Java example source code file (EncodingHelper.java)

This example Java source code file (EncodingHelper.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

applycasefold, emptychars, encodinghelper, intholder, line_separator, new_line, object, paragraph_separator, return, runtimeexception, sorry, util

The EncodingHelper.java Java example source code

/*
 * 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.
 */
package jdk.nashorn.internal.runtime.regexp.joni;

import jdk.nashorn.internal.runtime.regexp.joni.encoding.CharacterType;
import jdk.nashorn.internal.runtime.regexp.joni.encoding.IntHolder;

import java.util.Arrays;

public final class EncodingHelper {

    final static int NEW_LINE            = 0x000a;
    final static int RETURN              = 0x000d;
    final static int LINE_SEPARATOR      = 0x2028;
    final static int PARAGRAPH_SEPARATOR = 0x2029;

    final static char[] EMPTYCHARS = new char[0];
    final static int[][] codeRanges = new int[15][];

    public static int digitVal(int code) {
        return code - '0';
    }

    public static int odigitVal(int code) {
        return digitVal(code);
    }

    public static boolean isXDigit(int code) {
        return Character.isDigit(code) || (code >= 'a' && code <= 'f') || (code >= 'A' && code <= 'F');
    }

    public static int xdigitVal(int code) {
        if (Character.isDigit(code)) {
            return code - '0';
        } else if (code >= 'a' && code <= 'f') {
            return code - 'a' + 10;
        } else {
            return code - 'A' + 10;
        }
    }

    public static boolean isDigit(int code) {
        return code >= '0' && code <= '9';
    }

    public static boolean isWord(int code) {
        // letter, digit, or '_'
        return (1 << Character.getType(code) & CharacterType.WORD_MASK) != 0;
    }

    public static boolean isNewLine(int code) {
        return code == NEW_LINE || code == RETURN || code == LINE_SEPARATOR || code == PARAGRAPH_SEPARATOR;
    }

    public static boolean isNewLine(char[] chars, int p, int end) {
        return p < end && isNewLine(chars[p]);
    }

    // Encoding.prevCharHead
    public static int prevCharHead(int p, int s) {
        return s <= p ? -1 : s - 1;
    }

    /* onigenc_get_right_adjust_char_head_with_prev */
    public static int rightAdjustCharHeadWithPrev(int s, IntHolder prev) {
        if (prev != null) prev.value = -1; /* Sorry */
        return s;
    }

    // Encoding.stepBack
    public static int stepBack(int p, int s, int n) {
       while (s != -1 && n-- > 0) {
           if (s <= p) return -1;
           s--;
       }
       return s;
    }

    public static int mbcToCode(byte[] bytes, int p, int end) {
        int code = 0;
        for (int i = p; i < end; i++) {
            code = (code << 8) | (bytes[i] & 0xff);
        }
        return code;
    }

    public static int mbcodeStartPosition() {
        return 0x80;
    }

    public static char[] caseFoldCodesByString(int flag, char c) {
        if (Character.isUpperCase(c)) {
            return new char[] {Character.toLowerCase(c)};
        } else if (Character.isLowerCase(c)) {
            return new char[] {Character.toUpperCase(c)};
        } else {
            return EMPTYCHARS;
        }
    }

    public static void applyAllCaseFold(int flag, ApplyCaseFold fun, Object arg) {
        int[] code = new int[1];

        for (int c = 0; c < 0xffff; c++) {
            if (Character.getType(c) == Character.LOWERCASE_LETTER) {

                int upper = code[0] = Character.toUpperCase(c);
                fun.apply(c, code, 1, arg);

                code[0] = c;
                fun.apply(upper, code, 1, arg);
            }
        }
    }

    public static int[] ctypeCodeRange(int ctype, IntHolder sbOut) {
        sbOut.value = 0x100; // use bitset for codes smaller than 256
        int[] range = null;

        if (ctype < codeRanges.length) {
            range = codeRanges[ctype];

