import java.util.List;
/**
- * This class contains a number of utility methods for analyzing characters and
- * strings in a terminal context. The main purpose is to make it easier to work
- * with text that may or may not contain double-width text characters, such as
- * CJK (Chinese, Japanese, Korean) and other special symbols. This class assumes
- * those are all double-width and in case the terminal (-emulator) chooses to
- * draw them (somehow) as single-column then all the calculations in this class
- * will be wrong. It seems safe to assume what this class considers double-width
- * really is taking up two columns though.
+ * This class contains a number of utility methods for analyzing characters and strings in a terminal context. The main
+ * purpose is to make it easier to work with text that may or may not contain double-width text characters, such as CJK
+ * (Chinese, Japanese, Korean) and other special symbols. This class assumes those are all double-width and in case the
+ * terminal (-emulator) chooses to draw them (somehow) as single-column then all the calculations in this class will be
+ * wrong. It seems safe to assume what this class considers double-width really is taking up two columns though.
*
* @author Martin
*/
public class TerminalTextUtils {
- private TerminalTextUtils() {
- }
+ private TerminalTextUtils() {
+ }
- /**
- * Given a character, is this character considered to be a CJK character?
- * Shamelessly stolen from <a href="http://stackoverflow.com/questions/1499804/how-can-i-detect-japanese-text-in-a-java-string"
- * >StackOverflow</a> where it was contributed by user Rakesh N
- *
- * @param c
- * Character to test
- * @return {@code true} if the character is a CJK character
- *
- */
- public static boolean isCharCJK(final char c) {
- Character.UnicodeBlock unicodeBlock = Character.UnicodeBlock.of(c);
- return (unicodeBlock == Character.UnicodeBlock.HIRAGANA)
- || (unicodeBlock == Character.UnicodeBlock.KATAKANA)
- || (unicodeBlock == Character.UnicodeBlock.KATAKANA_PHONETIC_EXTENSIONS)
- || (unicodeBlock == Character.UnicodeBlock.HANGUL_COMPATIBILITY_JAMO)
- || (unicodeBlock == Character.UnicodeBlock.HANGUL_JAMO)
- || (unicodeBlock == Character.UnicodeBlock.HANGUL_SYLLABLES)
- || (unicodeBlock == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS)
- || (unicodeBlock == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_A)
- || (unicodeBlock == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_B)
- || (unicodeBlock == Character.UnicodeBlock.CJK_COMPATIBILITY_FORMS)
- || (unicodeBlock == Character.UnicodeBlock.CJK_COMPATIBILITY_IDEOGRAPHS)
- || (unicodeBlock == Character.UnicodeBlock.CJK_RADICALS_SUPPLEMENT)
- || (unicodeBlock == Character.UnicodeBlock.CJK_SYMBOLS_AND_PUNCTUATION)
- || (unicodeBlock == Character.UnicodeBlock.ENCLOSED_CJK_LETTERS_AND_MONTHS)
- || (unicodeBlock == Character.UnicodeBlock.HALFWIDTH_AND_FULLWIDTH_FORMS && c < 0xFF61); // The
- // magic
- // number
- // here
- // is
- // the
- // separating
- // index
- // between
- // full-width
- // and
- // half-width
- }
+ /**
+ * Given a character, is this character considered to be a CJK character?
