/Signum.Utilities/Extensions.cs

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Reflection;

using System.IO;

using System.Runtime.Serialization.Formatters.Binary;

using System.Diagnostics;

using System.Globalization;



namespace Signum.Utilities

{

    [DebuggerStepThrough]

    public static class Extensions

    {

        #region Parse Number

        public static int? ToInt(this string str)

        {

            int result;

            if (int.TryParse(str, out result))

                return result;

            else

                return null;

        }



        public static long? ToLong(this string str)

        {

            long result;

            if (long.TryParse(str, out result))

                return result;

            else

                return null;

        }



        public static short? ToShort(this string str)

        {

            short result;

            if (short.TryParse(str, out result))

                return result;

            else

                return null;

        }



        public static float? ToFloat(this string str)

        {

            float result;

            if (float.TryParse(str, out result))

                return result;

            else

                return null;

        }



        public static double? ToDouble(this string str)

        {

            double result;

            if (double.TryParse(str, out result))

                return result;

            else

                return null;

        }



        public static decimal? ToDecimal(this string str)

        {

            decimal result;

            if (decimal.TryParse(str, out result))

                return result;

            else

                return null;

        }



        public static int ToInt(this string str, string error)

        {

            int result;

            if (int.TryParse(str, out result))

                return result;



            throw new FormatException(error);

        }



        public static long ToLong(this string str, string error)

        {

            long result;

            if (long.TryParse(str, out result))

                return result;



            throw new FormatException(error);

        }



        public static short ToShort(this string str, string error)

        {

            short result;

            if (short.TryParse(str, out result))

                return result;



            throw new FormatException(error);

        }





        public static float? ToFloat(this string str, string error)

        {

            float result;

            if (float.TryParse(str, out result))

                return result;



            throw new FormatException(error);

        }



        public static double ToDouble(this string str, string error)

        {

            double result;

            if (double.TryParse(str, out result))

                return result;



            throw new FormatException(error);

        }



        public static decimal ToDecimal(this string str, string error)

        {

            decimal result;

            if (decimal.TryParse(str, out result))

                return result;



            throw new FormatException(error);

        }

        

        #endregion



        #region Math



        //http://en.wikipedia.org/wiki/Modulo_operation

        public static int Mod(this int a, int b)

        {

            int result = a % b;



            if (a < 0)

                result += b;



            if (b < 0)

                result -= b;



            return result;

        }





        public static long Mod(this long a, long b)

        {

            long mod = a % b;



            if (a < 0)

                mod += b;



            if (b < 0)

                mod -= b;



            return mod;

        }



        public static int DivMod(this int a, int b, out int mod)

        {

            int result = Math.DivRem(a, b, out mod);



            if (a < 0)

            {

                result--;

                mod += b;

            }



            if (b < 0)

            {

                result++;

                mod -= b;

            }



            return result;

        }



        public static long DivMod(this long a, long b, out long mod)

        {

            long result = Math.DivRem(a, b, out mod);



            if (a < 0)

            {

                result--;

                mod += b;

            }



            if (b < 0)

            {

                result++;

                mod -= b;

            }



            return result;

        }



        #endregion



        public static T? DefaultToNull<T>(this T value)

            where T : struct

        {

            return EqualityComparer<T>.Default.Equals(default(T), value) ? (T?)null : value;

        }



        public static T? DefaultToNull<T>(this T value, T defaultValue)

            where T : struct

        {

            return EqualityComparer<T>.Default.Equals(defaultValue, value) ? (T?)null : value;

        }



        public static int? NotFoundToNull(this int value)

        {

            return value == -1 ? null : (int?)value; 

        }



        public static int NotFound(this int value, int defaultValue)

        {

            return value == -1 ? defaultValue : value;

        }



        public static T ThrowIfNullS<T>(this T? t, string mensaje)

         where T : struct

        {

            if (t == null)

                throw new NullReferenceException(mensaje);

            return t.Value;

