读取word、pdf某些位置的值

最近有个需求是要求读word或pdf形式合同里某些位置的值，但具体读什么位置，没有明确的定位。可自定义位置。

经思考过后，采取以下方式。

1、复制一份word/pdf。

2、把复制出来的word/pdf按要求修改，只修改需要读取值的位置，按${username}形式修改。

3、把原word/pdf以及复制后修改的word/pdf 里内容通过程序全部读取出来。

4、把读取出来的内容进行比较。

5、把修改的地方进行匹配，如username=张三,并输出出来。

读取word/pdf内容，这里省略，下面只贴重点（内容比较）

原文件内容

World模板替换
的点点滴滴多多多多多多多多多多 用户：张三 多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多
的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多 密码：123456 多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多
的点点滴滴多多多公司： 三七 多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多
多的点点滴滴多多多多 年龄：18 多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多

修改之后文件内容

World模板替换
的点点滴滴多多多多多多多多多多 用户：${username} 多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多
的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多 密码：${pwd} 多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多
的点点滴滴多多多公司： ${company} 多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多
多的点点滴滴多多多多 年龄：${age} 多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多

输出内容

company------三七
pwd------123456
age------18
username------张三

代码如下：

/*** * @author Samir**/
public class CompareUtil {private static Logger logger = LoggerFactory.getLogger(CompareUtil.class);/*** 对比文本* 列子* String altbe = "World模板替换\r\n"+ "的点点滴滴多多多多多多多多多多 用户：${username} 多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多\r\n"+ "的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多 密码：${pwd} 多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多\r\n"+ "的点点滴滴多多多公司： ${company} 多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多    \r\n"+ "多的点点滴滴多多多多 年龄：${age} 多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多\r\n"+ "";String altaf = "World模板替换\r\n" + "的点点滴滴多多多多多多多多多多 用户：张三 多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多\r\n"+ "的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多 密码：123456 多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多\r\n"+ "的点点滴滴多多多公司： 三七 多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多    \r\n"+ "多的点点滴滴多多多多 年龄：18 多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多sfdsfds\r\n"+ "";* * @param altbe* @param altaf* @return*/public static Map<String, String> compareText(String altbe,String altaf){Map<String, String> smap = new HashMap<>();try {if(StringUtil.isBlank(altbe) || StringUtil.isBlank(altaf)) {return smap;}Map<Integer, String> imap = new HashMap<>();Integer num = 0;List<Integer> beList = rememberSpacing(altbe);List<Integer> afList = rememberSpacing(altaf);altbe = altbe.replace(" ", "");altaf = altaf.replace(" ", "");Diff_match_patch diff_match_patch = new Diff_match_patch();LinkedList<Diff> t = diff_match_patch.diff_main(altbe, altaf);StringBuffer s1 = new StringBuffer();StringBuffer s2 = new StringBuffer();Integer indexBe = 0;Integer indexAf = 0;for (Diff diff : t) {StringBuffer diffTextBe = new StringBuffer(diff.text);StringBuffer diffTextAf = new StringBuffer(diff.text);if (diff.operation.toString().equalsIgnoreCase("EQUAL")) {addSpacing(beList, indexBe, diffTextBe);addSpacing(afList, indexAf, diffTextAf);s1.append(diffTextBe);s2.append(diffTextAf);indexBe += diffTextBe.length();indexAf += diffTextAf.length();}Integer[] resa = appendString2("DELETE", diff, s1, s2, beList, indexBe,smap,imap,num);indexBe = resa[0];num = resa[1];Integer[] resb = appendString2("INSERT", diff, s2, s1, afList, indexAf,smap,imap,num);indexAf = resb[0];num = resb[1];}System.out.println(s1.toString());System.out.println(s2.toString());} catch (Exception e) {logger.error("对比文本异常",e);}return smap;}private static List<Integer> rememberSpacing(String str) {List<Integer> list = new ArrayList<Integer>();for (int i = 0; i < str.length(); i++) {if (' ' == str.charAt(i)) {list.add(i);}}return list;}private static void addSpacing(List<Integer> list, Integer index, StringBuffer str) {for (Integer o : list) {if (o >= index && o < index + str.length()) {str.insert(o - index, ' ');}}}private static Integer[] appendString2(String type, Diff diff, StringBuffer sbOne, StringBuffer sbTwo,List<Integer> list, Integer i,Map<String, String> smap,Map<Integer, String> imap,Integer num) {Integer[] res = new Integer[2];Integer result = i;if (type.equals(diff.operation.toString())) {StringBuffer sb = new StringBuffer(diff.text);for (Integer o : list) {if (o >= i && o < i + sb.length()) {sb.insert(o - i, ' ');}}sbOne.append("<em class='f-required'>").append(sb).append("</em>");result = i + sb.length();num++;String str = getStr(sb,imap,num);if (num % 2 == 0 && null != imap.get(num - 1)) {smap.put(imap.get(num - 1), str);}}res[0] = result;res[1] = num;return res;}private static String getStr(StringBuffer sb,Map<Integer, String> imap,Integer num) {String str = sb.toString().trim();if (str.startsWith("${") && str.endsWith("}")) {str = str.substring(2, str.length() - 1);imap.put(num, str);}return str;}/*public static void main(String[] arge) {String altbe = "World模板替换\r\n"+ "的点点滴滴多多多多多多多多多多 用户：${username} 多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多\r\n"+ "的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多 密码：${pwd} 多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多\r\n"+ "的点点滴滴多多多公司： ${company} 多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多    \r\n"+ "多的点点滴滴多多多多 年龄：${age} 多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多\r\n"+ "";String altaf = "World模板替换\r\n" + "的点点滴滴多多多多多多多多多多 用户：张三 多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多\r\n"+ "的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多 密码：123456 多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多\r\n"+ "的点点滴滴多多多公司： 三七 多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多    \r\n"+ "多的点点滴滴多多多多 年龄：18 多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多的点点滴滴多多多多多多多多多多多多多多多多多多多多多多多多sfdsfds\r\n"+ "";Map<String, String> map = compareText(altbe, altaf);Set<String> sets = map.keySet();for (String str : sets) {System.out.println(str + "------" + map.get(str));}}*/
}

