PJW Hash

PJW is a hash function algorithm.

• C#
• VB.Net
• C
• C++

									unsigned int PJWHash(char* str, unsigned int length) {
	const unsigned int BitsInUnsignedInt = (unsigned int)(sizeof(unsigned int) * 8);
	const unsigned int ThreeQuarters = (unsigned int)((BitsInUnsignedInt * 3) / 4);
	const unsigned int OneEighth = (unsigned int)(BitsInUnsignedInt / 8);
	const unsigned int HighBits = (unsigned int)(0xFFFFFFFF) << (BitsInUnsignedInt - OneEighth);
	unsigned int hash = 0;
	unsigned int test = 0;
	unsigned int i = 0;

	for (i = 0; i < length; str++, i++)
	{
		hash = (hash << OneEighth) + (*str);

		if ((test = hash & HighBits) != 0)
		{
			hash = ((hash ^ (test >> ThreeQuarters)) & (~HighBits));
		}
	}

	return hash;
}
								

Example

									char* data = "jdfgsdhfsdfsd 6445dsfsd7fg/*/+bfjsdgf%$^";
unsigned int value = PJWHash(data, 40);
								

Output

									248446350