| /* |
| * 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.commons.codec.binary; |
| |
| import org.apache.commons.codec.CodecPolicy; |
| |
| /** |
| * Provides Base32 encoding and decoding as defined by <a href="http://www.ietf.org/rfc/rfc4648.txt">RFC 4648</a>. |
| * |
| * <p> |
| * The class can be parameterized in the following manner with various constructors: |
| * </p> |
| * <ul> |
| * <li>Whether to use the "base32hex" variant instead of the default "base32"</li> |
| * <li>Line length: Default 76. Line length that aren't multiples of 8 will still essentially end up being multiples of |
| * 8 in the encoded data. |
| * <li>Line separator: Default is CRLF ("\r\n")</li> |
| * </ul> |
| * <p> |
| * This class operates directly on byte streams, and not character streams. |
| * </p> |
| * <p> |
| * This class is thread-safe. |
| * </p> |
| * |
| * @see <a href="http://www.ietf.org/rfc/rfc4648.txt">RFC 4648</a> |
| * |
| * @since 1.5 |
| */ |
| public class Base32 extends BaseNCodec { |
| |
| /** |
| * BASE32 characters are 5 bits in length. |
| * They are formed by taking a block of five octets to form a 40-bit string, |
| * which is converted into eight BASE32 characters. |
| */ |
| private static final int BITS_PER_ENCODED_BYTE = 5; |
| private static final int BYTES_PER_ENCODED_BLOCK = 8; |
| private static final int BYTES_PER_UNENCODED_BLOCK = 5; |
| |
| /** |
| * This array is a lookup table that translates Unicode characters drawn from the "Base32 Alphabet" (as specified |
| * in Table 3 of RFC 4648) into their 5-bit positive integer equivalents. Characters that are not in the Base32 |
| * alphabet but fall within the bounds of the array are translated to -1. |
| */ |
| private static final byte[] DECODE_TABLE = { |
| // 0 1 2 3 4 5 6 7 8 9 A B C D E F |
| -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 00-0f |
| -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 10-1f |
| -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 20-2f |
| -1, -1, 26, 27, 28, 29, 30, 31, -1, -1, -1, -1, -1, -1, -1, -1, // 30-3f 2-7 |
| -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, // 40-4f A-O |
| 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, // 50-5a P-Z |
| -1, -1, -1, -1, -1, // 5b-5f |
| -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, // 60-6f a-o |
| 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, // 70-7a p-z |
| }; |
| |
| /** |
| * This array is a lookup table that translates 5-bit positive integer index values into their "Base32 Alphabet" |
| * equivalents as specified in Table 3 of RFC 4648. |
| */ |
| private static final byte[] ENCODE_TABLE = { |
| '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', |
| '2', '3', '4', '5', '6', '7', |
| }; |
| |
| /** |
| * This array is a lookup table that translates Unicode characters drawn from the "Base32 Hex Alphabet" (as |
| * specified in Table 4 of RFC 4648) into their 5-bit positive integer equivalents. Characters that are not in the |
| * Base32 Hex alphabet but fall within the bounds of the array are translated to -1. |
| */ |
| private static final byte[] HEX_DECODE_TABLE = { |
| // 0 1 2 3 4 5 6 7 8 9 A B C D E F |
| -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 00-0f |
| -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 10-1f |
| -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 20-2f |
| 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1, // 30-3f 0-9 |
| -1, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, // 40-4f A-O |
| 25, 26, 27, 28, 29, 30, 31, // 50-56 P-V |
| -1, -1, -1, -1, -1, -1, -1, -1, -1, // 57-5f |
| -1, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, // 60-6f a-o |
| 25, 26, 27, 28, 29, 30, 31 // 70-76 p-v |
| }; |
| |
| /** |
| * This array is a lookup table that translates 5-bit positive integer index values into their |
| * "Base32 Hex Alphabet" equivalents as specified in Table 4 of RFC 4648. |
| */ |
| private static final byte[] HEX_ENCODE_TABLE = { |
| '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', |
| 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', |
| 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', |
| }; |
| |
| /** Mask used to extract 5 bits, used when encoding Base32 bytes */ |
