del>
* <ins>A</ins>X<ins>C</ins><del>D</del>
* <ins>A</ins><del>B</del>X<ins>C</ins>
* <ins>A</del>X<ins>C</ins><del>D</del>
* <ins>A</ins><del>B</del>X<del>C</del>
*/
if (lastequality != null
&& ((pre_ins && pre_del && post_ins && post_del) || ((lastequality
.length() < Diff_EditCost / 2) && ((pre_ins ? 1 : 0)
+ (pre_del ? 1 : 0) + (post_ins ? 1 : 0) + (post_del ? 1 : 0)) == 3))) {
// System.out.println("Splitting: '" + lastequality + "'");
// Walk back to offending equality.
while (thisDiff != equalities.lastElement()) {
thisDiff = pointer.previous();
}
pointer.next();
// Replace equality with a delete.
pointer.set(new Diff(Operation.DELETE, lastequality));
// Insert a corresponding an insert.
pointer.add(thisDiff = new Diff(Operation.INSERT, lastequality));
equalities.pop(); // Throw away the equality we just
// deleted.
lastequality = null;
if (pre_ins && pre_del) {
// No changes made which could affect previous entry,
// keep going.
post_ins = post_del = true;
equalities.clear();
safeDiff = thisDiff;
} else {
if (!equalities.empty()) {
// Throw away the previous equality (it needs to be
// reevaluated).
equalities.pop();
}
if (equalities.empty()) {
// There are no previous questionable equalities,
// walk back to the last known safe diff.
thisDiff = safeDiff;
} else {
// There is an equality we can fall back to.
thisDiff = equalities.lastElement();
}
while (thisDiff != pointer.previous()) {
// Intentionally empty loop.
}
post_ins = post_del = false;
}
changes = true;
}
}
thisDiff = pointer.hasNext() ? pointer.next() : null;
}
if (changes) {
diff_cleanupMerge(diffs);
}
}
/**
* Reorder and merge like edit sections. Merge equalities. Any edit section
* can move as long as it doesn't cross an equality.
*
* @param diffs
* LinkedList of Diff objects.
*/
public void diff_cleanupMerge(LinkedList<Diff> diffs) {
diffs.add(new Diff(Operation.EQUAL, "")); // Add a dummy entry at the
// end.
ListIterator<Diff> pointer = diffs.listIterator();
int count_delete = 0;
int count_insert = 0;
String text_delete = "";
String text_insert = "";
Diff thisDiff = pointer.next();
Diff prevEqual = null;
int commonlength;
while (thisDiff != null) {
switch (thisDiff.operation) {
case INSERT:
count_insert++;
text_insert += thisDiff.text;
prevEqual = null;
break;
case DELETE:
count_delete++;
text_delete += thisDiff.text;
prevEqual = null;
break;
case EQUAL:
if (count_delete + count_insert > 1) {
boolean both_types = count_delete != 0 && count_insert != 0;
// Delete the offending records.
pointer.previous(); // Reverse direction.
while (count_delete-- > 0) {
pointer.previous();
pointer.remove();
}
while (count_insert-- > 0) {
pointer.previous();
pointer.remove();
}
if (both_types) {
// Factor out any common prefixies.
commonlength = diff_commonPrefix(text_insert, text_delete);
if (commonlength != 0) {
if (pointer.hasPrevious()) {
thisDiff = pointer.previous();
assert thisDiff.operation == Operation.EQUAL : "Previous diff should have been an equality.";
thisDiff.text += text_insert.substring(0, commonlength);
pointer.next();
} else {
pointer.add(new Diff(Operation.EQUAL, text_insert.substring(0,
commonlength)));
}
text_insert = text_insert.substring(commonlength);
text_delete = text_delete.substring(commonlength);
}
// Factor out any common suffixies.
commonlength = diff_commonSuffix(text_insert, text_delete);
if (commonlength != 0) {
thisDiff = pointer.next();
thisDiff.text = text_insert.substring(text_insert.length()
- commonlength)
+ thisDiff.text;
text_insert = text_insert.substring(0, text_insert.length()
- commonlength);
text_delete = text_delete.substring(0, text_delete.length()
- commonlength);
pointer.previous();
}
}
// Insert the merged records.
if (text_delete.length() != 0) {
pointer.add(new Diff(Operation.DELETE, text_delete));
}
if (text_insert.length() != 0) {
pointer.add(new Diff(Operation.INSERT, text_insert));
}
// Step forward to the equality.
thisDiff = pointer.hasNext() ? pointer.next() : null;
} else if (prevEqual != null) {
// Merge this equality with the previous one.
prevEqual.text += thisDiff.text;
pointer.remove();
thisDiff = pointer.previous();
pointer.next(); // Forward direction
}
count_insert = 0;
count_delete = 0;
text_delete = "";
text_insert = "";
prevEqual = thisDiff;
break;
}
thisDiff = pointer.hasNext() ? pointer.next() : null;
}
if (diffs.getLast().text.length() == 0) {
diffs.removeLast(); // Remove the dummy entry at the end.
}
/*
* Second pass: look for single edits surrounded on both sides by equalities
* which can be shifted sideways to eliminate an equality. e.g:
* A<ins>BA</ins>C -> <ins>AB</ins>AC
*/
boolean changes = false;
// Create a new iterator at the start.