/*** * @author Samir**/
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;/*** The size beyond which the double-ended diff activates. Double-ending is twice* as fast, but less accurate.*/public short Diff_DualThreshold = 32;/*** 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 does the* contents have to match the expected contents. (0.0 = perfection, 1.0 = very* loose). Note that Match_Threshold controls how closely the end points of a* delete need to match.*/public float Patch_DeleteThreshold = 0.5f;/*** Chunk size for context length.*/public short Patch_Margin = 4;/*** The number of bits in an int.*/private int 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. 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* @return Linked List of Diff objects.*/public LinkedList<Diff> diff_main(String text1, String text2, boolean checklines) {// Check for equality (speedup)LinkedList<Diff> diffs;if (text1.equals(text2)) {diffs = new LinkedList<Diff>();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 blockdiffs = diff_compute(text1, text2, checklines);// Restore the prefix and suffixif (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* @return Linked List of Diff objects.*/protected LinkedList<Diff> diff_compute(String text1, String text2, boolean checklines) {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;}longtext = shorttext = null; // Garbage collect.// 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);LinkedList<Diff> diffs_b = diff_main(text1_b, text2_b, checklines);// Merge the results.diffs = diffs_a;diffs.add(new Diff(Operation.EQUAL, mid_common));diffs.addAll(diffs_b);return diffs;}// Perform a real diff.if (checklines && (text1.length() < 100 || text2.length() < 100)) {checklines = false; // Too trivial for the overhead.}List<String> linearray = null;if (checklines) {// Scan the text on a line-by-line basis first.LinesToCharsResult b = diff_linesToChars(text1, text2);text1 = b.chars1;text2 = b.chars2;linearray = b.lineArray;}diffs = diff_map(text1, text2);if (diffs == null) {// No acceptable result.diffs = new LinkedList<Diff>();diffs.add(new Diff(Operation.DELETE, text1));diffs.add(new Diff(Operation.INSERT, text2));}if (checklines) {// 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)) {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;}/*** 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();}}/*** Explore the intersection points between the two texts.* * @param text1*            Old string to be diffed.* @param text2*            New string to be diffed.* @return LinkedList of Diff objects or null if no diff available.*/protected LinkedList<Diff> diff_map(String text1, String text2) {long ms_end = System.currentTimeMillis() + (long) (Diff_Timeout * 1000);// 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;boolean doubleEnd = Diff_DualThreshold * 2 < max_d;List<Set<Long>> v_map1 = new ArrayList<Set<Long>>();List<Set<Long>> v_map2 = new ArrayList<Set<Long>>();Map<Integer, Integer> v1 = new HashMap<Integer, Integer>();Map<Integer, Integer> v2 = new HashMap<Integer, Integer>();v1.put(1, 0);v2.put(1, 0);int x, y;Long footstep = 0L; // Used to track overlapping paths.Map<Long, Integer> footsteps = new HashMap<Long, Integer>();boolean done = false;// If the total number of characters is odd, then the front path will// collide with the reverse path.boolean front = ((text1_length + text2_length) % 2 == 1);for (int d = 0; d < max_d; d++) {// Bail out if timeout reached.if (Diff_Timeout > 0 && System.currentTimeMillis() > ms_end) {return null;}// Walk the front path one step.v_map1.add(new HashSet<Long>()); // Adds at index 'd'.for (int k = -d; k <= d; k += 2) {if (k == -d || k != d && v1.get(k - 1) < v1.get(k + 1)) {x = v1.get(k + 1);} else {x = v1.get(k - 1) + 1;}y = x - k;if (doubleEnd) {footstep = diff_footprint(x, y);if (front && (footsteps.containsKey(footstep))) {done = true;}if (!front) {footsteps.put(footstep, d);}}while (!done && x < text1_length && y < text2_length && text1.charAt(x) == text2.charAt(y)) {x++;y++;if (doubleEnd) {footstep = diff_footprint(x, y);if (front && (footsteps.containsKey(footstep))) {done = true;}if (!front) {footsteps.put(footstep, d);}}}v1.put(k, x);v_map1.get(d).add(diff_footprint(x, y));if (x == text1_length && y == text2_length) {// Reached the end in single-path mode.return diff_path1(v_map1, text1, text2);} else if (done) {// Front path ran over reverse path.v_map2 = v_map2.subList(0, footsteps.get(footstep) + 1);LinkedList<Diff> a = diff_path1(v_map1, text1.substring(0, x), text2.substring(0, y));a.addAll(diff_path2(v_map2, text1.substring(x), text2.substring(y)));return a;}}if (doubleEnd) {// Walk the reverse path one step.v_map2.add(new HashSet<Long>()); // Adds at index 'd'.for (int k = -d; k <= d; k += 2) {if (k == -d || k != d && v2.get(k - 1) < v2.get(k + 1)) {x = v2.get(k + 1);} else {x = v2.get(k - 1) + 1;}y = x - k;footstep = diff_footprint(text1_length - x, text2_length - y);if (!front && (footsteps.containsKey(footstep))) {done = true;}if (front) {footsteps.put(footstep, d);}while (!done && x < text1_length && y < text2_length&& text1.charAt(text1_length - x - 1) == text2.charAt(text2_length - y - 1)) {x++;y++;footstep = diff_footprint(text1_length - x, text2_length - y);if (!front && (footsteps.containsKey(footstep))) {done = true;}if (front) {footsteps.put(footstep, d);}}v2.put(k, x);v_map2.get(d).add(diff_footprint(x, y));if (done) {// Reverse path ran over front path.v_map1 = v_map1.subList(0, footsteps.get(footstep) + 1);LinkedList<Diff> a = diff_path1(v_map1, text1.substring(0, text1_length - x),text2.substring(0, text2_length - y));a.addAll(diff_path2(v_map2, text1.substring(text1_length - x),text2.substring(text2_length - y)));return a;}}}}// Number of diffs equals number of characters, no commonality at all.return null;}/*** Work from the middle back to the start to determine the path.* * @param v_map*            List of path sets.* @param text1*            Old string fragment to be diffed.* @param text2*            New string fragment to be diffed.* @return LinkedList of Diff objects.*/protected LinkedList<Diff> diff_path1(List<Set<Long>> v_map, String text1, String text2) {LinkedList<Diff> path = new LinkedList<Diff>();int x = text1.length();int y = text2.length();Operation last_op = null;for (int d = v_map.size() - 2; d >= 0; d--) {while (true) {if (v_map.get(d).contains(diff_footprint(x - 1, y))) {x--;if (last_op == Operation.DELETE) {path.getFirst().text = text1.charAt(x) + path.getFirst().text;} else {path.addFirst(new Diff(Operation.DELETE, text1.substring(x, x + 1)));}last_op = Operation.DELETE;break;} else if (v_map.get(d).contains(diff_footprint(x, y - 1))) {y--;if (last_op == Operation.INSERT) {path.getFirst().text = text2.charAt(y) + path.getFirst().text;} else {path.addFirst(new Diff(Operation.INSERT, text2.substring(y, y + 1)));}last_op = Operation.INSERT;break;} else {x--;y--;assert (text1.charAt(x) == text2.charAt(y)) : "No diagonal.  Can't happen. (diff_path1)";if (last_op == Operation.EQUAL) {path.getFirst().text = text1.charAt(x) + path.getFirst().text;} else {path.addFirst(new Diff(Operation.EQUAL, text1.substring(x, x + 1)));}last_op = Operation.EQUAL;}}}return path;}/*** Work from the middle back to the end to determine the path.* * @param v_map*            List of path sets.* @param text1*            Old string fragment to be diffed.* @param text2*            New string fragment to be diffed.* @return LinkedList of Diff objects.