magellan/Lucidiot.Raima/Helpers.cs

using System.IO;
using System.Runtime.InteropServices;
using System;

namespace Lucidiot.Raima {
    internal static class Helpers {
        internal class ParsingException : Exception {
            public readonly byte[] ErroneousBytes;
            public readonly Type DestinationType;

            public ParsingException(byte[] bytes, Type type)
                : this(bytes, type, String.Format("An error occurred while parsing binary data into a {0} type.", type.AssemblyQualifiedName)) { }

            public ParsingException(byte[] bytes, Type type, string message)
                : base(message) {
                this.ErroneousBytes = bytes;
                this.DestinationType = type;
            }

            public ParsingException(byte[] bytes, Type type, Exception innerException)
                : this(bytes, type, String.Format("An error occurred while parsing binary data into a {0} type.", type.AssemblyQualifiedName), innerException) { }

            public ParsingException(byte[] bytes, Type type, string message, Exception innerException)
                : base(message, innerException) {
                this.ErroneousBytes = bytes;
                this.DestinationType = type;
            }
        }

        internal static T ReadStruct<T>(BinaryReader reader) where T : struct {
            byte[] bytes = reader.ReadBytes(Marshal.SizeOf(typeof(T)));
            GCHandle handle = GCHandle.Alloc(bytes, GCHandleType.Pinned);
            T parsedStruct;
            try {
                parsedStruct = (T)Marshal.PtrToStructure(handle.AddrOfPinnedObject(), typeof(T));
            } catch (TypeLoadException e) {
                throw new ParsingException(bytes, typeof(T), e);
            } finally {
                handle.Free();
            }
            return parsedStruct;
        }
    }
}