// (As opposed to walking the current one back.)
pointer = diffs.listIterator();
Diff prevDiff = pointer.hasNext() ? pointer.next() : null;
thisDiff = pointer.hasNext() ? pointer.next() : null;
Diff nextDiff = pointer.hasNext() ? pointer.next() : null;
// Intentionally ignore the first and last element (don't need
// checking).
while (nextDiff != null) {
if (prevDiff.operation == Operation.EQUAL
&& nextDiff.operation == Operation.EQUAL) {
// This is a single edit surrounded by equalities.
if (thisDiff.text.endsWith(prevDiff.text)) {
// Shift the edit over the previous equality.
thisDiff.text = prevDiff.text
+ thisDiff.text.substring(0, thisDiff.text.length()
- prevDiff.text.length());
nextDiff.text = prevDiff.text + nextDiff.text;
pointer.previous(); // Walk past nextDiff.
pointer.previous(); // Walk past thisDiff.
pointer.previous(); // Walk past prevDiff.
pointer.remove(); // Delete prevDiff.
pointer.next(); // Walk past thisDiff.
thisDiff = pointer.next(); // Walk past nextDiff.
nextDiff = pointer.hasNext() ? pointer.next() : null;
changes = true;
} else if (thisDiff.text.startsWith(nextDiff.text)) {
// Shift the edit over the next equality.
prevDiff.text += nextDiff.text;
thisDiff.text = thisDiff.text.substring(nextDiff.text.length())
+ nextDiff.text;
pointer.remove(); // Delete nextDiff.
nextDiff = pointer.hasNext() ? pointer.next() : null;
changes = true;
}
}
prevDiff = thisDiff;
thisDiff = nextDiff;
nextDiff = pointer.hasNext() ? pointer.next() : null;
}
// If shifts were made, the diff needs reordering and another shift
// sweep.
if (changes) {
diff_cleanupMerge(diffs);
}
}
/**
* loc is a location in text1, compute and return the equivalent location in
* text2. e.g. "The cat" vs "The big cat", 1->1, 5->8
*
* @param diffs
* LinkedList of Diff objects.
* @param loc
* Location within text1.
* @return Location within text2.
*/
public int diff_xIndex(LinkedList<Diff> diffs, int loc) {
int chars1 = 0;
int chars2 = 0;
int last_chars1 = 0;
int last_chars2 = 0;
Diff lastDiff = null;
for (Diff aDiff : diffs) {
if (aDiff.operation != Operation.INSERT) {
// Equality or deletion.
chars1 += aDiff.text.length();
}
if (aDiff.operation != Operation.DELETE) {
// Equality or insertion.
chars2 += aDiff.text.length();
}
if (chars1 > loc) {
// Overshot the location.
lastDiff = aDiff;
break;
}
last_chars1 = chars1;
last_chars2 = chars2;
}
if (lastDiff != null && lastDiff.operation == Operation.DELETE) {
// The location was deleted.
return last_chars2;
}
// Add the remaining character length.
return last_chars2 + (loc - last_chars1);
}
/**
* Convert a Diff list into a pretty HTML report.
*
* @param diffs
* LinkedList of Diff objects.
* @return HTML representation.
*/
public String diff_prettyHtml(LinkedList<Diff> diffs) {
StringBuilder html = new StringBuilder();
for (Diff aDiff : diffs) {
String text = aDiff.text.replace("&", "&").replace("<", "<")
.replace(">", ">").replace("\n", "¶<br>");
switch (aDiff.operation) {
case INSERT:
html.append("<ins style=\"background:#e6ffe6;\">").append(text)
.append("</ins>");
break;
case DELETE:
html.append("<del style=\"background:#ffe6e6;\">").append(text)
.append("</del>");
break;
case EQUAL:
html.append("<span>").append(text).append("</span>");
break;
}
}
return html.toString();
}
/**
* Compute and return the source text (all equalities and deletions).
*
* @param diffs
* LinkedList of Diff objects.
* @return Source text.
*/
public String diff_text1(LinkedList<Diff> diffs) {
StringBuilder text = new StringBuilder();
for (Diff aDiff : diffs) {
if (aDiff.operation != Operation.INSERT) {
text.append(aDiff.text);
}
}
return text.toString();
}
/**
* Compute and return the destination text (all equalities and insertions).
*
* @param diffs
* LinkedList of Diff objects.
* @return Destination text.
*/
public String diff_text2(LinkedList<Diff> diffs) {
StringBuilder text = new StringBuilder();
for (Diff aDiff : diffs) {
if (aDiff.operation != Operation.DELETE) {
text.append(aDiff.text);
}
}
return text.toString();
}
/**
* Compute the Levenshtein distance; the number of inserted, deleted or
* substituted characters.
*
* @param diffs
* LinkedList of Diff objects.
* @return Number of changes.
*/
public int diff_levenshtein(LinkedList<Diff> diffs) {
int levenshtein = 0;
int insertions = 0;
int deletions = 0;
for (Diff aDiff : diffs) {
switch (aDiff.operation) {
case INSERT:
insertions += aDiff.text.length();
break;
case DELETE:
deletions += aDiff.text.length();
break;
case EQUAL:
// A deletion and an insertion is one substitution.
levenshtein += Math.max(insertions, deletions);
insertions = 0;
deletions = 0;
break;
}
}
levenshtein += Math.max(insertions, deletions);
return levenshtein;
}
/**
* Crush the diff into an encoded string which describes the operations
* required to transform text1 into text2. E.g. =3\t-2\t+ing -> Keep 3 chars,
* delete 2 chars, insert 'ing'. Operations are tab-separated. Inserted text
* is escaped using %xx notation.
*
* @param diffs
* Array of Diff objects.
* @return Delta text.
*/
public String diff_toDelta(LinkedList<Diff> diffs) {
// StringBuilder text = new StringBuilder();
// for (Diff aDiff : diffs) {
// switch (aDiff.operation) {
// case INSERT:
// try {
// text.append("+")
// .append(URLEncoder.encode(aDiff.text, "UTF-8")
// .replace('+', ' ')).append("\t");
// } catch (UnsupportedEncodingException e) {
// // Not likely on modern system.
// throw new Error("This system does not support UTF-8.", e);
// }
// break;
// case DELETE:
// text.append("-").append(aDiff.text.length()).append("\t");
// break;
// case EQUAL:
// text.append("=").append(aDiff.text.length()).append("\t");
// break;
// }
// }
// String delta = text.toString();
// if (delta.length() != 0) {
// // Strip off trailing tab character.