| private static final int MASK_5BITS = 0x1f; |
| /** Mask used to extract 4 bits, used when decoding final trailing character. */ |
| private static final long MASK_4BITS = 0x0fL; |
| /** Mask used to extract 3 bits, used when decoding final trailing character. */ |
| private static final long MASK_3BITS = 0x07L; |
| /** Mask used to extract 2 bits, used when decoding final trailing character. */ |
| private static final long MASK_2BITS = 0x03L; |
| /** Mask used to extract 1 bits, used when decoding final trailing character. */ |
| private static final long MASK_1BITS = 0x01L; |
| |
| // The static final fields above are used for the original static byte[] methods on Base32. |
| // The private member fields below are used with the new streaming approach, which requires |
| // some state be preserved between calls of encode() and decode(). |
| |
| /** |
| * Place holder for the bytes we're dealing with for our based logic. |
| * Bitwise operations store and extract the encoding or decoding from this variable. |
| */ |
| |
| /** |
| * Convenience variable to help us determine when our buffer is going to run out of room and needs resizing. |
| * {@code decodeSize = {@link #BYTES_PER_ENCODED_BLOCK} - 1 + lineSeparator.length;} |
| */ |
| private final int decodeSize; |
| |
| /** |
| * Decode table to use. |
| */ |
| private final byte[] decodeTable; |
| |
| /** |
| * Convenience variable to help us determine when our buffer is going to run out of room and needs resizing. |
| * {@code encodeSize = {@link #BYTES_PER_ENCODED_BLOCK} + lineSeparator.length;} |
| */ |
| private final int encodeSize; |
| |
| /** |
| * Encode table to use. |
| */ |
| private final byte[] encodeTable; |
| |
| /** |
| * Line separator for encoding. Not used when decoding. Only used if lineLength > 0. |
| */ |
| private final byte[] lineSeparator; |
| |
| /** |
| * Creates a Base32 codec used for decoding and encoding. |
| * <p> |
| * When encoding the line length is 0 (no chunking). |
| * </p> |
| * |
| */ |
| public Base32() { |
| this(false); |
| } |
| |
| /** |
| * Creates a Base32 codec used for decoding and encoding. |
| * <p> |
| * When encoding the line length is 0 (no chunking). |
| * </p> |
| * @param useHex if {@code true} then use Base32 Hex alphabet |
| */ |
| public Base32(final boolean useHex) { |
| this(0, null, useHex, PAD_DEFAULT); |
| } |
| |
| /** |
| * Creates a Base32 codec used for decoding and encoding. |
| * <p> |
| * When encoding the line length is 0 (no chunking). |
| * </p> |
| * @param useHex if {@code true} then use Base32 Hex alphabet |
| * @param padding byte used as padding byte. |
| */ |
| public Base32(final boolean useHex, final byte padding) { |
| this(0, null, useHex, padding); |
| } |
| |
| /** |
| * Creates a Base32 codec used for decoding and encoding. |
| * <p> |
| * When encoding the line length is 0 (no chunking). |
| * </p> |
| * @param pad byte used as padding byte. |
| */ |
| public Base32(final byte pad) { |
| this(false, pad); |
| } |
| |
| /** |
| * Creates a Base32 codec used for decoding and encoding. |
| * <p> |
| * When encoding the line length is given in the constructor, the line separator is CRLF. |
| * </p> |
| * |
| * @param lineLength |
| * Each line of encoded data will be at most of the given length (rounded down to nearest multiple of |
| * 8). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when |
| * decoding. |
| */ |
| public Base32(final int lineLength) { |
| this(lineLength, CHUNK_SEPARATOR); |
| } |
| |
| /** |
| * Creates a Base32 codec used for decoding and encoding. |
| * <p> |
| * When encoding the line length and line separator are given in the constructor. |
| * </p> |
| * <p> |
| * Line lengths that aren't multiples of 8 will still essentially end up being multiples of 8 in the encoded data. |
| * </p> |
| * |
| * @param lineLength |
| * Each line of encoded data will be at most of the given length (rounded down to nearest multiple of |
| * 8). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when |
| * decoding. |
| * @param lineSeparator |
| * Each line of encoded data will end with this sequence of bytes. |
| * @throws IllegalArgumentException |
| * Thrown when the {@code lineSeparator} contains Base32 characters. |
| */ |
