New file |
| | |
| | | package com.hx.util.rsa; |
| | | |
| | | public final class Base64 { |
| | | |
| | | static private final int BASELENGTH = 128; |
| | | static private final int LOOKUPLENGTH = 64; |
| | | static private final int TWENTYFOURBITGROUP = 24; |
| | | static private final int EIGHTBIT = 8; |
| | | static private final int SIXTEENBIT = 16; |
| | | static private final int FOURBYTE = 4; |
| | | static private final int SIGN = -128; |
| | | static private final char PAD = '='; |
| | | static private final boolean fDebug = false; |
| | | static final private byte[] base64Alphabet = new byte[BASELENGTH]; |
| | | static final private char[] lookUpBase64Alphabet = new char[LOOKUPLENGTH]; |
| | | |
| | | static { |
| | | for (int i = 0; i < BASELENGTH; ++i) { |
| | | base64Alphabet[i] = -1; |
| | | } |
| | | for (int i = 'Z'; i >= 'A'; i--) { |
| | | base64Alphabet[i] = (byte) (i - 'A'); |
| | | } |
| | | for (int i = 'z'; i >= 'a'; i--) { |
| | | base64Alphabet[i] = (byte) (i - 'a' + 26); |
| | | } |
| | | |
| | | for (int i = '9'; i >= '0'; i--) { |
| | | base64Alphabet[i] = (byte) (i - '0' + 52); |
| | | } |
| | | |
| | | base64Alphabet['+'] = 62; |
| | | base64Alphabet['/'] = 63; |
| | | |
| | | for (int i = 0; i <= 25; i++) { |
| | | lookUpBase64Alphabet[i] = (char) ('A' + i); |
| | | } |
| | | |
| | | for (int i = 26, j = 0; i <= 51; i++, j++) { |
| | | lookUpBase64Alphabet[i] = (char) ('a' + j); |
| | | } |
| | | |
| | | for (int i = 52, j = 0; i <= 61; i++, j++) { |
| | | lookUpBase64Alphabet[i] = (char) ('0' + j); |
| | | } |
| | | lookUpBase64Alphabet[62] = (char) '+'; |
| | | lookUpBase64Alphabet[63] = (char) '/'; |
| | | |
| | | } |
| | | |
| | | private static boolean isWhiteSpace(char octect) { |
| | | return (octect == 0x20 || octect == 0xd || octect == 0xa || octect == 0x9); |
| | | } |
| | | |
| | | private static boolean isPad(char octect) { |
| | | return (octect == PAD); |
| | | } |
| | | |
| | | private static boolean isData(char octect) { |
| | | return (octect < BASELENGTH && base64Alphabet[octect] != -1); |
| | | } |
| | | |
| | | /** |
| | | * Encodes hex octects into Base64 |
| | | * |
| | | * @param binaryData Array containing binaryData |
| | | * @return Encoded Base64 array |
| | | */ |
| | | public static String encode(byte[] binaryData) { |
| | | |
| | | if (binaryData == null) { |
| | | return null; |
| | | } |
| | | |
| | | int lengthDataBits = binaryData.length * EIGHTBIT; |
| | | if (lengthDataBits == 0) { |
| | | return ""; |
| | | } |
| | | |
| | | int fewerThan24bits = lengthDataBits % TWENTYFOURBITGROUP; |
| | | int numberTriplets = lengthDataBits / TWENTYFOURBITGROUP; |
| | | int numberQuartet = fewerThan24bits != 0 ? numberTriplets + 1 : numberTriplets; |
| | | char encodedData[] = null; |
| | | |
| | | encodedData = new char[numberQuartet * 4]; |
| | | |
| | | byte k = 0, l = 0, b1 = 0, b2 = 0, b3 = 0; |
| | | |
| | | int encodedIndex = 0; |
| | | int dataIndex = 0; |
| | | if (fDebug) { |
| | | System.out.println("number of triplets = " + numberTriplets); |
| | | } |
| | | |
