| /* |
| * Copyright (C) 2010 The Android Open Source Project |
| * |
| * 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 com.google.crypto.tink.subtle; |
| |
| import java.io.UnsupportedEncodingException; |
| import java.nio.charset.Charset; |
| |
| /** |
| * Utilities for encoding and decoding the Base64 representation of binary data. |
| * |
| * <p>See RFCs <a href="http://www.ietf.org/rfc/rfc2045.txt">2045</a> and <a |
| * href="http://www.ietf.org/rfc/rfc3548.txt">3548</a>. |
| * |
| * <p>This is a copy of android.util.Base64, with minor modifications to to fix style and ErrorProne |
| * errors. |
| * |
| * @since 1.0.0 |
| */ |
| public final class Base64 { |
| private static final Charset UTF_8 = Charset.forName("UTF-8"); |
| |
| /** Default values for encoder/decoder flags. */ |
| public static final int DEFAULT = 0; |
| |
| /** Encoder flag bit to omit the padding '=' characters at the end of the output (if any). */ |
| public static final int NO_PADDING = 1; |
| |
| /** Encoder flag bit to omit all line terminators (i.e., the output will be on one long line). */ |
| public static final int NO_WRAP = 2; |
| |
| /** |
| * Encoder flag bit to indicate lines should be terminated with a CRLF pair instead of just an LF. |
| * Has no effect if {@code NO_WRAP} is specified as well. |
| */ |
| public static final int CRLF = 4; |
| |
| /** |
| * Encoder/decoder flag bit to indicate using the "URL and filename safe" variant of Base64 (see |
| * RFC 3548 section 4) where {@code -} and {@code _} are used in place of {@code +} and {@code /}. |
| */ |
| public static final int URL_SAFE = 8; |
| |
| /** |
| * Flag to pass to {@link Base64OutputStream} to indicate that it should not close the output |
| * stream it is wrapping when it itself is closed. |
| */ |
| public static final int NO_CLOSE = 16; |
| |
| // -------------------------------------------------------- |
| // shared code |
| // -------------------------------------------------------- |
| |
| /* package */ abstract static class Coder { |
| public byte[] output; |
| public int op; |
| |
| /** |
| * Encode/decode another block of input data. this.output is provided by the caller, and must be |
| * big enough to hold all the coded data. On exit, this.opwill be set to the length of the coded |
| * data. |
| * |
| * @param finish true if this is the final call to process for this object. Will finalize the |
| * coder state and include any final bytes in the output. |
| * @return true if the input so far is good; false if some error has been detected in the input |
| * stream.. |
| */ |
| public abstract boolean process(byte[] input, int offset, int len, boolean finish); |
| |
| /** |
| * @return the maximum number of bytes a call to process() could produce for the given number of |
| * input bytes. This may be an overestimate. |
| */ |
| public abstract int maxOutputSize(int len); |
| } |
| |
| // -------------------------------------------------------- |
| // decoding |
| // -------------------------------------------------------- |
| |
| /** Decodes a base64 string to a byte array. */ |
| public static byte[] decode(String input) { |
| return decode(input, DEFAULT | NO_WRAP); |
| } |
| |
| /** Decodes a url-safe base64 string to a byte array. */ |
| public static byte[] urlSafeDecode(String input) { |
| return decode(input, DEFAULT | NO_PADDING | NO_WRAP | URL_SAFE); |
| } |
| |
| /** |
| * Decode the Base64-encoded data in input and return the data in a new byte array. |
| * |
| * <p>The padding '=' characters at the end are considered optional, but if any are present, there |
| * must be the correct number of them. |
| * |
| * @param str the input String to decode, which is converted to bytes using the default charset |
| * @param flags controls certain features of the decoded output. Pass {@code DEFAULT} to decode |
| * standard Base64. |
| * @throws IllegalArgumentException if the input contains incorrect padding |
| */ |
| public static byte[] decode(String str, int flags) { |
| return decode(str.getBytes(UTF_8), flags); |
| } |
| |
| /** |
| * Decode the Base64-encoded data in input and return the data in a new byte array. |
