srjblogs

A ruby on rails test project

package com.example.android.fragments;

import java.util.ArrayList;

public class CRC32new { private static ArrayList table2;

public static void main(String[] args) { 

   /**************************************************************************
    *  Using table lookup
    *  Reference: http://snippets.dzone.com/tag/crc32
    **************************************************************************/

    int[] table = {
    		  0x00000000,0x04C11DB7,0x09823B6E,0x0D4326D9,
    		    0x130476DC,0x17C56B6B,0x1A864DB2,0x1E475005,
    		    0x2608EDB8,0x22C9F00F,0x2F8AD6D6,0x2B4BCB61,
    		    0x350C9B64,0x31CD86D3,0x3C8EA00A,0x384FBDBD,
    		    0x4C11DB70,0x48D0C6C7,0x4593E01E,0x4152FDA9,
    		    0x5F15ADAC,0x5BD4B01B,0x569796C2,0x52568B75,
    		    0x6A1936C8,0x6ED82B7F,0x639B0DA6,0x675A1011,
    		    0x791D4014,0x7DDC5DA3,0x709F7B7A,0x745E66CD,
    		    0x9823B6E0,0x9CE2AB57,0x91A18D8E,0x95609039,
    		    0x8B27C03C,0x8FE6DD8B,0x82A5FB52,0x8664E6E5,
    		    0xBE2B5B58,0xBAEA46EF,0xB7A96036,0xB3687D81,
    		    0xAD2F2D84,0xA9EE3033,0xA4AD16EA,0xA06C0B5D,
    		    0xD4326D90,0xD0F37027,0xDDB056FE,0xD9714B49,
    		    0xC7361B4C,0xC3F706FB,0xCEB42022,0xCA753D95,
    		    0xF23A8028,0xF6FB9D9F,0xFBB8BB46,0xFF79A6F1,
    		    0xE13EF6F4,0xE5FFEB43,0xE8BCCD9A,0xEC7DD02D,
    		    0x34867077,0x30476DC0,0x3D044B19,0x39C556AE,
    		    0x278206AB,0x23431B1C,0x2E003DC5,0x2AC12072,
    		    0x128E9DCF,0x164F8078,0x1B0CA6A1,0x1FCDBB16,
    		    0x018AEB13,0x054BF6A4,0x0808D07D,0x0CC9CDCA,
    		    0x7897AB07,0x7C56B6B0,0x71159069,0x75D48DDE,
    		    0x6B93DDDB,0x6F52C06C,0x6211E6B5,0x66D0FB02,
    		    0x5E9F46BF,0x5A5E5B08,0x571D7DD1,0x53DC6066,
    		    0x4D9B3063,0x495A2DD4,0x44190B0D,0x40D816BA,
    		    0xACA5C697,0xA864DB20,0xA527FDF9,0xA1E6E04E,
    		    0xBFA1B04B,0xBB60ADFC,0xB6238B25,0xB2E29692,
    		    0x8AAD2B2F,0x8E6C3698,0x832F1041,0x87EE0DF6,
    		    0x99A95DF3,0x9D684044,0x902B669D,0x94EA7B2A,
    		    0xE0B41DE7,0xE4750050,0xE9362689,0xEDF73B3E,
    		    0xF3B06B3B,0xF771768C,0xFA325055,0xFEF34DE2,
    		    0xC6BCF05F,0xC27DEDE8,0xCF3ECB31,0xCBFFD686,
    		    0xD5B88683,0xD1799B34,0xDC3ABDED,0xD8FBA05A,
    		    0x690CE0EE,0x6DCDFD59,0x608EDB80,0x644FC637,
    		    0x7A089632,0x7EC98B85,0x738AAD5C,0x774BB0EB,
    		    0x4F040D56,0x4BC510E1,0x46863638,0x42472B8F,
    		    0x5C007B8A,0x58C1663D,0x558240E4,0x51435D53,
    		    0x251D3B9E,0x21DC2629,0x2C9F00F0,0x285E1D47,
    		    0x36194D42,0x32D850F5,0x3F9B762C,0x3B5A6B9B,
    		    0x0315D626,0x07D4CB91,0x0A97ED48,0x0E56F0FF,
    		    0x1011A0FA,0x14D0BD4D,0x19939B94,0x1D528623,
    		    0xF12F560E,0xF5EE4BB9,0xF8AD6D60,0xFC6C70D7,
    		    0xE22B20D2,0xE6EA3D65,0xEBA91BBC,0xEF68060B,
    		    0xD727BBB6,0xD3E6A601,0xDEA580D8,0xDA649D6F,
    		    0xC423CD6A,0xC0E2D0DD,0xCDA1F604,0xC960EBB3,
    		    0xBD3E8D7E,0xB9FF90C9,0xB4BCB610,0xB07DABA7,
    		    0xAE3AFBA2,0xAAFBE615,0xA7B8C0CC,0xA379DD7B,
    		    0x9B3660C6,0x9FF77D71,0x92B45BA8,0x9675461F,
    		    0x8832161A,0x8CF30BAD,0x81B02D74,0x857130C3,
    		    0x5D8A9099,0x594B8D2E,0x5408ABF7,0x50C9B640,
    		    0x4E8EE645,0x4A4FFBF2,0x470CDD2B,0x43CDC09C,
    		    0x7B827D21,0x7F436096,0x7200464F,0x76C15BF8,
    		    0x68860BFD,0x6C47164A,0x61043093,0x65C52D24,
    		    0x119B4BE9,0x155A565E,0x18197087,0x1CD86D30,
    		    0x029F3D35,0x065E2082,0x0B1D065B,0x0FDC1BEC,
    		    0x3793A651,0x3352BBE6,0x3E119D3F,0x3AD08088,
    		    0x2497D08D,0x2056CD3A,0x2D15EBE3,0x29D4F654,
    		    0xC5A92679,0xC1683BCE,0xCC2B1D17,0xC8EA00A0,
    		    0xD6AD50A5,0xD26C4D12,0xDF2F6BCB,0xDBEE767C,
    		    0xE3A1CBC1,0xE760D676,0xEA23F0AF,0xEEE2ED18,
    		    0xF0A5BD1D,0xF464A0AA,0xF9278673,0xFDE69BC4,
    		    0x89B8FD09,0x8D79E0BE,0x803AC667,0x84FBDBD0,
    		    0x9ABC8BD5,0x9E7D9662,0x933EB0BB,0x97FFAD0C,
    		    0xAFB010B1,0xAB710D06,0xA6322BDF,0xA2F33668,
    		    0xBCB4666D,0xB8757BDA,0xB5365D03,0xB1F740B4
    };
    
