diff options
Diffstat (limited to 'java/com/android/voicemailomtp/src/org/apache/james/mime4j/decoder/Base64InputStream.java')
| -rw-r--r-- | java/com/android/voicemailomtp/src/org/apache/james/mime4j/decoder/Base64InputStream.java | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/java/com/android/voicemailomtp/src/org/apache/james/mime4j/decoder/Base64InputStream.java b/java/com/android/voicemailomtp/src/org/apache/james/mime4j/decoder/Base64InputStream.java new file mode 100644 index 000000000..77f5d7d4a --- /dev/null +++ b/java/com/android/voicemailomtp/src/org/apache/james/mime4j/decoder/Base64InputStream.java @@ -0,0 +1,151 @@ +/**************************************************************** + * 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. * + ****************************************************************/ + +/** + * Modified to improve efficiency by Android 21-Aug-2009 + */ + +package org.apache.james.mime4j.decoder; + +import java.io.IOException; +import java.io.InputStream; + +/** + * Performs Base-64 decoding on an underlying stream. + * + * + * @version $Id: Base64InputStream.java,v 1.3 2004/11/29 13:15:47 ntherning Exp $ + */ +public class Base64InputStream extends InputStream { + private final InputStream s; + private int outCount = 0; + private int outIndex = 0; + private final int[] outputBuffer = new int[3]; + private final byte[] inputBuffer = new byte[4]; + private boolean done = false; + + public Base64InputStream(InputStream s) { + this.s = s; + } + + /** + * Closes the underlying stream. + * + * @throws IOException on I/O errors. + */ + @Override + public void close() throws IOException { + s.close(); + } + + @Override + public int read() throws IOException { + if (outIndex == outCount) { + fillBuffer(); + if (outIndex == outCount) { + return -1; + } + } + + return outputBuffer[outIndex++]; + } + + /** + * Retrieve data from the underlying stream, decode it, + * and put the results in the byteq. + * @throws IOException + */ + private void fillBuffer() throws IOException { + outCount = 0; + outIndex = 0; + int inCount = 0; + + int i; + // "done" is needed for the two successive '=' at the end + while (!done) { + switch (i = s.read()) { + case -1: + // No more input - just return, let outputBuffer drain out, and be done + return; + case '=': + // once we meet the first '=', avoid reading the second '=' + done = true; + decodeAndEnqueue(inCount); + return; + default: + byte sX = TRANSLATION[i]; + if (sX < 0) continue; + inputBuffer[inCount++] = sX; + if (inCount == 4) { + decodeAndEnqueue(inCount); + return; + } + break; + } + } + } + + private void decodeAndEnqueue(int len) { + int accum = 0; + accum |= inputBuffer[0] << 18; + accum |= inputBuffer[1] << 12; + accum |= inputBuffer[2] << 6; + accum |= inputBuffer[3]; + + // There's a bit of duplicated code here because we want to have straight-through operation + // for the most common case of len==4 + if (len == 4) { + outputBuffer[0] = (accum >> 16) & 0xFF; + outputBuffer[1] = (accum >> 8) & 0xFF; + outputBuffer[2] = (accum) & 0xFF; + outCount = 3; + return; + } else if (len == 3) { + outputBuffer[0] = (accum >> 16) & 0xFF; + outputBuffer[1] = (accum >> 8) & 0xFF; + outCount = 2; + return; + } else { // len == 2 + outputBuffer[0] = (accum >> 16) & 0xFF; + outCount = 1; + return; + } + } + + private static byte[] TRANSLATION = { + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0x00 */ + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0x10 */ + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, /* 0x20 */ + 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, /* 0x30 */ + -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, /* 0x40 */ + 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, /* 0x50 */ + -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, /* 0x60 */ + 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1, /* 0x70 */ + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0x80 */ + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0x90 */ + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0xA0 */ + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0xB0 */ + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0xC0 */ + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0xD0 */ + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0xE0 */ + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 /* 0xF0 */ + }; + + +} |