| * |
| * <p>The padding '=' characters at the end are considered optional, but if any are present, there |
| * must be the correct number of them. |
| * |
| * @param input the input array to decode |
| * @param flags controls certain features of the decoded output. Pass {@code DEFAULT} to decode |
| * standard Base64. |
| * @throws IllegalArgumentException if the input contains incorrect padding |
| */ |
| public static byte[] decode(byte[] input, int flags) { |
| return decode(input, 0, input.length, flags); |
| } |
| |
| /** |
| * Decode the Base64-encoded data in input and return the data in a new byte array. |
| * |
| * <p>The padding '=' characters at the end are considered optional, but if any are present, there |
| * must be the correct number of them. |
| * |
| * @param input the data to decode |
| * @param offset the position within the input array at which to start |
| * @param len the number of bytes of input to decode |
| * @param flags controls certain features of the decoded output. Pass {@code DEFAULT} to decode |
| * standard Base64. |
| * @throws IllegalArgumentException if the input contains incorrect padding |
| */ |
| public static byte[] decode(byte[] input, int offset, int len, int flags) { |
| // Allocate space for the most data the input could represent. |
| // (It could contain less if it contains whitespace, etc.) |
| Decoder decoder = new Decoder(flags, new byte[len * 3 / 4]); |
| |
| if (!decoder.process(input, offset, len, true)) { |
| throw new IllegalArgumentException("bad base-64"); |
| } |
| |
| // Maybe we got lucky and allocated exactly enough output space. |
| if (decoder.op == decoder.output.length) { |
| return decoder.output; |
| } |
| |
| // Need to shorten the array, so allocate a new one of the |
| // right size and copy. |
| byte[] temp = new byte[decoder.op]; |
| System.arraycopy(decoder.output, 0, temp, 0, decoder.op); |
| return temp; |
| } |
| |
| /* package */ static class Decoder extends Coder { |
| /** Lookup table for turning bytes into their position in the Base64 alphabet. */ |
| private static final int[] DECODE = { |
| -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, -2, -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 lookup table for the "web safe" variant (RFC 3548 sec. 4) where - and _ replace + and |
| * /. |
| */ |
| private static final int[] DECODE_WEBSAFE = { |
| -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, 62, -1, -1, |
| 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -2, -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, 63, |
| -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, |
| }; |
| |
| /** Non-data values in the DECODE arrays. */ |
| private static final int SKIP = -1; |
| |
| private static final int EQUALS = -2; |
| |
| /** |
| * States 0-3 are reading through the next input tuple. State 4 is having read one '=' and |
| * expecting exactly one more. State 5 is expecting no more data or padding characters in the |
| * input. State 6 is the error state; an error has been detected in the input and no future |
| * input can "fix" it. |
| */ |
| private int state; // state number (0 to 6) |
| |
| private int value; |
| |
| private final int[] alphabet; |
| |
| public Decoder(int flags, byte[] output) { |
| this.output = output; |
| |
| alphabet = ((flags & URL_SAFE) == 0) ? DECODE : DECODE_WEBSAFE; |
| state = 0; |
| value = 0; |
| } |
| |
| /** @return an overestimate for the number of bytes {@code len} bytes could decode to. */ |
| @Override |
| public int maxOutputSize(int len) { |
| return len * 3 / 4 + 10; |
| } |
| |
| /** |
| * Decode another block of input data. |
| * |
| * @return true if the state machine is still healthy. false if bad base-64 data has been |
| * detected in the input stream. |
| */ |
| @Override |
| public boolean process(byte[] input, int offset, int len, boolean finish) { |
| if (this.state == 6) { |
| return false; |
| } |
| |
| int p = offset; |
| len += offset; |
| |
| // Using local variables makes the decoder about 12% |
| // faster than if we manipulate the member variables in |
| // the loop. (Even alphabet makes a measurable |
