| // |
| // NOTE: The following source code is heavily derived from the |
| // iHarder.net public domain Base64 library. See the original at |
| // http://iharder.sourceforge.net/current/java/base64/ |
| // |
| |
| package org.eclipse.jgit.util; |
| |
| import static org.eclipse.jgit.lib.Constants.CHARSET; |
| |
| import java.text.MessageFormat; |
| import java.util.Arrays; |
| |
| import org.eclipse.jgit.internal.JGitText; |
| |
| /** |
| * Encodes and decodes to and from Base64 notation. |
| * <p> |
| * I am placing this code in the Public Domain. Do with it as you will. This |
| * software comes with no guarantees or warranties but with plenty of |
| * well-wishing instead! Please visit |
| * <a href="http://iharder.net/base64">http://iharder.net/base64</a> |
| * periodically to check for updates or to contribute improvements. |
| * </p> |
| * |
| * @author Robert Harder |
| * @author rob@iharder.net |
| */ |
| public class Base64 { |
| /** The equals sign (=) as a byte. */ |
| private final static byte EQUALS_SIGN = (byte) '='; |
| |
| /** Indicates equals sign in encoding. */ |
| private final static byte EQUALS_SIGN_DEC = -1; |
| |
| /** Indicates white space in encoding. */ |
| private final static byte WHITE_SPACE_DEC = -2; |
| |
| /** Indicates an invalid byte during decoding. */ |
| private final static byte INVALID_DEC = -3; |
| |
| /** The 64 valid Base64 values. */ |
| private final static byte[] ENC; |
| |
| /** |
| * Translates a Base64 value to either its 6-bit reconstruction value or a |
| * negative number indicating some other meaning. The table is only 7 bits |
| * wide, as the 8th bit is discarded during decoding. |
| */ |
| private final static byte[] DEC; |
| |
| static { |
| ENC = ("ABCDEFGHIJKLMNOPQRSTUVWXYZ" // //$NON-NLS-1$ |
| + "abcdefghijklmnopqrstuvwxyz" // //$NON-NLS-1$ |
| + "0123456789" // //$NON-NLS-1$ |
| + "+/" // //$NON-NLS-1$ |
| ).getBytes(CHARSET); |
| |
| DEC = new byte[128]; |
| Arrays.fill(DEC, INVALID_DEC); |
| |
| for (int i = 0; i < 64; i++) |
| DEC[ENC[i]] = (byte) i; |
| DEC[EQUALS_SIGN] = EQUALS_SIGN_DEC; |
| |
| DEC['\t'] = WHITE_SPACE_DEC; |
| DEC['\n'] = WHITE_SPACE_DEC; |
| DEC['\r'] = WHITE_SPACE_DEC; |
| DEC[' '] = WHITE_SPACE_DEC; |
| } |
| |
| /** Defeats instantiation. */ |
| private Base64() { |
| // Suppress empty block warning. |
| } |
| |
| /** |
| * Encodes up to three bytes of the array <var>source</var> and writes the |
| * resulting four Base64 bytes to <var>destination</var>. The source and |
| * destination arrays can be manipulated anywhere along their length by |
| * specifying <var>srcOffset</var> and <var>destOffset</var>. This method |
| * does not check to make sure your arrays are large enough to accommodate |
| * <var>srcOffset</var> + 3 for the <var>source</var> array or |
| * <var>destOffset</var> + 4 for the <var>destination</var> array. The |
| * actual number of significant bytes in your array is given by |
| * <var>numSigBytes</var>. |
| * |
| * @param source |
| * the array to convert |
| * @param srcOffset |
| * the index where conversion begins |
| * @param numSigBytes |
| * the number of significant bytes in your array |
| * @param destination |
| * the array to hold the conversion |
| * @param destOffset |
| * the index where output will be put |
| */ |
| private static void encode3to4(byte[] source, int srcOffset, |
| int numSigBytes, byte[] destination, int destOffset) { |
| // We have to shift left 24 in order to flush out the 1's that appear |
| // when Java treats a value as negative that is cast from a byte. |
| |
| int inBuff = 0; |
| switch (numSigBytes) { |
| case 3: |
| inBuff |= (source[srcOffset + 2] << 24) >>> 24; |
| //$FALL-THROUGH$ |
| |
| case 2: |
| inBuff |= (source[srcOffset + 1] << 24) >>> 16; |
| //$FALL-THROUGH$ |
| |
| case 1: |
| inBuff |= (source[srcOffset] << 24) >>> 8; |
| } |
| |
| switch (numSigBytes) { |
| case 3: |
| destination[destOffset] = ENC[(inBuff >>> 18)]; |
| destination[destOffset + 1] = ENC[(inBuff >>> 12) & 0x3f]; |
| destination[destOffset + 2] = ENC[(inBuff >>> 6) & 0x3f]; |
| destination[destOffset + 3] = ENC[(inBuff) & 0x3f]; |
| break; |
| |
| case 2: |
| destination[destOffset] = ENC[(inBuff >>> 18)]; |
| destination[destOffset + 1] = ENC[(inBuff >>> 12) & 0x3f]; |
| destination[destOffset + 2] = ENC[(inBuff >>> 6) & 0x3f]; |
| destination[destOffset + 3] = EQUALS_SIGN; |
| break; |
| |
| case 1: |
| destination[destOffset] = ENC[(inBuff >>> 18)]; |
| destination[destOffset + 1] = ENC[(inBuff >>> 12) & 0x3f]; |
| destination[destOffset + 2] = EQUALS_SIGN; |
| destination[destOffset + 3] = EQUALS_SIGN; |
| break; |
| } |
| } |
| |
| /** |
| * Encodes a byte array into Base64 notation. |
| * |
| * @param source |
| * The data to convert |
