proquint/Proquint.java at master · erilor/proquint · GitHub

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/* This file is part of proquint: http://github.com/dsw/proquint .
 * See License.txt for copyright and terms of use.
 */

import java.io.*;

/**
 * Convert between proquint, hex, and decimal strings.
 * Please see the article on proquints: http://arXiv.org/html/0901.4016
 * Daniel S. Wilkerson
 */
public class Proquint {

  /** Map uints to consonants. */
  static final char uint2consonant[] = {
    'b', 'd', 'f', 'g',
    'h', 'j', 'k', 'l',
    'm', 'n', 'p', 'r',
    's', 't', 'v', 'z'
  };

  /** Map uints to vowels. */
  static final char uint2vowel[] = {
    'a', 'i', 'o', 'u'
  };

  /** Convert an unsigned int to a proquint; the output is appended to
   * quint; sepChar will be omitted if -1.
   */
  static String uint2quint(int i, String sepChar)
  {
    // http://docs.oracle.com/javase/tutorial/java/nutsandbolts/opsummary.html
    // ">>>" Unsigned right shift
		StringBuffer quint = new StringBuffer();

		quint.append(uint2consonant[i >>> 28]);
		i <<= 4;
		quint.append(uint2vowel[i >>> 30]);
		i <<= 2;
		quint.append(uint2consonant[i >>> 28]);
		i <<= 4;
		quint.append(uint2vowel[i >>> 30]);
		i <<= 2;
		quint.append(uint2consonant[i >>> 28]);
		i <<= 4;

		quint.append(sepChar);

		quint.append(uint2consonant[i >>> 28]);
		i <<= 4;
		quint.append(uint2vowel[i >>> 30]);
		i <<= 2;
		quint.append(uint2consonant[i >>> 28]);
		i <<= 4;
		quint.append(uint2vowel[i >>> 30]);
		i <<= 2;
		quint.append(uint2consonant[i >>> 28]);
		i <<= 4;

		return quint.toString();
  }

  /**
   * Convert a proquint to an unsigned int (long).
   */
	static long quint2uint(String quint) {
		long res = 0;

    for (char c : quint.toCharArray()) {
      switch(c) {

          /* consonants */
        case 'b': res <<= 4; res +=  0; break;
        case 'd': res <<= 4; res +=  1; break;
        case 'f': res <<= 4; res +=  2; break;
        case 'g': res <<= 4; res +=  3; break;

        case 'h': res <<= 4; res +=  4; break;
        case 'j': res <<= 4; res +=  5; break;
        case 'k': res <<= 4; res +=  6; break;
        case 'l': res <<= 4; res +=  7; break;

        case 'm': res <<= 4; res +=  8; break;
        case 'n': res <<= 4; res +=  9; break;
        case 'p': res <<= 4; res += 10; break;
        case 'r': res <<= 4; res += 11; break;

        case 's': res <<= 4; res += 12; break;
        case 't': res <<= 4; res += 13; break;
        case 'v': res <<= 4; res += 14; break;
        case 'z': res <<= 4; res += 15; break;

          /* vowels */
        case 'a': res <<= 2; res +=  0; break;
        case 'i': res <<= 2; res +=  1; break;
        case 'o': res <<= 2; res +=  2; break;
        case 'u': res <<= 2; res +=  3; break;

          /* separators */
        default: break;
      }
  }

		return res;
	}
}