region = findEnclosingRegion(text, offset, startMarker,
+ endMarker);
+ if (region == null)
+ return null;
+ String s = text.substring(region.first, region.second);
+ return s;
+ }
+
+ /**
+ * Format a block of text to use the given line-width. I.e. adjust the line
+ * breaks. Also known as hard line-wrapping. Paragraphs are
+ * recognised by a line of blank space between them (e.g. two returns).
+ *
+ * Note: a side-effect of this method is that it converts all line-breaks
+ * into the local system's line-breaks. E.g. on Windows, \n will become \r\n
+ *
+ * @param text
+ * The text to format
+ * @param lineWidth
+ * The number of columns in a line. Typically 78 or 80.
+ * @param respectLeadingCharacters
+ * Can be null. If set, the specified leading characters will be
+ * copied if the line is split. Use with " \t" to keep indented
+ * paragraphs properly indented. Use with "> \t" to also handle
+ * email-style quoting. Note that respected leading characters
+ * receive no special treatment when they are used inside a
+ * paragraph.
+ * @return A copy of text, formatted to the given line-width.
+ *
+ * TODO: recognise paragraphs by changes in the respected leading
+ * characters
+ */
+ public static String format(String text, int lineWidth, int tabWidth,
+ String respectLeadingCharacters) {
+ // Switch to Linux line breaks for easier internal workings
+ text = convertLineBreaks(text, "\n");
+ // Find paragraphs
+ List paras = format2_splitParagraphs(text,
+ respectLeadingCharacters);
+ // Rebuild text
+ StringBuilder sb = new StringBuilder(text.length() + 10);
+ for (String p : paras) {
+ String fp = format3_oneParagraph(p, lineWidth, tabWidth,
+ respectLeadingCharacters);
+ sb.append(fp);
+ // Paragraphs end with a double line break
+ sb.append("\n\n");
+ }
+ // Pop the last line breaks
+ sb.delete(sb.length() - 2, sb.length());
+ // Convert line breaks to system ones
+ text = convertLineBreaks(sb.toString());
+ // Done
+ return text;
+ }
+
+ private static List format2_splitParagraphs(String text,
+ String respectLeadingCharacters) {
+ List paras = new ArrayList();
+ Mutable.Int index = new Mutable.Int(0);
+ // TODO The characters prefacing this paragraph
+ String leadingChars = "";
+ while (index.value < text.length()) {
+ // One paragraph
+ boolean inSpace = false;
+ int start = index.value;
+ while (index.value < text.length()) {
+ char c = text.charAt(index.value);
+ index.value++;
+ if (!Character.isWhitespace(c)) {
+ inSpace = false;
+ continue;
+ }
+ // Line end?
+ if (c == '\r' || c == '\n') {
+ // // Handle MS Windows 2 character \r\n line breaks
+ // if (index.value < text.length()) {
+ // char c2 = text.charAt(index.value);
+ // if (c=='\r' && c2=='\n') index.value++; // Push on past
+ // the 2nd line break char
+ // }
+ // Double line end - indicating a paragraph break
+ if (inSpace)
+ break;
+ inSpace = true;
+ }
+ // TODO Other paragraph markers, spotted by a change in
+ // leadingChars
+ }
+ String p = text.substring(start, index.value);
+ paras.add(p);
+ }
+ // Done
+ return paras;
+ }
+
+ /**
+ * Format a block of text to fit the given line width
+ *
+ * @param p
+ * @param lineWidth
+ * @param tabWidth
+ * @param respectLeadingCharacters
+ * @return
+ */
+ private static String format3_oneParagraph(String p, int lineWidth,
+ int tabWidth, String respectLeadingCharacters) {
+ // Collect the reformatted paragraph
+ StringBuilder sb = new StringBuilder(p.length() + 10); // Allow for
+ // some extra
+ // line-breaks
+ // Get respected leading chars
+ String leadingChars = format4_getLeadingChars(p,
+ respectLeadingCharacters);
+ // First Line
+ sb.append(leadingChars);
+ int lineLength = leadingChars.length();
+ int index = leadingChars.length();
+ // Loop
+ while (index < p.length()) {
+ // Get the next word
+ StringBuilder word = new StringBuilder();
+ char c = p.charAt(index);
+ index++;
+ while (!Character.isWhitespace(c)) {
+ word.append(c);
+ if (index == p.length())
+ break;
+ c = p.charAt(index);
+ index++;
+ }
+ // Break the line if the word will not fit
+ if (lineLength + word.length() > lineWidth && lineLength != 0) {
+ trimEnd(sb);
+ sb.append('\n'); // lineEnd(sb);
+ // New line
+ sb.append(leadingChars);
+ lineLength = leadingChars.length();
+ }
+ // Add word
+ sb.append(word);
+ lineLength += word.length();
+ // Add the whitespace
+ if (index != p.length() && lineLength < lineWidth) {
+ if (c == '\n') {
+ c = ' ';
+ }
+ sb.append(c);
+ lineLength += (c == '\t') ? tabWidth : 1;
+ }
+ }
+ // A final trim
+ trimEnd(sb);
+ // Done
+ return sb.toString();
+ }
+
+ /**
+ *
+ * @param text
+ * @param respectLeadingCharacters
+ * Can be null
+ * @return The characters at the beginning of text which are respected. E.g.
