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Diffstat (limited to 'src/org/apache/commons/codec/binary/Base64.java')
| -rw-r--r-- | src/org/apache/commons/codec/binary/Base64.java | 524 |
1 files changed, 524 insertions, 0 deletions
diff --git a/src/org/apache/commons/codec/binary/Base64.java b/src/org/apache/commons/codec/binary/Base64.java new file mode 100644 index 0000000..ea479e9 --- /dev/null +++ b/src/org/apache/commons/codec/binary/Base64.java @@ -0,0 +1,524 @@ +/* + * Copyright 2001-2004 The Apache Software Foundation. + * + * Licensed 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.commons.codec.binary; + +import org.apache.commons.codec.BinaryDecoder; +import org.apache.commons.codec.BinaryEncoder; +import org.apache.commons.codec.DecoderException; +import org.apache.commons.codec.EncoderException; + +/** + * Provides Base64 encoding and decoding as defined by RFC 2045. + * + * <p>This class implements section <cite>6.8. Base64 Content-Transfer-Encoding</cite> + * from RFC 2045 <cite>Multipurpose Internet Mail Extensions (MIME) Part One: + * Format of Internet Message Bodies</cite> by Freed and Borenstein.</p> + * + * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a> + * @author Apache Software Foundation + * @since 1.0-dev + * @version $Id: Base64.java,v 1.20 2004/05/24 00:21:24 ggregory Exp $ + */ +public class Base64 implements BinaryEncoder, BinaryDecoder { + + /** + * Chunk size per RFC 2045 section 6.8. + * + * <p>The {@value} character limit does not count the trailing CRLF, but counts + * all other characters, including any equal signs.</p> + * + * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 6.8</a> + */ + static final int CHUNK_SIZE = 76; + + /** + * Chunk separator per RFC 2045 section 2.1. + * + * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 2.1</a> + */ + static final byte[] CHUNK_SEPARATOR = "\r\n".getBytes(); + + /** + * The base length. + */ + static final int BASELENGTH = 255; + + /** + * Lookup length. + */ + static final int LOOKUPLENGTH = 64; + + /** + * Used to calculate the number of bits in a byte. + */ + static final int EIGHTBIT = 8; + + /** + * Used when encoding something which has fewer than 24 bits. + */ + static final int SIXTEENBIT = 16; + + /** + * Used to determine how many bits data contains. + */ + static final int TWENTYFOURBITGROUP = 24; + + /** + * Used to get the number of Quadruples. + */ + static final int FOURBYTE = 4; + + /** + * Used to test the sign of a byte. + */ + static final int SIGN = -128; + + /** + * Byte used to pad output. + */ + static final byte PAD = (byte) '='; + + // Create arrays to hold the base64 characters and a + // lookup for base64 chars + private static byte[] base64Alphabet = new byte[BASELENGTH]; + private static byte[] lookUpBase64Alphabet = new byte[LOOKUPLENGTH]; + + // Populating the lookup and character arrays + static { + for (int i = 0; i < BASELENGTH; i++) { + base64Alphabet[i] = (byte) -1; + } + for (int i = 'Z'; i >= 'A'; i--) { + base64Alphabet[i] = (byte) (i - 'A'); + } + for (int i = 'z'; i >= 'a'; i--) { + base64Alphabet[i] = (byte) (i - 'a' + 26); + } + for (int i = '9'; i >= '0'; i--) { + base64Alphabet[i] = (byte) (i - '0' + 52); + } + + base64Alphabet['+'] = 62; + base64Alphabet['/'] = 63; + + for (int i = 0; i <= 25; i++) { + lookUpBase64Alphabet[i] = (byte) ('A' + i); + } + + for (int i = 26, j = 0; i <= 51; i++, j++) { + lookUpBase64Alphabet[i] = (byte) ('a' + j); + } + + for (int i = 52, j = 0; i <= 61; i++, j++) { + lookUpBase64Alphabet[i] = (byte) ('0' + j); + } + + lookUpBase64Alphabet[62] = (byte) '+'; + lookUpBase64Alphabet[63] = (byte) '/'; + } + + private static boolean isBase64(byte octect) { + if (octect == PAD) { + return true; + } else if (base64Alphabet[octect] == -1) { + return false; + } else { + return true; + } + } + + /** + * Tests a given byte array to see if it contains + * only valid characters within the Base64 alphabet. + * + * @param arrayOctect byte array to test + * @return true if all bytes are valid characters in the Base64 + * alphabet or if the byte array is empty; false, otherwise + */ + public static boolean isArrayByteBase64(byte[] arrayOctect) { + + arrayOctect = discardWhitespace(arrayOctect); + + int length = arrayOctect.length; + if (length == 0) { + // shouldn't a 0 length array be valid base64 data? + // return false; + return true; + } + for (int i = 0; i < length; i++) { + if (!isBase64(arrayOctect[i])) { + return false; + } + } + return true; + } + + /** + * Encodes binary data using the base64 algorithm but + * does not chunk the output. + * + * @param binaryData binary data to encode + * @return Base64 characters + */ + public static byte[] encodeBase64(byte[] binaryData) { + return encodeBase64(binaryData, false); + } + + /** + * Encodes binary data using the base64 algorithm and chunks + * the encoded output into 76 character blocks + * + * @param binaryData binary data to encode + * @return Base64 characters chunked in 76 character blocks + */ + public static byte[] encodeBase64Chunked(byte[] binaryData) { + return encodeBase64(binaryData, true); + } + + + /** + * Decodes an Object using the base64 algorithm. This method + * is provided in order to satisfy the requirements of the + * Decoder interface, and will throw a DecoderException if the + * supplied object is not of type byte[]. + * + * @param pObject Object to decode + * @return An object (of type byte[]) containing the + * binary data which corresponds to the byte[] supplied. + * @throws DecoderException if the parameter supplied is not + * of type byte[] + */ + public Object decode(Object pObject) throws DecoderException { + if (!(pObject instanceof byte[])) { + throw new DecoderException("Parameter supplied to Base64 decode is not a byte[]"); + } + return decode((byte[]) pObject); + } + + /** + * Decodes a byte[] containing containing + * characters in the Base64 alphabet. + * + * @param pArray A byte array containing Base64 character data + * @return a byte array containing binary data + */ + public byte[] decode(byte[] pArray) { + return decodeBase64(pArray); + } + + /** + * Encodes binary data using the base64 algorithm, optionally + * chunking the output into 76 character blocks. + * + * @param binaryData Array containing binary data to encode. + * @param isChunked if isChunked is true this encoder will chunk + * the base64 output into 76 character blocks + * @return Base64-encoded data. + */ + public static byte[] encodeBase64(byte[] binaryData, boolean isChunked) { + int lengthDataBits = binaryData.length * EIGHTBIT; + int fewerThan24bits = lengthDataBits % TWENTYFOURBITGROUP; + int numberTriplets = lengthDataBits / TWENTYFOURBITGROUP; + byte encodedData[] = null; + int encodedDataLength = 0; + int nbrChunks = 0; + + if (fewerThan24bits != 0) { + //data not divisible by 24 bit + encodedDataLength = (numberTriplets + 1) * 4; + } else { + // 16 or 8 bit + encodedDataLength = numberTriplets * 4; + } + + // If the output is to be "chunked" into 76 character sections, + // for compliance with RFC 2045 MIME, then it is important to + // allow for extra length to account for the separator(s) + if (isChunked) { + + nbrChunks = + (CHUNK_SEPARATOR.length == 0 ? 