crc32

i want to calculate the CRC value for a file using 32-bit algorithm in C#.net.... Algorithm is straightforward (rewritten from c++) class Crc32 { public static uint CountCrc(byte[] pBuf) { // Table of CRC-32's of all single byte values uint[] crctab = new uint[] { 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,

i want to calculate 32 bit CRC value for 'input field value" in Ruby on rails. need the sample code , please help me anyone. You could use Ruby's Zlib module. require 'zlib' crc32 = Zlib::crc32('input field value') 来源： https://stackoverflow.com/questions/4273281/how-to-calculate-32-bit-crc-in-ruby-on-rails

I use this trivial function to calculate the CRC checksum of a given file: long i, j = 0; int k = 0; uint crc = 0xFFFFFFFF; FileInfo file_info = new FileInfo(file); byte[] file_buffer = new byte[32768]; FileStream file_stream = new FileStream(@file, FileMode.Open); while ((i = file_stream.Read(file_buffer, 0, file_buffer.Count())) > 0) { for (j = 0; j < i; j++) { uint before = crc; k = (int)((crc ^ file_buffer[j]) & 0x000000FFL); uint after = (uint)((crc >> 8) & 0x00FFFFFFL) ^ crc32_table[k]; crc = after; uint test = (uint)((crc << 8) & 0x00FFFFFFL) ^ crc32_table[k]; MessageBox.Show((~crc)

I want to create a 32 bit number out of an ASCII-string. CRC32 algorithm is exactly what I'm looking for but I can't use it because the table it requires is way too huge (it is for an embedded systems where ressources are VERY rare). So: any suggestions for a fast and slim CRC algorithm? It does not matter when collissions are a bit more probable than with the original CRC32. Thanks! CRC implementations use tables for speed. They are not required. Here is a short CRC32 using either the Castagnoli polynomial (same one as used by the Intel crc32 instruction), or the Ethernet polynomial (same one

I was looking for a CRC32 implementation I could use on the .Net Micro framework. I found this implementation , but the micro framework has not yet implemented the HashAlgorithm. What would be the best way to get this working ? .net microframework has Utility.ComputeCRC method albeit I am not sure about what algorithm actually uses. It certainly doesn't use one from OP. Utility.ComputeCRC Try the CRC implementation from http://vbcity.com/cfs-file.ashx/__key/CommunityServer.Components.PostAttachments/00.00.47.04.55/CRC_5F00_Lib.zip . This is an implementation discussed at http://vbcity.com

I'm using the Spartan 3E Starter Kit and I'm trying to receive Ethernet frames on it via a 100 MBit link. For those who don't know, the board features a PHY chip, exposing the receiving clock with 25 MHz. I have (pretty much) verified that receiving works fine by buffering the received frames and resending them via a serial link. Furthermore, I'm using a CRC32 generator from outputlogic.com . I aggregate the received nybbles to bytes and forward them to the CRC. At the end of the frame, I latch the generated CRC and display it on the LCD, together with the CRC I found in the ethernet frame.

I use java.util.zip.CRC32 which I understand implements CRC32 (and not CRC32b), but it seems like I need to use CRC32b instead of CRC32. is there a Java open source code I can use for CRC32b calculation? CRC32b is a coined term if I remember correctly, equal to CRC32 with the 4 bytes reversed. int crc32b(int crc) { ByteBuffer buf = ByteBuffer.allocate(4); buf.putInt(crc); // BIG_ENDIAN by default. buf.order(ByteOrder.LITTLE_ENDIAN); return buf.getInt(0); } For instance for input '1': byte b = (byte) '1'; CRC32 crc = new CRC32(); crc.update(b); System.out.printf("%x%n", crc.getValue()); int