using System;
using System.IO;

namespace PinkbrainSilverlightApplication.Id3Reader.Util
{
    public class Id3BinaryReader: BinaryReader
    {
        public Id3BinaryReader(Stream stream): base(stream)
        {

        }

        public UInt32 ReadUInt32FromUnsafeBigEndian()
        {
            byte[] unsafeUIntBytes = this.ReadBytes(4);
            byte[] correctedBytes = new byte[4];

            correctedBytes[3] = (byte)(((unsafeUIntBytes[3] >> 0) & 0x7f) | ((unsafeUIntBytes[2] & 0x01) << 7));
            correctedBytes[2] = (byte)(((unsafeUIntBytes[2] >> 1) & 0x3f) | ((unsafeUIntBytes[1] & 0x03) << 6));
            correctedBytes[1] = (byte)(((unsafeUIntBytes[1] >> 2) & 0x1f) | ((unsafeUIntBytes[0] & 0x07) << 5));
            correctedBytes[0] = (byte)(((unsafeUIntBytes[0] >> 3) & 0x0f));

            return (UInt32) ((correctedBytes[0] << 24) | (correctedBytes[1] << 16) | (correctedBytes[2] << 8) | correctedBytes[3]);
        }
    }
}