pgxview.cs

关于JPEG2000压缩标准的模板程序的内容,是我们导师给的,据说是国外的版本.

using System;
using System.IO;
using System.Text;
using System.Text.RegularExpressions;
using System.Drawing;
using System.Windows.Forms;
using System.Security.Cryptography;

namespace J2000.Utils {
	
	class PGXReader {
		private static string ReadLine(BinaryReader br) {
			StringBuilder sb=new StringBuilder();
			char c;
			while ((c=br.ReadChar())!='\n') {
				sb.Append(c);	
			}
			return sb.ToString();
		}
		
		public static Bitmap Read(string filename, out string hash) {
			FileStream f=new FileStream(filename, FileMode.Open, FileAccess.Read, FileShare.Read);
			BinaryReader br=new BinaryReader(f);
			Regex r=new Regex(@"[\s]+");
			string[] head=r.Split(ReadLine(br));
			Console.WriteLine(String.Join(",",head));
			if (head[0]!="PG") throw new Exception("Not a PGX file");
			bool bigendian=head[1]=="ML";
			int prec=Math.Abs(int.Parse(head[2]));
			bool sgnd=int.Parse(head[2])<0;
			int w=int.Parse(head[3]);
			int h=int.Parse(head[4]);
			Console.WriteLine("prec="+prec+", sgnd="+sgnd+", w="+w+", h="+h);
			HashAlgorithm md5=new MD5CryptoServiceProvider();
			CryptoStream cs=new CryptoStream(Stream.Null, md5, CryptoStreamMode.Write);
			BinaryWriter bw=new BinaryWriter(cs);

			Bitmap bmp=new Bitmap(w, h);
			for (int j=0; j<h; j++) {
				for (int i=0; i<w; i++) {
					int v, c;
					if (prec<=8) {
						v=sgnd?(int)br.ReadSByte():(int)br.ReadByte(); 
					}
					else if (prec<=16) {
						v=sgnd?(int)br.ReadInt16():(int)br.ReadUInt16(); 
						if (bigendian) v=System.Net.IPAddress.HostToNetworkOrder((short)v);
					}
					else {
						v=sgnd?(int)br.ReadInt32():(int)br.ReadUInt32(); 
						if (bigendian) v=System.Net.IPAddress.HostToNetworkOrder(v);
					}
					if (sgnd) c=(int)(128+v*127.0/(1<<(prec-1)));
					else c=(int)(v*255.0/(1<<prec));
					bmp.SetPixel(i, j, Color.FromArgb(255, c, c, c));
					bw.Write(v);
				}
			}
			bw.Close();
			hash=Convert.ToBase64String(md5.Hash);
			return bmp;
		}
	}
}

class PGXView:Form {
	public static int Main(string[] args) {
		Application.Run(new PGXView(args[0]));
		return 0;
	}

	static string hash;

	static void PrintMD5(object sender, EventArgs e) {
		MessageBox.Show(hash, "MD5");
	}

	public PGXView(string filename) {
		Text="J2000.PGXView";
		FormBorderStyle=FormBorderStyle.FixedToolWindow;
		PictureBox pbox=new PictureBox();
		ContextMenu cm=new ContextMenu();
		cm.MenuItems.Add("&MD5", new EventHandler(PrintMD5));
		pbox.ContextMenu=cm;

		try {
			pbox.Image=J2000.Utils.PGXReader.Read(filename, out hash);
			pbox.SizeMode=PictureBoxSizeMode.AutoSize;
			ClientSize=pbox.Size;
		}
		catch (Exception e) {
			Console.WriteLine(e.Message);
		}
		Controls.Add(pbox);
	}
}