content: /*
   * Copyright 2001-2004 The Apache Software Foundation.
   *
   * 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.alipay.api.internal.util.codec;
  
  import java.io.UnsupportedEncodingException;
  
  /**
   * Provides Base64 encoding and decoding as defined by RFC 2045.
   *
   * <p>This class implements section <cite>6.8. Base64 Content-Transfer-Encoding</cite>
   * from RFC 2045 <cite>Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies</cite> by Freed and
   * Borenstein.</p>
   *
   * @author Apache Software Foundation
   * @version $Id: Base64.java,v 1.20 2004/05/24 00:21:24 ggregory Exp $
   * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>
   * @since 1.0-dev
   */
  public class Base64 implements BinaryEncoder, BinaryDecoder {
  
      /**
       * Chunk size per RFC 2045 section 6.8.
       *
       * <p>The {@value} character limit does not count the trailing CRLF, but counts
       * all other characters, including any equal signs.</p>
       *
       * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 6.8</a>
       */
      static final int CHUNK_SIZE = 76;
  
      /**
       * Chunk separator per RFC 2045 section 2.1.
       *
       * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 2.1</a>
       */
      static final byte[] CHUNK_SEPARATOR = "\r\n".getBytes();
  
      /**
       * The base length.
       */
      static final int BASELENGTH = 255;
  
      /**
       * Lookup length.
       */
      static final int LOOKUPLENGTH = 64;
  
      /**
       * Used to calculate the number of bits in a byte.
       */
      static final int EIGHTBIT = 8;
  
      /**
       * Used when encoding something which has fewer than 24 bits.
       */
      static final int SIXTEENBIT = 16;
  
      /**
       * Used to determine how many bits data contains.
       */
      static final int TWENTYFOURBITGROUP = 24;
  
      /**
       * Used to get the number of Quadruples.
       */
      static final int FOURBYTE = 4;
  
      /**
       * Used to test the sign of a byte.
       */
      static final int SIGN = -128;
  
      /**
       * Byte used to pad output.
       */
      static final byte PAD = (byte) '=';
  
      // Create arrays to hold the base64 characters and a 
      // lookup for base64 chars
      private static byte[] base64Alphabet       = new byte[BASELENGTH];
      private static byte[] lookUpBase64Alphabet = new byte[LOOKUPLENGTH];
  
      // Populating the lookup and character arrays
      static {
          for (int i = 0; i < BASELENGTH; i++) {
              base64Alphabet[i] = (byte) -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] = (byte) ('A' + i);
          }
  
          for (int i = 26, j = 0; i <= 51; i++, j++) {
              lookUpBase64Alphabet[i] = (byte) ('a' + j);
          }
  
          for (int i = 52, j = 0; i <= 61; i++, j++) {
              lookUpBase64Alphabet[i] = (byte) ('0' + j);
          }
  
          lookUpBase64Alphabet[62] = (byte) '+';
          lookUpBase64Alphabet[63] = (byte) '/';
      }
  
      private static boolean isBase64(byte octect) {
          if (octect == PAD) {
              return true;
          } else if (base64Alphabet[octect] == -1) {
              return false;
          } else {
              return true;
          }
      }
  
      /**
       * Tests a given byte array to see if it contains only valid characters within the Base64 alphabet.
       *
       * @param arrayOctect byte array to test
       * @return true if all bytes are valid characters in the Base64 alphabet or if the byte array is empty; false, otherwise
       */
      public static boolean isArrayByteBase64(byte[] arrayOctect) {
  
          arrayOctect = discardWhitespace(arrayOctect);
  
          int length = arrayOctect.length;
          if (length == 0) {
              // shouldn't a 0 length array be valid base64 data?
              // return false;
              return true;
          }
          for (int i = 0; i < length; i++) {
              if (!isBase64(arrayOctect[i])) {
                  return false;
              }
          }
          return true;
      }
  
      /**
       * Encodes binary data using the base64 algorithm but does not chunk the output.
       *
       * @param binaryData binary data to encode
       * @return Base64 characters
       */
      public static byte[] encodeBase64(byte[] binaryData) {
          return encodeBase64(binaryData, false);
      }
  
      /**
       * Encodes binary data using the base64 algorithm and chunks the encoded output into 76 character blocks
       *
       * @param binaryData binary data to encode
       * @return Base64 characters chunked in 76 character blocks
       */
      public static byte[] encodeBase64Chunked(byte[] binaryData) {
          return encodeBase64(binaryData, true);
      }
  
      /**
       * Decodes an Object using the base64 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[].
       *
       * @param pObject Object to decode
       * @return An object (of type byte[]) containing the binary data which corresponds to the byte[] supplied.
       * @throws DecoderException if the parameter supplied is not of type byte[]
       */
      public Object decode(Object pObject) throws DecoderException {
          if (!(pObject instanceof byte[])) {
              throw new DecoderException("Parameter supplied to Base64 decode is not a byte[]");
          }
          return decode((byte[]) pObject);
      }
  
