/**
 * freebsdのDigest-FNV-1.00の移植
 * License: Public Domain
 */

uint FNV_32_PRIME=0x01000193u;///32 bit magic FNV-0 and FNV-1 prime

uint FNV0_32_INIT=0u;
uint FNV1_32_INIT=0x811c9dc5u;

private uint toFnv32(ubyte[] buf, uint hval){
    //FNV-1 hash each octet in the buffer
    foreach(ubyte bp;buf){
      // multiply by the 32 bit FNV magic prime mod 2^32
      version(NO_FNV_GCC_OPTIMIZATION)
        hval *= FNV_32_PRIME;
      else
        hval += (hval<<1) + (hval<<4) + (hval<<7) + (hval<<8) + (hval<<24);
      hval ^= cast(uint)bp;//xor the bottom with the current octet
    }
    return hval;//return our new hash value
}

///ラッパ
class Fnv32{
  ///fnv-0で初期化します。
  this(){
    this(0);
  }
  ///バージョンを指定して初期化します。
  this(uint ver){
    if(ver==0){
      hval=FNV0_32_INIT;
    }else if(ver==1){
      hval=FNV1_32_INIT;
    }else assert(0);
  }
  protected uint hval;
  ///計算します。
  uint sum(ubyte[] buf){
    hval=toFnv32(buf,hval);
    return hval;
  }
}

unittest{
  Fnv32 fnv=new Fnv32(1);
  assert(fnv.sum(cast(ubyte[])"test")==3157003241);
  assert(fnv.sum(cast(ubyte[])"test")==341400645);
}
//int main(){return 0;}