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/*
* Copyright (C) 2018, 2019 HaiYang Li
*
* 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.landawn.abacus.util;
import java.math.BigInteger;
import java.nio.charset.Charset;
import java.util.Arrays;
// TODO: Auto-generated Javadoc
/**
* Note: this file contains the source codes and docs copied from {@code Apache commons-codec} under Apache License v2 and may be modified.
*
*/
final class Base64 {
/**
*
* @since 1.7
*/
private static final int EOF = -1;
/**
* MIME chunk size per RFC 2045 section 6.8.
*
*
* The {@value} character limit does not count the trailing CRLF, but counts all other characters, including any
* equal signs.
*
*
* @see RFC 2045 section 6.8
*/
private static final int MIME_CHUNK_SIZE = 76;
/** The Constant DEFAULT_BUFFER_RESIZE_FACTOR. */
private static final int DEFAULT_BUFFER_RESIZE_FACTOR = 2;
/** Defines the default buffer size - currently {@value} - must be large enough for at least one encoded block+separator. */
private static final int DEFAULT_BUFFER_SIZE = 8192;
/** Mask used to extract 8 bits, used in decoding bytes. */
protected static final int MASK_8BITS = 0xff;
/**
* Byte used to pad output.
*/
protected static final byte PAD_DEFAULT = '='; // Allow static access to default
/**
*
* @deprecated Use {@link #pad}. Will be removed in 2.0.
*/
@Deprecated
protected final byte PAD = PAD_DEFAULT; // instance variable just in case it needs to vary later
/**
* BASE32 characters are 6 bits in length.
* They are formed by taking a block of 3 octets to form a 24-bit string,
* which is converted into 4 BASE64 characters.
*/
private static final int BITS_PER_ENCODED_BYTE = 6;
/** The Constant BYTES_PER_UNENCODED_BLOCK. */
private static final int BYTES_PER_UNENCODED_BLOCK = 3;
/** The Constant BYTES_PER_ENCODED_BLOCK. */
private static final int BYTES_PER_ENCODED_BLOCK = 4;
/**
* Chunk separator per RFC 2045 section 2.1.
*
*
* N.B. The next major release may break compatibility and make this field private.
*
*
* @see RFC 2045 section 2.1
*/
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[] STANDARD_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', '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 is a copy of the STANDARD_ENCODE_TABLE above, but with + and /
* changed to - and _ to make the encoded Base64 results more URL-SAFE.
* This table is only used when the Base64's mode is set to URL-SAFE.
*/
private static final byte[] URL_SAFE_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', '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.
*
* Note: '+' and '-' both decode to 62. '/' and '_' both decode to 63. This means decoder seamlessly handles both
* URL_SAFE and STANDARD base64. (The encoder, on the other hand, needs to know ahead of time what to emit).
*
* 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[] 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, 62, -1, 62, -1, 63, // 20-2f + - /
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, // 30-3f 0-9
-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, -1, -1, -1, -1, 63, // 50-5f P-Z _
-1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, // 60-6f a-o
41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51 // 70-7a p-z
};
/**
* Base64 uses 6-bit fields.
*/
/** Mask used to extract 6 bits, used when encoding */
private static final int MASK_6BITS = 0x3f;
// 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().
/**
* Encode table to use: either STANDARD or URL_SAFE. Note: the DECODE_TABLE above remains static because it is able
* to decode both STANDARD and URL_SAFE streams, but the encodeTable must be a member variable so we can switch
* between the two modes.
*/
private final byte[] encodeTable;
/** The decode table. */
// Only one decode table currently; keep for consistency with Base32 code
private final byte[] decodeTable = DECODE_TABLE;
/**
* 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.
* decodeSize = 3 + lineSeparator.length;
*/
private final int decodeSize;
/**
* Convenience variable to help us determine when our buffer is going to run out of room and needs resizing.