// delta = delta.substring(0, delta.length() - 1);
// delta = unescapeForEncodeUriCompatability(delta);
// }
// return delta;
System.out.println("Diff Match cette fonction est utile noob 1555");
return null;
}
/**
* Given the original text1, and an encoded string which describes the
* operations required to transform text1 into text2, compute the full diff.
*
* @param text1
* Source string for the diff.
* @param delta
* Delta text.
* @return Array of Diff objects or null if invalid.
* @throws IllegalArgumentException
* If invalid input.
*/
public LinkedList<Diff> diff_fromDelta(String text1, String delta)
throws IllegalArgumentException {
// LinkedList<Diff> diffs = new LinkedList<Diff>();
// int pointer = 0; // Cursor in text1
// String[] tokens = delta.split("\t");
// for (String token : tokens) {
// if (token.length() == 0) {
// // Blank tokens are ok (from a trailing \t).
// continue;
// }
// // Each token begins with a one character parameter which specifies
// // the
// // operation of this token (delete, insert, equality).
// String param = token.substring(1);
// switch (token.charAt(0)) {
// case '+':
// // decode would change all "+" to " "
// param = param.replace("+", "%2B");
// try {
// param = URLDecoder.decode(param, "UTF-8");
// } catch (UnsupportedEncodingException e) {
// // Not likely on modern system.
// throw new Error("This system does not support UTF-8.", e);
// } catch (IllegalArgumentException e) {
// // Malformed URI sequence.
// throw new IllegalArgumentException(
// "Illegal escape in diff_fromDelta: " + param, e);
// }
// diffs.add(new Diff(Operation.INSERT, param));
// break;
// case '-':
// // Fall through.
// case '=':
// int n;
// try {
// n = Integer.parseInt(param);
// } catch (NumberFormatException e) {
// throw new IllegalArgumentException(
// "Invalid number in diff_fromDelta: " + param, e);
// }
// if (n < 0) {
// throw new IllegalArgumentException(
// "Negative number in diff_fromDelta: " + param);
// }
// String text;
// try {
// text = text1.substring(pointer, pointer += n);
// } catch (StringIndexOutOfBoundsException e) {
// throw new IllegalArgumentException("Delta length ("
// + pointer + ") larger than source text length ("
// + text1.length() + ").", e);
// }
// if (token.charAt(0) == '=') {
// diffs.add(new Diff(Operation.EQUAL, text));
// } else {
// diffs.add(new Diff(Operation.DELETE, text));
// }
// break;
// default:
// // Anything else is an error.
// throw new IllegalArgumentException(
// "Invalid diff operation in diff_fromDelta: "
// + token.charAt(0));
// }
// }
// if (pointer != text1.length()) {
// throw new IllegalArgumentException("Delta length (" + pointer
// + ") smaller than source text length (" + text1.length()
// + ").");
// }
// return diffs;
System.out.println("Diff Match cette fonction est utile noob 1642");
return null;
}
// MATCH FUNCTIONS
/**
* Locate the best instance of 'pattern' in 'text' near 'loc'. Returns -1 if
* no match found.
*
* @param text
* The text to search.
* @param pattern
* The pattern to search for.
* @param loc
* The location to search around.
* @return Best match index or -1.
*/
public int match_main(String text, String pattern, int loc) {
// Check for null inputs.
if (text == null || pattern == null) {
throw new IllegalArgumentException("Null inputs. (match_main)");
}
loc = Math.max(0, Math.min(loc, text.length()));
if (text.equals(pattern)) {
// Shortcut (potentially not guaranteed by the algorithm)
return 0;
} else if (text.length() == 0) {
// Nothing to match.
return -1;
} else if (loc + pattern.length() <= text.length()
&& text.substring(loc, loc + pattern.length()).equals(pattern)) {
// Perfect match at the perfect spot! (Includes case of null
// pattern)
return loc;
} else {
// Do a fuzzy compare.
return match_bitap(text, pattern, loc);
}
}
/**
* Locate the best instance of 'pattern' in 'text' near 'loc' using the Bitap
* algorithm. Returns -1 if no match found.
*
* @param text
* The text to search.
* @param pattern
* The pattern to search for.
* @param loc
* The location to search around.
* @return Best match index or -1.
*/
protected int match_bitap(String text, String pattern, int loc) {
assert (Match_MaxBits == 0 || pattern.length() <= Match_MaxBits) : "Pattern too long for this application.";
// Initialise the alphabet.
Map<Character, Integer> s = match_alphabet(pattern);
// Highest score beyond which we give up.
double score_threshold = Match_Threshold;
// Is there a nearby exact match? (speedup)
int best_loc = text.indexOf(pattern, loc);
if (best_loc != -1) {
score_threshold = Math.min(match_bitapScore(0, best_loc, loc, pattern),
score_threshold);
// What about in the other direction? (speedup)
best_loc = text.lastIndexOf(pattern, loc + pattern.length());
if (best_loc != -1) {
score_threshold = Math.min(match_bitapScore(0, best_loc, loc, pattern),
score_threshold);
}
}
// Initialise the bit arrays.
int matchmask = 1 << (pattern.length() - 1);
best_loc = -1;
int bin_min, bin_mid;
int bin_max = pattern.length() + text.length();
// Empty initialization added to appease Java compiler.
int[] last_rd = new int[0];
for (int d = 0; d < pattern.length(); d++) {
// Scan for the best match; each iteration allows for one more
// error.
