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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 com.android.email.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; import java.io.UnsupportedEncodingException; import java.math.BigInteger; /** * 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 $Id$ */ 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' }; /** * 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. * * Thanks to "commons" project in ws.apache.org for this code. * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/ */ private static final byte[] 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', '+', '/' }; /** * Byte used to pad output. */ private static final byte PAD = '='; /** * 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. * * Thanks to "commons" project in ws.apache.org for this code. * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/ */ 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 }; /** Mask used to extract 6 bits, used when encoding */ private static final int MASK_6BITS = 0x3f; /** Mask used to extract 8 bits, used in decoding base64 bytes */ private static final int MASK_8BITS = 0xff; // The static final fields above are used for the original static byte[] methods on Base64. // The private member fields below are used with the new streaming approach, which requires // some state be preserved between calls of encode() and decode(). /** * Line length for encoding. Not used when decoding. A value of zero or less implies * no chunking of the base64 encoded data. */ private final int lineLength; /** * Line separator for encoding. Not used when decoding. Only used if lineLength > 0. */ private final byte[] lineSeparator; /** * Convenience variable to help us determine when our buffer is going to run out of * room and needs resizing. <code>decodeSize = 3 + lineSeparator.length;</code> */ private final int decodeSize; /** * Convenience variable to help us determine when our buffer is going to run out of * room and needs resizing. <code>encodeSize = 4 + lineSeparator.length;</code> */ private final int encodeSize; /** * Buffer for streaming. */ private byte[] buf; /** * Position where next character should be written in the buffer. */ private int pos; /** * Position where next character should be read from the buffer. */ private int readPos; /** * Variable tracks how many characters have been written to the current line. * Only used when encoding. We use it to make sure each encoded line never * goes beyond lineLength (if lineLength > 0). */ private int currentLinePos; /** * Writes to the buffer only occur after every 3 reads when encoding, an * every 4 reads when decoding. This variable helps track that. */ private int modulus; /** * Boolean flag to indicate the EOF has been reached. Once EOF has been * reached, this Base64 object becomes useless, and must be thrown away. */ private boolean eof; /** * Place holder for the 3 bytes we're dealing with for our base64 logic. * Bitwise operations store and extract the base64 encoding or decoding from * this variable. */ private int x; /** * Default constructor: lineLength is 76, and the lineSeparator is CRLF * when encoding, and all forms can be decoded. */ public Base64() { this(CHUNK_SIZE, CHUNK_SEPARATOR); } /** * <p> * Consumer can use this constructor to choose a different lineLength * when encoding (lineSeparator is still CRLF). All forms of data can * be decoded. * </p><p> * Note: lineLengths that aren't multiples of 4 will still essentially * end up being multiples of 4 in the encoded data. * </p> * * @param lineLength each line of encoded data will be at most this long * (rounded up to nearest multiple of 4). * If lineLength <= 0, then the output will not be divided into lines (chunks). * Ignored when decoding. */ public Base64(int lineLength) { this(lineLength, CHUNK_SEPARATOR); } /** * <p> * Consumer can use this constructor to choose a different lineLength * and lineSeparator when encoding. All forms of data can * be decoded. * </p><p> * Note: lineLengths that aren't multiples of 4 will still essentially * end up being multiples of 4 in the encoded data. * </p> * @param lineLength Each line of encoded data will be at most this long * (rounded up to nearest multiple of 4). Ignored when decoding. * If <= 