+ * Shamelessly stolen from
+ * <a href="http://stackoverflow.com/questions/1499804/how-can-i-detect-japanese-text-in-a-java-string">StackOverflow</a>
+ * where it was contributed by user Rakesh N
+ * @param c Character to test
+ * @return {@code true} if the character is a CJK character
+ *
+ */
+ public static boolean isCharCJK(final char c) {
+ Character.UnicodeBlock unicodeBlock = Character.UnicodeBlock.of(c);
+ return (unicodeBlock == Character.UnicodeBlock.HIRAGANA)
+ || (unicodeBlock == Character.UnicodeBlock.KATAKANA)
+ || (unicodeBlock == Character.UnicodeBlock.KATAKANA_PHONETIC_EXTENSIONS)
+ || (unicodeBlock == Character.UnicodeBlock.HANGUL_COMPATIBILITY_JAMO)
+ || (unicodeBlock == Character.UnicodeBlock.HANGUL_JAMO)
+ || (unicodeBlock == Character.UnicodeBlock.HANGUL_SYLLABLES)
+ || (unicodeBlock == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS)
+ || (unicodeBlock == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_A)
+ || (unicodeBlock == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_B)
+ || (unicodeBlock == Character.UnicodeBlock.CJK_COMPATIBILITY_FORMS)
+ || (unicodeBlock == Character.UnicodeBlock.CJK_COMPATIBILITY_IDEOGRAPHS)
+ || (unicodeBlock == Character.UnicodeBlock.CJK_RADICALS_SUPPLEMENT)
+ || (unicodeBlock == Character.UnicodeBlock.CJK_SYMBOLS_AND_PUNCTUATION)
+ || (unicodeBlock == Character.UnicodeBlock.ENCLOSED_CJK_LETTERS_AND_MONTHS)
+ || (unicodeBlock == Character.UnicodeBlock.HALFWIDTH_AND_FULLWIDTH_FORMS && c < 0xFF61); //The magic number here is the separating index between full-width and half-width
+ }
- /**
- * Checks if a character is expected to be taking up two columns if printed
- * to a terminal. This will generally be {@code true} for CJK (Chinese,
- * Japanese and Korean) characters.
- *
- * @param c
- * Character to test if it's double-width when printed to a
- * terminal
- * @return {@code true} if this character is expected to be taking up two
- * columns when printed to the terminal, otherwise {@code false}
- */
- public static boolean isCharDoubleWidth(final char c) {
- return isCharCJK(c);
- }
+ /**
+ * Checks if a character is expected to be taking up two columns if printed to a terminal. This will generally be
+ * {@code true} for CJK (Chinese, Japanese and Korean) characters.
+ * @param c Character to test if it's double-width when printed to a terminal
+ * @return {@code true} if this character is expected to be taking up two columns when printed to the terminal,
+ * otherwise {@code false}
+ */
+ public static boolean isCharDoubleWidth(final char c) {
+ return isCharCJK(c);
+ }
- /**
- * @deprecated Call {@code getColumnWidth(s)} instead
- */
- @Deprecated
- public static int getTrueWidth(String s) {
- return getColumnWidth(s);
- }
+ /**
+ * @deprecated Call {@code getColumnWidth(s)} instead
+ */
+ @Deprecated
+ public static int getTrueWidth(String s) {
+ return getColumnWidth(s);
+ }
- /**
- * Given a string, returns how many columns this string would need to occupy
- * in a terminal, taking into account that CJK characters takes up two
- * columns.
- *
- * @param s
- * String to check length
- * @return Number of actual terminal columns the string would occupy
- */
- public static int getColumnWidth(String s) {
- return getColumnIndex(s, s.length());
- }
+ /**
+ * Given a string, returns how many columns this string would need to occupy in a terminal, taking into account that
+ * CJK characters takes up two columns.
+ * @param s String to check length
+ * @return Number of actual terminal columns the string would occupy
+ */
+ public static int getColumnWidth(String s) {
+ return getColumnIndex(s, s.length());
+ }
- /**
- * Given a string and a character index inside that string, find out what
- * the column index of that character would be if printed in a terminal. If
- * the string only contains non-CJK characters then the returned value will
- * be same as {@code stringCharacterIndex}, but if there are CJK characters
- * the value will be different due to CJK characters taking up two columns
- * in width. If the character at the index in the string is a CJK character
- * itself, the returned value will be the index of the left-side of
- * character.
- *
- * @param s
- * String to translate the index from
- * @param stringCharacterIndex
- * Index within the string to get the terminal column index of
- * @return Index of the character inside the String at {@code
- * stringCharacterIndex} when it has been writted to a terminal
- * @throws StringIndexOutOfBoundsException
- * if the index given is outside the String length or negative
- */
- public static int getColumnIndex(String s, int stringCharacterIndex)
- throws StringIndexOutOfBoundsException {
- int index = 0;
- for (int i = 0; i < stringCharacterIndex; i++) {
- if (isCharCJK(s.charAt(i))) {
- index++;
- }
- index++;
- }
- return index;
- }
+ /**
+ * Given a string and a character index inside that string, find out what the column index of that character would
+ * be if printed in a terminal. If the string only contains non-CJK characters then the returned value will be same
+ * as {@code stringCharacterIndex}, but if there are CJK characters the value will be different due to CJK
+ * characters taking up two columns in width. If the character at the index in the string is a CJK character itself,
+ * the returned value will be the index of the left-side of character.