*/protected LinkedList<Diff> diff_path2(List<Set<Long>> v_map, String text1, String text2) {LinkedList<Diff> path = new LinkedList<Diff>();int x = text1.length();int y = text2.length();Operation last_op = null;for (int d = v_map.size() - 2; d >= 0; d--) {while (true) {if (v_map.get(d).contains(diff_footprint(x - 1, y))) {x--;if (last_op == Operation.DELETE) {path.getLast().text += text1.charAt(text1.length() - x - 1);} else {path.addLast(new Diff(Operation.DELETE,text1.substring(text1.length() - x - 1, text1.length() - x)));}last_op = Operation.DELETE;break;} else if (v_map.get(d).contains(diff_footprint(x, y - 1))) {y--;if (last_op == Operation.INSERT) {path.getLast().text += text2.charAt(text2.length() - y - 1);} else {path.addLast(new Diff(Operation.INSERT,text2.substring(text2.length() - y - 1, text2.length() - y)));}last_op = Operation.INSERT;break;} else {x--;y--;assert (text1.charAt(text1.length() - x - 1) == text2.charAt(text2.length() - y - 1)) : "No diagonal.  Can't happen. (diff_path2)";if (last_op == Operation.EQUAL) {path.getLast().text += text1.charAt(text1.length() - x - 1);} else {path.addLast(new Diff(Operation.EQUAL, text1.substring(text1.length() - x - 1, text1.length() - x)));}last_op = Operation.EQUAL;}}}return path;}/*** Compute a good hash of two integers.* * @param x*            First int.* @param y*            Second int.* @return A long made up of both ints.*/protected long diff_footprint(int x, int y) {// The maximum size for a long is 9,223,372,036,854,775,807// The maximum size for an int is 2,147,483,647// Two ints fit nicely in one long.long result = x;result = result << 32;result += y;return result;}/*** 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;}/*** Do the two texts share a substring which is at least half the length of the* longer text?* * @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) {String longtext = text1.length() > text2.length() ? text1 : text2;String shorttext = text1.length() > text2.length() ? text2 : text1;if (longtext.length() < 10 || shorttext.length() < 1) {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() >= longtext.length() / 2) {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().textListIterator<Diff> pointer = diffs.listIterator();// Number of characters that changed prior to the equality.int length_changes1 = 0;// Number of characters that changed after the equality.int length_changes2 = 0;Diff thisDiff = pointer.next();while (thisDiff != null) {if (thisDiff.operation == Operation.EQUAL) {// equality foundequalities.push(thisDiff);length_changes1 = length_changes2;length_changes2 = 0;lastequality = thisDiff.text;} else {// an insertion or deletionlength_changes2 += thisDiff.text.length();if (lastequality != null && (lastequality.length() <= length_changes1)&& (lastequality.length() <= length_changes2)) {// 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_changes1 = 0; // Reset the counters.length_changes2 = 0;lastequality = null;changes = true;}}thisDiff = pointer.hasNext() ? pointer.next() : null;}if (changes) {diff_cleanupMerge(diffs);}diff_cleanupSemanticLossless(diffs);}/*** Look for single edits surrounded on both sides by equalities which can be* shifted sideways to align the edit to a word boundary. e.g: The c<ins>at* c</ins>ame. -> The <ins>cat </ins>came.* * @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 5 (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 5;}// Each port of this function behaves slightly differently due to// subtle differences in each language's definition of things like// 'whitespace'. Since this function's purpose is largely cosmetic,// the choice has been made to use each language's native features// rather than force total conformity.int score = 0;// One point for non-alphanumeric.if (!Character.isLetterOrDigit(one.charAt(one.length() - 1)) || !Character.isLetterOrDigit(two.charAt(0))) {score++;// Two points for whitespace.if (Character.isWhitespace(one.charAt(one.length() - 1)) || Character.isWhitespace(two.charAt(0))) {score++;// Three