| /** |
| * 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.solr.common.util; |
| |
| /** |
| * Static methods for translating Base64 encoded strings to byte arrays |
| * and vice-versa. |
| */ |
| |
| public class Base64 { |
| /** |
| * This array is a lookup table that translates 6-bit positive integer |
| * index values into their "Base64 Alphabet" equivalents as specified |
| * in Table 1 of RFC 2045. |
| */ |
| private static final char intToBase64[] = { |
| 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', |
| 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', |
| 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', |
| 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', |
| '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/' |
| }; |
| |
| /** |
| * This array is a lookup table that translates unicode characters |
| * drawn from the "Base64 Alphabet" (as specified in Table 1 of RFC 2045) |
| * into their 6-bit positive integer equivalents. Characters that |
| * are not in the Base64 alphabet but fall within the bounds of the |
| * array are translated to -1. |
| */ |
| private static final byte base64ToInt[] = { |
| -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 |
| }; |
| |
| public static String byteArrayToBase64(byte[] a, int offset, int len) { |
| int aLen = len; |
| int numFullGroups = aLen / 3; |
| int numBytesInPartialGroup = aLen - 3 * numFullGroups; |
| int resultLen = 4 * ((aLen + 2) / 3); |
| StringBuffer result = new StringBuffer(resultLen); |
| char[] intToAlpha = intToBase64; |
| |
| // Translate all full groups from byte array elements to Base64 |
| int inCursor = offset; |
| for (int i = 0; i < numFullGroups; i++) { |
| int byte0 = a[inCursor++] & 0xff; |
| int byte1 = a[inCursor++] & 0xff; |
| int byte2 = a[inCursor++] & 0xff; |
| result.append(intToAlpha[byte0 >> 2]); |
| result.append(intToAlpha[(byte0 << 4) & 0x3f | (byte1 >> 4)]); |
| result.append(intToAlpha[(byte1 << 2) & 0x3f | (byte2 >> 6)]); |
| result.append(intToAlpha[byte2 & 0x3f]); |
| } |
| |
| // Translate partial group if present |
| if (numBytesInPartialGroup != 0) { |
| int byte0 = a[inCursor++] & 0xff; |
| result.append(intToAlpha[byte0 >> 2]); |
| if (numBytesInPartialGroup == 1) { |
| result.append(intToAlpha[(byte0 << 4) & 0x3f]); |
| result.append("=="); |
| } else { |
| // assert numBytesInPartialGroup == 2; |
| int byte1 = a[inCursor++] & 0xff; |
| result.append(intToAlpha[(byte0 << 4) & 0x3f | (byte1 >> 4)]); |
| result.append(intToAlpha[(byte1 << 2) & 0x3f]); |
| result.append('='); |
| } |
| } |
| return result.toString(); |
| } |
| |
| public static byte[] base64ToByteArray(String s) { |
| byte[] alphaToInt = base64ToInt; |
| int sLen = s.length(); |
| int numGroups = sLen / 4; |
| if (4 * numGroups != sLen) |
| throw new IllegalArgumentException( |
| "String length must be a multiple of four."); |
| int missingBytesInLastGroup = 0; |
| int numFullGroups = numGroups; |
| if (sLen != 0) { |
| if (s.charAt(sLen - 1) == '=') { |
| missingBytesInLastGroup++; |
| numFullGroups--; |
| } |
| if (s.charAt(sLen - 2) == '=') |
| missingBytesInLastGroup++; |
| } |
| byte[] result = new byte[3 * numGroups - missingBytesInLastGroup]; |
| |
| // Translate all full groups from base64 to byte array elements |
| int inCursor = 0, outCursor = 0; |
| for (int i = 0; i < numFullGroups; i++) { |
| int ch0 = base64toInt(s.charAt(inCursor++), alphaToInt); |
| int ch1 = base64toInt(s.charAt(inCursor++), alphaToInt); |
| int ch2 = base64toInt(s.charAt(inCursor++), alphaToInt); |
| int ch3 = base64toInt(s.charAt(inCursor++), alphaToInt); |
| result[outCursor++] = (byte) ((ch0 << 2) | (ch1 >> 4)); |
| result[outCursor++] = (byte) ((ch1 << 4) | (ch2 >> 2)); |
| result[outCursor++] = (byte) ((ch2 << 6) | ch3); |
| } |
| |
| // Translate partial group, if present |
| if (missingBytesInLastGroup != 0) { |
| int ch0 = base64toInt(s.charAt(inCursor++), alphaToInt); |
| int ch1 = base64toInt(s.charAt(inCursor++), alphaToInt); |
| result[outCursor++] = (byte) ((ch0 << 2) | (ch1 >> 4)); |
| |
| if (missingBytesInLastGroup == 1) { |
| int ch2 = base64toInt(s.charAt(inCursor++), alphaToInt); |
| result[outCursor++] = (byte) ((ch1 << 4) | (ch2 >> 2)); |
| } |
| } |
| // assert inCursor == s.length()-missingBytesInLastGroup; |
| // assert outCursor == result.length; |
| return result; |
| } |
| |
| /** |
| * Translates the specified character, which is assumed to be in the |
| * "Base 64 Alphabet" into its equivalent 6-bit positive integer. |
| * |
| * @throw IllegalArgumentException or ArrayOutOfBoundsException if |
| * c is not in the Base64 Alphabet. |
| */ |
| private static int base64toInt(char c, byte[] alphaToInt) { |
| int result = alphaToInt[c]; |
| if (result < 0) |
| throw new IllegalArgumentException("Illegal character " + c); |
| return result; |
| } |
| } |