      /**
       * Decodes a byte[] containing containing characters in the Base64 alphabet.
       *
       * @param pArray A byte array containing Base64 character data
       * @return a byte array containing binary data
       */
      public byte[] decode(byte[] pArray) {
          return decodeBase64(pArray);
      }
  
      /**
       * Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
       *
       * @param binaryData Array containing binary data to encode.
       * @param isChunked  if isChunked is true this encoder will chunk the base64 output into 76 character blocks
       * @return Base64-encoded data.
       */
      public static byte[] encodeBase64(byte[] binaryData, boolean isChunked) {
          int lengthDataBits = binaryData.length * EIGHTBIT;
          int fewerThan24bits = lengthDataBits % TWENTYFOURBITGROUP;
          int numberTriplets = lengthDataBits / TWENTYFOURBITGROUP;
          byte encodedData[] = null;
          int encodedDataLength = 0;
          int nbrChunks = 0;
  
          if (fewerThan24bits != 0) {
              //data not divisible by 24 bit
              encodedDataLength = (numberTriplets + 1) * 4;
          } else {
              // 16 or 8 bit
              encodedDataLength = numberTriplets * 4;
          }
  
          // If the output is to be "chunked" into 76 character sections, 
          // for compliance with RFC 2045 MIME, then it is important to 
          // allow for extra length to account for the separator(s)
          if (isChunked) {
  
              nbrChunks =
                      (CHUNK_SEPARATOR.length == 0 ? 0 : (int) Math.ceil((float) encodedDataLength / CHUNK_SIZE));
              encodedDataLength += nbrChunks * CHUNK_SEPARATOR.length;
          }
  
          encodedData = new byte[encodedDataLength];
  
          byte k = 0, l = 0, b1 = 0, b2 = 0, b3 = 0;
  
          int encodedIndex = 0;
          int dataIndex = 0;
          int i = 0;
          int nextSeparatorIndex = CHUNK_SIZE;
          int chunksSoFar = 0;
  
          //log.debug("number of triplets = " + numberTriplets);
          for (i = 0; i < numberTriplets; i++) {
              dataIndex = i * 3;
              b1 = binaryData[dataIndex];
              b2 = binaryData[dataIndex + 1];
              b3 = binaryData[dataIndex + 2];
  
              //log.debug("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);
  
              encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
              //log.debug( "val2 = " + val2 );
              //log.debug( "k4   = " + (k<<4) );
              //log.debug(  "vak  = " + (val2 | (k<<4)) );
              encodedData[encodedIndex + 1] =
                      lookUpBase64Alphabet[val2 | (k << 4)];
              encodedData[encodedIndex + 2] =
                      lookUpBase64Alphabet[(l << 2) | val3];
              encodedData[encodedIndex + 3] = lookUpBase64Alphabet[b3 & 0x3f];
  
              encodedIndex += 4;
  
              // If we are chunking, let's put a chunk separator down.
              if (isChunked) {
                  // this assumes that CHUNK_SIZE % 4 == 0
                  if (encodedIndex == nextSeparatorIndex) {
                      System.arraycopy(
                              CHUNK_SEPARATOR,
                              0,
                              encodedData,
                              encodedIndex,
                              CHUNK_SEPARATOR.length);
                      chunksSoFar++;
                      nextSeparatorIndex =
                              (CHUNK_SIZE * (chunksSoFar + 1)) +
                                      (chunksSoFar * CHUNK_SEPARATOR.length);
                      encodedIndex += CHUNK_SEPARATOR.length;
                  }
              }
          }
  
          // form integral number of 6-bit groups
          dataIndex = i * 3;
  
          if (fewerThan24bits == EIGHTBIT) {
              b1 = binaryData[dataIndex];
              k = (byte) (b1 & 0x03);
              //log.debug("b1=" + b1);
              //log.debug("b1<<2 = " + (b1>>2) );
              byte val1 =
                      ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0);
              encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
              encodedData[encodedIndex + 1] = lookUpBase64Alphabet[k << 4];
              encodedData[encodedIndex + 2] = PAD;
              encodedData[encodedIndex + 3] = 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 + 1] =
                      lookUpBase64Alphabet[val2 | (k << 4)];
              encodedData[encodedIndex + 2] = lookUpBase64Alphabet[l << 2];
              encodedData[encodedIndex + 3] = PAD;
          }
  
          if (isChunked) {
              // we also add a separator to the end of the final chunk.
              if (chunksSoFar < nbrChunks) {
                  System.arraycopy(
                          CHUNK_SEPARATOR,
                          0,
                          encodedData,
                          encodedDataLength - CHUNK_SEPARATOR.length,
                          CHUNK_SEPARATOR.length);
              }
          }
  
          return encodedData;
      }
  
      /**
       * Decodes Base64 data into octects
       *
       * @param base64Data Byte array containing Base64 data
       * @return Array containing decoded data.
       */
      public static byte[] decodeBase64(byte[] base64Data) {
          // RFC 2045 requires that we discard ALL non-Base64 characters
          base64Data = discardNonBase64(base64Data);
  