        }



        public static T ThrowIfNullC<T>(this T t, string mensaje)

            where T : class

        {

            if (t == null)

                throw new NullReferenceException(mensaje);

            return t;

        }



        public static string TryToString(this object obj)

        {

            if (obj == null)

                return null;

            return obj.ToString(); 

        }



        public static string TryToString(this IFormattable obj, string format)

        {

            if (obj == null)

                return null;

            return obj.ToString(format, CultureInfo.CurrentCulture);

        }



        #region Map Try Do TryDo

        public static R Map<T, R>(this T t, Func<T, R> func)

        {

            return func(t);

        }



        public static R TryCC<T, R>(this T t, Func<T, R> func)

            where T : class

            where R : class

        {

            if (t == null) return null;

            return func(t);

        }



        public static R? TryCS<T, R>(this T t, Func<T, R> func)

            where T : class

            where R : struct

        {

            if (t == null) return null;

            return func(t);

        }



        public static R? TryCS<T, R>(this T t, Func<T, R?> func)

            where T : class

            where R : struct

        {

            if (t == null) return null;

            return func(t);

        }



        public static R TrySC<T, R>(this T? t, Func<T, R> func)

            where T : struct

            where R : class

        {

            if (t == null) return null;

            return func(t.Value);

        }



        public static R? TrySS<T, R>(this T? t, Func<T, R> func)

            where T : struct

            where R : struct

        {

            if (t == null) return null;

            return func(t.Value);

        }



        public static R? TrySS<T, R>(this T? t, Func<T, R?> func)

            where T : struct

            where R : struct

        {

            if (t == null) return null;

            return func(t.Value);

        }







        public static T Do<T>(this T t, Action<T> action)

        {

            action(t);

            return t;

        }



        public static T TryDoC<T>(this T t, Action<T> action) where T : class

        {

            if (t != null)

                action(t);

            return t;

        }



        public static T? TryDoS<T>(this T? t, Action<T> action) where T : struct

        {

            if (t != null)

                action(t.Value);

            return t;

        } 

        #endregion



        public static IEnumerable<int> To(this int start, int endNotIncluded)

        {

            for (int i = start; i < endNotIncluded; i++)

                yield return i;

        }



        public static IEnumerable<int> To(this int start, int endNotIncluded, int step)

        {

            for (int i = start; i < endNotIncluded; i += step)

                yield return i;

        }



        public static IEnumerable<DateTime> To(this DateTime start, DateTime endNotIncluded)

        {

            for (DateTime i = start; i < endNotIncluded; i = i.AddDays(1))

                yield return i;

        }



        public static IEnumerable<DateTime> To(this DateTime start, DateTime endNotIncluded, TimeSpan span)

        {

            for (DateTime i = start; i < endNotIncluded; i = i.Add(span))

                yield return i;

        }



        public static IEnumerable<int> DownTo(this int startNotIncluded, int end)

        {

            for (int i = startNotIncluded - 1; i >= end; i--)

                yield return i;

        }



        public static IEnumerable<int> DownTo(this int startNotIncluded, int end, int step)

        {

            for (int i = startNotIncluded - 1; i >= end; i-= step)

                yield return i;

        }



        public static IEnumerable<T> For<T>(this T start, Func<T, bool> condition, Func<T, T> increment)

        {

            for (T i = start; condition(i); i = increment(i))

                yield return i;

        }



        public static IEnumerable<T> FollowC<T>(this T start, Func<T, T> next) where T : class

        {

            for (T i = start; i != null; i = next(i))

                yield return i;

        }



        public static IEnumerable<T> FollowS<T>(this T start, Func<T, T?> next) where T : struct

        {

            for (T? i = start; i.HasValue; i = next(i.Value))

                yield return i.Value;

        }



        public static IEnumerable<T> FollowS<T>(this T? start, Func<T, T?> next) where T : struct

        {

            for (T? i = start; i.HasValue; i = next(i.Value))

                yield return i.Value;

        }

    }



}