| public Base32(final int lineLength, final byte[] lineSeparator) { |
| this(lineLength, lineSeparator, false, PAD_DEFAULT); |
| } |
| |
| /** |
| * Creates a Base32 / Base32 Hex codec used for decoding and encoding. |
| * <p> |
| * When encoding the line length and line separator are given in the constructor. |
| * </p> |
| * <p> |
| * Line lengths that aren't multiples of 8 will still essentially end up being multiples of 8 in the encoded data. |
| * </p> |
| * |
| * @param lineLength |
| * Each line of encoded data will be at most of the given length (rounded down to nearest multiple of |
| * 8). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when |
| * decoding. |
| * @param lineSeparator |
| * Each line of encoded data will end with this sequence of bytes. |
| * @param useHex |
| * if {@code true}, then use Base32 Hex alphabet, otherwise use Base32 alphabet |
| * @throws IllegalArgumentException |
| * Thrown when the {@code lineSeparator} contains Base32 characters. Or the |
| * lineLength > 0 and lineSeparator is null. |
| */ |
| public Base32(final int lineLength, final byte[] lineSeparator, final boolean useHex) { |
| this(lineLength, lineSeparator, useHex, PAD_DEFAULT); |
| } |
| |
| /** |
| * Creates a Base32 / Base32 Hex codec used for decoding and encoding. |
| * <p> |
| * When encoding the line length and line separator are given in the constructor. |
| * </p> |
| * <p> |
| * Line lengths that aren't multiples of 8 will still essentially end up being multiples of 8 in the encoded data. |
| * </p> |
| * |
| * @param lineLength |
| * Each line of encoded data will be at most of the given length (rounded down to nearest multiple of |
| * 8). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when |
| * decoding. |
| * @param lineSeparator |
| * Each line of encoded data will end with this sequence of bytes. |
| * @param useHex |
| * if {@code true}, then use Base32 Hex alphabet, otherwise use Base32 alphabet |
| * @param padding byte used as padding byte. |
| * @throws IllegalArgumentException |
| * Thrown when the {@code lineSeparator} contains Base32 characters. Or the |
| * lineLength > 0 and lineSeparator is null. |
| */ |
| public Base32(final int lineLength, final byte[] lineSeparator, final boolean useHex, final byte padding) { |
| this(lineLength, lineSeparator, useHex, padding, DECODING_POLICY_DEFAULT); |
| } |
| |
| /** |
| * Creates a Base32 / Base32 Hex codec used for decoding and encoding. |
| * <p> |
| * When encoding the line length and line separator are given in the constructor. |
| * </p> |
| * <p> |
| * Line lengths that aren't multiples of 8 will still essentially end up being multiples of 8 in the encoded data. |
| * </p> |
| * |
| * @param lineLength |
| * Each line of encoded data will be at most of the given length (rounded down to nearest multiple of |
| * 8). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when |
| * decoding. |
| * @param lineSeparator |
| * Each line of encoded data will end with this sequence of bytes. |
| * @param useHex |
| * if {@code true}, then use Base32 Hex alphabet, otherwise use Base32 alphabet |
| * @param padding byte used as padding byte. |
| * @param decodingPolicy The decoding policy. |
| * @throws IllegalArgumentException |
| * Thrown when the {@code lineSeparator} contains Base32 characters. Or the |
| * lineLength > 0 and lineSeparator is null. |
| * @since 1.15 |
| */ |
| public Base32(final int lineLength, final byte[] lineSeparator, final boolean useHex, |
| final byte padding, final CodecPolicy decodingPolicy) { |
| super(BYTES_PER_UNENCODED_BLOCK, BYTES_PER_ENCODED_BLOCK, lineLength, |
| lineSeparator == null ? 0 : lineSeparator.length, padding, decodingPolicy); |
| if (useHex) { |
| this.encodeTable = HEX_ENCODE_TABLE; |
| this.decodeTable = HEX_DECODE_TABLE; |
| } else { |
| this.encodeTable = ENCODE_TABLE; |
| this.decodeTable = DECODE_TABLE; |
| } |
| if (lineLength > 0) { |
| if (lineSeparator == null) { |
| throw new IllegalArgumentException("lineLength " + lineLength + " > 0, but lineSeparator is null"); |
| } |
| // Must be done after initializing the tables |
| if (containsAlphabetOrPad(lineSeparator)) { |
| final String sep = StringUtils.newStringUtf8(lineSeparator); |
| throw new IllegalArgumentException("lineSeparator must not contain Base32 characters: [" + sep + "]"); |
