Android Base64 InputStream Encode encode(InputStream in, OutputStream out)

Description

Outputs base64 representation of the specified stream data to an OutputStream.

Declaration

public static void encode(InputStream in, OutputStream out)
        throws IOException 

Method Source Code

//package com.java2s;

import java.io.IOException;
import java.io.InputStream;

import java.io.OutputStream;
import java.io.OutputStreamWriter;

import java.io.StringWriter;
import java.io.Writer;

public class Main {
    /**//from  w  w w .  j  a  va2s .  c o  m
     * Charset used for base64 encoded data (7-bit ASCII).
     */
    private final static String CHARSET = "US-ASCII";
    /**
     * Encoding table (the 64 valid base64 characters).
     */
    private final static char[] BASE64CHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
            .toCharArray();
    /**
     * pad character.
     */
    private static final char BASE64PAD = '=';

    /**
     * Outputs base64 representation of the specified stream data to a <code>Writer</code>.
     */
    public static void encode(InputStream in, Writer writer)
            throws IOException {
        byte[] buffer = new byte[9 * 1024];
        int read;

        while ((read = in.read(buffer)) > 0) {
            encode(buffer, 0, read, writer);
        }
    }

    /**
     * Outputs base64 representation of the specified stream data to a <code>String</code>.
     */
    public static String encode(byte[] data) {
        StringWriter writer = new StringWriter();
        try {
            encode(data, 0, data.length, writer);
        } catch (IOException ioe) {
            throw new IllegalStateException(ioe);
        }
        return writer.toString();
    }

    /**
     * Outputs base64 representation of the specified stream data to an <code>OutputStream</code>.
     */
    public static void encode(InputStream in, OutputStream out)
            throws IOException {
        Writer writer = new OutputStreamWriter(out, CHARSET);
        encode(in, writer);
    }

    /**
     * Outputs base64 representation of the specified data to a <code>Writer</code>.
     */
    public static void encode(byte[] data, int off, int len, Writer writer)
            throws IOException {
        if (len == 0) {
            return;
        }
        if (len < 0 || off >= data.length || len + off > data.length) {
            throw new IllegalArgumentException();
        }
        char[] enc = new char[4];
        while (len >= 3) {
            int i = ((data[off] & 0xff) << 16)
                    + ((data[off + 1] & 0xff) << 8)
                    + (data[off + 2] & 0xff);
            enc[0] = BASE64CHARS[i >> 18];
            enc[1] = BASE64CHARS[(i >> 12) & 0x3f];
            enc[2] = BASE64CHARS[(i >> 6) & 0x3f];
            enc[3] = BASE64CHARS[i & 0x3f];
            writer.write(enc, 0, 4);
            off += 3;
            len -= 3;
        }
        // add padding if necessary
        if (len == 1) {
            int i = data[off] & 0xff;
            enc[0] = BASE64CHARS[i >> 2];
            enc[1] = BASE64CHARS[(i << 4) & 0x3f];
            enc[2] = BASE64PAD;
            enc[3] = BASE64PAD;
            writer.write(enc, 0, 4);
        } else if (len == 2) {
            int i = ((data[off] & 0xff) << 8) + (data[off + 1] & 0xff);
            enc[0] = BASE64CHARS[i >> 10];
            enc[1] = BASE64CHARS[(i >> 4) & 0x3f];
            enc[2] = BASE64CHARS[(i << 2) & 0x3f];
            enc[3] = BASE64PAD;
            writer.write(enc, 0, 4);
        }
    }
}

Related

1. encode(InputStream in, Writer writer)
2. streamToBase64(InputStream in, StringBuilder sb)