    table2 = new ArrayList<Long>();
    table2 = getLongTable(table);
    
    String[] ary = "abc".split("");
    String a = "abc";
    byte[] bytes = a.getBytes();
    int crc = 0xffffffff;
    for (byte b : bytes) {
    //    crc = (crc >>> 8) ^ table[(crc ^ b) & 0xff];
      //  crc = (int) (table2.get(b ^ ((crc >> 24) & 0xff)) ^ (crc << 8));
        crc = table[b ^ ((crc >> 24) & 0xff)] ^ (crc << 8);
    }
    int ab = 0xBCB4666D;
    long yb = ab & 0x00000000ffffffffL ;
  
    System.out.println("CRC32 (via table lookup)check       = " + yb);
    // flip bits
    crc = crc ^ 0xffffffff;

    System.out.println("CRC32 (via table lookup)       = " + Integer.toHexString(crc));
    System.out.println("CRC32 (via table lookup)2       = " + crc);
    long y = crc & 0x00000000ffffffffL ;
    System.out.println("CRC32 (via table lookup)3       = " + y);
    



   /**************************************************************************
    *  Using direct calculation
    **************************************************************************/

    crc  = 0xFFFFFFFF;       // initial contents of LFBSR
    int poly = 0xEDB88320;   // reverse polynomial

    for (byte b : bytes) {
        int temp = (crc ^ b) & 0xff;

        // read 8 bits one at a time
        for (int i = 0; i < 8; i++) {
            if ((temp & 1) == 1) temp = (temp >>> 1) ^ poly;
            else                 temp = (temp >>> 1);
        }
        crc = (crc >>> 8) ^ temp;
    }

    // flip bits
    crc = crc ^ 0xffffffff;

    System.out.println("CRC32 (via direct calculation) = " + Integer.toHexString(crc));



   /**************************************************************************
    *  Using Java's java.util.zip.CRC32 library
    **************************************************************************/
    java.util.zip.CRC32 x = new java.util.zip.CRC32();
    x.update(bytes);
    System.out.println("CRC32 (via Java's library)     = " + Long.toHexString(x.getValue()));

}

public static ArrayList<Long> getLongTable(int [] s)
{
	ArrayList<Long> bb = new ArrayList<Long>();
	for (int b : s)
	{
		long c = b & 0x00000000ffffffffL;
		bb.add(c);
	}
	
	return bb;
}

}