Java URL Decode urlDecodeInplace(StringBuilder input)

Description

url Decode Inplace

License

Apache License

Declaration

public static void urlDecodeInplace(StringBuilder input) 

Method Source Code

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

public class Main {
    public static final char INVALID_HEX = (char) 256;

    public static void urlDecodeInplace(StringBuilder input) {
        urlDecodeInto(input, 0, input.length(), input, true);
    }/*from   w  w w  . j  av a  2  s  .c om*/

    public static void urlDecodeInto(CharSequence input, int start, int end, StringBuilder result) {
        urlDecodeInto(input, start, end, result, false);
    }

    private static void urlDecodeInto(CharSequence input, int start, int end, StringBuilder result,
            boolean inplace) {
        int writeHead = start;
        for (int i = start; i < end; i++) {
            char c = input.charAt(i);
            if (c == '%' && i + 2 < end) {
                char val = decodeHexPair(input.charAt(i + 1), input.charAt(i + 2));
                if ((val & 0xE0) == 0xC0) {
                    if (i + 5 < end && input.charAt(i + 3) == '%') {
                        char val2 = decodeHexPair(input.charAt(i + 4), input.charAt(i + 5));
                        if (val2 != INVALID_HEX && (val2 & 0xC0) == 0x80) {
                            // zimmerm%C3%A4dchen
                            c = (char) (((val & 0x1F) << 6) | (val2 & 0x3F));
                            i += 5;
                        }
                    }
                } else if ((val & 0xF0) == 0xE0) {
                    if (i + 8 < end && input.charAt(i + 3) == '%' && input.charAt(i + 6) == '%') {
                        char val2 = decodeHexPair(input.charAt(i + 4), input.charAt(i + 5));
                        char val3 = decodeHexPair(input.charAt(i + 7), input.charAt(i + 8));
                        if (val2 != INVALID_HEX && val3 != INVALID_HEX && (val2 & 0xC0) == 0x80
                                && (val3 & 0xC0) == 0x80) {
                            // Technologist+%E2%80%93+Full+Time
                            c = (char) (((val & 0x0F) << 12) | ((val2 & 0x3F) << 6) | (val3 & 0x3F));
                            i += 8;
                        }
                    }
                } else if ((val & 0xF8) == 0xF0) {
                    //these are code points > 0XFFFF, they need a surrogate pair to represent them
                    if (i + 11 < end && input.charAt(i + 3) == '%' && input.charAt(i + 6) == '%'
                            && input.charAt(i + 9) == '%') {
                        char val2 = decodeHexPair(input.charAt(i + 4), input.charAt(i + 5));
                        char val3 = decodeHexPair(input.charAt(i + 7), input.charAt(i + 8));
                        char val4 = decodeHexPair(input.charAt(i + 10), input.charAt(i + 11));
                        if (val2 != INVALID_HEX && val3 != INVALID_HEX && val4 != INVALID_HEX
                                && (val2 & 0xC0) == 0x80 && (val3 & 0xC0) == 0x80 && (val4 & 0xC0) == 0x80) {
                            final int codePoint = (((val & 0x0F) << 15) | ((val2 & 0x3F) << 12)
                                    | ((val3 & 0x3F) << 6) | (val4 & 0x3F));
                            if (codePoint < Character.MIN_SUPPLEMENTARY_CODE_POINT) {
                                c = (char) codePoint;
                            } else {
                                final int offset = codePoint - Character.MIN_SUPPLEMENTARY_CODE_POINT;
                                final char highChar = (char) ((offset >>> 10) + Character.MIN_HIGH_SURROGATE);
                                final char lowChar = (char) ((offset & 0x3ff) + Character.MIN_LOW_SURROGATE);
                                if (!inplace) {
                                    result.append(highChar);
                                } else {
                                    result.setCharAt(writeHead++, highChar);
                                }
                                c = lowChar; // let normal machinery take over here
                            }
                            i += 11;
                        }
                    }
                } else if (val != INVALID_HEX) {
                    c = val;
                    i += 2;
                }
            } else if (c == '+') {
                c = ' ';
            }

            if (!inplace) {
                result.append(c);
            } else {
                result.setCharAt(writeHead++, c);
            }
        }
        if (inplace) {
            result.delete(writeHead, end);
        }
    }

    public static char decodeHexPair(char c1, char c2) {
        char ret = 0;
        if (c1 >= '0' && c1 <= '9') {
            ret |= c1 - '0';
        } else if (c1 >= 'a' && c1 <= 'f') {
            ret |= c1 - 'a' + 10;
        } else if (c1 >= 'A' && c1 <= 'F') {
            ret |= c1 - 'A' + 10;
        } else {
            return INVALID_HEX;
        }
        ret <<= 4;
        if (c2 >= '0' && c2 <= '9') {
            ret |= c2 - '0';
        } else if (c2 >= 'a' && c2 <= 'f') {
            ret |= c2 - 'a' + 10;
        } else if (c2 >= 'A' && c2 <= 'F') {
            ret |= c2 - 'A' + 10;
        } else {
            return INVALID_HEX;
        }
        return ret;
    }
}

Related

1. urldecode(String str)
2. urlDecode(String str)
3. urlDecode(String text)
4. urlDecodeBytes(String key)
5. urlDecodeFilename(char[] input)
6. urlDecoder(String encoded)
7. xmlDecode(String s)