stream.cs

using System;
using System.Numerics;
using System.Collections.Generic;
using Hash;

namespace Hash {
    public static class Stream{
        
        //Wrap-function to make use of stream easier
        public static List<Tuple<ulong, int>> CreateStreamWrap( int n , int l ) {
            IEnumerable <Tuple<ulong, int>> stream = CreateStream(n,l);
            List<Tuple<ulong,int>> retLst = new List<Tuple<ulong, int>>();
            var e = stream.GetEnumerator();
            while (e.MoveNext()) {
                retLst.Add(e.Current);
            }
            return retLst;
        }

        // Copy-paste fun from project describtion
        public static IEnumerable <Tuple<ulong, int>> CreateStream( int n , int l ) {
            // We generate a random uint64 number .
            Random rnd = new System.Random () ;
            ulong a = 0UL ;
            Byte [] b = new Byte [8];
            rnd . NextBytes ( b ) ;
            for( int i = 0; i < 8; ++ i ) {
                a = ( a << 8) + ( ulong ) b [ i ];
            }
            // We demand that our random number has 30 zeros on the least
            // significant bits and then a one.
            a = ( a | ((1UL << 31) - 1UL ) ) ^ ((1UL << 30) - 1UL ) ;
            ulong x = 0UL ;
            for( int i = 0; i < n /3; ++ i ) {
            x = x + a ;
            yield return Tuple . Create ( x & (((1UL << l ) - 1UL ) <<
            30) , 1) ;
            }
            for( int i = 0; i < ( n + 1) /3; ++ i ) {
            x = x + a ;
            yield return Tuple . Create ( x & (((1UL << l ) - 1UL ) <<
            30) , -1) ;
            }
            for( int i = 0; i < ( n + 2) /3; ++ i ) {
            x = x + a ;
            yield return Tuple . Create ( x & (((1UL << l ) - 1UL ) <<
            30) , 1) ;
            }
        }
    }
}