* encodeSize = 4 + lineSeparator.length;
*/
private final int encodeSize;
/** The pad. */
protected final byte pad; // instance variable just in case it needs to vary later
/** Number of bytes in each full block of unencoded data, e.g. 4 for Base64 and 5 for Base32 */
private final int unencodedBlockSize;
/** Number of bytes in each full block of encoded data, e.g. 3 for Base64 and 8 for Base32 */
private final int encodedBlockSize;
/**
* Chunksize for encoding. Not used when decoding.
* A value of zero or less implies no chunking of the encoded data.
* Rounded down to nearest multiple of encodedBlockSize.
*/
protected final int lineLength;
/**
* Size of chunk separator. Not used unless {@link #lineLength} > 0.
*/
private final int chunkSeparatorLength;
/**
* Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
*
* When encoding the line length is 0 (no chunking), and the encoding table is STANDARD_ENCODE_TABLE.
*
*
*
* When decoding all variants are supported.
*
*/
Base64() {
this(0);
}
/**
* Creates a Base64 codec used for decoding (all modes) and encoding in the given URL-safe mode.
*
* When encoding the line length is 76, the line separator is CRLF, and the encoding table is STANDARD_ENCODE_TABLE.
*
*
*
* When decoding all variants are supported.
*
*
* @param urlSafe
* if true
, URL-safe encoding is used. In most cases this should be set to
* false
.
* @since 1.4
*/
Base64(final boolean urlSafe) {
this(MIME_CHUNK_SIZE, CHUNK_SEPARATOR, urlSafe);
}
/**
* Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
*
* When encoding the line length is given in the constructor, the line separator is CRLF, and the encoding table is
* STANDARD_ENCODE_TABLE.
*
*
* Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
*
*
* When decoding all variants are supported.
*
*
* @param lineLength
* Each line of encoded data will be at most of the given length (rounded down to nearest multiple of
* 4). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when
* decoding.
* @since 1.4
*/
Base64(final int lineLength) {
this(lineLength, CHUNK_SEPARATOR);
}
/**
* Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
*
* When encoding the line length and line separator are given in the constructor, and the encoding table is
* STANDARD_ENCODE_TABLE.
*
*
* Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
*
*
* When decoding all variants are supported.
*
*
* @param lineLength
* Each line of encoded data will be at most of the given length (rounded down to nearest multiple of
* 4). 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 provided lineSeparator included some base64 characters.
* @since 1.4
*/
Base64(final int lineLength, final byte[] lineSeparator) {
this(lineLength, lineSeparator, false);
}
/**
* Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
*
* When encoding the line length and line separator are given in the constructor, and the encoding table is
* STANDARD_ENCODE_TABLE.
*
*
* Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
*
*
* When decoding all variants are supported.
*
*
* @param lineLength
* Each line of encoded data will be at most of the given length (rounded down to nearest multiple of
* 4). 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 urlSafe
* Instead of emitting '+' and '/' we emit '-' and '_' respectively. urlSafe is only applied to encode
* operations. Decoding seamlessly handles both modes.
* Note: no padding is added when using the URL-safe alphabet.
* @throws IllegalArgumentException
* The provided lineSeparator included some base64 characters. That's not going to work!
* @since 1.4
*/
Base64(final int lineLength, final byte[] lineSeparator, final boolean urlSafe) {
this.unencodedBlockSize = BYTES_PER_UNENCODED_BLOCK;
this.encodedBlockSize = BYTES_PER_ENCODED_BLOCK;
this.chunkSeparatorLength = lineSeparator == null ? 0 : lineSeparator.length;
final boolean useChunking = lineLength > 0 && chunkSeparatorLength > 0;
this.lineLength = useChunking ? (lineLength / encodedBlockSize) * encodedBlockSize : 0;
this.pad = PAD_DEFAULT;
// TODO could be simplified if there is no requirement to reject invalid line sep when length <=0
// @see test case Base64Test.testConstructors()
if (lineSeparator != null) {
if (containsAlphabetOrPad(lineSeparator)) {
final String sep = newString(lineSeparator, Charsets.UTF_8);
throw new IllegalArgumentException("lineSeparator must not contain base64 characters: [" + sep + "]");
}
if (lineLength > 0) { // null line-sep forces no chunking rather than throwing IAE
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;
}
} else {
this.encodeSize = BYTES_PER_ENCODED_BLOCK;
this.lineSeparator = null;
}
this.decodeSize = this.encodeSize - 1;
this.encodeTable = urlSafe ? URL_SAFE_ENCODE_TABLE : STANDARD_ENCODE_TABLE;
}
/**
* Returns whether or not the octet
is in the base 64 alphabet.