| * @return encoded base64 representation of source. |
| */ |
| public static String encodeBytes(byte[] source) { |
| return encodeBytes(source, 0, source.length); |
| } |
| |
| /** |
| * Encodes a byte array into Base64 notation. |
| * |
| * @param source |
| * The data to convert |
| * @param off |
| * Offset in array where conversion should begin |
| * @param len |
| * Length of data to convert |
| * @return encoded base64 representation of source. |
| */ |
| public static String encodeBytes(byte[] source, int off, int len) { |
| final int len43 = len * 4 / 3; |
| |
| byte[] outBuff = new byte[len43 + ((len % 3) > 0 ? 4 : 0)]; |
| int d = 0; |
| int e = 0; |
| int len2 = len - 2; |
| |
| for (; d < len2; d += 3, e += 4) |
| encode3to4(source, d + off, 3, outBuff, e); |
| |
| if (d < len) { |
| encode3to4(source, d + off, len - d, outBuff, e); |
| e += 4; |
| } |
| |
| return new String(outBuff, 0, e, CHARSET); |
| } |
| |
| /** |
| * Decodes four bytes from array <var>source</var> and writes the resulting |
| * bytes (up to three of them) to <var>destination</var>. The source and |
| * destination arrays can be manipulated anywhere along their length by |
| * specifying <var>srcOffset</var> and <var>destOffset</var>. This method |
| * does not check to make sure your arrays are large enough to accommodate |
| * <var>srcOffset</var> + 4 for the <var>source</var> array or |
| * <var>destOffset</var> + 3 for the <var>destination</var> array. This |
| * method returns the actual number of bytes that were converted from the |
| * Base64 encoding. |
| * |
| * @param source |
| * the array to convert |
| * @param srcOffset |
| * the index where conversion begins |
| * @param destination |
| * the array to hold the conversion |
| * @param destOffset |
| * the index where output will be put |
| * @return the number of decoded bytes converted |
| */ |
| private static int decode4to3(byte[] source, int srcOffset, |
| byte[] destination, int destOffset) { |
| // Example: Dk== |
| if (source[srcOffset + 2] == EQUALS_SIGN) { |
| int outBuff = ((DEC[source[srcOffset]] & 0xFF) << 18) |
| | ((DEC[source[srcOffset + 1]] & 0xFF) << 12); |
| destination[destOffset] = (byte) (outBuff >>> 16); |
| return 1; |
| } |
| |
| // Example: DkL= |
| else if (source[srcOffset + 3] == EQUALS_SIGN) { |
| int outBuff = ((DEC[source[srcOffset]] & 0xFF) << 18) |
| | ((DEC[source[srcOffset + 1]] & 0xFF) << 12) |
| | ((DEC[source[srcOffset + 2]] & 0xFF) << 6); |
| destination[destOffset] = (byte) (outBuff >>> 16); |
| destination[destOffset + 1] = (byte) (outBuff >>> 8); |
| return 2; |
| } |
| |
| // Example: DkLE |
| else { |
| int outBuff = ((DEC[source[srcOffset]] & 0xFF) << 18) |
| | ((DEC[source[srcOffset + 1]] & 0xFF) << 12) |
| | ((DEC[source[srcOffset + 2]] & 0xFF) << 6) |
| | ((DEC[source[srcOffset + 3]] & 0xFF)); |
| |
| destination[destOffset] = (byte) (outBuff >> 16); |
| destination[destOffset + 1] = (byte) (outBuff >> 8); |
| destination[destOffset + 2] = (byte) (outBuff); |
| |
| return 3; |
| } |
| } |
| |
| /** |
| * Low-level decoding ASCII characters from a byte array. |
| * |
| * @param source |
| * The Base64 encoded data |
| * @param off |
| * The offset of where to begin decoding |
| * @param len |
| * The length of characters to decode |
| * @return decoded data |
| * @throws java.lang.IllegalArgumentException |
| * the input is not a valid Base64 sequence. |
| */ |
| public static byte[] decode(byte[] source, int off, int len) { |
| byte[] outBuff = new byte[len * 3 / 4]; // Upper limit on size of output |
| int outBuffPosn = 0; |
| |
| byte[] b4 = new byte[4]; |
| int b4Posn = 0; |
| |
| for (int i = off; i < off + len; i++) { |
| byte sbiCrop = (byte) (source[i] & 0x7f); |
| byte sbiDecode = DEC[sbiCrop]; |
| |
| if (EQUALS_SIGN_DEC <= sbiDecode) { |
| b4[b4Posn++] = sbiCrop; |
| if (b4Posn > 3) { |
| outBuffPosn += decode4to3(b4, 0, outBuff, outBuffPosn); |
| b4Posn = 0; |
| |
| // If that was the equals sign, break out of 'for' loop |
| if (sbiCrop == EQUALS_SIGN) |
| break; |
| } |
| |
| } else if (sbiDecode != WHITE_SPACE_DEC) |
| throw new IllegalArgumentException(MessageFormat.format( |
| JGitText.get().badBase64InputCharacterAt, |
| Integer.valueOf(i), Integer.valueOf(source[i] & 0xff))); |
| } |
| |
| if (outBuff.length == outBuffPosn) |
| return outBuff; |
| |
| byte[] out = new byte[outBuffPosn]; |
| System.arraycopy(outBuff, 0, out, 0, outBuffPosn); |
| return out; |
| } |
| |
| /** |
| * Decodes data from Base64 notation. |
| * |
| * @param s |
| * the string to decode |
| * @return the decoded data |
| */ |
| public static byte[] decode(String s) { |
| byte[] bytes = s.getBytes(CHARSET); |
| return decode(bytes, 0, bytes.length); |
| } |
| } |