Java Hex Calculate toHexFromOct(final String octSymbols)

Description

Given a String of octal digits, convert them to hex representation

License

Open Source License

Parameter

Parameter	Description
octSymbols	A string of octal digits

Return

The corresponding string of hex digits

Declaration

public static String toHexFromOct(final String octSymbols) 

Method Source Code

//package com.java2s;
//License from project: Open Source License 

public class Main {
    /** Allowable hex values */
    private final static String[] hexSymbols = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c",
            "d", "e", "f" };
    public final static int BITS_PER_OCT_DIGIT = 3;
    public final static int BITS_PER_HEX_DIGIT = 4;
    public final static int BINARY_RADIX = 2;
    public static final String BINARY_STRING_PREFIX1 = "0b";
    public static final String BINARY_STRING_PREFIX2 = "0B";

    /**/*from   ww w . j av  a 2s  . c  om*/
     * Given a String of octal digits, convert them to hex representation
     *
     * @param octSymbols
     *            A string of octal digits
     * @return The corresponding string of hex digits
     */
    public static String toHexFromOct(final String octSymbols) {
        return (toHexFromBin(toBinFromOct(octSymbols)));
    }

    /**
     * Transform a string of binary symbols to a string of hex symbols
     *
     * @param binSymbols
     *            The binary symbol string to transform
     * @return The hex string corresponding to the input binary string
     */
    public static String toHexFromBin(final String binSymbols) {
        String bits = stripBinaryPrefix(binSymbols);

        while ((bits.length() % BITS_PER_HEX_DIGIT) != 0) {
            bits = "0" + bits;
        }

        StringBuilder hex = new StringBuilder(bits.length() / BITS_PER_HEX_DIGIT);
        for (int i = 0; i < bits.length(); i += BITS_PER_HEX_DIGIT) {
            String bitsToAdd = null;
            if ((i + BITS_PER_HEX_DIGIT) < bits.length()) {
                bitsToAdd = bits.substring(i, i + BITS_PER_HEX_DIGIT);
            } else {
                bitsToAdd = bits.substring(i);
            }
            hex.append(toHexCharFromBin(bitsToAdd));
        }

        return (hex.toString());
    }

    /**
     * Transform a string of octal symbols to a string of binary symbols
     *
     * @param octSymbols
     *            The oct symbol string to transform
     * @return The binary string that corresponds to the input octal string
     */
    public static String toBinFromOct(final String octSymbols) {
        StringBuilder bits = new StringBuilder(octSymbols.length() * BITS_PER_OCT_DIGIT);
        for (int i = 0; i < octSymbols.length(); i++) {
            bits.append(toBinFromOctChar(octSymbols.charAt(i)));
        }

        return (bits.toString());
    }

    public static String stripBinaryPrefix(String binSymbols) {
        if (binSymbols.startsWith(BINARY_STRING_PREFIX1)) {
            binSymbols = binSymbols.substring(BINARY_STRING_PREFIX1.length());
        } else if (binSymbols.startsWith(BINARY_STRING_PREFIX2)) {
            binSymbols = binSymbols.substring(BINARY_STRING_PREFIX2.length());
        }

        return (binSymbols);
    }

    public static char toHexCharFromBin(final String bin) {
        String bits = stripBinaryPrefix(bin);
        while (bits.length() < BITS_PER_HEX_DIGIT) {
            bits = "0" + bits;
        }

        if (bits.length() > BITS_PER_HEX_DIGIT) {
            throw new IllegalArgumentException(
                    "Input bit string \"" + bin + "\" is too long to be a hexadecimal character.");
        }

        int value = Integer.parseInt(bits, BINARY_RADIX);
        return (hexSymbols[value].charAt(0));
    }

    public static String toBinFromOctChar(final char oct) {
        switch (oct) {
        case '0':
            return ("000");
        case '1':
            return ("001");
        case '2':
            return ("010");
        case '3':
            return ("011");
        case '4':
            return ("100");
        case '5':
            return ("101");
        case '6':
            return ("110");
        case '7':
            return ("111");
        default:
            throw new IllegalArgumentException(
                    "The input character \'" + oct + "\'is not a valid octal character.");
        }
    }
}

Related

1. toHexFromBin(final String binSymbols)
2. toHexFromByte(byte b)
3. toHexFromByte(final byte b)
4. toHexFromBytes(byte[] bytes)
5. toHexFromBytes(final byte[] bytes)
6. toHexHashString(byte[] id)
7. toHexLiteral(int v)
8. toHexN(long src, int hexn)
9. ToHexNumber(int c)