How to do CRC checks?

[PT Exorcist]

I have a SFV file that has many files with CRC's and I'd like to know how to check my files against it to check if they are alright

anybody has any ideias of how to accomplish this?

[Cander]

Here is a c# CRC checking class. Should be what you need.

using System;
using System.Text;
using System.IO;

namespace Fesersoft.Hashing
{
	/// <summary>
	/// Get the CRC-32 Value for a String, Byte array or Stream
	/// </summary>
	public class crc32
		//  CRC32 Calculation on Strings, Byte arrays and Stream objects for .Net 
		//  Released to the public domain with the following 
		//  restrictions:
		//  
		//  1.  You may not modify the namespace.
		//  2.  Your software must include acknowledgement that portions of the code are provided
		//      by Fesersoft, Inc.
		//
		//  Copyright © 2001-2002 Fesersoft, Inc.  All Rights Reserved.
		//  http://www.fesersoft.com/dotNet for updates and other software.
	{
		/// <summary>
		/// Create a new instance of the crc32 assembly.
		/// </summary>
		public crc32()
		{
			//
			// TODO: Add constructor logic here
			//
		}

		readonly static ulong[] crcLookup = new ulong[] {
			0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA,
			0x076DC419, 0x706AF48F, 0xE963A535, 0x9E6495A3,
			0x0EDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988,
			0x09B64C2B, 0x7EB17CBD, 0xE7B82D07, 0x90BF1D91,
			0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE,
			0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7,
			0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC,
			0x14015C4F, 0x63066CD9, 0xFA0F3D63, 0x8D080DF5,
			0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172,
			0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B,
			0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940,
			0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59,
			0x26D930AC, 0x51DE003A, 0xC8D75180, 0xBFD06116,
			0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F,
			0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924,
			0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D,

			0x76DC4190, 0x01DB7106, 0x98D220BC, 0xEFD5102A,
			0x71B18589, 0x06B6B51F, 0x9FBFE4A5, 0xE8B8D433,
			0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818,
			0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01,
			0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E,
			0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457,
			0x65B0D9C6, 0x12B7E950, 0x8BBEB8EA, 0xFCB9887C,
			0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65,
			0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2,
			0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB,
			0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0,
			0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9,
			0x5005713C, 0x270241AA, 0xBE0B1010, 0xC90C2086,
			0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
			0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4,
			0x59B33D17, 0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD,

			0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A,
			0xEAD54739, 0x9DD277AF, 0x04DB2615, 0x73DC1683,
			0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8,
			0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1,
			0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE,
			0xF762575D, 0x806567CB, 0x196C3671, 0x6E6B06E7,
			0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC,
			0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5,
			0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252,
			0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B,
			0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60,
			0xDF60EFC3, 0xA867DF55, 0x316E8EEF, 0x4669BE79,
			0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236,
			0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F,
			0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04,
			0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D,

			0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A,
			0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713,
			0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38,
			0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21,
			0x86D3D2D4, 0xF1D4E242, 0x68DDB3F8, 0x1FDA836E,
			0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777,
			0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C,
			0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45,
			0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2,
			0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB,
			0xAED16A4A, 0xD9D65ADC, 0x40DF0B66, 0x37D83BF0,
			0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,
			0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6,
			0xBAD03605, 0xCDD70693, 0x54DE5729, 0x23D967BF,
			0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94,
			0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D};
		
		readonly static Encoding encoder = Encoding.GetEncoding(1252);
		readonly static ulong poly = 4294967295;

		/// <summary>
		/// Get the crc32 value for an entire Stream, setting the position to zero.
		/// </summary>
		/// <param name="st">The stream to perform the crc32 calculation on.</param>
		/// <returns>The crc32 value.</returns>
		public long CRC(Stream st) 
		{
			return CRC(st,0,st.Length); 
		} 

		/// <summary>
		/// Get the crc32 value for a Stream, setting the position to to the beginPosition and calculation to the length.
		/// The position is set back to the original position when complete.
		/// </summary>
		/// <param name="st">The stream to perform the crc32 calculation on.</param>
		/// <param name="beginPosition">The begin position of the stream to start the calculation.</param>
		/// <param name="length">The length you wish to run the calculation on.</param>
		/// <returns>The crc32 value.</returns>
		public long CRC(Stream st, long beginPosition, long length) 
		{
			ulong ulCRC = poly;
			long originalPos = st.Position;
			long endPos = beginPosition + length;
			byte by;

			if (endPos > st.Length) 
			{
				throw new Exception("Out of bounds. beginposition + length is greater than the length of the Stream");
			}

			try
			{
				st.Position = beginPosition;
				BufferedStream bs = new BufferedStream(st);
				
				for(long i = beginPosition; i < endPos; i++) 
				{ 
					by =  Convert.ToByte(bs.ReadByte());
					ulCRC = (ulCRC >> 8) ^ crcLookup[(ulCRC & 0xFF) ^ by];
				}
			}
			catch (Exception e)
			{
				Console.WriteLine(e.ToString());
			}
			finally
			{
			//For now do nothing
			}
			st.Position = originalPos;
			return Convert.ToInt64( ulCRC ^ poly); 
		} 

		/// <summary>
		/// Get the crc32 value for a String.
		/// </summary>
		/// <param name="text">The string you wish to calculate the crc32 value on.</param>
		/// <returns>The CRC-32 value.</returns>
		public long CRC(string text) 
		{
			byte[] buffer; 
			buffer = encoder.GetBytes(text);
			return CRC(buffer); 
		} 

		/// <summary>
		/// Get the CRC-32 value for a byte[].
		/// </summary>
		/// <param name="by">The byte[] you wish to calculate the crc32 value on</param>
		/// <returns>The CRC-32 value.</returns>
		public long CRC(byte[] by) 
		{
			ulong ulCRC = poly;
			long len;
			len = by.Length;
			for(long i = 0; i < len; i++) 
			{ 
				ulCRC = (ulCRC >> 8) ^ crcLookup[(ulCRC & 0xFF) ^ by[i]];
			}
			return Convert.ToInt64( ulCRC ^ poly); 
		} 
	}
}

[PT Exorcist]

ty ill try it

[PT Exorcist]

thanks! worked great!

[Cander]

Cool. your welcome.