+ * @param s String to translate the index from
+ * @param stringCharacterIndex Index within the string to get the terminal column index of
+ * @return Index of the character inside the String at {@code stringCharacterIndex} when it has been writted to a
+ * terminal
+ * @throws StringIndexOutOfBoundsException if the index given is outside the String length or negative
+ */
+ public static int getColumnIndex(String s, int stringCharacterIndex) throws StringIndexOutOfBoundsException {
+ int index = 0;
+ for(int i = 0; i < stringCharacterIndex; i++) {
+ if(isCharCJK(s.charAt(i))) {
+ index++;
+ }
+ index++;
+ }
+ return index;
+ }
- /**
- * This method does the reverse of getColumnIndex, given a String and
- * imagining it has been printed out to the top-left corner of a terminal,
- * in the column specified by {@code columnIndex}, what is the index of that
- * character in the string. If the string contains no CJK characters, this
- * will always be the same as {@code columnIndex}. If the index specified is
- * the right column of a CJK character, the index is the same as if the
- * column was the left column. So calling {@code
- * getStringCharacterIndex("英", 0)} and {@code getStringCharacterIndex("英",
- * 1)} will both return 0.
- *
- * @param s
- * String to translate the index to
- * @param columnIndex
- * Column index of the string written to a terminal
- * @return The index in the string of the character in terminal column
- * {@code columnIndex}
- */
- public static int getStringCharacterIndex(String s, int columnIndex) {
- int index = 0;
- int counter = 0;
- while (counter < columnIndex) {
- if (isCharCJK(s.charAt(index++))) {
- counter++;
- if (counter == columnIndex) {
- return index - 1;
- }
- }
- counter++;
- }
- return index;
- }
+ /**
+ * This method does the reverse of getColumnIndex, given a String and imagining it has been printed out to the
+ * top-left corner of a terminal, in the column specified by {@code columnIndex}, what is the index of that
+ * character in the string. If the string contains no CJK characters, this will always be the same as
+ * {@code columnIndex}. If the index specified is the right column of a CJK character, the index is the same as if
+ * the column was the left column. So calling {@code getStringCharacterIndex("英", 0)} and
+ * {@code getStringCharacterIndex("英", 1)} will both return 0.
+ * @param s String to translate the index to
+ * @param columnIndex Column index of the string written to a terminal
+ * @return The index in the string of the character in terminal column {@code columnIndex}
+ */
+ public static int getStringCharacterIndex(String s, int columnIndex) {
+ int index = 0;
+ int counter = 0;
+ while(counter < columnIndex) {
+ if(isCharCJK(s.charAt(index++))) {
+ counter++;
+ if(counter == columnIndex) {
+ return index - 1;
+ }
+ }
+ counter++;
+ }
+ return index;
+ }
- /**
- * Given a string that may or may not contain CJK characters, returns the
- * substring which will fit inside <code>availableColumnSpace</code>
- * columns. This method does not handle special cases like tab or new-line.
- * <p>
- * Calling this method is the same as calling {@code fitString(string, 0,
- * availableColumnSpace)}.
- *
- * @param string
- * The string to fit inside the availableColumnSpace
- * @param availableColumnSpace
- * Number of columns to fit the string inside
- * @return The whole or part of the input string which will fit inside the
- * supplied availableColumnSpace
- */
- public static String fitString(String string, int availableColumnSpace) {
- return fitString(string, 0, availableColumnSpace);
- }
+ /**
+ * Given a string that may or may not contain CJK characters, returns the substring which will fit inside
+ * <code>availableColumnSpace</code> columns. This method does not handle special cases like tab or new-line.
+ * <p>
+ * Calling this method is the same as calling {@code fitString(string, 0, availableColumnSpace)}.
+ * @param string The string to fit inside the availableColumnSpace
+ * @param availableColumnSpace Number of columns to fit the string inside
+ * @return The whole or part of the input string which will fit inside the supplied availableColumnSpace
+ */
+ public static String fitString(String string, int availableColumnSpace) {
+ return fitString(string, 0, availableColumnSpace);
+ }
- /**
- * Given a string that may or may not contain CJK characters, returns the
- * substring which will fit inside <code>availableColumnSpace</code>
- * columns. This method does not handle special cases like tab or new-line.