0, then output will not be divided into lines (chunks). * @param lineSeparator Each line of encoded data will end with this * sequence of bytes. * If lineLength <= 0, then the lineSeparator is not used. * @throws IllegalArgumentException The provided lineSeparator included * some base64 characters. That's not going to work! */ public Base64(int lineLength, byte[] lineSeparator) { this.lineLength = lineLength; this.lineSeparator = new byte[lineSeparator.length]; System.arraycopy(lineSeparator, 0, this.lineSeparator, 0, lineSeparator.length); if (lineLength > 0) { this.encodeSize = 4 + lineSeparator.length; } else { this.encodeSize = 4; } this.decodeSize = encodeSize - 1; if (containsBase64Byte(lineSeparator)) { String sep; try { sep = new String(lineSeparator, "UTF-8"); } catch (UnsupportedEncodingException uee) { sep = new String(lineSeparator); } throw new IllegalArgumentException("lineSeperator must not contain base64 characters: [" + sep + "]"); } } /** * Returns true if this Base64 object has buffered data for reading. * * @return true if there is Base64 object still available for reading. */ boolean hasData() { return buf != null; } /** * Returns the amount of buffered data available for reading. * * @return The amount of buffered data available for reading. */ int avail() { return buf != null ? pos - readPos : 0; } /** Doubles our buffer. */ private void resizeBuf() { if (buf == null) { buf = new byte[8192]; pos = 0; readPos = 0; } else { byte[] b = new byte[buf.length * 2]; System.arraycopy(buf, 0, b, 0, buf.length); buf = b; } } /** * Extracts buffered data into the provided byte[] array, starting * at position bPos, up to a maximum of bAvail bytes. Returns how * many bytes were actually extracted. * * @param b byte[] array to extract the buffered data into. * @param bPos position in byte[] array to start extraction at. * @param bAvail amount of bytes we're allowed to extract. We may extract * fewer (if fewer are available). * @return The number of bytes successfully extracted into the provided * byte[] array. */ int readResults(byte[] b, int bPos, int bAvail) { if (buf != null) { int len = Math.min(avail(), bAvail); if (buf != b) { System.arraycopy(buf, readPos, b, bPos, len); readPos += len; if (readPos >= pos) { buf = null; } } else { // Re-using the original consumer's output array is only // allowed for one round. buf = null; } return len; } else { return eof ? -1 : 0; } } /** * Small optimization where we try to buffer directly to the consumer's * output array for one round (if consumer calls this method first!) instead * of starting our own buffer. * * @param out byte[] array to buffer directly to. * @param outPos Position to start buffering into. * @param outAvail Amount of bytes available for direct buffering. */ void setInitialBuffer(byte[] out, int outPos, int outAvail) { // We can re-use consumer's original output array under // special circumstances, saving on some System.arraycopy(). if (out != null && out.length == outAvail) { buf = out; pos = outPos; readPos = outPos; } } /** * <p> * Encodes all of the provided data, starting at inPos, for inAvail bytes. * Must be called at least twice: once with the data to encode, and once * with inAvail set to "-1" to alert encoder that EOF has been reached, * so flush last remaining bytes (if not multiple of 3). * </p><p> * Thanks to "commons" project in ws.apache.org for the bitwise operations, * and general approach. * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/ * </p> * * @param in byte[] array of binary data to base64 encode. * @param inPos Position to start reading data from. * @param inAvail Amount of bytes available from input for encoding. */ void encode(byte[] in, int inPos, int inAvail) { if (eof) { return; } // inAvail < 0 is how we're informed of EOF in the underlying data we're // encoding. if (inAvail < 0) { eof = true; if (buf == null || buf.length - pos < encodeSize) { resizeBuf(); } switch (modulus) { case 1: buf[pos++] = intToBase64[(x >> 2) & MASK_6BITS]; buf[pos++] = intToBase64[(x << 4) & MASK_6BITS]; buf[pos++] = PAD; buf[pos++] = PAD; break; case 2: buf[pos++] = intToBase64[(x >> 10) & MASK_6BITS]; buf[pos++] = intToBase64[(x >> 4) & MASK_6BITS]; buf[pos++] = intToBase64[(x << 2) & MASK_6BITS]; buf[pos++] = PAD; break; } if (lineLength > 0) { System.arraycopy(lineSeparator, 0, buf, pos, lineSeparator.length); pos += lineSeparator.length; } } else { for (int i = 0; i < inAvail; i++) { if (buf == null || buf.length - pos < encodeSize) { resizeBuf(); } modulus = (++modulus) % 3; int b = in[inPos++]; if (b < 0) { b += 256; } x = (x << 8) + b; if (0 == modulus) { buf[pos++] = intToBase64[(x >> 18) & MASK_6BITS]; buf[pos++] = intToBase64[(x >> 12) & MASK_6BITS]; buf[pos++] = intToBase64[(x >> 6) & MASK_6BITS]; buf[pos++] = intToBase64[x & MASK_6BITS]; currentLinePos += 4; if (lineLength > 0 && lineLength <= currentLinePos) { System.arraycopy(lineSeparator, 0, buf, pos, lineSeparator.length); pos += lineSeparator.length; currentLinePos = 0; } } } } } /** * <p> * Decodes all of the provided data, starting at inPos, for inAvail bytes. * Should be called at least twice: once with the data to decode, and once * with inAvail set to "-1" to alert decoder that EOF has been reached. * The "-1" call is not necessary when decoding, but it doesn't hurt, either. * </p><p> * Ignores all non-base64 characters. This is how chunked (e.g. 76 character) * data is handled, since CR and LF are silently ignored, but has implications * for other bytes, too. This method subscribes to the garbage-in, garbage-out * philosophy: it will not check the provided data for validity. * </p><p> * Thanks to "commons" project in ws.apache.org for the bitwise operations, * and general approach. * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/ * </p> * @param in byte[] array of ascii data to base64 decode. * @param inPos Position to start reading data from. * @param inAvail Amount of bytes available from input for encoding. */ void decode(byte[] in, int inPos, int inAvail) { if (eof) { return; } if (inAvail < 0) { eof = true; } for (int i = 0; i < inAvail; i++) { if (buf == null || buf.length - pos < decodeSize) { resizeBuf(); } byte b = in[inPos++]; if (b == PAD) { x = x << 6; switch (modulus) { case 2: x = x << 6; buf[pos++] = (byte) ((x >> 16) & MASK_8BITS); break; case 3: buf[pos++] = (byte) ((x >> 16) & MASK_8BITS); buf[pos++] = (byte) ((x >> 8) & MASK_8BITS); break; } // WE'RE DONE!!!! eof = true; return; } else { if (b >= 0 && b < base64ToInt.length) { int result = base64ToInt[b]; if (result >= 0) { modulus = (++modulus) % 4; x = (x << 6) + result; if (modulus == 0) { buf[pos++] = (byte) ((x >> 16) & MASK_8BITS); buf[pos++] = (byte) ((x >> 8) & MASK_8BITS); buf[pos++] = (byte) (x & MASK_8BITS); } } } } } } /** * Returns whether or not the <code>octet</code> is in the base 64 alphabet. * * @param octet * The value to test * @return <code>true</code> if the value is defined in the the base 64 alphabet, <code>false</code> otherwise. */ public static boolean isBase64(byte octet) { return octet == PAD || (octet >= 0 && octet < base64ToInt.length && base64ToInt[octet] != -1); } /** * Tests a given byte array to see if it contains only valid characters within the Base64 alphabet. * Currently the method treats whitespace as valid. * * @param arrayOctet * byte array to test * @return <code>true</code> if all bytes are valid characters in the Base64 alphabet or if the byte array is * empty; false, otherwise */ public static boolean isArrayByteBase64(byte[] arrayOctet) { for (int i = 0; i < arrayOctet.length; i++) { if (!isBase64(arrayOctet[i]) && !isWhiteSpace(arrayOctet[i])) { return false; } } return true; } /* * Tests a given byte array to see if it contains only valid characters within the Base64 alphabet. * * @param arrayOctet * byte array to test * @return <code>true</code> if any byte is a valid character in the Base64 alphabet; false herwise */ private static boolean containsBase64Byte(byte[] arrayOctet) { for (int i = 0; i < arrayOctet.length; i++) { if (isBase64(arrayOctet[i])) { return true; } } return false; } /** * 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 <code>true</code> this encoder will chunk the base64 output into 76 character blocks * @return Base64-encoded data. * @throws IllegalArgumentException * Thrown when the input array needs an output array bigger than {@link Integer#MAX_VALUE} */ public static byte[] encodeBase64(byte[] binaryData, boolean isChunked) { if (binaryData == null || binaryData.length == 0) { return binaryData; } Base64 b64 = isChunked ? new Base64() : new