using System;
using System.Text;

namespace TEAMModelOS.SDK.Helper.Common.StringHelper
{
    public class StringHelper
    {
        #region 截取字符串
        public static string GetSubString(string pSrcString, int pLength, string pTailString)
        {
            return GetSubString(pSrcString, 0, pLength, pTailString);
        }
        public static string GetSubString(string pSrcString, int pStartIndex, int pLength, string pTailString)
        {
            string str = pSrcString;
            byte[] bytes = Encoding.UTF8.GetBytes(pSrcString);
            foreach (char ch in Encoding.UTF8.GetChars(bytes))
            {
                if (((ch > 'ࠀ') && (ch < '一')) || ((ch > 0xac00) && (ch < 0xd7a3)))
                {
                    if (pStartIndex >= pSrcString.Length)
                    {
                        return "";
                    }
                    return pSrcString.Substring(pStartIndex, ((pLength + pStartIndex) > pSrcString.Length) ? (pSrcString.Length - pStartIndex) : pLength);
                }
            }
            if (pLength < 0)
            {
                return str;
            }
            byte[] sourceArray = Encoding.Default.GetBytes(pSrcString);
            if (sourceArray.Length <= pStartIndex)
            {
                return str;
            }
            int length = sourceArray.Length;
            if (sourceArray.Length > (pStartIndex + pLength))
            {
                length = pLength + pStartIndex;
            }
            else
            {
                pLength = sourceArray.Length - pStartIndex;
                pTailString = "";
            }
            int num2 = pLength;
            int[] numArray = new int[pLength];
            byte[] destinationArray = null;
            int num3 = 0;
            for (int i = pStartIndex; i < length; i++)
            {
                if (sourceArray[i] > 0x7f)
                {
                    num3++;
                    if (num3 == 3)
                    {
                        num3 = 1;
                    }
                }
                else
                {
                    num3 = 0;
                }
                numArray[i] = num3;
            }
            if ((sourceArray[length - 1] > 0x7f) && (numArray[pLength - 1] == 1))
            {
                num2 = pLength + 1;
            }
            destinationArray = new byte[num2];
            Array.Copy(sourceArray, pStartIndex, destinationArray, 0, num2);
            return (Encoding.Default.GetString(destinationArray) + pTailString);
        }
        #endregion
    }
}