// Run a binary search to determine how far from 'loc' we can stray
// at
// this error level.
bin_min = 0;
bin_mid = bin_max;
while (bin_min < bin_mid) {
if (match_bitapScore(d, loc + bin_mid, loc, pattern) <= score_threshold) {
bin_min = bin_mid;
} else {
bin_max = bin_mid;
}
bin_mid = (bin_max - bin_min) / 2 + bin_min;
}
// Use the result from this iteration as the maximum for the next.
bin_max = bin_mid;
int start = Math.max(1, loc - bin_mid + 1);
int finish = Math.min(loc + bin_mid, text.length()) + pattern.length();
int[] rd = new int[finish + 2];
rd[finish + 1] = (1 << d) - 1;
for (int j = finish; j >= start; j--) {
int charMatch;
if (text.length() <= j - 1 || !s.containsKey(text.charAt(j - 1))) {
// Out of range.
charMatch = 0;
} else {
charMatch = s.get(text.charAt(j - 1));
}
if (d == 0) {
// First pass: exact match.
rd[j] = ((rd[j + 1] << 1) | 1) & charMatch;
} else {
// Subsequent passes: fuzzy match.
rd[j] = (((rd[j + 1] << 1) | 1) & charMatch)
| (((last_rd[j + 1] | last_rd[j]) << 1) | 1) | last_rd[j + 1];
}
if ((rd[j] & matchmask) != 0) {
double score = match_bitapScore(d, j - 1, loc, pattern);
// This match will almost certainly be better than any
// existing
// match. But check anyway.
if (score <= score_threshold) {
// Told you so.
score_threshold = score;
best_loc = j - 1;
if (best_loc > loc) {
// When passing loc, don't exceed our current
// distance from loc.
start = Math.max(1, 2 * loc - best_loc);
} else {
// Already passed loc, downhill from here on in.
break;
}
}
}
}
if (match_bitapScore(d + 1, loc, loc, pattern) > score_threshold) {
// No hope for a (better) match at greater error levels.
break;
}
last_rd = rd;
}
return best_loc;
}
/**
* Compute and return the score for a match with e errors and x location.
*
* @param e
* Number of errors in match.
* @param x
* Location of match.
* @param loc
* Expected location of match.
* @param pattern
* Pattern being sought.
* @return Overall score for match (0.0 = good, 1.0 = bad).
*/
private double match_bitapScore(int e, int x, int loc, String pattern) {
float accuracy = (float) e / pattern.length();
int proximity = Math.abs(loc - x);
if (Match_Distance == 0) {
// Dodge divide by zero error.
return proximity == 0 ? accuracy : 1.0;
}
return accuracy + (proximity / (float) Match_Distance);
}
/**
* Initialise the alphabet for the Bitap algorithm.
*
* @param pattern
* The text to encode.
* @return Hash of character locations.
*/
protected Map<Character, Integer> match_alphabet(String pattern) {
Map<Character, Integer> s = new HashMap<Character, Integer>();
char[] char_pattern = pattern.toCharArray();
for (char c : char_pattern) {
s.put(c, 0);
}
int i = 0;
for (char c : char_pattern) {
s.put(c, s.get(c) | (1 << (pattern.length() - i - 1)));
i++;
}
return s;
}
// PATCH FUNCTIONS
/**
* Increase the context until it is unique, but don't let the pattern expand
* beyond Match_MaxBits.
*
* @param patch
* The patch to grow.
* @param text
* Source text.
*/
// protected void patch_addContext(Patch patch, String text) {
// if (text.length() == 0) {
// return;
// }
// String pattern = text.substring(patch.start2, patch.start2
// + patch.length1);
// int padding = 0;
//
// // Look for the first and last matches of pattern in text. If two
// // different
// // matches are found, increase the pattern length.
// while (text.indexOf(pattern) != text.lastIndexOf(pattern)
// && pattern.length() < Match_MaxBits - Patch_Margin
// - Patch_Margin) {
// padding += Patch_Margin;
// pattern = text.substring(
// Math.max(0, patch.start2 - padding),
// Math.min(text.length(), patch.start2 + patch.length1
// + padding));
// }
// // Add one chunk for good luck.
// padding += Patch_Margin;
//
// // Add the prefix.
// String prefix = text.substring(Math.max(0, patch.start2 - padding),
// patch.start2);
// if (prefix.length() != 0) {
// patch.diffs.addFirst(new Diff(Operation.EQUAL, prefix));
// }
// // Add the suffix.
// String suffix = text
// .substring(
// patch.start2 + patch.length1,
// Math.min(text.length(), patch.start2 + patch.length1
// + padding));
// if (suffix.length() != 0) {
// patch.diffs.addLast(new Diff(Operation.EQUAL, suffix));
// }
//
// // Roll back the start points.
// patch.start1 -= prefix.length();
// patch.start2 -= prefix.length();
// // Extend the lengths.
// patch.length1 += prefix.length() + suffix.length();
// patch.length2 += prefix.length() + suffix.length();
// }
//
// /**
// * Compute a list of patches to turn text1 into text2. A set of diffs will
// * be computed.
// *
// * @param text1
// * Old text.
// * @param text2
// * New text.
// * @return LinkedList of Patch objects.
// */
// public LinkedList<Patch> patch_make(String text1, String text2) {
// if (text1 == null || text2 == null) {
// throw new IllegalArgumentException("Null inputs. (patch_make)");
// }
// // No diffs provided, compute our own.
// LinkedList<Diff> diffs = diff_main(text1, text2, true);
// if (diffs.size() > 2) {
// diff_cleanupSemantic(diffs);
// diff_cleanupEfficiency(diffs);
// }
// return patch_make(text1, diffs);
// }
//
// /**
// * Compute a list of patches to turn text1 into text2. text1 will be derived
// * from the provided diffs.
// *
// * @param diffs
// * Array of Diff objects for text1 to text2.
// * @return LinkedList of Patch objects.
// */
// public LinkedList<Patch> patch_make(LinkedList<Diff> diffs) {
// if (diffs == null) {
// throw new IllegalArgumentException("Null inputs. (patch_make)");
// }
// // No origin string provided, compute our own.