Base64(0); long len = (binaryData.length * 4) / 3; long mod = len % 4; if (mod != 0) { len += 4 - mod; } // If chunked, add space for one CHUNK_SEPARATOR per chunk. (Technically, these are chunk // terminators, because even a single chunk message has one.) // // User length Encoded length Rounded up by 4 Num chunks Final buf len // 56 74 76 1 78 // 57 76 76 1 78 // 58 77 80 2 84 // 59 78 80 2 84 // // Or... // Rounded up size: 4...76 Chunks: 1 // Rounded up size: 80..152 Chunks: 2 // Rounded up size: 156..228 Chunks: 3 ...etc... if (isChunked) { len += ((len + CHUNK_SIZE - 1) / CHUNK_SIZE) * CHUNK_SEPARATOR.length; } if (len > Integer.MAX_VALUE) { throw new IllegalArgumentException( "Input array too big, output array would be bigger than Integer.MAX_VALUE=" + Integer.MAX_VALUE); } byte[] buf = new byte[(int) len]; b64.setInitialBuffer(buf, 0, buf.length); b64.encode(binaryData, 0, binaryData.length); b64.encode(binaryData, 0, -1); // Notify encoder of EOF. // Encoder might have resized, even though it was unnecessary. if (b64.buf != buf) { b64.readResults(buf, 0, buf.length); } return buf; } /** * Decodes Base64 data into octets * * @param base64Data Byte array containing Base64 data * @return Array containing decoded data. */ public static byte[] decodeBase64(byte[] base64Data) { if (base64Data == null || base64Data.length == 0) { return base64Data; } Base64 b64 = new Base64(); long len = (base64Data.length * 3) / 4; byte[] buf = new byte[(int) len]; b64.setInitialBuffer(buf, 0, buf.length); b64.decode(base64Data, 0, base64Data.length); b64.decode(base64Data, 0, -1); // Notify decoder of EOF. // We have no idea what the line-length was, so we // cannot know how much of our array wasn't used. byte[] result = new byte[b64.pos]; b64.readResults(result, 0, result.length); return result; } /** * 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). * @deprecated This method is no longer needed */ 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 ' ': case '\n': case '\r': case '\t': break; default: groomedData[bytesCopied++] = data[i]; } } byte packedData[] = new byte[bytesCopied]; System.arraycopy(groomedData, 0, packedData, 0, bytesCopied); return packedData; } /** * Check if a byte value is whitespace or not. * * @param byteToCheck the byte to check * @return true if byte is whitespace, false otherwise */ private static boolean isWhiteSpace(byte byteToCheck) { switch (byteToCheck) { case ' ': case '\n': case '\r': case '\t': return true; default: return false; } } /** * 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); } // Implementation of integer encoding used for crypto /** * Decode a byte64-encoded integer according to crypto * standards such as W3C's XML-Signature * * @param pArray a byte array containing base64 character data * @return A BigInteger */ public static BigInteger decodeInteger(byte[] pArray) { return new BigInteger(1, decodeBase64(pArray)); } /** * Encode to a byte64-encoded integer according to crypto * standards such as W3C's XML-Signature * * @param bigInt a BigInteger * @return A byte array containing base64 character data * @throws NullPointerException if null is passed in */ public static byte[] encodeInteger(BigInteger bigInt) { if (bigInt == null) { throw new NullPointerException("encodeInteger called with null parameter"); } return encodeBase64(toIntegerBytes(bigInt), false); } /** * Returns a byte-array representation of a <code>BigInteger</code> * without sign bit. * * @param bigInt <code>BigInteger</code> to be converted * @return a byte array representation of the BigInteger parameter */ static byte[] toIntegerBytes(BigInteger bigInt) { int bitlen = bigInt.bitLength(); // round bitlen bitlen = ((bitlen + 7) >> 3) << 3; byte[] bigBytes = bigInt.toByteArray(); if (((bigInt.bitLength() % 8) != 0) && (((bigInt.bitLength() / 8) + 1) == (bitlen / 8))) { return bigBytes; } // set up params for copying everything but sign bit int startSrc = 0; int len = bigBytes.length; // if bigInt is exactly byte-aligned, just skip signbit in copy if ((bigInt.bitLength() % 8) == 0) { startSrc = 1; len--; } int startDst = bitlen / 8 - len; // to pad w/ nulls as per spec byte[] resizedBytes = new byte[bitlen / 8]; System.arraycopy(bigBytes, startSrc, resizedBytes, startDst, len); return resizedBytes; } }