| | | for (int i = 0; i < numberTriplets; i++) { |
| | | b1 = binaryData[dataIndex++]; |
| | | b2 = binaryData[dataIndex++]; |
| | | b3 = binaryData[dataIndex++]; |
| | | |
| | | if (fDebug) { |
| | | System.out.println("b1= " + b1 + ", b2= " + b2 + ", b3= " + b3); |
| | | } |
| | | |
| | | l = (byte) (b2 & 0x0f); |
| | | k = (byte) (b1 & 0x03); |
| | | |
| | | byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0); |
| | | byte val2 = ((b2 & SIGN) == 0) ? (byte) (b2 >> 4) : (byte) ((b2) >> 4 ^ 0xf0); |
| | | byte val3 = ((b3 & SIGN) == 0) ? (byte) (b3 >> 6) : (byte) ((b3) >> 6 ^ 0xfc); |
| | | |
| | | if (fDebug) { |
| | | System.out.println("val2 = " + val2); |
| | | System.out.println("k4 = " + (k << 4)); |
| | | System.out.println("vak = " + (val2 | (k << 4))); |
| | | } |
| | | |
| | | encodedData[encodedIndex++] = lookUpBase64Alphabet[val1]; |
| | | encodedData[encodedIndex++] = lookUpBase64Alphabet[val2 | (k << 4)]; |
| | | encodedData[encodedIndex++] = lookUpBase64Alphabet[(l << 2) | val3]; |
| | | encodedData[encodedIndex++] = lookUpBase64Alphabet[b3 & 0x3f]; |
| | | } |
| | | |
| | | // form integral number of 6-bit groups |
| | | if (fewerThan24bits == EIGHTBIT) { |
| | | b1 = binaryData[dataIndex]; |
| | | k = (byte) (b1 & 0x03); |
| | | if (fDebug) { |
| | | System.out.println("b1=" + b1); |
| | | System.out.println("b1<<2 = " + (b1 >> 2)); |
| | | } |
| | | byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0); |
| | | encodedData[encodedIndex++] = lookUpBase64Alphabet[val1]; |
| | | encodedData[encodedIndex++] = lookUpBase64Alphabet[k << 4]; |
| | | encodedData[encodedIndex++] = PAD; |
| | | encodedData[encodedIndex++] = PAD; |
| | | } else if (fewerThan24bits == SIXTEENBIT) { |
| | | b1 = binaryData[dataIndex]; |
| | | b2 = binaryData[dataIndex + 1]; |
| | | l = (byte) (b2 & 0x0f); |
| | | k = (byte) (b1 & 0x03); |
| | | |
| | | byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0); |
| | | byte val2 = ((b2 & SIGN) == 0) ? (byte) (b2 >> 4) : (byte) ((b2) >> 4 ^ 0xf0); |
| | | |
| | | encodedData[encodedIndex++] = lookUpBase64Alphabet[val1]; |
| | | encodedData[encodedIndex++] = lookUpBase64Alphabet[val2 | (k << 4)]; |
| | | encodedData[encodedIndex++] = lookUpBase64Alphabet[l << 2]; |
| | | encodedData[encodedIndex++] = PAD; |
| | | } |
| | | |
| | | return new String(encodedData); |
| | | } |
| | | |
| | | /** |
| | | * Decodes Base64 data into octects |
| | | * |
| | | * @param encoded string containing Base64 data |
| | | * @return Array containind decoded data. |
| | | */ |
| | | public static byte[] decode(String encoded) { |
| | | |
| | | if (encoded == null) { |
| | | return null; |
| | | } |
| | | |
| | | char[] base64Data = encoded.toCharArray(); |
| | | // remove white spaces |
| | | int len = removeWhiteSpace(base64Data); |
| | | |
| | | if (len % FOURBYTE != 0) { |
| | | return null;//should be divisible by four |
| | | } |
| | | |
| | | int numberQuadruple = (len / FOURBYTE); |
| | | |
| | | if (numberQuadruple == 0) { |
| | | return new byte[0]; |
| | | } |
| | | |
| | | byte decodedData[] = null; |
| | | byte b1 = 0, b2 = 0, b3 = 0, b4 = 0; |
