package org.bouncycastle.util.encoders;

import java.io.IOException;
import java.io.OutputStream;

A streaming Hex encoder.
/** * A streaming Hex encoder. */
public class HexEncoder implements Encoder { protected final byte[] encodingTable = { (byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4', (byte)'5', (byte)'6', (byte)'7', (byte)'8', (byte)'9', (byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e', (byte)'f' }; /* * set up the decoding table. */ protected final byte[] decodingTable = new byte[128]; protected void initialiseDecodingTable() { for (int i = 0; i < decodingTable.length; i++) { decodingTable[i] = (byte)0xff; } for (int i = 0; i < encodingTable.length; i++) { decodingTable[encodingTable[i]] = (byte)i; } decodingTable['A'] = decodingTable['a']; decodingTable['B'] = decodingTable['b']; decodingTable['C'] = decodingTable['c']; decodingTable['D'] = decodingTable['d']; decodingTable['E'] = decodingTable['e']; decodingTable['F'] = decodingTable['f']; } public HexEncoder() { initialiseDecodingTable(); }
encode the input data producing a Hex output stream.
Returns:the number of bytes produced.
/** * encode the input data producing a Hex output stream. * * @return the number of bytes produced. */
public int encode( byte[] data, int off, int length, OutputStream out) throws IOException { for (int i = off; i < (off + length); i++) { int v = data[i] & 0xff; out.write(encodingTable[(v >>> 4)]); out.write(encodingTable[v & 0xf]); } return length * 2; } private static boolean ignore( char c) { return c == '\n' || c =='\r' || c == '\t' || c == ' '; }
decode the Hex encoded byte data writing it to the given output stream, whitespace characters will be ignored.
Returns:the number of bytes produced.
/** * decode the Hex encoded byte data writing it to the given output stream, * whitespace characters will be ignored. * * @return the number of bytes produced. */
public int decode( byte[] data, int off, int length, OutputStream out) throws IOException { byte b1, b2; int outLen = 0; int end = off + length; while (end > off) { if (!ignore((char)data[end - 1])) { break; } end--; } int i = off; while (i < end) { while (i < end && ignore((char)data[i])) { i++; } b1 = decodingTable[data[i++]]; while (i < end && ignore((char)data[i])) { i++; } b2 = decodingTable[data[i++]]; if ((b1 | b2) < 0) { throw new IOException("invalid characters encountered in Hex data"); } out.write((b1 << 4) | b2); outLen++; } return outLen; }
decode the Hex encoded String data writing it to the given output stream, whitespace characters will be ignored.
Returns:the number of bytes produced.
/** * decode the Hex encoded String data writing it to the given output stream, * whitespace characters will be ignored. * * @return the number of bytes produced. */
public int decode( String data, OutputStream out) throws IOException { byte b1, b2; int length = 0; int end = data.length(); while (end > 0) { if (!ignore(data.charAt(end - 1))) { break; } end--; } int i = 0; while (i < end) { while (i < end && ignore(data.charAt(i))) { i++; } b1 = decodingTable[data.charAt(i++)]; while (i < end && ignore(data.charAt(i))) { i++; } b2 = decodingTable[data.charAt(i++)]; if ((b1 | b2) < 0) { throw new IOException("invalid characters encountered in Hex string"); } out.write((b1 << 4) | b2); length++; } return length; } }