*
* @param octet
* The value to test
* @return true
if the value is defined in the the base 64 alphabet, false
otherwise.
* @since 1.4
*/
public static boolean isBase64(final byte octet) {
return octet == PAD_DEFAULT || (octet >= 0 && octet < DECODE_TABLE.length && DECODE_TABLE[octet] != -1);
}
/**
* Tests a given String to see if it contains only valid characters within the Base64 alphabet. Currently the
* method treats whitespace as valid.
*
* @param base64
* String to test
* @return true
if all characters in the String are valid characters in the Base64 alphabet or if
* the String is empty; false
, otherwise
* @since 1.5
*/
public static boolean isBase64(final String base64) {
return isBase64(getBytes(base64, Charsets.UTF_8));
}
/**
* 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 true
if all bytes are valid characters in the Base64 alphabet or if the byte array is empty;
* false
, otherwise
* @since 1.5
*/
public static boolean isBase64(final byte[] arrayOctet) {
for (int i = 0; i < arrayOctet.length; i++) {
if (!isBase64(arrayOctet[i]) && !isWhiteSpace(arrayOctet[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 byte[] containing Base64 characters in their UTF-8 representation.
*/
public static byte[] encodeBase64(final byte[] binaryData) {
return encodeBase64(binaryData, false);
}
/**
* Encodes binary data using the base64 algorithm but does not chunk the output.
*
* NOTE: We changed the behaviour of this method from multi-line chunking (commons-codec-1.4) to
* single-line non-chunking (commons-codec-1.5).
*
* @param binaryData
* binary data to encode
* @return String containing Base64 characters.
* @since 1.4 (NOTE: 1.4 chunked the output, whereas 1.5 does not).
*/
public static String encodeBase64String(final byte[] binaryData) {
return newString(encodeBase64(binaryData, false), Charsets.US_ASCII);
}
/**
* Encodes binary data using a URL-safe variation of the base64 algorithm but does not chunk the output. The
* url-safe variation emits - and _ instead of + and / characters.
* Note: no padding is added.
* @param binaryData
* binary data to encode
* @return byte[] containing Base64 characters in their UTF-8 representation.
* @since 1.4
*/
public static byte[] encodeBase64URLSafe(final byte[] binaryData) {
return encodeBase64(binaryData, false, true);
}
/**
* Encodes binary data using a URL-safe variation of the base64 algorithm but does not chunk the output. The
* url-safe variation emits - and _ instead of + and / characters.
* Note: no padding is added.
* @param binaryData
* binary data to encode
* @return String containing Base64 characters
* @since 1.4
*/
public static String encodeBase64URLSafeString(final byte[] binaryData) {
return newString(encodeBase64(binaryData, false, true), Charsets.US_ASCII);
}
/**
* Encodes binary data using the base64 algorithm and chunks the encoded output into 76 character blocks.
*
binary data to encode
* @return Base64 characters chunked in 76 character blocks
*/
public static byte[] encodeBase64Chunked(final byte[] binaryData) {
return encodeBase64(binaryData, true);
}
/**
* 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 true
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(final byte[] binaryData, final boolean isChunked) {
return encodeBase64(binaryData, isChunked, false);
}
/**
* 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 true
this encoder will chunk the base64 output into 76 character blocks
* @param urlSafe
* if true
this encoder will emit - and _ instead of the usual + and / characters.
* Note: no padding is added when encoding using the URL-safe alphabet.
* @return Base64-encoded data.
