android.util.Base64InputStream Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of android-util Show documentation

Utility classes mimicking classes from android.os and android.net.morimekta.util that does not really require an android phone to run. Created to facilitate testing and usage of android compatible libraries without having to run it on an actual phone. Note that android.os.Parcel and android.os.Bundle only supports a subset of it's original interface as these parts actually are dependent on the native phone library to work properly, or they have no real need on modern phones / outside android.

There is a newer version: 3.0.1

Show newest version

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package android.util;

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

/**
 * A {@link Base64InputStream} will read data from another
 * InputStream, given in the constructor, and encode
 * to Base64 notation on the fly.
 *
 * @see Base64
 */
public class Base64InputStream extends FilterInputStream {
    private final byte[] decodabet;      // Local copies to avoid extra method calls
    private final byte[] buffer3;         // Small buffer holding converted data
    private final int options;        // Record options used to create the stream.
    private final byte[] buffer4;

    private int position;       // Current position in the buffer
    private int numSigBytes;    // Number of meaningful bytes in the buffer

    /**
     * An InputStream that performs Base64 decoding on the data read from the wrapped stream.
     *
     * @param in      the InputStream to read the source data from
     * @param options bit flags for controlling the decoder; see the constants in Base64
     */
    public Base64InputStream(InputStream in, int options) {
        super(in);
        if (in == null) throw new IllegalArgumentException("null input stream");
        this.options = options; // Record for later
        this.buffer3 = new byte[3];
        this.buffer4 = new byte[4];
        this.position = -1;
        this.numSigBytes = 0;
        this.decodabet = Base64.getDecodabet(options);
    }   // end constructor

    @Override
    public int read() throws IOException {
        if (in == null) {
            throw new IOException("Reading from a closed Base64InputStream");
        }

        if (position < 0) {
            int i;

            // Read four "meaningful" bytes:
            for (i = 0; i < 4; i++) {
                int b;
                do {
                    b = in.read();
                    // treat bytes as ASCII, skip white space only.
                } while ((b >= 0) && (decodabet[b & 0x7f] == Base64.WHITE_SPACE_ENC));

                if (b < 0) {
                    break;
                }

                buffer4[i] = (byte) b;
            }

            position = 0;
            if (i == 0) {
                numSigBytes = 0;
                return -1;
            }
            try {
                numSigBytes = Base64.decode4to3(buffer4, i, buffer3, 0, decodabet);
            } catch (IllegalArgumentException e) {
                throw new IOException(e.getMessage(), e);
            }
        }   // end else: get data

        // Got data?
        if (position >= numSigBytes) {
            return -1;
        }

        int b = buffer3[position++] & 0xFF;

        if (position >= 3) {
            position = -1;
            numSigBytes = 0;
        }

        return b;
    }

    @Override
    public int read(byte[] dest, int off, int len) throws IOException {
        if (len == 0) return 0;

        int i;
        int b;
        for (i = 0; i < len; i++) {
            b = read();
            if (b < 0) break;
            dest[off + i] = (byte) b;
        }

        return i > 0 ? i : -1;
    }

    @Override
    public void close() throws IOException {
        if (in != null) {
            try {
                in.close();
            } finally {
                in = null;
            }
        }
    }

    @Override
    public int available() throws IOException {
        return (position >= 0 ? numSigBytes - position : 0) +
               (in.available() > 0 ? 1 : 0);
    }

    @Override
    public boolean markSupported() {
        return false;
    }

    @Override
    public void mark(int readlimit) {
    }

    @Override
    public long skip(long n) throws IOException {
        throw new IOException("skip/reset not supported");
    }

    @Override
    public void reset() throws IOException {
        throw new IOException("mark/reset not supported");
    }
}