// String text1 = diff_text1(diffs);
// return patch_make(text1, diffs);
// }
//
// /**
// * Compute a list of patches to turn text1 into text2. text2 is ignored,
// * diffs are the delta between text1 and text2.
// *
// * @param text1
// * Old text
// * @param text2
// * Ignored.
// * @param diffs
// * Array of Diff objects for text1 to text2.
// * @return LinkedList of Patch objects.
// * @deprecated Prefer patch_make(String text1, LinkedList<Diff> diffs).
// */
// public LinkedList<Patch> patch_make(String text1, String text2,
// LinkedList<Diff> diffs) {
// return patch_make(text1, diffs);
// }
//
// /**
// * Compute a list of patches to turn text1 into text2. text2 is not
// * provided, diffs are the delta between text1 and text2.
// *
// * @param text1
// * Old text.
// * @param diffs
// * Array of Diff objects for text1 to text2.
// * @return LinkedList of Patch objects.
// */
// // public LinkedList<Patch> patch_make(String text1, LinkedList<Diff>
// diffs) {
// // if (text1 == null || diffs == null) {
// // throw new IllegalArgumentException("Null inputs. (patch_make)");
// // }
// //
// // LinkedList<Patch> patches = new LinkedList<Patch>();
// // if (diffs.isEmpty()) {
// // return patches; // Get rid of the null case.
// // }
// // Patch patch = new Patch();
// // int char_count1 = 0; // Number of characters into the text1 string.
// // int char_count2 = 0; // Number of characters into the text2 string.
// // // Start with text1 (prepatch_text) and apply the diffs until we arrive
// // // at
// // // text2 (postpatch_text). We recreate the patches one by one to
// // // determine
// // // context info.
// // String prepatch_text = text1;
// // String postpatch_text = text1;
// // for (Diff aDiff : diffs) {
// // if (patch.diffs.isEmpty() && aDiff.operation != Operation.EQUAL) {
// // // A new patch starts here.
// // patch.start1 = char_count1;
// // patch.start2 = char_count2;
// // }
// //
// // switch (aDiff.operation) {
// // case INSERT:
// // patch.diffs.add(aDiff);
// // patch.length2 += aDiff.text.length();
// // postpatch_text = postpatch_text.substring(0, char_count2)
// // + aDiff.text + postpatch_text.substring(char_count2);
// // break;
// // case DELETE:
// // patch.length1 += aDiff.text.length();
// // patch.diffs.add(aDiff);
// // postpatch_text = postpatch_text.substring(0, char_count2)
// // + postpatch_text.substring(char_count2
// // + aDiff.text.length());
// // break;
// // case EQUAL:
// // if (aDiff.text.length() <= 2 * Patch_Margin
// // && !patch.diffs.isEmpty() && aDiff != diffs.getLast()) {
// // // Small equality inside a patch.
// // patch.diffs.add(aDiff);
// // patch.length1 += aDiff.text.length();
// // patch.length2 += aDiff.text.length();
// // }
// //
// // if (aDiff.text.length() >= 2 * Patch_Margin) {
// // // Time for a new patch.
// // if (!patch.diffs.isEmpty()) {
// // patch_addContext(patch, prepatch_text);
// // patches.add(patch);
// // patch = new Patch();
// // // Unlike Unidiff, our patch lists have a rolling
// // // context.
// // // http://code.google.com/p/google-diff-match-patch/wiki/Unidiff
// // // Update prepatch text & pos to reflect the application
// // // of the
// // // just completed patch.
// // prepatch_text = postpatch_text;
// // char_count1 = char_count2;
// // }
// // }
// // break;
// // }
// //
// // // Update the current character count.
// // if (aDiff.operation != Operation.INSERT) {
// // char_count1 += aDiff.text.length();
// // }
// // if (aDiff.operation != Operation.DELETE) {
// // char_count2 += aDiff.text.length();
// // }
// // }
// // // Pick up the leftover patch if not empty.
// // if (!patch.diffs.isEmpty()) {
// // patch_addContext(patch, prepatch_text);
// // patches.add(patch);
// // }
// //
// // return patches;
// // }
//
// /**
// * Given an array of patches, return another array that is identical.
// *
// * @param patches
// * Array of Patch objects.
// * @return Array of Patch objects.
// */
// // public LinkedList<Patch> patch_deepCopy(LinkedList<Patch> patches) {
// // LinkedList<Patch> patchesCopy = new LinkedList<Patch>();
// // for (Patch aPatch : patches) {
// // Patch patchCopy = new Patch();
// // for (Diff aDiff : aPatch.diffs) {
// // Diff diffCopy = new Diff(aDiff.operation, aDiff.text);
// // patchCopy.diffs.add(diffCopy);
// // }
// // patchCopy.start1 = aPatch.start1;
// // patchCopy.start2 = aPatch.start2;
// // patchCopy.length1 = aPatch.length1;
// // patchCopy.length2 = aPatch.length2;
// // patchesCopy.add(patchCopy);
// // }
// // return patchesCopy;
// // }
//
// /**
// * Merge a set of patches onto the text. Return a patched text, as well as
// * an array of true/false values indicating which patches were applied.
// *
// * @param patches
// * Array of Patch objects
// * @param text
// * Old text.
// * @return Two element Object array, containing the new text and an array of
// * boolean values.
// */
// public Object[] patch_apply(LinkedList<Patch> patches, String text) {
// if (patches.isEmpty()) {
// return new Object[] { text, new boolean[0] };
// }
//
// // Deep copy the patches so that no changes are made to originals.
// patches = patch_deepCopy(patches);
//
// String nullPadding = patch_addPadding(patches);
// text = nullPadding + text + nullPadding;
// patch_splitMax(patches);
//
// int x = 0;
// // delta keeps track of the offset between the expected and actual
// // location
// // of the previous patch. If there are patches expected at positions 10
// // and
// // 20, but the first patch was found at 12, delta is 2 and the second
// // patch
// // has an effective expected position of 22.
