apk analyzer

link : http://www.androidpub.com/480571

import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

public class APKAnalyzer {
    private static int bufferSize = 4096;
    public static void main(String[] args) throws Exception {
        System.out.println( findPackageNameFromAPK("c:/sample/1.apk") );
    }

    private static String findPackageName( String str )
    {
        int index1 = str.indexOf("manifest") + "manifest".length();
        int index2 = str.indexOf("application");

        if( index1 == -1 || index2 == -1 ) return null;

        boolean isStart = false, isFinish = false;
        for( int i = index1 ; i < index2 ; i++ )
        {
            isFinish = true;
            char d = str.charAt(i);
            //패턴은 되도록 쓰지말라는 권고에 따라서 아스키값으로 비교
            if( 46 <= d && d <= 122 )
            {
                isStart = true;
                isFinish = false;
            }

            if( isStart == false ) index1++;
            if( isStart && isFinish) {
                index2 = i;
                break;
            }
        }
        return str.substring(index1, index2);
    }
    
    public static String findPackageNameFromAPK( String path ) throws IOException
    {
        FileInputStream fis = new FileInputStream(path);
        ZipInputStream zis = new ZipInputStream(fis);

        ZipEntry zentry;
        String fileName;
        String packageName = null;
        while( (zentry = zis.getNextEntry()) != null )
        {
            fileName = zentry.getName();
            if( zentry.getName().equalsIgnoreCase("AndroidManifest.xml") )
            {
                BufferedInputStream bis = new BufferedInputStream( zis );
                int c = 0;
                int b = 0xFFFFFFFF ;


                byte[] buffer1 = new byte[bufferSize];
                byte[] buffer2 = new byte[bufferSize];

                int cnt1=0, cnt2=0;
                while( (c = bis.read()) != -1 )
                {
                    if ( ( b ^= 0xFFFFFFFF ) == 0)
                    {
                        buffer1[cnt1++] = (byte)c;
                    }
                    else
                    {
                        buffer2[cnt2++] = (byte)c;
                    }

                    if( cnt1 == bufferSize || cnt2 == bufferSize ) break;
                }

                String str1 = new String( buffer1 );

                if((packageName = findPackageName(str1)) != null )
                {
                    break;    
                }
                String str2 = new String( buffer2 );
                packageName = findPackageName(str2);
                break;
            }
        }
        return packageName;

    }
}