| | | char d1 = 0, d2 = 0, d3 = 0, d4 = 0; |
| | | |
| | | int i = 0; |
| | | int encodedIndex = 0; |
| | | int dataIndex = 0; |
| | | decodedData = new byte[(numberQuadruple) * 3]; |
| | | |
| | | for (; i < numberQuadruple - 1; i++) { |
| | | |
| | | if (!isData((d1 = base64Data[dataIndex++])) || !isData((d2 = base64Data[dataIndex++])) |
| | | || !isData((d3 = base64Data[dataIndex++])) |
| | | || !isData((d4 = base64Data[dataIndex++]))) { |
| | | return null; |
| | | }//if found "no data" just return null |
| | | |
| | | b1 = base64Alphabet[d1]; |
| | | b2 = base64Alphabet[d2]; |
| | | b3 = base64Alphabet[d3]; |
| | | b4 = base64Alphabet[d4]; |
| | | |
| | | decodedData[encodedIndex++] = (byte) (b1 << 2 | b2 >> 4); |
| | | decodedData[encodedIndex++] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf)); |
| | | decodedData[encodedIndex++] = (byte) (b3 << 6 | b4); |
| | | } |
| | | |
| | | if (!isData((d1 = base64Data[dataIndex++])) || !isData((d2 = base64Data[dataIndex++]))) { |
| | | return null;//if found "no data" just return null |
| | | } |
| | | |
| | | b1 = base64Alphabet[d1]; |
| | | b2 = base64Alphabet[d2]; |
| | | |
| | | d3 = base64Data[dataIndex++]; |
| | | d4 = base64Data[dataIndex++]; |
| | | if (!isData((d3)) || !isData((d4))) {//Check if they are PAD characters |
| | | if (isPad(d3) && isPad(d4)) { |
| | | if ((b2 & 0xf) != 0)//last 4 bits should be zero |
| | | { |
| | | return null; |
| | | } |
| | | byte[] tmp = new byte[i * 3 + 1]; |
| | | System.arraycopy(decodedData, 0, tmp, 0, i * 3); |
| | | tmp[encodedIndex] = (byte) (b1 << 2 | b2 >> 4); |
| | | return tmp; |
| | | } else if (!isPad(d3) && isPad(d4)) { |
| | | b3 = base64Alphabet[d3]; |
| | | if ((b3 & 0x3) != 0)//last 2 bits should be zero |
| | | { |
| | | return null; |
| | | } |
| | | byte[] tmp = new byte[i * 3 + 2]; |
| | | System.arraycopy(decodedData, 0, tmp, 0, i * 3); |
| | | tmp[encodedIndex++] = (byte) (b1 << 2 | b2 >> 4); |
| | | tmp[encodedIndex] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf)); |
| | | return tmp; |
| | | } else { |
| | | return null; |
| | | } |
| | | } else { //No PAD e.g 3cQl |
| | | b3 = base64Alphabet[d3]; |
| | | b4 = base64Alphabet[d4]; |
| | | decodedData[encodedIndex++] = (byte) (b1 << 2 | b2 >> 4); |
| | | decodedData[encodedIndex++] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf)); |
| | | decodedData[encodedIndex++] = (byte) (b3 << 6 | b4); |
| | | |
| | | } |
| | | |
| | | return decodedData; |
| | | } |
| | | |
| | | /** |
| | | * remove WhiteSpace from MIME containing encoded Base64 data. |
| | | * |
| | | * @param data the byte array of base64 data (with WS) |
| | | * @return the new length |
| | | */ |
| | | private static int removeWhiteSpace(char[] data) { |
| | | if (data == null) { |
| | | return 0; |
| | | } |
| | | |
| | | // count characters that's not whitespace |
| | | int newSize = 0; |
| | | int len = data.length; |
| | | for (int i = 0; i < len; i++) { |
| | | if (!isWhiteSpace(data[i])) { |
| | | data[newSize++] = data[i]; |
| | | } |
| | | } |
| | | return newSize; |
| | | } |
| | | } |