New text justification (some tests missing)

[fanfix.git] / src / be / nikiroo / utils / StringJustifier.java

/*
 * This file was taken from:
 * Jexer - Java Text User Interface
 *
 * The MIT License (MIT)
 *
 * Copyright (C) 2017 Kevin Lamonte
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 *
 * @author Kevin Lamonte [kevin.lamonte@gmail.com]
 * @version 1
 */
package be.nikiroo.utils;

import java.util.LinkedList;
import java.util.List;

/**
 * StringJustifier contains methods to convert one or more long lines of strings
 * into justified text paragraphs.
 */
class StringJustifier {

	/**
	 * Left-justify a string into a list of lines.
	 * 
	 * @param str
	 *            the string
	 * @param n
	 *            the maximum number of characters in a line
	 * @return the list of lines
	 */
	static List<String> left(final String str, final int n) {
		List<String> result = new LinkedList<String>();

		/*
		 * General procedure:
		 * 
		 * 1. Split on '\n' into paragraphs.
		 * 
		 * 2. Scan each line, noting the position of the last
		 * beginning-of-a-word.
		 * 
		 * 3. Chop at the last #2 if the next beginning-of-a-word exceeds n.
		 * 
		 * 4. Return the lines.
		 */

		String[] rawLines = str.split("\n");
		for (int i = 0; i < rawLines.length; i++) {
			StringBuilder line = new StringBuilder();
			StringBuilder word = new StringBuilder();
			boolean inWord = false;
			for (int j = 0; j < rawLines[i].length(); j++) {
				char ch = rawLines[i].charAt(j);
				if ((ch == ' ') || (ch == '\t')) {
					if (inWord == true) {
						// We have just transitioned from a word to
						// whitespace. See if we have enough space to add
						// the word to the line.
						if (word.length() + line.length() > n) {
							// This word will exceed the line length. Wrap
							// at it instead.
							result.add(line.toString());
							line = new StringBuilder();
						}
						if ((word.toString().startsWith(" "))
								&& (line.length() == 0)) {
							line.append(word.substring(1));
						} else {
							line.append(word);
						}
						word = new StringBuilder();
						word.append(ch);
						inWord = false;
					} else {
						// We are in the whitespace before another word. Do
						// nothing.
					}
				} else {
					if (inWord == true) {
						// We are appending to a word.
						word.append(ch);
					} else {
						// We have transitioned from whitespace to a word.
						word.append(ch);
						inWord = true;
					}
				}
			} // for (int j = 0; j < rawLines[i].length(); j++)

			if (word.length() + line.length() > n) {
				// This word will exceed the line length. Wrap at it
				// instead.
				result.add(line.toString());
				line = new StringBuilder();
			}
			if ((word.toString().startsWith(" ")) && (line.length() == 0)) {
				line.append(word.substring(1));
			} else {
				line.append(word);
			}
			result.add(line.toString());
		} // for (int i = 0; i < rawLines.length; i++) {

		return result;
	}

	/**
	 * Right-justify a string into a list of lines.
	 * 
	 * @param str
	 *            the string
	 * @param n
	 *            the maximum number of characters in a line
	 * @return the list of lines
	 */
	static List<String> right(final String str, final int n) {
		List<String> result = new LinkedList<String>();

		/*
		 * Same as left(), but preceed each line with spaces to make it n chars
		 * long.
		 */
		List<String> lines = left(str, n);
		for (String line : lines) {
			StringBuilder sb = new StringBuilder();
			for (int i = 0; i < n - line.length(); i++) {
				sb.append(' ');
			}
			sb.append(line);
			result.add(sb.toString());
		}

		return result;
	}

	/**
	 * Center a string into a list of lines.
	 * 
	 * @param str
	 *            the string
	 * @param n
	 *            the maximum number of characters in a line
	 * @return the list of lines
	 */
	static List<String> center(final String str, final int n) {
		List<String> result = new LinkedList<String>();

		/*
		 * Same as left(), but preceed/succeed each line with spaces to make it
		 * n chars long.
		 */
		List<String> lines = left(str, n);
		for (String line : lines) {
			StringBuilder sb = new StringBuilder();
			int l = (n - line.length()) / 2;
			int r = n - line.length() - l;
			for (int i = 0; i < l; i++) {
				sb.append(' ');
			}
			sb.append(line);
			for (int i = 0; i < r; i++) {
				sb.append(' ');
			}
			result.add(sb.toString());
		}

		return result;
	}

	/**
	 * Fully-justify a string into a list of lines.
	 * 
	 * @param str
	 *            the string
	 * @param n
	 *            the maximum number of characters in a line
	 * @return the list of lines
	 */
	static List<String> full(final String str, final int n) {
		List<String> result = new LinkedList<String>();

		/*
		 * Same as left(), but insert spaces between words to make each line n
		 * chars long. The "algorithm" here is pretty dumb: it performs a split
		 * on space and then re-inserts multiples of n between words.
		 */
		List<String> lines = left(str, n);
		for (int lineI = 0; lineI < lines.size() - 1; lineI++) {
			String line = lines.get(lineI);
			String[] words = line.split(" ");
			if (words.length > 1) {
				int charCount = 0;
				for (int i = 0; i < words.length; i++) {
					charCount += words[i].length();
				}
				int spaceCount = n - charCount;
				int q = spaceCount / (words.length - 1);
				int r = spaceCount % (words.length - 1);
				StringBuilder sb = new StringBuilder();
				for (int i = 0; i < words.length - 1; i++) {
					sb.append(words[i]);
					for (int j = 0; j < q; j++) {
						sb.append(' ');
					}
					if (r > 0) {
						sb.append(' ');
						r--;
					}
				}
				for (int j = 0; j < r; j++) {
					sb.append(' ');
				}
				sb.append(words[words.length - 1]);
				result.add(sb.toString());
			} else {
				result.add(line);
			}
		}
		if (lines.size() > 0) {
			result.add(lines.get(lines.size() - 1));
		}

		return result;
	}
}