/WCFWebApi/src/System.Net.Http/System/Net/Http/Headers/Int64NumberHeaderParser.cs

using System.Diagnostics.Contracts;

using System.Globalization;



namespace System.Net.Http.Headers

{

    internal class Int64NumberHeaderParser : BaseHeaderParser

    {

        // Note that we don't need a custom comparer even though we have a value type that gets boxed (comparing two

        // equal boxed value types returns 'false' since the object instances used for boxing the two values are 

        // different). The reason is that the comparer is only used by HttpHeaders when comparing values in a collection.

        // Value types are never used in collections (in fact HttpHeaderValueCollection expects T to be a reference

        // type).



        internal static readonly Int64NumberHeaderParser Parser = new Int64NumberHeaderParser();



        private Int64NumberHeaderParser()

            : base(false)

        {

        }



        public override string ToString(object value)

        {

            Contract.Assert(value is long);



            return ((long)value).ToString(NumberFormatInfo.InvariantInfo);

        }



        protected override int GetParsedValueLength(string value, int startIndex, object storeValue, 

            out object parsedValue)

        {

            parsedValue = null;



            int numberLength = HttpRuleParser.GetNumberLength(value, startIndex, false);



            if ((numberLength == 0) || (numberLength > HttpRuleParser.MaxInt64Digits))

            {

                return 0;

            }



            long result = 0;

            if (!HeaderUtilities.TryParseInt64(value.Substring(startIndex, numberLength), out result))

            {

                return 0;

            }



            parsedValue = result;

            return numberLength;

        }

    }

}