我如何计算CRC32作为C＃中的有符号整数？ [英] How can I calculate a CRC32 as a signed integer in C#?
问题描述
我是一名PHP开发人员，并且在C＃中出现了一点问题。在PHP中，有一个 crc32（）函数，它返回一个有符号整数任何你传入的字符串。
所以这就是我习惯的：
<？php
echo crc32（test）;
//显示-662733300
我想在C＃中做同样的事情。我遇到了这个C＃类库，但对此知之甚少。根据他的指示，我应该这样做：
//首先将字符串转换为字节数组
String input =test;
byte [] bytes = new byte [input.length * sizeof（char）];
System.Buffer.BlockCopy（input.ToCharArray（），0，bytes，0，bytes.Length）;
//然后计算
的值Crc32 crc32 = new Crc32（）;
String output =;
foreach（crc32.ComputeHash（bytes）中的字节b）
{
output + = b.ToString（x2）。ToLower（）;
}
这给了我一个 27d86d6a 。我需要做什么来返回一个有符号的整数？ （在这个例子中，它应该等于 -662733300 ）
var crcVal = BitConverter.ToInt32（crc32.ComputeHash（bytes），0）;
编辑
<看起来你使用了不同的Crc32算法实现，请尝试以下方法之一：使用System;使用System;
使用System.Collections.Generic;
使用System.Security.Cryptography;
public class Program
{
public void Main（）
{
//首先将字符串转换为字节数组
String输入= 测试;
byte [] bytes = new byte [input.Length * sizeof（char）];
System.Buffer.BlockCopy（input.ToCharArray（），0，bytes，0，bytes.Length）;
//然后计算
的值var crcVal = crc32（input）;
Console.WriteLine（（int）crcVal）;
$ b public uint crc32（string input）{
var table = 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，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 0x5F058 808，0xC60CD9B2，0xB10BE924，
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，0x29D9C9 98，0xB0D09822，0xC7D7A8B4，0x59B33D17，0x2EB40D81，
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，0xC4614AB8，0x5D681B02，0x2A6F2 B94，
0xB40BBE37，0xC30C8EA1，0x5A05DF1B，0x2D02EF8D
};
unchecked
{
uint crc =（uint）（（（uint）0）^（-1））;
var len = input.Length;
for（var i = 0; i< len; i ++）{
crc =（crc>> 8）^ table [
（crc ^（byte）input [i] ）& 0xFF
];
}
crc =（uint）（crc ^（-1））;
if（crc <0）{
crc + =（uint）4294967296;
}
return crc;
$ b
I'm a PHP developer and a little out of my element in C#. In PHP, there's a crc32() function which returns a signed integer for any string that you pass in.
So this is what I'm used to:
<?php
echo crc32("test");
// displays -662733300
I would like to do the same thing in C#. I came across this C# class library but understand little about it. According to his instructions, I'm supposed to do this:
// first convert string to byte-array
String input = "test";
byte[] bytes = new byte[input.length * sizeof(char)];
System.Buffer.BlockCopy(input.ToCharArray(), 0, bytes, 0, bytes.Length);
// then calculate the value
Crc32 crc32 = new Crc32();
String output = "";
foreach (byte b in crc32.ComputeHash(bytes))
{
output += b.ToString("x2").ToLower();
}
That gives me an output string of 27d86d6a. What do I need to do instead to return a signed integer? (Which in this example should equal -662733300)
Try use BitConverter.ToInt32 method:
var crcVal = BitConverter.ToInt32(crc32.ComputeHash(bytes), 0);
EDIT
It's seems you use different Crc32 algorithm implementation, try the following one:
using System;
using System.Collections.Generic;
using System.Security.Cryptography;
public class Program
{
public void Main()
{
// first convert string to byte-array
String input = "test";
byte[] bytes = new byte[input.Length * sizeof(char)];
System.Buffer.BlockCopy(input.ToCharArray(), 0, bytes, 0, bytes.Length);
// then calculate the value
var crcVal = crc32(input);
Console.WriteLine((int)crcVal);
}
public uint crc32(string input) {
var table = 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, 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
};
unchecked
{
uint crc = (uint)(((uint)0) ^ (-1));
var len = input.Length;
for (var i=0; i < len; i++) {
crc = (crc >> 8) ^ table[
(crc ^ (byte)input[i]) & 0xFF
];
}
crc = (uint)(crc ^ (-1));
if (crc < 0) {
crc += (uint)4294967296;
}
return crc;
}
}
}
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