| // difference, which is somewhat surprising to me since |
| // the member variable is final.) |
| int state = this.state; |
| int value = this.value; |
| int op = 0; |
| final byte[] output = this.output; |
| final int[] alphabet = this.alphabet; |
| |
| while (p < len) { |
| if (state == 0) { |
| while (p + 4 <= len |
| && (value = |
| ((alphabet[input[p] & 0xff] << 18) |
| | (alphabet[input[p + 1] & 0xff] << 12) |
| | (alphabet[input[p + 2] & 0xff] << 6) |
| | (alphabet[input[p + 3] & 0xff]))) |
| >= 0) { |
| output[op + 2] = (byte) value; |
| output[op + 1] = (byte) (value >> 8); |
| output[op] = (byte) (value >> 16); |
| op += 3; |
| p += 4; |
| } |
| if (p >= len) { |
| break; |
| } |
| } |
| |
| // The fast path isn't available -- either we've read a |
| // partial tuple, or the next four input bytes aren't all |
| // data, or whatever. Fall back to the slower state |
| // machine implementation. |
| |
| int d = alphabet[input[p++] & 0xff]; |
| |
| switch (state) { |
| case 0: |
| if (d >= 0) { |
| value = d; |
| ++state; |
| } else if (d != SKIP) { |
| this.state = 6; |
| return false; |
| } |
| break; |
| |
| case 1: |
| if (d >= 0) { |
| value = (value << 6) | d; |
| ++state; |
| } else if (d != SKIP) { |
| this.state = 6; |
| return false; |
| } |
| break; |
| |
| case 2: |
| if (d >= 0) { |
| value = (value << 6) | d; |
| ++state; |
| } else if (d == EQUALS) { |
| // Emit the last (partial) output tuple; |
| // expect exactly one more padding character. |
| output[op++] = (byte) (value >> 4); |
| state = 4; |
| } else if (d != SKIP) { |
| this.state = 6; |
| return false; |
| } |
| break; |
| |
| case 3: |
| if (d >= 0) { |
| // Emit the output triple and return to state 0. |
| value = (value << 6) | d; |
| output[op + 2] = (byte) value; |
| output[op + 1] = (byte) (value >> 8); |
| output[op] = (byte) (value >> 16); |
| op += 3; |
| state = 0; |
| } else if (d == EQUALS) { |
| // Emit the last (partial) output tuple; |
| // expect no further data or padding characters. |
| output[op + 1] = (byte) (value >> 2); |
| output[op] = (byte) (value >> 10); |
| op += 2; |
| state = 5; |
| } else if (d != SKIP) { |
| this.state = 6; |
| return false; |
| } |
| break; |
| |
| case 4: |
| if (d == EQUALS) { |
| ++state; |
| } else if (d != SKIP) { |
| this.state = 6; |
| return false; |
| } |
| break; |
| |
| case 5: |
| if (d != SKIP) { |
| this.state = 6; |
| return false; |
| } |
| break; |
| default: |
| break; |
| } |
| } |
| |
| if (!finish) { |
| // We're out of input, but a future call could provide |
| // more. |
| this.state = state; |
| this.value = value; |
| this.op = op; |
| return true; |
| } |
| |
| // Done reading input. Now figure out where we are left in |
| // the state machine and finish up. |
| |
| switch (state) { |
| case 0: |
| // Output length is a multiple of three. Fine. |
| break; |
| case 1: |
| // Read one extra input byte, which isn't enough to |
| // make another output byte. Illegal. |
| this.state = 6; |
| return false; |
| case 2: |
| // Read two extra input bytes, enough to emit 1 more |
| // output byte. Fine. |
| output[op++] = (byte) (value >> 4); |
| break; |
| case 3: |
| // Read three extra input bytes, enough to emit 2 more |
| // output bytes. Fine. |
| output[op++] = (byte) (value >> 10); |
| output[op++] = (byte) (value >> 2); |
| break; |
| case 4: |
| // Read one padding '=' when we expected 2. Illegal. |
| this.state = 6; |
| return false; |
| case 5: |
| // Read all the padding '='s we expected and no more. |
| // Fine. |
| break; |
| default: |
| break; |
| } |
| |
| this.state = state; |
| this.op = op; |
| return true; |
| } |
| } |
| |
| // -------------------------------------------------------- |
| // encoding |
| // -------------------------------------------------------- |
| |
| /** Base64 encodes a byte array to a string. */ |
| public static String encode(final byte[] input) { |
| return encodeToString(input, DEFAULT | NO_WRAP); |
| } |
| |
| /** Url-safe base64 encodes a byte array to a string. */ |
| public static String urlSafeEncode(final byte[] input) { |
| return encodeToString(input, DEFAULT | NO_PADDING | NO_WRAP | URL_SAFE); |