          // handle the edge case, so we don't have to worry about it later
          if (base64Data.length == 0) {
              return new byte[0];
          }
  
          int numberQuadruple = base64Data.length / FOURBYTE;
          byte decodedData[] = null;
          byte b1 = 0, b2 = 0, b3 = 0, b4 = 0, marker0 = 0, marker1 = 0;
  
          // Throw away anything not in base64Data
  
          int encodedIndex = 0;
          int dataIndex = 0;
          {
              // this sizes the output array properly - rlw
              int lastData = base64Data.length;
              // ignore the '=' padding
              while (base64Data[lastData - 1] == PAD) {
                  if (--lastData == 0) {
                      return new byte[0];
                  }
              }
              decodedData = new byte[lastData - numberQuadruple];
          }
  
          for (int i = 0; i < numberQuadruple; i++) {
              dataIndex = i * 4;
              marker0 = base64Data[dataIndex + 2];
              marker1 = base64Data[dataIndex + 3];
  
              b1 = base64Alphabet[base64Data[dataIndex]];
              b2 = base64Alphabet[base64Data[dataIndex + 1]];
  
              if (marker0 != PAD && marker1 != PAD) {
                  //No PAD e.g 3cQl
                  b3 = base64Alphabet[marker0];
                  b4 = base64Alphabet[marker1];
  
                  decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
                  decodedData[encodedIndex + 1] =
                          (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));
                  decodedData[encodedIndex + 2] = (byte) (b3 << 6 | b4);
              } else if (marker0 == PAD) {
                  //Two PAD e.g. 3c[Pad][Pad]
                  decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
              } else if (marker1 == PAD) {
                  //One PAD e.g. 3cQ[Pad]
                  b3 = base64Alphabet[marker0];
  
                  decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
                  decodedData[encodedIndex + 1] =
                          (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));
              }
              encodedIndex += 3;
          }
          return decodedData;
      }
  
      /**
       * Discards any whitespace from a base-64 encoded block.
       *
       * @param data The base-64 encoded data to discard the whitespace from.
       * @return The data, less whitespace (see RFC 2045).
       */
      static byte[] discardWhitespace(byte[] data) {
          byte groomedData[] = new byte[data.length];
          int bytesCopied = 0;
  
          for (int i = 0; i < data.length; i++) {
              switch (data[i]) {
                  case (byte) ' ':
                  case (byte) '\n':
                  case (byte) '\r':
                  case (byte) '\t':
                      break;
                  default:
                      groomedData[bytesCopied++] = data[i];
              }
          }
  
          byte packedData[] = new byte[bytesCopied];
  
          System.arraycopy(groomedData, 0, packedData, 0, bytesCopied);
  
          return packedData;
      }
  
      /**
       * Discards any characters outside of the base64 alphabet, per the requirements on page 25 of RFC 2045 - "Any characters outside of the
       * base64 alphabet are to be ignored in base64 encoded data."
       *
       * @param data The base-64 encoded data to groom
       * @return The data, less non-base64 characters (see RFC 2045).
       */
      static byte[] discardNonBase64(byte[] data) {
          byte groomedData[] = new byte[data.length];
          int bytesCopied = 0;
  
          for (int i = 0; i < data.length; i++) {
              if (isBase64(data[i])) {
                  groomedData[bytesCopied++] = data[i];
              }
          }
  
          byte packedData[] = new byte[bytesCopied];
  
          System.arraycopy(groomedData, 0, packedData, 0, bytesCopied);
  
          return packedData;
      }
  
      // Implementation of the Encoder Interface
  
      /**
       * Encodes an Object using the base64 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 pObject Object to encode
       * @return An object (of type byte[]) containing the base64 encoded data which corresponds to the byte[] supplied.
       * @throws EncoderException if the parameter supplied is not of type byte[]
       */
      public Object encode(Object pObject) throws EncoderException {
          if (!(pObject instanceof byte[])) {
              throw new EncoderException(
                      "Parameter supplied to Base64 encode is not a byte[]");
          }
          return encode((byte[]) pObject);
      }
  
      /**
       * Encodes a byte[] containing binary data, into a byte[] containing characters in the Base64 alphabet.
       *
       * @param pArray a byte array containing binary data
       * @return A byte array containing only Base64 character data
       */
      public byte[] encode(byte[] pArray) {
          return encodeBase64(pArray, false);
      }
  
      public static String encodeBase64String(byte[] input) {
          try {
              return new String(encodeBase64(input), "utf-8");
          } catch (UnsupportedEncodingException e) {
              throw new RuntimeException(e.getMessage(), e);
          }
      }
  
      public static byte[] decodeBase64String(String base64String) {
          try {
              return Base64.decodeBase64(base64String.getBytes("utf-8"));
          } catch (UnsupportedEncodingException e) {
              throw new RuntimeException(e.getMessage(), e);
          }
      }
  }
  