* @throws IllegalArgumentException
* Thrown when the input array needs an output array bigger than {@link Integer#MAX_VALUE}
* @since 1.4
*/
public static byte[] encodeBase64(final byte[] binaryData, final boolean isChunked, final boolean urlSafe) {
return encodeBase64(binaryData, isChunked, urlSafe, Integer.MAX_VALUE);
}
/**
* 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 true
this encoder will chunk the base64 output into 76 character blocks
* @param urlSafe
* if true
this encoder will emit - and _ instead of the usual + and / characters.
* Note: no padding is added when encoding using the URL-safe alphabet.
* @param maxResultSize
* The maximum result size to accept.
* @return Base64-encoded data.
* @throws IllegalArgumentException
* Thrown when the input array needs an output array bigger than maxResultSize
* @since 1.4
*/
public static byte[] encodeBase64(final byte[] binaryData, final boolean isChunked, final boolean urlSafe, final int maxResultSize) {
if (binaryData == null || binaryData.length == 0) {
return binaryData;
}
// Create this so can use the super-class method
// Also ensures that the same roundings are performed by the ctor and the code
final Base64 b64 = isChunked ? new Base64(urlSafe) : new Base64(0, CHUNK_SEPARATOR, urlSafe);
final long len = b64.getEncodedLength(binaryData);
if (len > maxResultSize) {
throw new IllegalArgumentException(
"Input array too big, the output array would be bigger (" + len + ") than the specified maximum size of " + maxResultSize);
}
return b64.encode(binaryData);
}
/**
* Decodes a Base64 String into octets.
*
* Note: this method seamlessly handles data encoded in URL-safe or normal mode.
*
*
* @param base64String
* String containing Base64 data
* @return Array containing decoded data.
* @since 1.4
*/
public static byte[] decodeBase64(final String base64String) {
return new Base64().decode(base64String);
}
/**
* Decodes Base64 data into octets.
*
* Note: this method seamlessly handles data encoded in URL-safe or normal mode.
*
*
* @param base64Data
* Byte array containing Base64 data
* @return Array containing decoded data.
*/
public static byte[] decodeBase64(final byte[] base64Data) {
return new Base64().decode(base64Data);
}
/**
* Decode base 64 URL.
*
* @param base64String
* @return
*/
public static byte[] decodeBase64URL(final String base64String) {
return new Base64(true).decode(base64String);
}
/**
* Decodes Base64 data into octets.
*
* Note: this method seamlessly handles data encoded in URL-safe or normal mode.
*
*
* @param base64Data
* Byte array containing Base64 data
* @return Array containing decoded data.
*/
public static byte[] decodeBase64URL(final byte[] base64Data) {
return new Base64(true).decode(base64Data);
}
/**
* Decodes 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
* @since 1.4
*/
public static BigInteger decodeInteger(final byte[] pArray) {
return new BigInteger(1, decodeBase64(pArray));
}
/**
* Encodes 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
* @since 1.4
*/
public static byte[] encodeInteger(final BigInteger bigInt) {
if (bigInt == null) {
throw new NullPointerException("encodeInteger called with null parameter");
}
return encodeBase64(toIntegerBytes(bigInt), false);
}
/**
* Decodes a String containing characters in the Base-N alphabet.
*
* @param pArray
* A String containing Base-N character data
* @return a byte array containing binary data
*/
byte[] decode(final String pArray) {
return decode(getBytes(pArray, Charsets.UTF_8));
}
/**
* Decodes a byte[] containing characters in the Base-N alphabet.
*
* @param pArray
* A byte array containing Base-N character data
* @return a byte array containing binary data
*/
byte[] decode(final byte[] pArray) {
if (pArray == null || pArray.length == 0) {
return pArray;
}
final Context context = new Context();
decode(pArray, 0, pArray.length, context);
decode(pArray, 0, EOF, context); // Notify decoder of EOF.
final byte[] result = new byte[context.pos];
readResults(result, 0, result.length, context);
return result;
}
/**
* Encodes a byte[] containing binary data, into a byte[] containing characters in the alphabet.
