Java String Quote Unescape unescape(CharSequence string, int quoteChar, boolean useAsciiEscapes, StringBuilder sb)

Description

Unescape the given string

License

Apache License

Parameter

Parameter	Description
string	a parameter
quoteChar	a parameter
useAsciiExcapes	a parameter
sb	a scratch buffer to use

Declaration

public static String unescape(CharSequence string, int quoteChar, boolean useAsciiEscapes, StringBuilder sb) 

Method Source Code

//package com.java2s;
//License from project: Apache License 

public class Main {
    /**//from  w w  w . ja  va2s .  c o m
     * Unescape the given string
     * @param string
     * @param quoteChar
     * @param useAsciiExcapes
     * @param sb a scratch buffer to use
     * @return
     */
    public static String unescape(CharSequence string, int quoteChar, boolean useAsciiEscapes, StringBuilder sb) {
        boolean escaped = false;

        for (int i = 0; i < string.length(); i++) {
            char c = string.charAt(i);
            if (escaped) {
                switch (c) {
                case 'b':
                    sb.append('\b');
                    break;
                case 't':
                    sb.append('\t');
                    break;
                case 'n':
                    sb.append('\n');
                    break;
                case 'f':
                    sb.append('\f');
                    break;
                case 'r':
                    sb.append('\r');
                    break;
                case 'u':
                    i = parseNumericValue(string, sb, i, 0, 4, 4);
                    //TODO: this should probably be strict about needing 4 digits
                    break;
                default:
                    if (c == quoteChar) {
                        sb.append(quoteChar);
                    } else if (useAsciiEscapes) {
                        int value = Character.digit(c, 8);
                        if (value == -1) {
                            sb.append(c);
                        } else {
                            int possibleDigits = value < 3 ? 2 : 1;
                            int radixExp = 3;
                            i = parseNumericValue(string, sb, i, value, possibleDigits, radixExp);
                        }
                    }
                }
                escaped = false;
            } else {
                if (c == '\\') {
                    escaped = true;
                } else if (c == quoteChar) {
                    break;
                } else {
                    sb.append(c);
                }
            }
        }
        //TODO: should this be strict?
        //if (escaped) {
        //throw new FunctionExecutionException();
        //}
        return sb.toString();
    }

    private static int parseNumericValue(CharSequence string, StringBuilder sb, int i, int value,
            int possibleDigits, int radixExp) {
        for (int j = 0; j < possibleDigits; j++) {
            if (i + 1 == string.length()) {
                break;
            }
            char digit = string.charAt(i + 1);
            int val = Character.digit(digit, 1 << radixExp);
            if (val == -1) {
                break;
            }
            i++;
            value = (value << radixExp) + val;
        }
        sb.append((char) value);
        return i;
    }

    /**
     * Return a stringified version of the array.
     * @param array the array
     * @param delim the delimiter to use between array components
     * @return the string form of the array
     */
    public static String toString(final Object[] array, final String delim) {
        return toString(array, delim, true);
    }

    /**
     * Return a stringified version of the array.
     * @param array the array
     * @param delim the delimiter to use between array components
     * @return the string form of the array
     */
    public static String toString(final Object[] array, final String delim, boolean includeBrackets) {
        if (array == null) {
            return ""; //$NON-NLS-1$
        }
        final StringBuffer sb = new StringBuffer();
        if (includeBrackets) {
            sb.append('[');
        }
        for (int i = 0; i < array.length; ++i) {
            if (i != 0) {
                sb.append(delim);
            }
            sb.append(array[i]);
        }
        if (includeBrackets) {
            sb.append(']');
        }
        return sb.toString();
    }

    /**
     * Return a stringified version of the array, using a ',' as a delimiter
     * @param array the array
     * @return the string form of the array
     * @see #toString(Object[], String)
     */
    public static String toString(final Object[] array) {
        return toString(array, ",", true); //$NON-NLS-1$
    }
}

Related

1. unescapeDoubleQuote(String string)
2. unescapeDoubleQuote(String stringToReplace)
3. unescapeDoubleQuotes(String string)
4. unescapeDoubleQuotesAndBackslashes(final String input)