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Client library used for adding authentication to http messages as required by IdentityX Rest Services
/*
* Copyright Daon.
*
* 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.identityx.auth.util;
import java.nio.charset.Charset;
import java.util.Arrays;
/**
* Abstract superclass for Base-N encoders and decoders.
*
* This class is thread-safe.
*
* @since 1.0.RC, gratefully imported from the Apache Commons-Codec library.
*/
public abstract class BaseNCodec {
public static Charset UTF_8 = Charset.forName("UTF-8");
/**
* 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;
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);
}
}
/**
* EOF
*
* @since 1.7
*/
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
*/
public static final int MIME_CHUNK_SIZE = 76;
/**
* PEM chunk size per RFC 1421 section 4.3.2.4.
*
* The {@value} character limit does not count the trailing CRLF, but counts all other characters, including any
* equal signs.
*
*
* @see RFC 1421 section 4.3.2.4
*/
public static final int PEM_CHUNK_SIZE = 64;
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
protected final byte PAD = PAD_DEFAULT; // 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;
/**
* Note lineLength is rounded down to the nearest multiple of {@link #encodedBlockSize}
* If chunkSeparatorLength is zero, then chunking is disabled.
*
* @param unencodedBlockSize the size of an unencoded block (e.g. Base64 = 3)
* @param encodedBlockSize the size of an encoded block (e.g. Base64 = 4)
* @param lineLength if > 0, use chunking with a length lineLength
* @param chunkSeparatorLength the chunk separator length, if relevant
*/
protected BaseNCodec(final int unencodedBlockSize, final int encodedBlockSize,
final int lineLength, final int chunkSeparatorLength) {
this.unencodedBlockSize = unencodedBlockSize;
this.encodedBlockSize = encodedBlockSize;
final boolean useChunking = lineLength > 0 && chunkSeparatorLength > 0;
this.lineLength = useChunking ? (lineLength / encodedBlockSize) * encodedBlockSize : 0;
this.chunkSeparatorLength = chunkSeparatorLength;
}
/**
* Returns true if this object has buffered data for reading.
*
* @param context the context to be used
* @return true if there is data still available for reading.
*/
boolean hasData(final Context context) { // package protected for access from I/O streams
return context.buffer != null;
}
/**
* 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.
*/
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}
*/
protected int getDefaultBufferSize() {
return DEFAULT_BUFFER_SIZE;
}
/**
* Increases our buffer by the {@link #DEFAULT_BUFFER_RESIZE_FACTOR}.
*
* @param context the context to be used
*/
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
*/
protected 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.
*/
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
*/
protected static boolean isWhiteSpace(final byte byteToCheck) {
switch (byteToCheck) {
case ' ':
case '\n':
case '\r':
case '\t':
return true;
default:
return false;
}
}
/**
* Encodes an Object using the Base-N 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 obj Object to encode
* @return An object (of type byte[]) containing the Base-N encoded data which corresponds to the byte[] supplied.
* if the parameter supplied is not of type byte[]
*/
public Object encode(final Object obj) {
if (!(obj instanceof byte[])) {
throw new IllegalArgumentException("Parameter supplied to Base-N encode is not a byte[]");
}
return encode((byte[]) obj);
}
/**
* Encodes a byte[] containing binary data, into a String containing characters in the Base-N alphabet.
* Uses UTF8 encoding.
*
* @param pArray a byte array containing binary data
* @return A String containing only Base-N character data
*/
public String encodeToString(final byte[] pArray) {
return newStringUtf8(encode(pArray));
}
/**
* Encodes a byte[] containing binary data, into a String containing characters in the appropriate alphabet.
* Uses UTF8 encoding.
*
* @param pArray a byte array containing binary data
* @return String containing only character data in the appropriate alphabet.
*/
public String encodeAsString(final byte[] pArray) {
return newStringUtf8(encode(pArray));
}
/**
* Decodes an Object using the Base-N 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[] or String.
*
* @param obj Object to decode
* @return An object (of type byte[]) containing the binary data which corresponds to the byte[] or String
* supplied.
