Encodes a byte array into Base 64 format and breaks the output into lines of 76 characters. - Java java.lang

Java examples for java.lang:byte Array to int

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Description

Encodes a byte array into Base 64 format and breaks the output into lines of 76 characters.

Demo Code


//package com.java2s;

public class Main {
    public static void main(String[] argv) throws Exception {
        byte[] in = new byte[] { 34, 35, 36, 37, 37, 37, 67, 68, 69 };
        System.out.println(encodeLines(in));
    }//from  w w w .  j a  va2 s. co  m

    private static final String systemLineSeparator = System
            .getProperty("line.separator");
    private static final char[] map1 = new char[64];

    /**
     * Encodes a byte array into Base 64 format and breaks the output into lines of 76 characters.
     * This method is compatible with <code>sun.misc.BASE64Encoder.encodeBuffer(byte[])</code>.
     *
     * @param in An array containing the data bytes to be encoded.
     * @return A String containing the Base64 encoded data, broken into lines.
     */
    public static String encodeLines(byte[] in) {
        return encodeLines(in, 0, in.length, 76, systemLineSeparator);
    }

    /**
     * Encodes a byte array into Base 64 format and breaks the output into lines.
     *
     * @param in            An array containing the data bytes to be encoded.
     * @param iOff          Offset of the first byte in <code>in</code> to be processed.
     * @param iLen          Number of bytes to be processed in <code>in</code>, starting at <code>iOff</code>.
     * @param lineLen       Line length for the output data. Should be a multiple of 4.
     * @param lineSeparator The line separator to be used to separate the output lines.
     * @return A String containing the Base64 encoded data, broken into lines.
     */
    public static String encodeLines(byte[] in, int iOff, int iLen,
            int lineLen, String lineSeparator) {
        int blockLen = (lineLen * 3) / 4;
        if (blockLen <= 0)
            throw new IllegalArgumentException();
        int lines = (iLen + blockLen - 1) / blockLen;
        int bufLen = ((iLen + 2) / 3) * 4 + lines * lineSeparator.length();
        StringBuilder buf = new StringBuilder(bufLen);
        int ip = 0;
        while (ip < iLen) {
            int l = Math.min(iLen - ip, blockLen);
            buf.append(encode(in, iOff + ip, l));
            buf.append(lineSeparator);
            ip += l;
        }
        return buf.toString();
    }

    /**
     * Encodes a byte array into Base64 format.
     * No blanks or line breaks are inserted in the output.
     *
     * @param in An array containing the data bytes to be encoded.
     * @return A character array containing the Base64 encoded data.
     */
    public static char[] encode(byte[] in) {
        return encode(in, 0, in.length);
    }

    /**
     * Encodes a byte array into Base64 format.
     * No blanks or line breaks are inserted in the output.
     *
     * @param in   An array containing the data bytes to be encoded.
     * @param iLen Number of bytes to process in <code>in</code>.
     * @return A character array containing the Base64 encoded data.
     */
    public static char[] encode(byte[] in, int iLen) {
        return encode(in, 0, iLen);
    }

    /**
     * Encodes a byte array into Base64 format.
     * No blanks or line breaks are inserted in the output.
     *
     * @param in   An array containing the data bytes to be encoded.
     * @param iOff Offset of the first byte in <code>in</code> to be processed.
     * @param iLen Number of bytes to process in <code>in</code>, starting at <code>iOff</code>.
     * @return A character array containing the Base64 encoded data.
     */
    public static char[] encode(byte[] in, int iOff, int iLen) {
        int oDataLen = (iLen * 4 + 2) / 3; // output length without padding
        int oLen = ((iLen + 2) / 3) * 4; // output length including padding
        char[] out = new char[oLen];
        int ip = iOff;
        int iEnd = iOff + iLen;
        int op = 0;
        while (ip < iEnd) {
            int i0 = in[ip++] & 0xff;
            int i1 = ip < iEnd ? in[ip++] & 0xff : 0;
            int i2 = ip < iEnd ? in[ip++] & 0xff : 0;
            int o0 = i0 >>> 2;
            int o1 = ((i0 & 3) << 4) | (i1 >>> 4);
            int o2 = ((i1 & 0xf) << 2) | (i2 >>> 6);
            int o3 = i2 & 0x3F;
            out[op++] = map1[o0];
            out[op++] = map1[o1];
            out[op] = op < oDataLen ? map1[o2] : '=';
            op++;
            out[op] = op < oDataLen ? map1[o3] : '=';
            op++;
        }
        return out;
    }
}

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