| } |
| this.encodeSize = BYTES_PER_ENCODED_BLOCK + lineSeparator.length; |
| this.lineSeparator = new byte[lineSeparator.length]; |
| System.arraycopy(lineSeparator, 0, this.lineSeparator, 0, lineSeparator.length); |
| } else { |
| this.encodeSize = BYTES_PER_ENCODED_BLOCK; |
| this.lineSeparator = null; |
| } |
| this.decodeSize = this.encodeSize - 1; |
| |
| if (isInAlphabet(padding) || isWhiteSpace(padding)) { |
| throw new IllegalArgumentException("pad must not be in alphabet or whitespace"); |
| } |
| } |
| |
| /** |
| * <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-Base32 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> |
| * Output is written to {@link org.apache.commons.codec.binary.BaseNCodec.Context#buffer Context#buffer} as 8-bit |
| * octets, using {@link org.apache.commons.codec.binary.BaseNCodec.Context#pos Context#pos} as the buffer position |
| * </p> |
| * |
| * @param input byte[] array of ascii data to Base32 decode. |
| * @param inPos Position to start reading data from. |
| * @param inAvail Amount of bytes available from input for decoding. |
| * @param context the context to be used |
| */ |
| @Override |
| void decode(final byte[] input, int inPos, final int inAvail, final Context context) { |
| // package protected for access from I/O streams |
| |
| if (context.eof) { |
| return; |
| } |
| if (inAvail < 0) { |
| context.eof = true; |
| } |
| for (int i = 0; i < inAvail; i++) { |
| final byte b = input[inPos++]; |
| if (b == pad) { |
| // We're done. |
| context.eof = true; |
| break; |
| } |
| final byte[] buffer = ensureBufferSize(decodeSize, context); |
| if (b >= 0 && b < this.decodeTable.length) { |
| final int result = this.decodeTable[b]; |
| if (result >= 0) { |
| context.modulus = (context.modulus+1) % BYTES_PER_ENCODED_BLOCK; |
| // collect decoded bytes |
| context.lbitWorkArea = (context.lbitWorkArea << BITS_PER_ENCODED_BYTE) + result; |
| if (context.modulus == 0) { // we can output the 5 bytes |
| buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 32) & MASK_8BITS); |
| buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 24) & MASK_8BITS); |
| buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 16) & MASK_8BITS); |
| buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 8) & MASK_8BITS); |
| buffer[context.pos++] = (byte) (context.lbitWorkArea & MASK_8BITS); |
| } |
| } |
| } |
| } |
| |
| // Two forms of EOF as far as Base32 decoder is concerned: actual |
| // EOF (-1) and first time '=' character is encountered in stream. |
| // This approach makes the '=' padding characters completely optional. |
| if (context.eof && context.modulus > 0) { // if modulus == 0, nothing to do |
| final byte[] buffer = ensureBufferSize(decodeSize, context); |
| |
| // We ignore partial bytes, i.e. only multiples of 8 count. |
| // Any combination not part of a valid encoding is either partially decoded |
| // or will raise an exception. Possible trailing characters are 2, 4, 5, 7. |
| // It is not possible to encode with 1, 3, 6 trailing characters. |
| // For backwards compatibility 3 & 6 chars are decoded anyway rather than discarded. |
| // See the encode(byte[]) method EOF section. |
| switch (context.modulus) { |
| // case 0 : // impossible, as excluded above |
| case 1 : // 5 bits - either ignore entirely, or raise an exception |
| validateTrailingCharacters(); |
| case 2 : // 10 bits, drop 2 and output one byte |
| validateCharacter(MASK_2BITS, context); |
| buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 2) & MASK_8BITS); |
| break; |
| case 3 : // 15 bits, drop 7 and output 1 byte, or raise an exception |
| validateTrailingCharacters(); |
| // Not possible from a valid encoding but decode anyway |
| buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 7) & MASK_8BITS); |
| break; |
| case 4 : // 20 bits = 2*8 + 4 |
| validateCharacter(MASK_4BITS, context); |
| context.lbitWorkArea = context.lbitWorkArea >> 4; // drop 4 bits |
| buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 8) & MASK_8BITS); |
| buffer[context.pos++] = (byte) ((context.lbitWorkArea) & MASK_8BITS); |
| break; |
| case 5 : // 25 bits = 3*8 + 1 |
| validateCharacter(MASK_1BITS, context); |