// int delta = 0;
// boolean[] results = new boolean[patches.size()];
// for (Patch aPatch : patches) {
// int expected_loc = aPatch.start2 + delta;
// String text1 = diff_text1(aPatch.diffs);
// int start_loc;
// int end_loc = -1;
// if (text1.length() > this.Match_MaxBits) {
// // patch_splitMax will only provide an oversized pattern in the
// // case of
// // a monster delete.
// start_loc = match_main(text,
// text1.substring(0, this.Match_MaxBits), expected_loc);
// if (start_loc != -1) {
// end_loc = match_main(text, text1.substring(text1.length()
// - this.Match_MaxBits),
// expected_loc + text1.length() - this.Match_MaxBits);
// if (end_loc == -1 || start_loc >= end_loc) {
// // Can't find valid trailing context. Drop this patch.
// start_loc = -1;
// }
// }
// } else {
// start_loc = match_main(text, text1, expected_loc);
// }
// if (start_loc == -1) {
// // No match found. :(
// results[x] = false;
// // Subtract the delta for this failed patch from subsequent
// // patches.
// delta -= aPatch.length2 - aPatch.length1;
// } else {
// // Found a match. :)
// results[x] = true;
// delta = start_loc - expected_loc;
// String text2;
// if (end_loc == -1) {
// text2 = text
// .substring(
// start_loc,
// Math.min(start_loc + text1.length(),
// text.length()));
// } else {
// text2 = text.substring(
// start_loc,
// Math.min(end_loc + this.Match_MaxBits,
// text.length()));
// }
// if (text1.equals(text2)) {
// // Perfect match, just shove the replacement text in.
// text = text.substring(0, start_loc)
// + diff_text2(aPatch.diffs)
// + text.substring(start_loc + text1.length());
// } else {
// // Imperfect match. Run a diff to get a framework of
// // equivalent
// // indices.
// LinkedList<Diff> diffs = diff_main(text1, text2, false);
// if (text1.length() > this.Match_MaxBits
// && diff_levenshtein(diffs) / (float) text1.length() >
// this.Patch_DeleteThreshold) {
// // The end points match, but the content is unacceptably
// // bad.
// results[x] = false;
// } else {
// diff_cleanupSemanticLossless(diffs);
// int index1 = 0;
// for (Diff aDiff : aPatch.diffs) {
// if (aDiff.operation != Operation.EQUAL) {
// int index2 = diff_xIndex(diffs, index1);
// if (aDiff.operation == Operation.INSERT) {
// // Insertion
// text = text
// .substring(0, start_loc + index2)
// + aDiff.text
// + text.substring(start_loc + index2);
// } else if (aDiff.operation == Operation.DELETE) {
// // Deletion
// text = text
// .substring(0, start_loc + index2)
// + text.substring(start_loc
// + diff_xIndex(
// diffs,
// index1
// + aDiff.text
// .length()));
// }
// }
// if (aDiff.operation != Operation.DELETE) {
// index1 += aDiff.text.length();
// }
// }
// }
// }
// }
// x++;
// }
// // Strip the padding off.
// text = text.substring(nullPadding.length(),
// text.length() - nullPadding.length());
// return new Object[] { text, results };
// }
//
// /**
// * Add some padding on text start and end so that edges can match something.
// * Intended to be called only from within patch_apply.
// *
// * @param patches
// * Array of Patch objects.
// * @return The padding string added to each side.
// */
// public String patch_addPadding(LinkedList<Patch> patches) {
// short paddingLength = this.Patch_Margin;
// String nullPadding = "";
// for (short x = 1; x <= paddingLength; x++) {
// nullPadding += String.valueOf((char) x);
// }
//
// // Bump all the patches forward.
// for (Patch aPatch : patches) {
// aPatch.start1 += paddingLength;
// aPatch.start2 += paddingLength;
// }
//
// // Add some padding on start of first diff.
// Patch patch = patches.getFirst();
// LinkedList<Diff> diffs = patch.diffs;
// if (diffs.isEmpty() || diffs.getFirst().operation != Operation.EQUAL) {
// // Add nullPadding equality.
// diffs.addFirst(new Diff(Operation.EQUAL, nullPadding));
// patch.start1 -= paddingLength; // Should be 0.
// patch.start2 -= paddingLength; // Should be 0.
// patch.length1 += paddingLength;
// patch.length2 += paddingLength;
// } else if (paddingLength > diffs.getFirst().text.length()) {
// // Grow first equality.
// Diff firstDiff = diffs.getFirst();
// int extraLength = paddingLength - firstDiff.text.length();
// firstDiff.text = nullPadding.substring(firstDiff.text.length())
// + firstDiff.text;
// patch.start1 -= extraLength;
// patch.start2 -= extraLength;
// patch.length1 += extraLength;
// patch.length2 += extraLength;
// }
//
// // Add some padding on end of last diff.
// patch = patches.getLast();
// diffs = patch.diffs;
// if (diffs.isEmpty() || diffs.getLast().operation != Operation.EQUAL) {
// // Add nullPadding equality.
// diffs.addLast(new Diff(Operation.EQUAL, nullPadding));
// patch.length1 += paddingLength;
// patch.length2 += paddingLength;
// } else if (paddingLength > diffs.getLast().text.length()) {
// // Grow last equality.
// Diff lastDiff = diffs.getLast();
// int extraLength = paddingLength - lastDiff.text.length();
// lastDiff.text += nullPadding.substring(0, extraLength);
// patch.length1 += extraLength;
// patch.length2 += extraLength;
// }
//
// return nullPadding;
// }
//
// /**
// * Look through the patches and break up any which are longer than the
// * maximum limit of the match algorithm. Intended to be called only from
// * within patch_apply.
// *
// * @param patches
// * LinkedList of Patch objects.