*
* @param pArray
* a byte array containing binary data
* @return A byte array containing only the base N alphabetic character data
*/
byte[] encode(final byte[] pArray) {
if (pArray == null || pArray.length == 0) {
return pArray;
}
return encode(pArray, 0, pArray.length);
}
/**
* Encodes a byte[] containing binary data, into a byte[] containing
* characters in the alphabet.
*
* @param pArray
* a byte array containing binary data
* @param offset
* initial offset of the subarray.
* @param length
* length of the subarray.
* @return A byte array containing only the base N alphabetic character data
* @since 1.11
*/
byte[] encode(final byte[] pArray, final int offset, final int length) {
if (pArray == null || pArray.length == 0) {
return pArray;
}
final Context context = new Context();
encode(pArray, offset, length, context);
encode(pArray, offset, EOF, context); // Notify encoder of EOF.
final byte[] buf = new byte[context.pos - context.readPos];
readResults(buf, 0, buf.length, context);
return buf;
}
/**
*
* 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, to flush last
* remaining bytes (if not multiple of 3).
*
* Note: no padding is added when encoding using the URL-safe alphabet.
*
* 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/
*
*
* @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.
* @param context
* the context to be used
*/
private void encode(final byte[] in, int inPos, final int inAvail, final Context context) {
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) { // 0-2
case 0: // nothing to do here
break;
case 1: // 8 bits = 6 + 2
// top 6 bits:
buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 2) & MASK_6BITS];
// remaining 2:
buffer[context.pos++] = encodeTable[(context.ibitWorkArea << 4) & MASK_6BITS];
// URL-SAFE skips the padding to further reduce size.
if (encodeTable == STANDARD_ENCODE_TABLE) {
buffer[context.pos++] = pad;
buffer[context.pos++] = pad;
}
break;
case 2: // 16 bits = 6 + 6 + 4
buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 10) & MASK_6BITS];
buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 4) & MASK_6BITS];
buffer[context.pos++] = encodeTable[(context.ibitWorkArea << 2) & MASK_6BITS];
// URL-SAFE skips the padding to further reduce size.
if (encodeTable == STANDARD_ENCODE_TABLE) {
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) {
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 = in[inPos++];
if (b < 0) {
b += 256;
}
context.ibitWorkArea = (context.ibitWorkArea << 8) + b; // BITS_PER_BYTE
if (0 == context.modulus) { // 3 bytes = 24 bits = 4 * 6 bits to extract
buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 18) & MASK_6BITS];
buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 12) & MASK_6BITS];
buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 6) & MASK_6BITS];
buffer[context.pos++] = encodeTable[context.ibitWorkArea & MASK_6BITS];
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;
}
}
}
}
}
/**
*
* 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.
*
*
* 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.
*
*
* 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/
*
*
* @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.
* @param context
* the context to be used
*/
private void decode(final byte[] in, int inPos, final int inAvail, final Context context) {
if (context.eof) {
return;
}
if (inAvail < 0) {
context.eof = true;
}
for (int i = 0; i < inAvail; i++) {
final byte[] buffer = ensureBufferSize(decodeSize, context);
final byte b = in[inPos++];
if (b == pad) {
// We're done.
context.eof = true;
break;
}
if (b >= 0 && b < DECODE_TABLE.length) {
final int result = DECODE_TABLE[b];
if (result >= 0) {
context.modulus = (context.modulus + 1) % BYTES_PER_ENCODED_BLOCK;
context.ibitWorkArea = (context.ibitWorkArea << BITS_PER_ENCODED_BYTE) + result;
if (context.modulus == 0) {
buffer[context.pos++] = (byte) ((context.ibitWorkArea >> 16) & MASK_8BITS);
buffer[context.pos++] = (byte) ((context.ibitWorkArea >> 8) & MASK_8BITS);
buffer[context.pos++] = (byte) (context.ibitWorkArea & MASK_8BITS);
}
}
}
}
// Two forms of EOF as far as base64 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) {
final byte[] buffer = ensureBufferSize(decodeSize, context);
// We have some spare bits remaining
// Output all whole multiples of 8 bits and ignore the rest
switch (context.modulus) {
// case 0 : // impossible, as excluded above
case 1: // 6 bits - ignore entirely
// TODO not currently tested; perhaps it is impossible?
