From 0c8c9ad976879f7c90f9915a60845ccb0cdb337d Mon Sep 17 00:00:00 2001 From: manuel Date: Wed, 25 Dec 2013 13:25:16 +0100 Subject: initial commit --- .../apache/commons/codec/binary/BaseNCodec.java | 500 +++++++++++++++++++++ 1 file changed, 500 insertions(+) create mode 100644 java/client/src/org/apache/commons/codec/binary/BaseNCodec.java (limited to 'java/client/src/org/apache/commons/codec/binary/BaseNCodec.java') diff --git a/java/client/src/org/apache/commons/codec/binary/BaseNCodec.java b/java/client/src/org/apache/commons/codec/binary/BaseNCodec.java new file mode 100644 index 0000000..2edd754 --- /dev/null +++ b/java/client/src/org/apache/commons/codec/binary/BaseNCodec.java @@ -0,0 +1,500 @@ +/* + * 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.BinaryDecoder; +import org.apache.commons.codec.BinaryEncoder; +import org.apache.commons.codec.DecoderException; +import org.apache.commons.codec.EncoderException; + +/** + * Abstract superclass for Base-N encoders and decoders. + * + *

+ * This class is thread-safe. + *

+ * + * @version $Id$ + */ +public abstract class BaseNCodec implements BinaryEncoder, BinaryDecoder { + + /** + * 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(), 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. + * @throws EncoderException + * if the parameter supplied is not of type byte[] + */ + @Override + public Object encode(final Object obj) throws EncoderException { + if (!(obj instanceof byte[])) { + throw new EncoderException("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 StringUtils.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 StringUtils.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. + * @throws DecoderException + * if the parameter supplied is not of type byte[] + */ + @Override + public Object decode(final Object obj) throws DecoderException { + if (obj instanceof byte[]) { + return decode((byte[]) obj); + } else if (obj instanceof String) { + return decode((String) obj); + } else { + throw new DecoderException("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(StringUtils.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 + */ + @Override + 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 + */ + @Override + 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(StringUtils.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; + } +} -- cgit v1.2.3