package com.newvideo.util;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class SHA1Util {
	public static String getFileMD5(File file) {
		if (!file.isFile()) {
			return null;
		}
		MessageDigest digest = null;
		FileInputStream in = null;
		byte buffer[] = new byte[1024];
		int len;
		try {
			digest = MessageDigest.getInstance("SHA-1");
			in = new FileInputStream(file);
			while ((len = in.read(buffer, 0, 1024)) != -1) {
				digest.update(buffer, 0, len);
			}
			in.close();
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		}
		return byte2hex(digest.digest());
	}

	public static String byte2hex(byte abyte0[]) {
		StringBuilder stringbuilder = new StringBuilder("");
		int i = 0;
		while (i < abyte0.length) {
			String s = Integer.toHexString(0xff & abyte0[i]);
			String s1;
			if (s.length() == 1)
				s1 = (new StringBuilder()).append("0").append(s).toString();
			else
				s1 = s;
			stringbuilder.append(s1);
			i++;
		}

		return stringbuilder.toString().trim();
	}

	public static String leshiYunSHA1(File file)
			throws NoSuchAlgorithmException, IOException {
		MessageDigest messagedigest = MessageDigest.getInstance("SHA-1");
		RandomAccessFile randomaccessfile1 = new RandomAccessFile(file, "r");
		byte abyte0[] = new byte[0x10000];
		long l;
		int j;
		int k;
		if (file.length() % 8L == 0L)
			l = file.length() / 8L;
		else
			l = 1L + file.length() / 8L;
		for (int i = 0; i < 8; i++) {
			randomaccessfile1.seek(l * (long) i);
			j = 0;
			do {
				if (j >= 0x10000)
					break;
				k = randomaccessfile1.read(abyte0);
				if (k <= 0)
					break;
				messagedigest.update(abyte0, 0, k);
				j += k;
			} while (true);
		}
		messagedigest.update(String.valueOf(file.length()).getBytes());
		return byte2hex(messagedigest.digest());
	}
	
	
	
	

}