break;
case 2: // 12 bits = 8 + 4
context.ibitWorkArea = context.ibitWorkArea >> 4; // dump the extra 4 bits
buffer[context.pos++] = (byte) ((context.ibitWorkArea) & MASK_8BITS);
break;
case 3: // 18 bits = 8 + 8 + 2
context.ibitWorkArea = context.ibitWorkArea >> 2; // dump 2 bits
buffer[context.pos++] = (byte) ((context.ibitWorkArea >> 8) & MASK_8BITS);
buffer[context.pos++] = (byte) ((context.ibitWorkArea) & MASK_8BITS);
break;
default:
throw new IllegalStateException("Impossible modulus " + context.modulus);
}
}
}
/**
* Returns a byte-array representation of a BigInteger
without sign bit.
*
* @param bigInt
* BigInteger
to be converted
* @return a byte array representation of the BigInteger parameter
*/
private static byte[] toIntegerBytes(final BigInteger bigInt) {
int bitlen = bigInt.bitLength();
// round bitlen
bitlen = ((bitlen + 7) >> 3) << 3;
final 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--;
}
final int startDst = bitlen / 8 - len; // to pad w/ nulls as per spec
final byte[] resizedBytes = new byte[bitlen / 8];
System.arraycopy(bigBytes, startSrc, resizedBytes, startDst, len);
return resizedBytes;
}
/**
* Returns whether or not the octet
is in the Base64 alphabet.
*
* @param octet
* The value to test
* @return true
if the value is defined in the the Base64 alphabet false
otherwise.
*/
private boolean isInAlphabet(final byte octet) {
return octet >= 0 && octet < decodeTable.length && decodeTable[octet] != -1;
}
/**
* Returns the amount of buffered data available for reading.
*
* @param context the context to be used
* @return The amount of buffered data available for reading.
*/
private int available(final Context context) { // package protected for access from I/O streams
return context.buffer != null ? context.pos - context.readPos : 0;
}
/**
* Get the default buffer size. Can be overridden.
*
* @return {@link #DEFAULT_BUFFER_SIZE}
*/
private int getDefaultBufferSize() {
return DEFAULT_BUFFER_SIZE;
}
/**
* Increases our buffer by the {@link #DEFAULT_BUFFER_RESIZE_FACTOR}.
*
* @param context the context to be used
* @return
*/
private byte[] resizeBuffer(final Context context) {
if (context.buffer == null) {
context.buffer = new byte[getDefaultBufferSize()];
context.pos = 0;
context.readPos = 0;
} else {
final byte[] b = new byte[context.buffer.length * DEFAULT_BUFFER_RESIZE_FACTOR];
System.arraycopy(context.buffer, 0, b, 0, context.buffer.length);
context.buffer = b;
}
return context.buffer;
}
/**
* Ensure that the buffer has room for size
bytes.
*
* @param size minimum spare space required
* @param context the context to be used
* @return
*/
private byte[] ensureBufferSize(final int size, final Context context) {
if ((context.buffer == null) || (context.buffer.length < context.pos + size)) {
return resizeBuffer(context);
}
return context.buffer;
}
/**
* 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.
*
* Package protected for access from I/O streams.
*
* @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).
* @param context
* the context to be used
* @return The number of bytes successfully extracted into the provided byte[] array.
*/
private int readResults(final byte[] b, final int bPos, final int bAvail, final Context context) {
if (context.buffer != null) {
final int len = Math.min(available(context), bAvail);
System.arraycopy(context.buffer, context.readPos, b, bPos, len);
context.readPos += len;
if (context.readPos >= context.pos) {
context.buffer = null; // so hasData() will return false, and this method can return -1
}
return len;
}
return context.eof ? EOF : 0;
}
/**
* Checks if a byte value is whitespace or not.
