/*
 * Copyright 2016-2017 the original author or authors.
 * 
 * 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.github.ibole.infrastructure.common.utils;

import java.util.Locale;

/*********************************************************************************************
 * .
 * 
 * 
 * <p>Copyright 2016, iBole Inc. All rights reserved.
 * 
 * <p>
 * </p>
 *********************************************************************************************/


/**
 * <pre>
 * 16进制值与String/Byte之间的转换.
 * </pre>
 * 
 * @author bwang
 *
 */
public class HexUtil {

  private static final char[] mChars = "0123456789ABCDEF".toCharArray();
  private static final String mHexStr = "0123456789ABCDEF";

  /**
   * 检查16进制字符串是否有效.
   * 
   * @param sHex String 16进制字符串
   * @return boolean
   */
  public static boolean checkHexStr(String sHex) {
    String sTmp = sHex.toString().trim().replace(" ", "").toUpperCase(Locale.US);
    int iLen = sTmp.length();

    if (iLen > 1 && iLen % 2 == 0) {
      for (int i = 0; i < iLen; i++) {
        if (!mHexStr.contains(sTmp.substring(i, i + 1))) {
          return false;
        }
      }
      return true;

    } else {
      return false;
    }

  }

  /**
   * 字符串转换成十六进制字符串.
   * 
   * @param str String 待转换的ASCII字符串
   * @return String 每个Byte之间空格分隔，如: [61 6C 6B]
   */
  public static String str2HexStr(String str) {
    StringBuilder sb = new StringBuilder();
    byte[] bs = str.getBytes();

    for (int i = 0; i < bs.length; i++) {
      sb.append(mChars[(bs[i] & 0xFF) >> 4]);
      sb.append(mChars[bs[i] & 0x0F]);
      sb.append(' ');
    }
    return sb.toString().trim();
  }

  /**
   * 十六进制字符串转换成 ASCII字符串.
   * 
   * @param hexStr String Byte字符串
   * @return String 对应的字符串
   */
  public static String hexStr2Str(String hexStr) {
    hexStr = hexStr.toString().trim().replace(" ", "").toUpperCase(Locale.US);
    char[] hexs = hexStr.toCharArray();
    byte[] bytes = new byte[hexStr.length() / 2];
    int iTmp = 0x00;;

    for (int i = 0; i < bytes.length; i++) {
      // equals to: iTmp = mHexStr.indexOf(hexs[2 * i]) * 16;
      iTmp = mHexStr.indexOf(hexs[2 * i]) << 4;
      iTmp |= mHexStr.indexOf(hexs[2 * i + 1]);
      bytes[i] = (byte) (iTmp & 0xFF);
    }
    return new String(bytes);
  }

  /**
   * bytes转换成十六进制字符串.
   * 
   * @param b byte[] byte数组
   * @param iLen int 取前N位处理 N=iLen
   * @return String 每个Byte值之间空格分隔
   */
  public static String byte2HexStr(byte[] b, int iLen) {
    StringBuilder sb = new StringBuilder();
    for (int n = 0; n < iLen; n++) {
      sb.append(mChars[(b[n] & 0xFF) >> 4]);
      sb.append(mChars[b[n] & 0x0F]);
      sb.append(' ');
    }
    return sb.toString().trim().toUpperCase(Locale.US);
  }

  /**
   * bytes字符串转换为Byte值.
   * 
   * @param src String Byte字符串，每个Byte之间没有分隔符(字符范围:0-9 A-F)
   * @return byte[]
   */
  public static byte[] hexStr2Bytes(String src) {
    /* 对输入值进行规范化整理 */
    src = src.trim().replace(" ", "").toUpperCase(Locale.US);
    // 处理值初始化
    int m = 0;
    int n = 0;
    int iLen = src.length() / 2; // 计算长度
    byte[] ret = new byte[iLen]; // 分配存储空间

    for (int i = 0; i < iLen; i++) {
      m = i * 2 + 1;
      n = m + 1;
      ret[i] = (byte) (Integer.decode("0x" + src.substring(i * 2, m) + src.substring(m, n)) & 0xFF);
    }
    return ret;
  }

  /**
   * String的字符串转换成unicode的String.
   * 
   * @param strText String 全角字符串
   * @return String 每个unicode之间无分隔符
   * @throws Exception Exception
   */
  public static String strToUnicode(String strText) throws Exception {
    char c;
    StringBuilder str = new StringBuilder();
    int intAsc;
    String strHex;
    for (int i = 0; i < strText.length(); i++) {
      c = strText.charAt(i);
      intAsc = (int) c;
      strHex = Integer.toHexString(intAsc);
      if (intAsc > 128) {
        str.append("\\u");
      } else {
        // 低位在前面补00
        str.append("\\u00");
      }
      str.append(strHex);
    }
    return str.toString();
  }

  /**
   * unicode的String转换成String的字符串.
   * 
   * @param hex String 16进制值字符串 （一个unicode为2byte）
   * @return String 全角字符串
   * 
   */
  public static String unicodeToString(String hex) {
    int t = hex.length() / 6;
    int iTmp = 0;
    StringBuilder str = new StringBuilder();
    for (int i = 0; i < t; i++) {
      String s = hex.substring(i * 6, (i + 1) * 6);
      // 将16进制的string转为int
      iTmp = (Integer.valueOf(s.substring(2, 4), 16) << 8) | Integer.valueOf(s.substring(4), 16);
      // 将int转换为字符
      str.append(new String(Character.toChars(iTmp)));
    }
    return str.toString();
  }
  
}