* if the parameter supplied is not of type byte[]
*/
public Object decode(final Object obj) {
if (obj instanceof byte[]) {
return decode((byte[]) obj);
} else if (obj instanceof String) {
return decode((String) obj);
} else {
throw new IllegalArgumentException("Parameter supplied to Base-N decode is not a byte[] or a String");
}
}
/**
* 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
*/
public byte[] decode(final String pArray) {
return decode(getBytesUtf8(pArray));
}
/**
* 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
*/
public 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 basen alphabetic character data
*/
public byte[] encode(final byte[] pArray) {
if (pArray == null || pArray.length == 0) {
return pArray;
}
final Context context = new Context();
encode(pArray, 0, pArray.length, context);
encode(pArray, 0, EOF, context); // Notify encoder of EOF.
final byte[] buf = new byte[context.pos - context.readPos];
readResults(buf, 0, buf.length, context);
return buf;
}
// package protected for access from I/O streams
abstract void encode(byte[] pArray, int i, int length, Context context);
// package protected for access from I/O streams
abstract void decode(byte[] pArray, int i, int length, Context context);
/**
* Returns whether or not the octet is in the current alphabet.
* Does not allow whitespace or pad.
*
* @param value The value to test
* @return {@code true} if the value is defined in the current alphabet, {@code false} otherwise.
*/
protected abstract boolean isInAlphabet(byte value);
/**
* Tests a given byte array to see if it contains only valid characters within the alphabet.
* The method optionally treats whitespace and pad as valid.
*
* @param arrayOctet byte array to test
* @param allowWSPad if {@code true}, then whitespace and PAD are also allowed
* @return {@code true} if all bytes are valid characters in the alphabet or if the byte array is empty;
* {@code false}, otherwise
*/
public boolean isInAlphabet(final byte[] arrayOctet, final boolean allowWSPad) {
for (int i = 0; i < arrayOctet.length; i++) {
if (!isInAlphabet(arrayOctet[i]) &&
(!allowWSPad || (arrayOctet[i] != PAD) && !isWhiteSpace(arrayOctet[i]))) {
return false;
}
}
return true;
}
/**
* Tests a given String to see if it contains only valid characters within the alphabet.
* The method treats whitespace and PAD as valid.
*
* @param basen String to test
* @return {@code true} if all characters in the String are valid characters in the alphabet or if
* the String is empty; {@code false}, otherwise
* @see #isInAlphabet(byte[], boolean)
*/
public boolean isInAlphabet(final String basen) {
return isInAlphabet(getBytesUtf8(basen), true);
}
/**
* 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 {@code true} if any byte is a valid character in the alphabet or PAD; {@code false} otherwise
*/
protected 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
*/
public 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;
}
/**
* Calls {@link String#getBytes(java.nio.charset.Charset)}
*
* @param string The string to encode (if null, return null).
* @param charset The {@link java.nio.charset.Charset} to encode the {@code String}
* @return the encoded bytes
*/
private static byte[] getBytes(final String string, final Charset charset) {
if (string == null) {
return null;
}
return string.getBytes(charset);
}
/**
* 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 {@code String}
* @return A new String decoded from the specified array of bytes using the given charset,
* or {@code null} if the input byte array was {@code null}.
* @throws NullPointerException Thrown if {@link #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);
}
/**
* Constructs a new String by decoding the specified array of bytes using the UTF-8 charset.
*
* @param bytes The bytes to be decoded into characters
* @return A new String decoded from the specified array of bytes using the UTF-8 charset,
* or {@code null} if the input byte array was {@code null}.
* @throws NullPointerException Thrown if {@link #UTF_8} is not initialized, which should never happen since it is
* required by the Java platform specification.
* @since As of 1.7, throws {@link NullPointerException} instead of UnsupportedEncodingException
*/
public static String newStringUtf8(final byte[] bytes) {
return newString(bytes, UTF_8);
}
/**
* Encodes the given string into a sequence of bytes using the UTF-8 charset, storing the result into a new byte
* array.
*
* @param string the String to encode, may be {@code null}
* @return encoded bytes, or {@code null} if the input string was {@code null}
* @throws NullPointerException Thrown if {@link #UTF_8} is not initialized, which should never happen since it is
* required by the Java platform specification.
* @see Standard charsets
* @since As of 1.7, throws {@link NullPointerException} instead of UnsupportedEncodingException
*/
public static byte[] getBytesUtf8(final String string) {
return getBytes(string, UTF_8);
}
}
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