+ * ("> Hello", " \t>") --> "> "
+ */
+ private static String format4_getLeadingChars(String text,
+ String respectLeadingCharacters) {
+ if (respectLeadingCharacters == null)
+ return "";
+ // Line-breaks cannot be respected
+ assert respectLeadingCharacters.indexOf('\n') == -1;
+ // Look for the first non-respected char
+ for (int i = 0; i < text.length(); i++) {
+ char c = text.charAt(i);
+ if (respectLeadingCharacters.indexOf(c) == -1) {
+ // Return the previous chars
+ return text.substring(0, i);
+ }
+ }
+ // All chars are respected
+ return text;
+ }
+
+ /**
+ * Ensure that line ends with the right line-end character(s)
+ */
+ public static final String lineEnd(String line) {
+ // strip possibly inappropriate line-endings
+ if (line.endsWith("\n")) {
+ line = line.substring(0, line.length() - 1);
+ }
+ if (line.endsWith("\r\n")) {
+ line = line.substring(0, line.length() - 2);
+ }
+ if (line.endsWith("\r")) {
+ line = line.substring(0, line.length() - 1);
+ }
+ // add in proper line end
+ if (!line.endsWith(LINEEND)) {
+ line += LINEEND;
+ }
+ return line;
+ }
+
+ /**
+ * Ensure that line ends with the right line-end character(s). This is more
+ * efficient than the version for Strings.
+ *
+ * @param line
+ */
+ public static final void lineEnd(final StringBuilder line) {
+ if (line.length() == 0) {
+ line.append(LINEEND);
+ return;
+ }
+ // strip possibly inappropriate line-endings
+ final char last = line.charAt(line.length() - 1);
+ if (last == '\n') {
+ if ((line.length() > 1) && (line.charAt(line.length() - 2) == '\r')) {
+ // \r\n
+ line.replace(line.length() - 2, line.length(), LINEEND);
+ return;
+ }
+ line.replace(line.length() - 1, line.length(), LINEEND);
+ return;
+ }
+ if (last == '\r') {
+ line.replace(line.length() - 1, line.length(), LINEEND);
+ return;
+ }
+ line.append(LINEEND);
+ return;
+ }
+
+
+
+ /**
+ * @param string
+ * @return the MD5 sum of the string using the default charset. Null if
+ * there was an error in calculating the hash.
+ * @author Sam Halliday
+ */
+ public static String md5Hash(String string) {
+ MessageDigest md5 = null;
+ try {
+ md5 = MessageDigest.getInstance("MD5");
+ } catch (NoSuchAlgorithmException e) {
+ // ignore this exception, we know MD5 exists
+ }
+ md5.update(string.getBytes());
+ BigInteger hash = new BigInteger(1, md5.digest());
+ return hash.toString(16);
+ }
+
+ /**
+ * Removes HTML-style tags from a string.
+ *
+ * @param s
+ * a String from which to remove tags
+ * @return a string with all instances of <.*> removed.
+ */
+ public static String removeTags(String s) {
+ StringBuffer sb = new StringBuffer();
+ boolean inTag = false;
+ for (int i = 0; i < s.length(); i++) {
+ char c = s.charAt(i);
+ if (c == '<')
+ inTag = true;
+ if (!inTag)
+ sb.append(c);
+ if (c == '>')
+ inTag = false;
+ }
+ return sb.toString();
+ }
+
+ /**
+ * Repeat a character.
+ *
+ * @param c
+ * @param i
+ * @return A String consisting of i x c.
+ * @example assert repeat('-', 5).equals("-----");
+ */
+ public static String repeat(Character c, int i) {
+ StringBuilder dashes = new StringBuilder(i);
+ for (int j = 0; j < i; j++)
+ dashes.append(c);
+ return dashes.toString();
+ }
+
+ /**
+ * Split a piece of text into separate lines. The line breaks are left at
+ * the end of each line.
+ *
+ * @param text
+ * @return The individual lines in the text.
+ */
+ public static List splitLines(String text) {
+ List lines = new ArrayList();
+ // Search for lines
+ int start = 0;
+ for (int i = 0; i < text.length(); i++) {
+ char c = text.charAt(i);
+ if (c == '\r' || c == '\n') {
+ // Handle MS Windows 2 character \r\n line breaks
+ if (i + 1 < text.length()) {
+ char c2 = text.charAt(i + 1);
+ if (c == '\r' && c2 == '\n')
+ i++;
+ }
+ // Get the line, with the line break
+ String line = text.substring(start, i + 1);
+ lines.add(line);
+ start = i + 1;
+ }
+ }
+ // Last one
+ if (start != text.length()) {
+ String line = text.substring(start);
+ lines.add(line);
+ }
+ return lines;
+ }
+
+ /**
+ * Remove trailing whitespace. c.f. String#trim() which removes
+ * leading and trailing whitespace.
+ *
+ * @param sb
+ */
+ private static void trimEnd(StringBuilder sb) {
+ while (true) {
+ // Get the last character
+ int i = sb.length() - 1;
+ if (i == -1)
+ return; // Quit if sb is empty
+ char c = sb.charAt(i);
+ if (!Character.isWhitespace(c))
+ return; // Finish?
+ sb.deleteCharAt(i); // Remove and continue
+ }
+ }
+
+ /**
+ * Returns true if the string is just whitespace, or empty, or null.
+ *
+ * @param s
+ */
+ public static final boolean whitespace(final String s) {
+ if (s == null) {
+ return true;
+ }
+ for (int i = 0; i < s.length(); i++) {
+ final char c = s.charAt(i);
+ if (!Character.isWhitespace(c)) {
+ return false;
+ }
+ }
+ return true;
+ }
+
+ /**
+ * @param text
+ * @return the number of words in text. Uses a crude whitespace
+ * measure.
+ */
+ public static int wordCount(String text) {
+ String[] bits = text.split("\\W+");
+ int wc = 0;
+ for (String string : bits) {
+ if (!whitespace(string)) wc++;
+ }
+ return wc;
+ }
+
+}