            if (range == null) {
                // format: [numberOfRanges, rangeStart, rangeEnd, ...]
                range = new int[16];
                int rangeCount = 0;
                int lastCode = -2;

                for (int code = 0; code <= 0xffff; code++) {
                    if (isCodeCType(code, ctype)) {
                        if (lastCode < code -1) {
                            if (rangeCount * 2 + 2 >= range.length) {
                                range = Arrays.copyOf(range, range.length * 2);
                            }
                            range[rangeCount * 2 + 1] = code;
                            rangeCount++;
                        }
                        range[rangeCount * 2] = lastCode = code;
                    }
                }

                if (rangeCount * 2 + 1 < range.length) {
                    range = Arrays.copyOf(range, rangeCount * 2 + 1);
                }

                range[0] = rangeCount;
                codeRanges[ctype] = range;
            }
        }

        return range;
    }

    // CodeRange.isInCodeRange
    public static boolean isInCodeRange(int[] p, int offset, int code) {
        int low = 0;
        int n = p[offset];
        int high = n ;

        while (low < high) {
            int x = (low + high) >> 1;
            if (code > p[(x << 1) + 2 + offset]) {
                low = x + 1;
            } else {
                high = x;
            }
        }
        return low < n && code >= p[(low << 1) + 1 + offset];
    }

    /**
     * @see <a href="http://www.geocities.jp/kosako3/oniguruma/doc/RE.txt">http://www.geocities.jp/kosako3/oniguruma/doc/RE.txt
     */
    public static boolean isCodeCType(int code, int ctype) {
        int type;
        switch (ctype) {
            case CharacterType.NEWLINE:
                return isNewLine(code);
            case CharacterType.ALPHA:
                return (1 << Character.getType(code) & CharacterType.ALPHA_MASK) != 0;
            case CharacterType.BLANK:
                return code == 0x09 || Character.getType(code) == Character.SPACE_SEPARATOR;
            case CharacterType.CNTRL:
                type = Character.getType(code);
                return (1 << type & CharacterType.CNTRL_MASK) != 0 || type == Character.UNASSIGNED;
            case CharacterType.DIGIT:
                return EncodingHelper.isDigit(code);
            case CharacterType.GRAPH:
                switch (code) {
                    case 0x09:
                    case 0x0a:
                    case 0x0b:
                    case 0x0c:
                    case 0x0d:
                        return false;
                    default:
                        type = Character.getType(code);
                        return (1 << type & CharacterType.GRAPH_MASK) == 0 && type != Character.UNASSIGNED;
                }
            case CharacterType.LOWER:
                return Character.isLowerCase(code);
            case CharacterType.PRINT:
                type = Character.getType(code);
                return (1 << type & CharacterType.PRINT_MASK) == 0 && type != Character.UNASSIGNED;
            case CharacterType.PUNCT:
                return (1 << Character.getType(code) & CharacterType.PUNCT_MASK) != 0;
            case CharacterType.SPACE:
                // ECMA 7.2 and 7.3
                switch (code) {
                    case 0x09:
                    case 0x0a:
                    case 0x0b:
                    case 0x0c:
                    case 0x0d:
                        return true;
                    default:
                        // true if Unicode separator or BOM
                        return (1 << Character.getType(code) & CharacterType.SPACE_MASK) != 0 || code == 0xfeff;
                }
            case CharacterType.UPPER:
                return Character.isUpperCase(code);
            case CharacterType.XDIGIT:
                return EncodingHelper.isXDigit(code);
            case CharacterType.WORD:
                return (1 << Character.getType(code) & CharacterType.WORD_MASK) != 0;
            case CharacterType.ALNUM:
                return (1 << Character.getType(code) & CharacterType.ALNUM_MASK) != 0;
            case CharacterType.ASCII:
                return code < 0x80;
            default:
                throw new RuntimeException("illegal character type: " + ctype);
        }
    }
}