将CRC C算法移植到C#

Question

我在C中有这个函数，我需要将它移植到C#。我做了几次尝试，但都不明白我做错了什么。

多项式为0x04C11DB7uL。

它不必包含while循环，我也尝试过使用For循环。

static uint32_t APPL_CalcCRC32(uint32_t u32Sum, uint8_t *pData, uint32_t count)
{
uint8_t iCounter;
uint32_t u32Word;
uint64_t u64Sum;
u64Sum = u32Sum;
count = count / 4;  // number of bytes --> number of words
// algorithm according to AN4187 (Figure 2)
while (count--)
{
u32Word = *((uint32_t*)pData)++;
u64Sum ^= u32Word;
for (iCounter = 0; iCounter < (8 * 4); ++iCounter)
{
u64Sum <<= 1;
if (u64Sum & 0x100000000)
{
u64Sum ^= 0x04C11DB7uL;
}
}
}
return (uint32_t)u64Sum;
}

这是我的尝试：

private uint CalculateBlockCheckSum( uint u32Sum, byte[] blockImage )
{
uint u32Word;
ulong u64Sum = u32Sum;
ulong comparisonValue = 0x100000000;
int count = blockImage.Length / 4;
int i = 0;
while ( count-- >= 0 )
{
u32Word = blockImage[i++];
u64Sum ^= u32Word;
for ( byte iCounter = 0; iCounter < ( 8 * 4 ); ++iCounter )
{
u64Sum <<= 1;
if ( ( u64Sum & comparisonValue ) != 0 )
{
u64Sum ^= 0x04C11DB7uL;
}
}
}
return (uint)u64Sum;
}

我的主要疑虑是C#函数中的u32Word赋值和循环标准，对吗？

我的测试设置是58个数组(块(，每个块1024字节。但这两个函数的输出并不相同。那么，是我的函数错了，还是其他原因？

Answer 1

您只需要在移动数据块的下一个值时更改行：

private uint CalculateBlockCheckSum(uint u32Sum, byte[] blockImage)
{
uint u32Word;
ulong u64Sum = u32Sum;
ulong comparisonValue = 0x100000000;
int count = blockImage.Length / sizeof(uint);
int i = 0;
while (count-- > 0)
{
u32Word = BitConverter.ToUInt32(blockImage,i*sizeof(uint));
u64Sum ^= u32Word;
for (byte iCounter = 0; iCounter < (8 * 4); ++iCounter)
{
u64Sum <<= 1;
if ((u64Sum & comparisonValue) != 0)
{
u64Sum ^= 0x04C11DB7uL;
}
}
i++;
}
return (uint)u64Sum;
}