crc32

This question already has an answer here: How do I calculate CRC32 of a string 2 answers Is there any function or example for VB.NET to calculate CRC32 of an string or Byte Array? Use this: Private Sub Main() Crc32.ComputeChecksum(Encoding.UTF8.GetBytes("Some string")).Dump() End Sub Public Class Crc32 Shared table As UInteger() Shared Sub New() Dim poly As UInteger = &Hedb88320UI table = New UInteger(255) {} Dim temp As UInteger = 0 For i As UInteger = 0 To table.Length - 1 temp = i For j As Integer = 8 To 1 Step -1 If (temp And 1) = 1 Then temp = CUInt((temp >> 1) Xor poly) Else temp >>= 1

While running APK expansion file sample I just skiped checking CRC32 to avoide crc bug algorithm and its working very fine!! But while XAPK File validation shows in correct downloaded data information 99% !!, how to avoid that and view full 100% by hard-coding? It's not a best sloution but I got the solution by hard coding the ProgressBar mPB; TextView mProgressPercent; TextView mProgressFraction; in DownloaderActivity onPostExecute method of validationAsynctask mPB.setMax(10); mPB.setProgress(100); mProgressPercent.setText(100 + "%"); mProgressFraction.setText("Download Completed Successfully

Why in the world was _mm_crc32_u64(...) defined like this? unsigned int64 _mm_crc32_u64( unsigned __int64 crc, unsigned __int64 v ); The "crc32" instruction always accumulates a 32-bit CRC, never a 64-bit CRC (It is, after all, CRC32 not CRC64). If the machine instruction CRC32 happens to have a 64-bit destination operand, the upper 32 bits are ignored, and filled with 0's on completion, so there is NO use to EVER have a 64-bit destination. I understand why Intel allowed a 64-bit destination operand on the instruction (for uniformity), but if I want to process data quickly, I want a source

On several places I've read that crc32 is additive and so: CRC(A xor B) = CRC(A) xor CRC(B). The above statement was disproven by the following code I wrote: import zlib def crc32(data): return zlib.crc32(data) & 0xffffffff print crc32(chr(ord("A") ^ ord("B"))) print crc32("A") ^ crc32("B") Program output: 1259060791 2567524794 Could someone provide a proper code proving this theory or point me where I've failed? CRC is additive in the mathematical sense since the CRC hash is just a remainder value from a carryless division of all the data (treated as a giant integer) divided by the polynomial

I generate a traffic between two PCs running Linux (by sending Ethernet frames), the goal of this is to capture some errors frames. The problem is when the Phy layer detect an error on a frame (if the CRC or FCS is not valid) the frame is dropped and I can't receive it in my program. Are the any way to receive the wrong frame (disable the drops in the Phy layer and receiving a indicator that indicate that this frame is wrong for example) and how can i consult the statistic of the NIC card (number of drops ...etc). You didn't specify which OS, but I can at least speak for Linux: It may on your

I am using the Zip utility package of Java and wanted to know how to create a zip file with no compression at all. Setting the level to 0 doesn't help. Is this right? Also, when I used the STORED method, it throws following exception: java.util.zip.ZipException: STORED entry missing size, compressed size, or crc-32 I can set the size but now following exception is thrown: java.util.zip.ZipException: invalid entry crc-32 I am just following all the examples available by searching on the web and I am not able to really understand it properly I guess. It would be great if someone can help me on

Given that SSE 4.2 (Intel Core i7 & i5 parts) includes a CRC32 instruction, it seems reasonable to investigate whether one could build a faster general-purpose hash function. According to this only 16 bits of a CRC32 are evenly distributed. So what other transformation would one apply to overcome that? Update How about this? Only 16 bits are suitable for a hash value. Fine. If your table is 65535 or less then great. If not, run the CRC value through the Nehalem POPCNT (population count) instruction to get the number of bits set. Then, use that as an index into an array of tables. This works if