* Whitespace is taken to mean: space, tab, CR, LF
* @param byteToCheck
* the byte to check
* @return true if byte is whitespace, false otherwise
*/
private static boolean isWhiteSpace(final byte byteToCheck) {
switch (byteToCheck) {
case ' ':
case '\n':
case '\r':
case '\t':
return true;
default:
return false;
}
}
/**
* Tests a given byte array to see if it contains any characters within the alphabet or PAD.
*
* Intended for use in checking line-ending arrays
*
* @param arrayOctet
* byte array to test
* @return true
if any byte is a valid character in the alphabet or PAD; false
otherwise
*/
private boolean containsAlphabetOrPad(final byte[] arrayOctet) {
if (arrayOctet == null) {
return false;
}
for (final byte element : arrayOctet) {
if (pad == element || isInAlphabet(element)) {
return true;
}
}
return false;
}
/**
* Calculates the amount of space needed to encode the supplied array.
*
* @param pArray byte[] array which will later be encoded
*
* @return amount of space needed to encoded the supplied array.
* Returns a long since a max-len array will require > Integer.MAX_VALUE
*/
private long getEncodedLength(final byte[] pArray) {
// Calculate non-chunked size - rounded up to allow for padding
// cast to long is needed to avoid possibility of overflow
long len = ((pArray.length + unencodedBlockSize - 1) / unencodedBlockSize) * (long) encodedBlockSize;
if (lineLength > 0) { // We're using chunking
// Round up to nearest multiple
len += ((len + lineLength - 1) / lineLength) * chunkSeparatorLength;
}
return len;
}
/**
* Constructs a new String
by decoding the specified array of bytes using the given charset.
*
* @param bytes
* The bytes to be decoded into characters
* @param charset
* The {@link Charset} to encode the String
* @return A new String
decoded from the specified array of bytes using the given charset,
* or null
if the input byte array was null
.
* @throws NullPointerException
* Thrown if {@link Charsets#UTF_8} is not initialized, which should never happen since it is
* required by the Java platform specification.
*/
private static String newString(final byte[] bytes, final Charset charset) {
return bytes == null ? null : new String(bytes, charset);
}
/**
* Gets the bytes.
*
* @param string
* @param charset
* @return
*/
private static byte[] getBytes(final String string, final Charset charset) {
if (string == null) {
return null;
}
return string.getBytes(charset);
}
/**
* Holds thread context so classes can be thread-safe.
*
* This class is not itself thread-safe; each thread must allocate its own copy.
*
* @since 1.7
*/
static class Context {
/**
* 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.
*/
int ibitWorkArea;
/**
* 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.
*/
long lbitWorkArea;
/**
* Buffer for streaming.
*/
byte[] buffer;
/**
* Position where next character should be written in the buffer.
*/
int pos;
/**
* Position where next character should be read from the buffer.
*/
int readPos;
/**
* Boolean flag to indicate the EOF has been reached. Once EOF has been reached, this object becomes useless,
* and must be thrown away.
*/
boolean eof;
/**
* 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).
*/
int currentLinePos;
/**
* Writes to the buffer only occur after every 3/5 reads when encoding, and every 4/8 reads when decoding. This
* variable helps track that.
*/
int modulus;
/**
* Instantiates a new context.
*/
Context() {
}
/**
* Returns a String useful for debugging (especially within a debugger.)
*
* @return a String useful for debugging.
*/
@SuppressWarnings("boxing") // OK to ignore boxing here
@Override
public String toString() {
return String.format("%s[buffer=%s, currentLinePos=%s, eof=%s, ibitWorkArea=%s, lbitWorkArea=%s, " + "modulus=%s, pos=%s, readPos=%s]",
this.getClass().getSimpleName(), Arrays.toString(buffer), currentLinePos, eof, ibitWorkArea, lbitWorkArea, modulus, pos, readPos);
}
}
}