| } |
| |
| /** |
| * Base64-encode the given data and return a newly allocated String with the result. |
| * |
| * @param input the data to encode |
| * @param flags controls certain features of the encoded output. Passing {@code DEFAULT} results |
| * in output that adheres to RFC 2045. |
| */ |
| public static String encodeToString(byte[] input, int flags) { |
| try { |
| return new String(encode(input, flags), "US-ASCII"); |
| } catch (UnsupportedEncodingException e) { |
| // US-ASCII is guaranteed to be available. |
| throw new AssertionError(e); |
| } |
| } |
| |
| /** |
| * Base64-encode the given data and return a newly allocated String with the result. |
| * |
| * @param input the data to encode |
| * @param offset the position within the input array at which to start |
| * @param len the number of bytes of input to encode |
| * @param flags controls certain features of the encoded output. Passing {@code DEFAULT} results |
| * in output that adheres to RFC 2045. |
| */ |
| public static String encodeToString(byte[] input, int offset, int len, int flags) { |
| try { |
| return new String(encode(input, offset, len, flags), "US-ASCII"); |
| } catch (UnsupportedEncodingException e) { |
| // US-ASCII is guaranteed to be available. |
| throw new AssertionError(e); |
| } |
| } |
| |
| /** |
| * Base64-encode the given data and return a newly allocated byte[] with the result. |
| * |
| * @param input the data to encode |
| * @param flags controls certain features of the encoded output. Passing {@code DEFAULT} results |
| * in output that adheres to RFC 2045. |
| */ |
| public static byte[] encode(byte[] input, int flags) { |
| return encode(input, 0, input.length, flags); |
| } |
| |
| /** |
| * Base64-encode the given data and return a newly allocated byte[] with the result. |
| * |
| * @param input the data to encode |
| * @param offset the position within the input array at which to start |
| * @param len the number of bytes of input to encode |
| * @param flags controls certain features of the encoded output. Passing {@code DEFAULT} results |
| * in output that adheres to RFC 2045. |
| */ |
| public static byte[] encode(byte[] input, int offset, int len, int flags) { |
| Encoder encoder = new Encoder(flags, null); |
| |
| // Compute the exact length of the array we will produce. |
| int outputLen = len / 3 * 4; |
| |
| // Account for the tail of the data and the padding bytes, if any. |
| if (encoder.doPadding) { |
| if (len % 3 > 0) { |
| outputLen += 4; |
| } |
| } else { |
| switch (len % 3) { |
| case 0: |
| break; |
| case 1: |
| outputLen += 2; |
| break; |
| case 2: |
| outputLen += 3; |
| break; |
| default: |
| break; |
| } |
| } |
| |
| // Account for the newlines, if any. |
| if (encoder.doNewline && len > 0) { |
| outputLen += (((len - 1) / (3 * Encoder.LINE_GROUPS)) + 1) * (encoder.doCr ? 2 : 1); |
| } |
| |
| encoder.output = new byte[outputLen]; |
| encoder.process(input, offset, len, true); |
| |
| assert encoder.op == outputLen; |
| |
| return encoder.output; |
| } |
| |
| /* package */ static class Encoder extends Coder { |
| /** |
| * Emit a new line every this many output tuples. Corresponds to a 76-character line length (the |
| * maximum allowable according to <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>). |
| */ |
| public static final int LINE_GROUPS = 19; |
| |
| /** Lookup table for turning Base64 alphabet positions (6 bits) into output bytes. */ |
| private static final byte[] ENCODE = { |
| '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', '+', '/', |
| }; |
| |
| /** Lookup table for turning Base64 alphabet positions (6 bits) into output bytes. */ |
| private static final byte[] ENCODE_WEBSAFE = { |
| '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', '-', '_', |
| }; |
| |
| private final byte[] tail; |
| /* package */ int tailLen; |
| private int count; |
| |
| public final boolean doPadding; |
| public final boolean doNewline; |
| public final boolean doCr; |
| private final byte[] alphabet; |
| |
| public Encoder(int flags, byte[] output) { |
| this.output = output; |
| |
| doPadding = (flags & NO_PADDING) == 0; |
