Package com.eatle.utils

Source Code of com.eatle.utils.Base64

package com.eatle.utils;

import java.util.Arrays;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.UnsupportedEncodingException;

/**
* @corpor ��˾����Ѷ�ſ�
* @author ���ߣ�̷����
* @explain ���壺Base64���롢������
* @version ���ڣ�2012-11-19 ����10:41:14
*/
public class Base64
{

  private static final char[] CHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
      .toCharArray();

  private static final int[] INV = new int[256];

  static
  {
    Arrays.fill(INV, -1);
    for (int i = 0, iS = CHARS.length; i < iS; i++)
    {
      INV[CHARS[i]] = i;
    }
    INV['='] = 0;
  }

  /**
   * Returns Base64 characters, a clone of used array.
   */
  public static char[] getAlphabet()
  {
    return CHARS.clone();
  }

  // ---------------------------------------------------------------- char[]

  public static char[] encodeToChar(String s)
  {
    try
    {
      return encodeToChar(s.getBytes("UTF-8"), false);
    }
    catch (UnsupportedEncodingException ignore)
    {
      return null;
    }
  }

  public static char[] encodeToChar(byte[] arr)
  {
    return encodeToChar(arr, false);
  }

  /**
   * Encodes a raw byte array into a BASE64 <code>char[]</code>.
   */
  public static char[] encodeToChar(byte[] arr, boolean lineSeparator)
  {
    int len = arr != null ? arr.length : 0;
    if (len == 0)
    {
      return new char[0];
    }

    int evenlen = (len / 3) * 3;
    int cnt = ((len - 1) / 3 + 1) << 2;
    int destLen = cnt + (lineSeparator ? (cnt - 1) / 76 << 1 : 0);
    char[] dest = new char[destLen];

    for (int s = 0, d = 0, cc = 0; s < evenlen;)
    {
      int i = (arr[s++] & 0xff) << 16 | (arr[s++] & 0xff) << 8
          | (arr[s++] & 0xff);

      dest[d++] = CHARS[(i >>> 18) & 0x3f];
      dest[d++] = CHARS[(i >>> 12) & 0x3f];
      dest[d++] = CHARS[(i >>> 6) & 0x3f];
      dest[d++] = CHARS[i & 0x3f];

      if (lineSeparator && (++cc == 19) && (d < (destLen - 2)))
      {
        dest[d++] = '\r';
        dest[d++] = '\n';
        cc = 0;
      }
    }

    int left = len - evenlen; // 0 - 2.
    if (left > 0)
    {
      int i = ((arr[evenlen] & 0xff) << 10)
          | (left == 2 ? ((arr[len - 1] & 0xff) << 2) : 0);

      dest[destLen - 4] = CHARS[i >> 12];
      dest[destLen - 3] = CHARS[(i >>> 6) & 0x3f];
      dest[destLen - 2] = left == 2 ? CHARS[i & 0x3f] : '=';
      dest[destLen - 1] = '=';
    }
    return dest;
  }

  /**
   * Decodes a BASE64 encoded char array.
   */
  public byte[] decode(char[] arr)
  {
    int length = arr.length;
    if (length == 0)
    {
      return new byte[0];
    }

    int sndx = 0, endx = length - 1;
    int pad = arr[endx] == '=' ? (arr[endx - 1] == '=' ? 2 : 1) : 0;
    int cnt = endx - sndx + 1;
    int sepCnt = length > 76 ? (arr[76] == '\r' ? cnt / 78 : 0) << 1 : 0;
    int len = ((cnt - sepCnt) * 6 >> 3) - pad;
    byte[] dest = new byte[len];

    int d = 0;
    for (int cc = 0, eLen = (len / 3) * 3; d < eLen;)
    {
      int i = INV[arr[sndx++]] << 18 | INV[arr[sndx++]] << 12
          | INV[arr[sndx++]] << 6 | INV[arr[sndx++]];

      dest[d++] = (byte) (i >> 16);
      dest[d++] = (byte) (i >> 8);
      dest[d++] = (byte) i;

      if (sepCnt > 0 && ++cc == 19)
      {
        sndx += 2;
        cc = 0;
      }
    }

    if (d < len)
    {
      int i = 0;
      for (int j = 0; sndx <= endx - pad; j++)
      {
        i |= INV[arr[sndx++]] << (18 - j * 6);
      }
      for (int r = 16; d < len; r -= 8)
      {
        dest[d++] = (byte) (i >> r);
      }
    }

    return dest;
  }

  // ---------------------------------------------------------------- byte

  public static byte[] encodeToByte(String s)
  {
    try
    {
      return encodeToByte(s.getBytes("UTF-8"), false);
    }
    catch (UnsupportedEncodingException ignore)
    {
      return null;
    }
  }

  public static byte[] encodeToByte(byte[] arr)
  {
    return encodeToByte(arr, false);
  }

