using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.IO;
using IWshRuntimeLibrary;

namespace WindowsApplication7
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private string name;
        //UTF-8字符标记
        private const Byte b1 = 239;
        private const Byte b2 = 187;
        private const Byte b3 = 191;
        bool ishavebom = false;
        /**//// <summary>
        /// 清除字符标记
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button2_Click(object sender, EventArgs e)
        {
            try
            {
                ishavebom = HasBom();

                using (BinaryReader br = new BinaryReader(System.IO.File.Open(this.textBox1.Text, FileMode.Open)))
                {
                    
                    FileInfo fi = new FileInfo(this.textBox1.Text);

                    using (BinaryWriter bw = new BinaryWriter(System.IO.File.Open(fi.DirectoryName + "\\ClearBom_" + fi.Name, FileMode.Create)))
                    {
                        try
                        {
                            if (ishavebom)
                            {
                                br.ReadByte();
                                br.ReadByte();
                                br.ReadByte();
                            }
                            do
                            {
                                bw.Write(br.ReadByte());
                            }
                            while (br != null);
                        }
                        catch (EndOfStreamException)
                        { }
                        bw.Close();
                    }
                    br.Close();
                }
                MessageBox.Show("Over");
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }


        }
        /**//// <summary>
        /// 添加上字符标记
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button3_Click(object sender, EventArgs e)
        {
            try
            {
                ishavebom = HasBom();
                using (BinaryReader br = new BinaryReader(System.IO.File.Open(this.textBox1.Text, FileMode.Open)))
                {
                    FileInfo fi = new FileInfo(this.textBox1.Text);

                    using (BinaryWriter bw = new BinaryWriter(System.IO.File.Open(fi.DirectoryName + "\\AddBom_" + fi.Name, FileMode.Create)))
                    {
                        try
                        {
                            if (!ishavebom)
                            {
                                bw.Write(b1);
                                bw.Write(b2);
                                bw.Write(b3);
                            }
                            do
                            {
                                bw.Write(br.ReadByte());
                            }
                            while (br != null);
                        }
                        catch (EndOfStreamException)
                        { }
                        bw.Close();
                    }
                    br.Close();
                }
                MessageBox.Show("Over");
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }
        /**//// <summary>
        /// 检查是否存在字符标记
        /// </summary>
        /// <returns></returns>
        private bool HasBom()
        {
            try
            {
                using (BinaryReader br = new BinaryReader(System.IO.File.Open(this.textBox1.Text, FileMode.Open)))
                {
                    FileInfo fi = new FileInfo(this.textBox1.Text);

                    if (br.ReadByte() == b1)
                    {
                        if (br.ReadByte() == b2)
                        {
                            if (br.ReadByte() == b3)
                            {
                                br.Close();
                                return true;
                            }
                        }
                    }
                  
                    br.Close();
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
            return false;
        }
        private void button1_Click(object sender, EventArgs e)
        {
            OpenFileDialog fd = new OpenFileDialog();
            DialogResult dr = fd.ShowDialog(this);
            if (dr == DialogResult.OK)
            {
                this.textBox1.Text = fd.FileName;
            }
        }
    }
}