Utils.java

/*
 * Copyright (C) 2011 René Jeschke <rene_jeschke@yahoo.de>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package io.kaif.kmark;

/**
 * Utilities.
 *
 * @author René Jeschke <rene_jeschke@yahoo.de>
 */
class Utils {

  /**
   * Skips spaces in the given String.
   *
   * @param in
   *     Input String.
   * @param start
   *     Starting position.
   * @return The new position or -1 if EOL has been reached.
   */
  public final static int skipSpaces(final String in, final int start) {
    int pos = start;
    while (pos < in.length() && (in.charAt(pos) == ' ' || in.charAt(pos) == '\n')) {
      pos++;
    }
    return pos < in.length() ? pos : -1;
  }

  /**
   * Reads a markdown link ID.
   *
   * @param out
   *     The StringBuilder to write to.
   * @param in
   *     Input String.
   * @param start
   *     Starting position.
   * @return The new position or -1 if this is no valid markdown link ID.
   */
  public final static int readMdLinkId(final StringBuilder out, final String in, final int start) {
    int pos = start;
    int counter = 1;
    while (pos < in.length()) {
      final char ch = in.charAt(pos);
      boolean endReached = false;
      switch (ch) {
        case '\n':
          out.append(' ');
          break;
        case '[':
          counter++;
          out.append(ch);
          break;
        case ']':
          counter--;
          if (counter == 0) {
            endReached = true;
          } else {
            out.append(ch);
          }
          break;
        default:
          out.append(ch);
          break;
      }
      if (endReached) {
        break;
      }
      pos++;
    }

    return (pos == in.length()) ? -1 : pos;
  }

  /**
   * Reads characters until the end character is encountered, ignoring escape
   * sequences.
   *
   * @param out
   *     The StringBuilder to write to.
   * @param in
   *     The Input String.
   * @param start
   *     Starting position.
   * @param end
   *     End characters.
   * @return The new position or -1 if no 'end' char was found.
   */
  public final static int readRawUntil(final StringBuilder out,
      final String in,
      final int start,
      final char end) {
    int pos = start;
    while (pos < in.length()) {
      final char ch = in.charAt(pos);
      if (ch == end) {
        break;
      }
      out.append(ch);
      pos++;
    }

    return (pos == in.length()) ? -1 : pos;
  }

  /**
   * Removes trailing <code>`</code> and trims spaces.
   *
   * @param fenceLine
   *     Fenced code block starting line
   * @return Rest of the line after trimming and backtick removal
   * @since 0.7
   */
  public final static String getMetaFromFence(String fenceLine) {
    for (int i = 0; i < fenceLine.length(); i++) {
      final char c = fenceLine.charAt(i);
      if (!Character.isWhitespace(c) && c != '`' && c != '~' && c != '%') {
        return fenceLine.substring(i).trim();
      }
    }
    return "";
  }
}