- * <p>
- * This overload has a {@code fromColumn} parameter that specified where
- * inside the string to start fitting. Please notice that {@code fromColumn}
- * is not a character index inside the string, but a column index as if the
- * string has been printed from the left-most side of the terminal. So if
- * the string is "日本語", fromColumn set to 1 will not starting counting from
- * the second character ("本") in the string but from the CJK filler
- * character belonging to "日". If you want to count from a particular
- * character index inside the string, please pass in a substring and use
- * fromColumn set to 0.
- *
- * @param string
- * The string to fit inside the availableColumnSpace
- * @param fromColumn
- * From what column of the input string to start fitting (see
- * description above!)
- * @param availableColumnSpace
- * Number of columns to fit the string inside
- * @return The whole or part of the input string which will fit inside the
- * supplied availableColumnSpace
- */
- public static String fitString(String string, int fromColumn,
- int availableColumnSpace) {
- if (availableColumnSpace <= 0) {
- return "";
- }
+ /**
+ * Given a string that may or may not contain CJK characters, returns the substring which will fit inside
+ * <code>availableColumnSpace</code> columns. This method does not handle special cases like tab or new-line.
+ * <p>
+ * This overload has a {@code fromColumn} parameter that specified where inside the string to start fitting. Please
+ * notice that {@code fromColumn} is not a character index inside the string, but a column index as if the string
+ * has been printed from the left-most side of the terminal. So if the string is "日本語", fromColumn set to 1 will
+ * not starting counting from the second character ("本") in the string but from the CJK filler character belonging
+ * to "日". If you want to count from a particular character index inside the string, please pass in a substring
+ * and use fromColumn set to 0.
+ * @param string The string to fit inside the availableColumnSpace
+ * @param fromColumn From what column of the input string to start fitting (see description above!)
+ * @param availableColumnSpace Number of columns to fit the string inside
+ * @return The whole or part of the input string which will fit inside the supplied availableColumnSpace
+ */
+ public static String fitString(String string, int fromColumn, int availableColumnSpace) {
+ if(availableColumnSpace <= 0) {
+ return "";
+ }
- StringBuilder bob = new StringBuilder();
- int column = 0;
- int index = 0;
- while (index < string.length() && column < fromColumn) {
- char c = string.charAt(index++);
- column += TerminalTextUtils.isCharCJK(c) ? 2 : 1;
- }
- if (column > fromColumn) {
- bob.append(" ");
- availableColumnSpace--;
- }
+ StringBuilder bob = new StringBuilder();
+ int column = 0;
+ int index = 0;
+ while(index < string.length() && column < fromColumn) {
+ char c = string.charAt(index++);
+ column += TerminalTextUtils.isCharCJK(c) ? 2 : 1;
+ }
+ if(column > fromColumn) {
+ bob.append(" ");
+ availableColumnSpace--;
+ }
- while (availableColumnSpace > 0 && index < string.length()) {
- char c = string.charAt(index++);
- availableColumnSpace -= TerminalTextUtils.isCharCJK(c) ? 2 : 1;
- if (availableColumnSpace < 0) {
- bob.append(' ');
- } else {
- bob.append(c);
- }
- }
- return bob.toString();
- }
+ while(availableColumnSpace > 0 && index < string.length()) {
+ char c = string.charAt(index++);
+ availableColumnSpace -= TerminalTextUtils.isCharCJK(c) ? 2 : 1;
+ if(availableColumnSpace < 0) {
+ bob.append(' ');
+ }
+ else {
+ bob.append(c);
+ }
+ }
+ return bob.toString();
+ }
- /**
- * This method will calculate word wrappings given a number of lines of text
- * and how wide the text can be printed. The result is a list of new rows
- * where word-wrapping was applied.
