Slash - Fast, efficient hash

README.md

Slash

Fast, efficient hash

Usage

char *str = "Slash";
unsigned long long hash = slash(str);

Implementation

1. The result is initialized at 1
2. For each byte (8 bits):
   • Set the result to (result @ prime) ^ (byte)
3. Return 64 bit unsigned result

Details

• @ denotes carry-less multiplication
• ^ denotes exclusive OR (XOR)
• byte denotes the current byte being operated on
• prime is a constant chosen by a simulated annealing algorithm (0xA171020315130201ULL)

License

Licensed under the MIT License by Kabir Shah

slash.c

/**
 * Slash
 * Fast, efficient hash
 * Copyright 2017 Kabir Shah
 * Released under the MIT License
 */

unsigned long long slash(const unsigned char *key) {
  unsigned long long result = 1;
  unsigned long long current;
  
  while((current = *key++) != '\0') {
    result = ((result) ^ (result << 9) ^ (result << 16) ^ (result << 17) ^ (result << 20) ^ (result << 24) ^ (result << 26) ^ (result << 28) ^ (result << 32) ^ (result << 33) ^ (result << 41) ^ (result << 48) ^ (result << 52) ^ (result << 53) ^ (result << 54) ^ (result << 56) ^ (result << 61) ^ (result << 63)) ^ (current);
    result = (result >> 7) | (result << 57);
  }
  
  return result;
}