// */
// public void patch_splitMax(LinkedList<Patch> patches) {
// short patch_size = Match_MaxBits;
// String precontext, postcontext;
// Patch patch;
// int start1, start2;
// boolean empty;
// Operation diff_type;
// String diff_text;
// ListIterator<Patch> pointer = patches.listIterator();
// Patch bigpatch = pointer.hasNext() ? pointer.next() : null;
// while (bigpatch != null) {
// if (bigpatch.length1 <= Match_MaxBits) {
// bigpatch = pointer.hasNext() ? pointer.next() : null;
// continue;
// }
// // Remove the big old patch.
// pointer.remove();
// start1 = bigpatch.start1;
// start2 = bigpatch.start2;
// precontext = "";
// while (!bigpatch.diffs.isEmpty()) {
// // Create one of several smaller patches.
// patch = new Patch();
// empty = true;
// patch.start1 = start1 - precontext.length();
// patch.start2 = start2 - precontext.length();
// if (precontext.length() != 0) {
// patch.length1 = patch.length2 = precontext.length();
// patch.diffs.add(new Diff(Operation.EQUAL, precontext));
// }
// while (!bigpatch.diffs.isEmpty()
// && patch.length1 < patch_size - Patch_Margin) {
// diff_type = bigpatch.diffs.getFirst().operation;
// diff_text = bigpatch.diffs.getFirst().text;
// if (diff_type == Operation.INSERT) {
// // Insertions are harmless.
// patch.length2 += diff_text.length();
// start2 += diff_text.length();
// patch.diffs.addLast(bigpatch.diffs.removeFirst());
// empty = false;
// } else if (diff_type == Operation.DELETE
// && patch.diffs.size() == 1
// && patch.diffs.getFirst().operation == Operation.EQUAL
// && diff_text.length() > 2 * patch_size) {
// // This is a large deletion. Let it pass in one chunk.
// patch.length1 += diff_text.length();
// start1 += diff_text.length();
// empty = false;
// patch.diffs.add(new Diff(diff_type, diff_text));
// bigpatch.diffs.removeFirst();
// } else {
// // Deletion or equality. Only take as much as we can
// // stomach.
// diff_text = diff_text.substring(
// 0,
// Math.min(diff_text.length(), patch_size
// - patch.length1 - Patch_Margin));
// patch.length1 += diff_text.length();
// start1 += diff_text.length();
// if (diff_type == Operation.EQUAL) {
// patch.length2 += diff_text.length();
// start2 += diff_text.length();
// } else {
// empty = false;
// }
// patch.diffs.add(new Diff(diff_type, diff_text));
// if (diff_text.equals(bigpatch.diffs.getFirst().text)) {
// bigpatch.diffs.removeFirst();
// } else {
// bigpatch.diffs.getFirst().text = bigpatch.diffs
// .getFirst().text.substring(diff_text
// .length());
// }
// }
// }
// // Compute the head context for the next patch.
// precontext = diff_text2(patch.diffs);
// precontext = precontext.substring(Math.max(0,
// precontext.length() - Patch_Margin));
// // Append the end context for this patch.
// if (diff_text1(bigpatch.diffs).length() > Patch_Margin) {
// postcontext = diff_text1(bigpatch.diffs).substring(0,
// Patch_Margin);
// } else {
// postcontext = diff_text1(bigpatch.diffs);
// }
// if (postcontext.length() != 0) {
// patch.length1 += postcontext.length();
// patch.length2 += postcontext.length();
// if (!patch.diffs.isEmpty()
// && patch.diffs.getLast().operation == Operation.EQUAL) {
// patch.diffs.getLast().text += postcontext;
// } else {
// patch.diffs.add(new Diff(Operation.EQUAL, postcontext));
// }
// }
// if (!empty) {
// pointer.add(patch);
// }
// }
// bigpatch = pointer.hasNext() ? pointer.next() : null;
// }
// }
//
// /**
// * Take a list of patches and return a textual representation.
// *
// * @param patches
// * List of Patch objects.
// * @return Text representation of patches.
// */
// public String patch_toText(List<Patch> patches) {
// StringBuilder text = new StringBuilder();
// for (Patch aPatch : patches) {
// text.append(aPatch);
// }
// return text.toString();
// }
//
// /**
// * Parse a textual representation of patches and return a List of Patch
// * objects.
// *
// * @param textline
// * Text representation of patches.
// * @return List of Patch objects.
// * @throws IllegalArgumentException
// * If invalid input.
// */
// public List<Patch> patch_fromText(String textline)
// throws IllegalArgumentException {
// List<Patch> patches = new LinkedList<Patch>();
// if (textline.length() == 0) {
// return patches;
// }
// List<String> textList = Arrays.asList(textline.split("\n"));
// LinkedList<String> text = new LinkedList<String>(textList);
// Patch patch;
// Pattern patchHeader = Pattern
// .compile("^@@ -(\\d+),?(\\d*) \\+(\\d+),?(\\d*) @@$");
// Matcher m;
// char sign;
// String line;
// while (!text.isEmpty()) {
// m = patchHeader.matcher(text.getFirst());
// if (!m.matches()) {
// throw new IllegalArgumentException("Invalid patch string: "
// + text.getFirst());
// }
// patch = new Patch();
// patches.add(patch);
// patch.start1 = Integer.parseInt(m.group(1));
// if (m.group(2).length() == 0) {
// patch.start1--;
// patch.length1 = 1;
// } else if (m.group(2).equals("0")) {
// patch.length1 = 0;
// } else {
// patch.start1--;
// patch.length1 = Integer.parseInt(m.group(2));
// }
//
// patch.start2 = Integer.parseInt(m.group(3));
// if (m.group(4).length() == 0) {
// patch.start2--;
// patch.length2 = 1;
// } else if (m.group(4).equals("0")) {
// patch.length2 = 0;
// } else {
// patch.start2--;
// patch.length2 = Integer.parseInt(m.group(4));
// }
// text.removeFirst();
//
// while (!text.isEmpty()) {
// try {
// sign = text.getFirst().charAt(0);
// } catch (IndexOutOfBoundsException e) {
// // Blank line? Whatever.
