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/*
* 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 org.apache.thrift.protocol;
/**
* Class for encoding and decoding Base64 data.
*
* <p>This class is kept at package level because the interface does no input validation and is
* therefore too low-level for generalized reuse.
*
* <p>Note also that the encoding does not pad with equal signs , as discussed in section 2.2 of the
* RFC (http://www.faqs.org/rfcs/rfc3548.html). Furthermore, bad data encountered when decoding is
* neither rejected or ignored but simply results in bad decoded data -- this is not in compliance
* with the RFC but is done in the interest of performance.
*/
class TBase64Utils {
private static final String ENCODE_TABLE =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
/**
* Encode len bytes of data in src at offset srcOff, storing the result into dst at offset dstOff.
* len must be 1, 2, or 3. dst must have at least len+1 bytes of space at dstOff. src and dst
* should not be the same object. This method does no validation of the input values in the
* interest of performance.
*
* @param src the source of bytes to encode
* @param srcOff the offset into the source to read the unencoded bytes
* @param len the number of bytes to encode (must be 1, 2, or 3).
* @param dst the destination for the encoding
* @param dstOff the offset into the destination to place the encoded bytes
*/
static final void encode(byte[] src, int srcOff, int len, byte[] dst, int dstOff) {
dst[dstOff] = (byte) ENCODE_TABLE.charAt((src[srcOff] >> 2) & 0x3F);
if (len == 3) {
dst[dstOff + 1] =
(byte) ENCODE_TABLE.charAt(((src[srcOff] << 4) & 0x30) | ((src[srcOff + 1] >> 4) & 0x0F));
dst[dstOff + 2] =
(byte)
ENCODE_TABLE.charAt(
((src[srcOff + 1] << 2) & 0x3C) | ((src[srcOff + 2] >> 6) & 0x03));
dst[dstOff + 3] = (byte) ENCODE_TABLE.charAt(src[srcOff + 2] & 0x3F);
} else if (len == 2) {
dst[dstOff + 1] =
(byte) ENCODE_TABLE.charAt(((src[srcOff] << 4) & 0x30) | ((src[srcOff + 1] >> 4) & 0x0F));
dst[dstOff + 2] = (byte) ENCODE_TABLE.charAt((src[srcOff + 1] << 2) & 0x3C);
} else { // len == 1) {
dst[dstOff + 1] = (byte) ENCODE_TABLE.charAt((src[srcOff] << 4) & 0x30);
}
}
private static final byte[] DECODE_TABLE = {
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1,
-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,
-1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
};
/**
* Decode len bytes of data in src at offset srcOff, storing the result into dst at offset dstOff.
* len must be 2, 3, or 4. dst must have at least len-1 bytes of space at dstOff. src and dst may
* be the same object as long as dstoff <= srcOff. This method does no validation of the input
* values in the interest of performance.
*
* @param src the source of bytes to decode
* @param srcOff the offset into the source to read the encoded bytes
* @param len the number of bytes to decode (must be 2, 3, or 4)
* @param dst the destination for the decoding
* @param dstOff the offset into the destination to place the decoded bytes
*/
static final void decode(byte[] src, int srcOff, int len, byte[] dst, int dstOff) {
dst[dstOff] =
(byte)
((DECODE_TABLE[src[srcOff] & 0x0FF] << 2)
| (DECODE_TABLE[src[srcOff + 1] & 0x0FF] >> 4));
if (len > 2) {
dst[dstOff + 1] =
(byte)
(((DECODE_TABLE[src[srcOff + 1] & 0x0FF] << 4) & 0xF0)
| (DECODE_TABLE[src[srcOff + 2] & 0x0FF] >> 2));
if (len > 3) {
dst[dstOff + 2] =
(byte)
(((DECODE_TABLE[src[srcOff + 2] & 0x0FF] << 6) & 0xC0)
| DECODE_TABLE[src[srcOff + 3] & 0x0FF]);
}
}
}
}
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