| context.lbitWorkArea = context.lbitWorkArea >> 1; |
| buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 16) & MASK_8BITS); |
| buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 8) & MASK_8BITS); |
| buffer[context.pos++] = (byte) ((context.lbitWorkArea) & MASK_8BITS); |
| break; |
| case 6 : // 30 bits = 3*8 + 6, or raise an exception |
| validateTrailingCharacters(); |
| // Not possible from a valid encoding but decode anyway |
| context.lbitWorkArea = context.lbitWorkArea >> 6; |
| buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 16) & MASK_8BITS); |
| buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 8) & MASK_8BITS); |
| buffer[context.pos++] = (byte) ((context.lbitWorkArea) & MASK_8BITS); |
| break; |
| case 7 : // 35 bits = 4*8 +3 |
| validateCharacter(MASK_3BITS, context); |
| context.lbitWorkArea = context.lbitWorkArea >> 3; |
| buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 24) & MASK_8BITS); |
| buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 16) & MASK_8BITS); |
| buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 8) & MASK_8BITS); |
| buffer[context.pos++] = (byte) ((context.lbitWorkArea) & MASK_8BITS); |
| break; |
| default: |
| // modulus can be 0-7, and we excluded 0,1 already |
| throw new IllegalStateException("Impossible modulus " + context.modulus); |
| } |
| } |
| } |
| |
| /** |
| * <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 5). |
| * </p> |
| * |
| * @param input |
| * byte[] array of binary data to Base32 encode. |
| * @param inPos |
| * Position to start reading data from. |
| * @param inAvail |
| * Amount of bytes available from input for encoding. |
| * @param context the context to be used |
| */ |
| @Override |
| void encode(final byte[] input, int inPos, final int inAvail, final Context context) { |
| // package protected for access from I/O streams |
| |
| if (context.eof) { |
| return; |
| } |
| // inAvail < 0 is how we're informed of EOF in the underlying data we're |
| // encoding. |
| if (inAvail < 0) { |
| context.eof = true; |
| if (0 == context.modulus && lineLength == 0) { |
| return; // no leftovers to process and not using chunking |
| } |
| final byte[] buffer = ensureBufferSize(encodeSize, context); |
| final int savedPos = context.pos; |
| switch (context.modulus) { // % 5 |
| case 0 : |
| break; |
| case 1 : // Only 1 octet; take top 5 bits then remainder |
| buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 3) & MASK_5BITS]; // 8-1*5 = 3 |
| buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea << 2) & MASK_5BITS]; // 5-3=2 |
| buffer[context.pos++] = pad; |
| buffer[context.pos++] = pad; |
| buffer[context.pos++] = pad; |
| buffer[context.pos++] = pad; |
| buffer[context.pos++] = pad; |
| buffer[context.pos++] = pad; |
| break; |
| case 2 : // 2 octets = 16 bits to use |
| buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 11) & MASK_5BITS]; // 16-1*5 = 11 |
| buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 6) & MASK_5BITS]; // 16-2*5 = 6 |
| buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 1) & MASK_5BITS]; // 16-3*5 = 1 |
| buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea << 4) & MASK_5BITS]; // 5-1 = 4 |
| buffer[context.pos++] = pad; |
| buffer[context.pos++] = pad; |
| buffer[context.pos++] = pad; |
| buffer[context.pos++] = pad; |
| break; |
| case 3 : // 3 octets = 24 bits to use |
| buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 19) & MASK_5BITS]; // 24-1*5 = 19 |
| buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 14) & MASK_5BITS]; // 24-2*5 = 14 |
| buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 9) & MASK_5BITS]; // 24-3*5 = 9 |
| buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 4) & MASK_5BITS]; // 24-4*5 = 4 |
| buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea << 1) & MASK_5BITS]; // 5-4 = 1 |
| buffer[context.pos++] = pad; |
| buffer[context.pos++] = pad; |
| buffer[context.pos++] = pad; |
| break; |
| case 4 : // 4 octets = 32 bits to use |
| buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 27) & MASK_5BITS]; // 32-1*5 = 27 |
| buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 22) & MASK_5BITS]; // 32-2*5 = 22 |
| buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 17) & MASK_5BITS]; // 32-3*5 = 17 |
| buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 12) & MASK_5BITS]; // 32-4*5 = 12 |
| buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 7) & MASK_5BITS]; // 32-5*5 = 7 |
| buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 2) & MASK_5BITS]; // 32-6*5 = 2 |
| buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea << 3) & MASK_5BITS]; // 5-2 = 3 |
| buffer[context.pos++] = pad; |
| break; |
| default: |
| throw new IllegalStateException("Impossible modulus " + context.modulus); |
| } |
| context.currentLinePos += context.pos - savedPos; // keep track of current line position |
| // if currentPos == 0 we are at the start of a line, so don't add CRLF |
| if (lineLength > 0 && context.currentLinePos > 0){ // add chunk separator if required |
| System.arraycopy(lineSeparator, 0, buffer, context.pos, lineSeparator.length); |
| context.pos += lineSeparator.length; |
| } |
| } else { |
| for (int i = 0; i < inAvail; i++) { |
| final byte[] buffer = ensureBufferSize(encodeSize, context); |
| context.modulus = (context.modulus+1) % BYTES_PER_UNENCODED_BLOCK; |
| int b = input[inPos++]; |
| if (b < 0) { |
| b += 256; |
| } |
| context.lbitWorkArea = (context.lbitWorkArea << 8) + b; // BITS_PER_BYTE |
| if (0 == context.modulus) { // we have enough bytes to create our output |
| buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 35) & MASK_5BITS]; |
| buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 30) & MASK_5BITS]; |
| buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 25) & MASK_5BITS]; |
| buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 20) & MASK_5BITS]; |
| buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 15) & MASK_5BITS]; |
| buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 10) & MASK_5BITS]; |
| buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 5) & MASK_5BITS]; |
| buffer[context.pos++] = encodeTable[(int)context.lbitWorkArea & MASK_5BITS]; |
| context.currentLinePos += BYTES_PER_ENCODED_BLOCK; |
| if (lineLength > 0 && lineLength <= context.currentLinePos) { |
| System.arraycopy(lineSeparator, 0, buffer, context.pos, lineSeparator.length); |
| context.pos += lineSeparator.length; |
| context.currentLinePos = 0; |
| } |
| } |
| } |
| } |
| } |
| |
| /** |
| * Returns whether or not the {@code octet} is in the Base32 alphabet. |
| * |
| * @param octet |
| * The value to test |
| * @return {@code true} if the value is defined in the the Base32 alphabet {@code false} otherwise. |
| */ |
| @Override |
| public boolean isInAlphabet(final byte octet) { |
| return octet >= 0 && octet < decodeTable.length && decodeTable[octet] != -1; |
| } |
| |
| /** |
| * Validates whether decoding the final trailing character is possible in the context |
| * of the set of possible base 32 values. |
| * |
| * <p>The character is valid if the lower bits within the provided mask are zero. This |
| * is used to test the final trailing base-32 digit is zero in the bits that will be discarded. |
| * |
| * @param emptyBitsMask The mask of the lower bits that should be empty |
| * @param context the context to be used |
| * |
| * @throws IllegalArgumentException if the bits being checked contain any non-zero value |
| */ |
| private void validateCharacter(final long emptyBitsMask, final Context context) { |
| // Use the long bit work area |
| if (isStrictDecoding() && (context.lbitWorkArea & emptyBitsMask) != 0) { |
| throw new IllegalArgumentException( |
| "Strict decoding: Last encoded character (before the paddings if any) is a valid " + |
| "base 32 alphabet but not a possible encoding. " + |
| "Expected the discarded bits from the character to be zero."); |
| } |
| } |
| |
| /** |
| * Validates whether decoding allows final trailing characters that cannot be |
| * created during encoding. |
| * |
| * @throws IllegalArgumentException if strict decoding is enabled |
| */ |
| private void validateTrailingCharacters() { |
| if (isStrictDecoding()) { |
| throw new IllegalArgumentException( |
| "Strict decoding: Last encoded character(s) (before the paddings if any) are valid " + |
| "base 32 alphabet but not a possible encoding. " + |
| "Decoding requires either 2, 4, 5, or 7 trailing 5-bit characters to create bytes."); |
| } |
| } |
| } |