0 : (int) Math.ceil((float) encodedDataLength / CHUNK_SIZE)); + encodedDataLength += nbrChunks * CHUNK_SEPARATOR.length; + } + + encodedData = new byte[encodedDataLength]; + + byte k = 0, l = 0, b1 = 0, b2 = 0, b3 = 0; + + int encodedIndex = 0; + int dataIndex = 0; + int i = 0; + int nextSeparatorIndex = CHUNK_SIZE; + int chunksSoFar = 0; + + //log.debug("number of triplets = " + numberTriplets); + for (i = 0; i < numberTriplets; i++) { + dataIndex = i * 3; + b1 = binaryData[dataIndex]; + b2 = binaryData[dataIndex + 1]; + b3 = binaryData[dataIndex + 2]; + + //log.debug("b1= " + b1 +", b2= " + b2 + ", b3= " + b3); + + l = (byte) (b2 & 0x0f); + k = (byte) (b1 & 0x03); + + byte val1 = + ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0); + byte val2 = + ((b2 & SIGN) == 0) ? (byte) (b2 >> 4) : (byte) ((b2) >> 4 ^ 0xf0); + byte val3 = + ((b3 & SIGN) == 0) ? (byte) (b3 >> 6) : (byte) ((b3) >> 6 ^ 0xfc); + + encodedData[encodedIndex] = lookUpBase64Alphabet[val1]; + //log.debug( "val2 = " + val2 ); + //log.debug( "k4 = " + (k<<4) ); + //log.debug( "vak = " + (val2 | (k<<4)) ); + encodedData[encodedIndex + 1] = + lookUpBase64Alphabet[val2 | (k << 4)]; + encodedData[encodedIndex + 2] = + lookUpBase64Alphabet[(l << 2) | val3]; + encodedData[encodedIndex + 3] = lookUpBase64Alphabet[b3 & 0x3f]; + + encodedIndex += 4; + + // If we are chunking, let's put a chunk separator down. + if (isChunked) { + // this assumes that CHUNK_SIZE % 4 == 0 + if (encodedIndex == nextSeparatorIndex) { + System.arraycopy( + CHUNK_SEPARATOR, + 0, + encodedData, + encodedIndex, + CHUNK_SEPARATOR.length); + chunksSoFar++; + nextSeparatorIndex = + (CHUNK_SIZE * (chunksSoFar + 1)) + + (chunksSoFar * CHUNK_SEPARATOR.length); + encodedIndex += CHUNK_SEPARATOR.length; + } + } + } + + // form integral number of 6-bit groups + dataIndex = i * 3; + + if (fewerThan24bits == EIGHTBIT) { + b1 = binaryData[dataIndex]; + k = (byte) (b1 & 0x03); + //log.debug("b1=" + b1); + //log.debug("b1<<2 = " + (b1>>2) ); + byte val1 = + ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0); + encodedData[encodedIndex] = lookUpBase64Alphabet[val1]; + encodedData[encodedIndex + 1] = lookUpBase64Alphabet[k << 4]; + encodedData[encodedIndex + 2] = PAD; + encodedData[encodedIndex + 3] = PAD; + } else if (fewerThan24bits == SIXTEENBIT) { + + b1 = binaryData[dataIndex]; + b2 = binaryData[dataIndex + 1]; + l = (byte) (b2 & 0x0f); + k = (byte) (b1 & 0x03); + + byte val1 = + ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0); + byte val2 = + ((b2 & SIGN) == 0) ? (byte) (b2 >> 4) : (byte) ((b2) >> 4 ^ 0xf0); + + encodedData[encodedIndex] = lookUpBase64Alphabet[val1]; + encodedData[encodedIndex + 1] = + lookUpBase64Alphabet[val2 | (k << 4)]; + encodedData[encodedIndex + 2] = lookUpBase64Alphabet[l << 2]; + encodedData[encodedIndex + 3] = PAD; + } + + if (isChunked) { + // we also add a separator to the end of the final chunk. + if (chunksSoFar < nbrChunks) { + System.arraycopy( + CHUNK_SEPARATOR, + 0, + encodedData, + encodedDataLength - CHUNK_SEPARATOR.length, + CHUNK_SEPARATOR.length); + } + } + + return encodedData; + } + + /** + * Decodes Base64 data into octects + * + * @param base64Data Byte array containing Base64 data + * @return Array containing decoded data. + */ + public static byte[] decodeBase64(byte[] base64Data) { + // RFC 2045 requires that we discard ALL non-Base64 characters + base64Data = discardNonBase64(base64Data); + + // handle the edge case, so we don't have to worry about it later + if (base64Data.length == 0) { + return new byte[0]; + } + + int numberQuadruple = base64Data.length / FOURBYTE; + byte decodedData[] = null; + byte b1 = 0, b2 = 0, b3 = 0, b4 = 0, marker0 = 0, marker1 = 0; + + // Throw away anything not in base64Data + + int encodedIndex = 0; + int dataIndex = 0; + { + // this sizes the output array properly - rlw + int lastData = base64Data.length; + // ignore the '=' padding + while (base64Data[lastData - 1] == PAD) { + if (--lastData == 0) { + return new byte[0]; + } + } + decodedData = new byte[lastData - numberQuadruple]; + } + + for (int i = 0; i < numberQuadruple; i++) { + dataIndex = i * 4; + marker0 = base64Data[dataIndex + 2]; + marker1 = base64Data[dataIndex + 3]; + + b1 = base64Alphabet[base64Data[dataIndex]]; + b2 = base64Alphabet[base64Data[dataIndex + 1]]; + + if (marker0 != PAD && marker1 != PAD) { + //No PAD e.g 3cQl + b3 = base64Alphabet[marker0]; + b4 = base64Alphabet[marker1]; + + decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4); + decodedData[encodedIndex + 1] = + (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf)); + decodedData[encodedIndex + 2] = (byte) (b3 << 6 | b4); + } else if (marker0 == PAD) { + //Two PAD e.g. 3c[Pad][Pad] + decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4); + } else if (marker1 == PAD) { + //One PAD e.g. 3cQ[Pad] + b3 = base64Alphabet[marker0]; + + decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4); + decodedData[encodedIndex + 1] = + (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf)); + } + encodedIndex += 3; + } + return decodedData; + } + + /** + * Discards any whitespace from a base-64 encoded block. + * + * @param data The base-64 encoded data to discard the whitespace + * from. + * @return The data, less whitespace (see RFC 2045). + */ + static byte[] discardWhitespace(byte[] data) { + byte groomedData[] = new byte[data.length]; + int bytesCopied = 0; + + for (int i = 0; i < data.length; i++) { + switch (data[i]) { + case (byte) ' ' : + case (byte) '\n' : + case (byte) '\r' : + case (byte) '\t' : + break; + default: + groomedData[bytesCopied++] = data[i]; + } + } + + byte packedData[] = new byte[bytesCopied]; + + System.arraycopy(groomedData, 0, packedData, 0, bytesCopied); + + return packedData; + } + + /** + * Discards any characters outside of the base64 alphabet, per + * the requirements on page 25 of RFC 2045 - "Any characters + * outside of the base64 alphabet are to be ignored in base64 + * encoded data." + * + * @param data The base-64 encoded data to groom + * @return The data, less non-base64 characters (see RFC 2045). + */ + static byte[] discardNonBase64(byte[] data) { + byte groomedData[] = new byte[data.length]; + int bytesCopied = 0; + + for (int i = 0; i < data.length; i++) { + if (isBase64(data[i])) { + groomedData[bytesCopied++] = data[i]; + } + } + + byte packedData[] = new byte[bytesCopied]; + + System.arraycopy(groomedData, 0, packedData, 0, bytesCopied); + + return packedData; + } + + + // Implementation of the Encoder Interface + + /** + * Encodes an Object using the base64 algorithm. This method + * is provided in order to satisfy the requirements of the + * Encoder interface, and will throw an EncoderException if the + * supplied object is not of type byte[]. + * + * @param pObject Object to encode + * @return An object (of type byte[]) containing the + * base64 encoded data which corresponds to the byte[] supplied. + * @throws EncoderException if the parameter supplied is not + * of type byte[] + */ + public Object encode(Object pObject) throws EncoderException { + if (!(pObject instanceof byte[])) { + throw new EncoderException( + "Parameter supplied to Base64 encode is not a byte[]"); + } + return encode((byte[]) pObject); + } + + /** + * Encodes a byte[] containing binary data, into a byte[] containing + * characters in the Base64 alphabet. + * + * @param pArray a byte array containing binary data + * @return A byte array containing only Base64 character data + */ + public byte[] encode(byte[] pArray) { + return encodeBase64(pArray, false); + } + +} |