points for line breaks.if (Character.getType(one.charAt(one.length() - 1)) == Character.CONTROL|| Character.getType(two.charAt(0)) == Character.CONTROL) {score++;// Four points for blank lines.if (BLANKLINEEND.matcher(one).find() || BLANKLINESTART.matcher(two).find()) {score++;}}}}return score;}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().textListIterator<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 foundif (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 deletionif (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 != 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 (count_delete != 0 && count_insert != 0) {// 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;}// System.out.println(diff);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();int i = 0;for (Diff aDiff : diffs) {String text = aDiff.text.replace("&", "&amp;").replace("<", "&lt;").replace(">", "&gt;").replace("\n","&para;<BR>");switch (aDiff.operation) {case INSERT:html.append("<INS STYLE=\"background:#E6FFE6;\" TITLE=\"i=").append(i).append("\">").append(text).append("</INS>");break;case DELETE:html.append("<DEL STYLE=\"background:#FFE6E6;\" TITLE=\"i=").append(i).append("\">").append(text).append("</DEL>");break;case EQUAL:html.append("<SPAN TITLE=\"i=").append(i).append("\">").append(text).append("</SPAN>");break;}if (aDiff.operation != Operation.DELETE) {i += aDiff.text.length();}}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 tuples.* @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;}/*** 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 tuples 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 text1String[] 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;}// 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) {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) {// 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 tuples for text1 to text2.* @return LinkedList of Patch objects.*/public LinkedList<Patch> patch_make(LinkedList<Diff> diffs) {// 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 tuples 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 tuples for text1 to text2.* @return LinkedList of Patch objects.*/public LinkedList<Patch> patch_make(String text1, LinkedList<Diff> diffs) {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) {// Insertiontext = text.substring(0, start_loc + index2) + aDiff.text+ text.substring(start_loc + index2);} else if (aDiff.operation == Operation.DELETE) {// Deletiontext = 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) {int paddingLength = this.Patch_Margin;String nullPadding = "";for (int 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.* * @param patches*            LinkedList of Patch objects.*/public void patch_splitMax(LinkedList<Patch> patches) {int patch_size;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();patch_size = Match_MaxBits;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 + "\")";}/*** Is this Diff equivalent to another Diff?* * @param d*            Another Diff to compare against.* @return true or false.*/public boolean equals(Object d) {try {return (((Diff) d).operation == this.operation) && (((Diff) d).text.equals(this.text));} catch (ClassCastException e) {return false;}}}/*** 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", "#");}public String getHtmlDiffString(String text1, String text2) {return diff_prettyHtml(diff_main(text1, text2));}// public static void main(String[] args){// Diff_match_patch dmp = new Diff_match_patch();// String text1 = "我方在“福市财政资金补助项目管理系统”的项目实施过程，为保证该项目的工程进度、质量，符合数办项目的实施管理规范与要求。";// String text2 =// "我方在“福州市财政资金补助项目管理系统”的项目实施过程，为保证该haha项目的工程进度、质量，符合目的实施管理规范与要求。";// System.out.println(dmp.getHtmlDiffString(text1,text2));// }
}

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