COD: MWR hash function (FNV1a)

cod_hash_dvars.py

# python cod_hash_dvars.py <dvars.txt>

import os
import sys
import ctypes

# COD: MWR
FNV32_PRIME = 0xB3CB2E29
FNV32_BASIS = 0x319712C3

def uint32(v):
  return ctypes.c_uint32(v).value

def fnv1a_hash(data):
  hval = FNV32_BASIS

  for i in range(0, len(data)):
    hval = uint32(hval ^ data[i])
    hval = uint32(hval * FNV32_PRIME)

  return hval

if len(sys.argv) == 2:
  input_file_path = sys.argv[1]
  output_file_path = os.path.splitext(sys.argv[1])[0] + '_hashes.txt'
  
  with open(input_file_path, "r") as input_file:
    with open(output_file_path, "w") as output_file:
      for dvar_name in input_file:
        dvar_name = dvar_name.rstrip("\r\n")
        dvar_hash = fnv1a_hash(bytearray(dvar_name.lower() + '\x00'))
        output_file.write("%-30s = 0x%08X\n" % (dvar_name, dvar_hash))

  print "done, output file is \"%s\"" % output_file_path