  /**
   * Encodes a raw byte array into a BASE64 <code>byte[]</code>.
   */
  public static byte[] encodeToByte(byte[] arr, boolean lineSep)
  {
    int len = arr != null ? arr.length : 0;
    if (len == 0)
    {
      return new byte[0];
    }

    int evenlen = (len / 3) * 3;
    int cnt = ((len - 1) / 3 + 1) << 2;
    int destlen = cnt + (lineSep ? (cnt - 1) / 76 << 1 : 0);
    byte[] dest = new byte[destlen];

    for (int s = 0, d = 0, cc = 0; s < evenlen;)
    {
      int i = (arr[s++] & 0xff) << 16 | (arr[s++] & 0xff) << 8
          | (arr[s++] & 0xff);

      dest[d++] = (byte) CHARS[(i >>> 18) & 0x3f];
      dest[d++] = (byte) CHARS[(i >>> 12) & 0x3f];
      dest[d++] = (byte) CHARS[(i >>> 6) & 0x3f];
      dest[d++] = (byte) CHARS[i & 0x3f];

      if (lineSep && ++cc == 19 && d < destlen - 2)
      {
        dest[d++] = '\r';
        dest[d++] = '\n';
        cc = 0;
      }
    }

    int left = len - evenlen;
    if (left > 0)
    {
      int i = ((arr[evenlen] & 0xff) << 10)
          | (left == 2 ? ((arr[len - 1] & 0xff) << 2) : 0);

      dest[destlen - 4] = (byte) CHARS[i >> 12];
      dest[destlen - 3] = (byte) CHARS[(i >>> 6) & 0x3f];
      dest[destlen - 2] = left == 2 ? (byte) CHARS[i & 0x3f] : (byte) '=';
      dest[destlen - 1] = '=';
    }
    return dest;
  }

  /**
   * Decodes a BASE64 encoded byte array.
   */
  public static byte[] decode(byte[] arr)
  {
    int length = arr.length;
    if (length == 0)
    {
      return new byte[0];
    }

    int sndx = 0, endx = length - 1;
    int pad = arr[endx] == '=' ? (arr[endx - 1] == '=' ? 2 : 1) : 0;
    int cnt = endx - sndx + 1;
    int sepCnt = length > 76 ? (arr[76] == '\r' ? cnt / 78 : 0) << 1 : 0;
    int len = ((cnt - sepCnt) * 6 >> 3) - pad;
    byte[] dest = new byte[len];

    int d = 0;
    for (int cc = 0, eLen = (len / 3) * 3; d < eLen;)
    {
      int i = INV[arr[sndx++]] << 18 | INV[arr[sndx++]] << 12
          | INV[arr[sndx++]] << 6 | INV[arr[sndx++]];

      dest[d++] = (byte) (i >> 16);
      dest[d++] = (byte) (i >> 8);
      dest[d++] = (byte) i;

      if (sepCnt > 0 && ++cc == 19)
      {
        sndx += 2;
        cc = 0;
      }
    }

    if (d < len)
    {
      int i = 0;
      for (int j = 0; sndx <= endx - pad; j++)
      {
        i |= INV[arr[sndx++]] << (18 - j * 6);
      }
      for (int r = 16; d < len; r -= 8)
      {
        dest[d++] = (byte) (i >> r);
      }
    }

    return dest;
  }

  // ---------------------------------------------------------------- string

  public static String encodeToString(String s)
  {
    try
    {
      return new String(encodeToChar(s.getBytes("UTF-8"), false));
    }
    catch (UnsupportedEncodingException ignore)
    {
      return null;
    }
  }

  public static String decodeToString(String s)
  {
    try
    {
      return new String(decode(s), "UTF-8");
    }
    catch (UnsupportedEncodingException ignore)
    {
      return null;
    }
  }

  public static String encodeToString(byte[] arr)
  {
    return new String(encodeToChar(arr, false));
  }

  /**
   * Encodes a raw byte array into a BASE64 <code>String</code>.
   */
  public static String encodeToString(byte[] arr, boolean lineSep)
  {
    return new String(encodeToChar(arr, lineSep));
  }

  /**
   * Decodes a BASE64 encoded string.
   */
  public static byte[] decode(String s)
  {
    int length = s.length();
    if (length == 0)
    {
      return new byte[0];
    }

    int sndx = 0, endx = length - 1;
    int pad = s.charAt(endx) == '=' ? (s.charAt(endx - 1) == '=' ? 2 : 1)
        : 0;
    int cnt = endx - sndx + 1;
    int sepCnt = length > 76 ? (s.charAt(76) == '\r' ? cnt / 78 : 0) << 1
        : 0;
    int len = ((cnt - sepCnt) * 6 >> 3) - pad;
    byte[] dest = new byte[len];

    int d = 0;
    for (int cc = 0, eLen = (len / 3) * 3; d < eLen;)
    {
      int i = INV[s.charAt(sndx++)] << 18 | INV[s.charAt(sndx++)] << 12
          | INV[s.charAt(sndx++)] << 6 | INV[s.charAt(sndx++)];

      dest[d++] = (byte) (i >> 16);
      dest[d++] = (byte) (i >> 8);
      dest[d++] = (byte) i;

      if (sepCnt > 0 && ++cc == 19)
      {
        sndx += 2;
        cc = 0;
      }
    }

    if (d < len)
    {
      int i = 0;
      for (int j = 0; sndx <= endx - pad; j++)
      {
        i |= INV[s.charAt(sndx++)] << (18 - j * 6);
      }
      for (int r = 16; d < len; r -= 8)
      {
        dest[d++] = (byte) (i >> r);
      }
    }

    return dest;
  }

  public static void main(String[] args) throws IOException
  {
    BufferedReader br = new BufferedReader(new FileReader("C:\\2.txt"));
    BufferedWriter bw = new BufferedWriter(new FileWriter("C:\\1.txt"));
    String s = "";
    while((s = br.readLine()) != null)
    {
      bw.write(Base64.decodeToString(s));
      bw.newLine();
    }
  }
}
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