| doNewline = (flags & NO_WRAP) == 0; |
| doCr = (flags & CRLF) != 0; |
| alphabet = ((flags & URL_SAFE) == 0) ? ENCODE : ENCODE_WEBSAFE; |
| |
| tail = new byte[2]; |
| tailLen = 0; |
| |
| count = doNewline ? LINE_GROUPS : -1; |
| } |
| |
| /** @return an overestimate for the number of bytes {@code len} bytes could encode to. */ |
| @Override |
| public int maxOutputSize(int len) { |
| return len * 8 / 5 + 10; |
| } |
| |
| @Override |
| public boolean process(byte[] input, int offset, int len, boolean finish) { |
| // Using local variables makes the encoder about 9% faster. |
| final byte[] alphabet = this.alphabet; |
| final byte[] output = this.output; |
| int op = 0; |
| int count = this.count; |
| |
| int p = offset; |
| len += offset; |
| int v = -1; |
| |
| // First we need to concatenate the tail of the previous call |
| // with any input bytes available now and see if we can empty |
| // the tail. |
| |
| switch (tailLen) { |
| case 0: |
| // There was no tail. |
| break; |
| |
| case 1: |
| if (p + 2 <= len) { |
| // A 1-byte tail with at least 2 bytes of |
| // input available now. |
| v = ((tail[0] & 0xff) << 16) | ((input[p++] & 0xff) << 8) | (input[p++] & 0xff); |
| tailLen = 0; |
| } |
| break; |
| |
| case 2: |
| if (p + 1 <= len) { |
| // A 2-byte tail with at least 1 byte of input. |
| v = ((tail[0] & 0xff) << 16) | ((tail[1] & 0xff) << 8) | (input[p++] & 0xff); |
| tailLen = 0; |
| } |
| break; |
| default: |
| break; |
| } |
| |
| if (v != -1) { |
| output[op++] = alphabet[(v >> 18) & 0x3f]; |
| output[op++] = alphabet[(v >> 12) & 0x3f]; |
| output[op++] = alphabet[(v >> 6) & 0x3f]; |
| output[op++] = alphabet[v & 0x3f]; |
| if (--count == 0) { |
| if (doCr) { |
| output[op++] = '\r'; |
| } |
| output[op++] = '\n'; |
| count = LINE_GROUPS; |
| } |
| } |
| |
| // At this point either there is no tail, or there are fewer |
| // than 3 bytes of input available. |
| |
| // The main loop, turning 3 input bytes into 4 output bytes on |
| // each iteration. |
| while (p + 3 <= len) { |
| v = ((input[p] & 0xff) << 16) | ((input[p + 1] & 0xff) << 8) | (input[p + 2] & 0xff); |
| output[op] = alphabet[(v >> 18) & 0x3f]; |
| output[op + 1] = alphabet[(v >> 12) & 0x3f]; |
| output[op + 2] = alphabet[(v >> 6) & 0x3f]; |
| output[op + 3] = alphabet[v & 0x3f]; |
| p += 3; |
| op += 4; |
| if (--count == 0) { |
| if (doCr) { |
| output[op++] = '\r'; |
| } |
| output[op++] = '\n'; |
| count = LINE_GROUPS; |
| } |
| } |
| |
| if (finish) { |
| // Finish up the tail of the input. Note that we need to |
| // consume any bytes in tail before any bytes |
| // remaining in input; there should be at most two bytes |
| // total. |
| |
| if (p - tailLen == len - 1) { |
| int t = 0; |
| v = ((tailLen > 0 ? tail[t++] : input[p++]) & 0xff) << 4; |
| tailLen -= t; |
| output[op++] = alphabet[(v >> 6) & 0x3f]; |
| output[op++] = alphabet[v & 0x3f]; |
| if (doPadding) { |
| output[op++] = '='; |
| output[op++] = '='; |
| } |
| if (doNewline) { |
| if (doCr) { |
| output[op++] = '\r'; |
| } |
| output[op++] = '\n'; |
| } |
| } else if (p - tailLen == len - 2) { |
| int t = 0; |
| v = |
| (((tailLen > 1 ? tail[t++] : input[p++]) & 0xff) << 10) |
| | (((tailLen > 0 ? tail[t++] : input[p++]) & 0xff) << 2); |
| tailLen -= t; |
| output[op++] = alphabet[(v >> 12) & 0x3f]; |
| output[op++] = alphabet[(v >> 6) & 0x3f]; |
| output[op++] = alphabet[v & 0x3f]; |
| if (doPadding) { |
| output[op++] = '='; |
| } |
| if (doNewline) { |
| if (doCr) { |
| output[op++] = '\r'; |
| } |
| output[op++] = '\n'; |
| } |
| } else if (doNewline && op > 0 && count != LINE_GROUPS) { |
| if (doCr) { |
| output[op++] = '\r'; |
| } |
| output[op++] = '\n'; |
| } |
| |
| assert tailLen == 0; |
| assert p == len; |
| } else { |
| // Save the leftovers in tail to be consumed on the next |
| // call to encodeInternal. |
| |
| if (p == len - 1) { |
| tail[tailLen++] = input[p]; |
| } else if (p == len - 2) { |
| tail[tailLen++] = input[p]; |
| tail[tailLen++] = input[p + 1]; |
| } |
| } |
| |
| this.op = op; |
| this.count = count; |
| |
| return true; |
| } |
| } |
| |
| private Base64() {} // don't instantiate |
| } |