// text.removeFirst();
// continue;
// }
// line = text.getFirst().substring(1);
// line = line.replace("+", "%2B"); // decode would change all "+"
// // to " "
// try {
// line = URLDecoder.decode(line, "UTF-8");
// } catch (UnsupportedEncodingException e) {
// // Not likely on modern system.
// throw new Error("This system does not support UTF-8.", e);
// } catch (IllegalArgumentException e) {
// // Malformed URI sequence.
// throw new IllegalArgumentException(
// "Illegal escape in patch_fromText: " + line, e);
// }
// if (sign == '-') {
// // Deletion.
// patch.diffs.add(new Diff(Operation.DELETE, line));
// } else if (sign == '+') {
// // Insertion.
// patch.diffs.add(new Diff(Operation.INSERT, line));
// } else if (sign == ' ') {
// // Minor equality.
// patch.diffs.add(new Diff(Operation.EQUAL, line));
// } else if (sign == '@') {
// // Start of next patch.
// break;
// } else {
// // WTF?
// throw new IllegalArgumentException("Invalid patch mode '"
// + sign + "' in: " + line);
// }
// text.removeFirst();
// }
// }
// return patches;
// }
/**
* Class representing one diff operation.
*/
public static class Diff {
/**
* One of: INSERT, DELETE or EQUAL.
*/
public Operation operation;
/**
* The text associated with this diff operation.
*/
public String text;
/**
* Constructor. Initializes the diff with the provided values.
*
* @param operation
* One of INSERT, DELETE or EQUAL.
* @param text
* The text being applied.
*/
public Diff(Operation operation, String text) {
// Construct a diff with the specified operation and text.
this.operation = operation;
this.text = text;
}
/**
* Display a human-readable version of this Diff.
*
* @return text version.
*/
public String toString() {
String prettyText = this.text.replace('\n', '\u00b6');
return "Diff(" + this.operation + ",\"" + prettyText + "\")";
}
/**
* Create a numeric hash value for a Diff. This function is not used by DMP.
*
* @return Hash value.
*/
@Override
public int hashCode() {
final int prime = 31;
int result = (operation == null) ? 0 : operation.hashCode();
result += prime * ((text == null) ? 0 : text.hashCode());
return result;
}
/**
* Is this Diff equivalent to another Diff?
*
* @param obj
* Another Diff to compare against.
* @return true or false.
*/
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null) {
return false;
}
if (getClass() != obj.getClass()) {
return false;
}
Diff other = (Diff) obj;
if (operation != other.operation) {
return false;
}
if (text == null) {
if (other.text != null) {
return false;
}
} else if (!text.equals(other.text)) {
return false;
}
return true;
}
}
/**
* Class representing one patch operation.
*/
// public static class Patch {
// public LinkedList<Diff> diffs;
// public int start1;
// public int start2;
// public int length1;
// public int length2;
//
// /**
// * Constructor. Initializes with an empty list of diffs.
// */
// public Patch() {
// this.diffs = new LinkedList<Diff>();
// }
//
// /**
// * Emmulate GNU diff's format. Header: @@ -382,8 +481,9 @@ Indicies are
// * printed as 1-based, not 0-based.
// *
// * @return The GNU diff string.
// */
// public String toString() {
// String coords1, coords2;
// if (this.length1 == 0) {
// coords1 = this.start1 + ",0";
// } else if (this.length1 == 1) {
// coords1 = Integer.toString(this.start1 + 1);
// } else {
// coords1 = (this.start1 + 1) + "," + this.length1;
// }
// if (this.length2 == 0) {
// coords2 = this.start2 + ",0";
// } else if (this.length2 == 1) {
// coords2 = Integer.toString(this.start2 + 1);
// } else {
// coords2 = (this.start2 + 1) + "," + this.length2;
// }
// StringBuilder text = new StringBuilder();
// text.append("@@ -").append(coords1).append(" +").append(coords2)
// .append(" @@\n");
// // Escape the body of the patch with %xx notation.
// for (Diff aDiff : this.diffs) {
// switch (aDiff.operation) {
// case INSERT:
// text.append('+');
// break;
// case DELETE:
// text.append('-');
// break;
// case EQUAL:
// text.append(' ');
// break;
// }
// try {
// text.append(
// URLEncoder.encode(aDiff.text, "UTF-8").replace('+',
// ' ')).append("\n");
// } catch (UnsupportedEncodingException e) {
// // Not likely on modern system.
// throw new Error("This system does not support UTF-8.", e);
// }
// }
// return unescapeForEncodeUriCompatability(text.toString());
// }
// }
/**
* Unescape selected chars for compatability with JavaScript's encodeURI. In
* speed critical applications this could be dropped since the receiving
* application will certainly decode these fine. Note that this function is
* case-sensitive. Thus "%3f" would not be unescaped. But this is ok because
* it is only called with the output of URLEncoder.encode which returns
* uppercase hex.
*
* Example: "%3F" -> "?", "%24" -> "$", etc.
*
* @param str
* The string to escape.
* @return The escaped string.
*/
// private static String unescapeForEncodeUriCompatability(String str) {
// return str.replace("%21", "!").replace("%7E", "~").replace("%27", "'")
// .replace("%28", "(").replace("%29", ")").replace("%3B", ";")
// .replace("%2F", "/").replace("%3F", "?").replace("%3A", ":")
// .replace("%40", "@").replace("%26", "&").replace("%3D", "=")
// .replace("%2B", "+").replace("%24", "$").replace("%2C", ",")
// .replace("%23", "#");
// }
}