- *
- * @param maxWidth
- * Maximum number of columns that can be used before
- * word-wrapping is applied
- * @param lines
- * Input text
- * @return The input text word-wrapped at {@code maxWidth}; this may contain
- * more rows than the input text
- */
- public static List<String> getWordWrappedText(int maxWidth, String... lines) {
- List<String> result = new ArrayList<String>();
- LinkedList<String> linesToBeWrapped = new LinkedList<String>(Arrays
- .asList(lines));
- while (!linesToBeWrapped.isEmpty()) {
- String row = linesToBeWrapped.removeFirst();
- int rowWidth = getColumnWidth(row);
- if (rowWidth <= maxWidth) {
- result.add(row);
- } else {
- // Now search in reverse and find the first possible line-break
- int characterIndex = getStringCharacterIndex(row, maxWidth);
- while (!Character.isSpaceChar(row.charAt(characterIndex))
- && !isCharCJK(row.charAt(characterIndex))
- && characterIndex > 0) {
- characterIndex--;
- }
+ /**
+ * This method will calculate word wrappings given a number of lines of text and how wide the text can be printed.
+ * The result is a list of new rows where word-wrapping was applied.
+ * @param maxWidth Maximum number of columns that can be used before word-wrapping is applied, if <= 0 then the
+ * lines will be returned unchanged
+ * @param lines Input text
+ * @return The input text word-wrapped at {@code maxWidth}; this may contain more rows than the input text
+ */
+ public static List<String> getWordWrappedText(int maxWidth, String... lines) {
+ //Bounds checking
+ if(maxWidth <= 0) {
+ return Arrays.asList(lines);
+ }
- if (characterIndex == 0) {
- // Failed! There was no 'nice' place to cut so just cut it
- // at maxWidth
- result.add(row.substring(0, maxWidth));
- linesToBeWrapped.addFirst(row.substring(maxWidth));
- } else {
- // Ok, split the row, add it to the result and continue
- // processing the second half on a new line
- result.add(row.substring(0, characterIndex));
- int spaceCharsToSkip = 0;
- while (characterIndex < row.length()
- && Character
- .isSpaceChar(row.charAt(characterIndex))) {
- characterIndex++;
- }
- ;
- linesToBeWrapped.addFirst(row.substring(characterIndex));
- }
- }
- }
- return result;
- }
+ List<String> result = new ArrayList<String>();
+ LinkedList<String> linesToBeWrapped = new LinkedList<String>(Arrays.asList(lines));
+ while(!linesToBeWrapped.isEmpty()) {
+ String row = linesToBeWrapped.removeFirst();
+ int rowWidth = getColumnWidth(row);
+ if(rowWidth <= maxWidth) {
+ result.add(row);
+ }
+ else {
+ //Now search in reverse and find the first possible line-break
+ final int characterIndexMax = getStringCharacterIndex(row, maxWidth);
+ int characterIndex = characterIndexMax;
+ while(characterIndex >= 0 &&
+ !Character.isSpaceChar(row.charAt(characterIndex)) &&
+ !isCharCJK(row.charAt(characterIndex))) {
+ characterIndex--;
+ }
+ // right *after* a CJK is also a "nice" spot to break the line!
+ if (characterIndex >= 0 && characterIndex < characterIndexMax &&
+ isCharCJK(row.charAt(characterIndex))) {
+ characterIndex++; // with these conditions it fits!
+ }
+
+ if(characterIndex < 0) {
+ //Failed! There was no 'nice' place to cut so just cut it at maxWidth
+ characterIndex = Math.max(characterIndexMax, 1); // at least 1 char
+ result.add(row.substring(0, characterIndex));
+ linesToBeWrapped.addFirst(row.substring(characterIndex));
+ }
+ else {
+ // characterIndex == 0 only happens, if either
+ // - first char is CJK and maxWidth==1 or
+ // - first char is whitespace
+ // either way: put it in row before break to prevent infinite loop.
+ characterIndex = Math.max( characterIndex, 1); // at least 1 char
+
+ //Ok, split the row, add it to the result and continue processing the second half on a new line
+ result.add(row.substring(0, characterIndex));
+ while(characterIndex < row.length() &&
+ Character.isSpaceChar(row.charAt(characterIndex))) {
+ characterIndex++;
+ };
+ if (characterIndex < row.length()) { // only if rest contains non-whitespace
+ linesToBeWrapped.addFirst(row.substring(characterIndex));
+ }
+ }
+ }
+ }
+ return result;
+ }
}
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