lyfz_repos/铂金版源码/C＃基本媒体文件格式库/basemedia/BMFF/MatrixIO.IO.Bmff/IO/Bmff/BmffReader.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using MatrixIO.IO.Bmff;

namespace MatrixIO.IO.Bmff
{
    public class BmffReader : ISuperBox, IEnumerable<Box>
    {
        private readonly Stream _baseStream;
        public Stream BaseStream { get { return _baseStream; } }

        private IList<Box> _rootBoxes;
        public IList<Box> RootBoxes
        {
            get
            {
#pragma warning disable 612,618
                if (_rootBoxes == null) return _rootBoxes = Portability.CreateList<Box>(GetBoxes());
#pragma warning restore 612,618
                return _rootBoxes;
            }
        }

        public bool RandomAccess { get { return _baseStream.CanSeek; } }

        #region Navigation
        private readonly Stack<Box> _boxStack = new Stack<Box>();

        public int Depth
        {
            get
            {
                return _boxStack.Count;
            }
        }

        public Box CurrentBox
        {
            get
            {
                return _boxStack.Peek();
            }
        }

        public bool HasChildren
        {
            get
            {
                if (CurrentBox is ISuperBox) return true;
                else return false;
            }
        }
        #endregion

        public BmffReader(Stream stream)
        {
            if (stream.CanSeek && stream.Position!=0) stream.Seek(0, SeekOrigin.Begin);
            _baseStream = stream;
        }

        [Obsolete("Use the BaseMedia class instead.")]
        public void Scan()
        {
            GetBoxes();
        }

        /// <summary>
        /// Traverses the tree of Boxes in file order (depth-first)
        /// </summary>
        /// <returns>IEnumerable collection of Box types in file order.</returns>
        [Obsolete("Use the BaseMedia class instead.")]
        public IEnumerable<Box> GetBoxes()
        {
            Box box = null;
            do
            {
                box = Box.FromStream(_baseStream);
                if (box != null) yield return box;
            } while (box != null);
        }
        /// <summary>
        /// Seeks to the beginning of the file and reads the "ftyp" Box.
        /// </summary>
        /// <returns>FileTypeBox</returns>
        [Obsolete]
        public Boxes.FileTypeBox GetFileTypeBox()
        {
            if (_baseStream.CanSeek && _baseStream.Position!=0) _baseStream.Seek(0, SeekOrigin.Begin);

            // TODO: Support files where "ftyp" is not the first FourCC like JPEG2000.
            return Box.FromStream<Boxes.FileTypeBox>(_baseStream);
        }

        /// <summary>
        /// Seek to the end of the file and returns the "mfro" Box for a Microsoft Smooth Streaming PIFF format file that gives
        /// you the chunk offsets within the file.
        /// </summary>
        /// <returns>MovieFragmentRandomAccessBox</returns>
        // TODO: Move to a new MatrixIO.IO.Piff.??? class
        public Boxes.MovieFragmentRandomAccessBox GetMovieFragmentRandomAccessBox()
        {
            _baseStream.Seek(-24, SeekOrigin.End);

            byte[] mfrobuf = _baseStream.ReadBytes(24);

            uint mfraOffset;
            if (BitConverter.ToUInt32(mfrobuf, 12).NetworkToHostOrder() == 0x6d66726f ||
                BitConverter.ToUInt32(mfrobuf, 4).NetworkToHostOrder() == 0x6d66726f) // 'mfro'
            {
                mfraOffset = BitConverter.ToUInt32(mfrobuf, 20).NetworkToHostOrder();
            }
            else return null;

            _baseStream.Seek(-mfraOffset, SeekOrigin.End);

            return new Boxes.MovieFragmentRandomAccessBox(_baseStream);
        }

        [Obsolete("Use the BaseMedia class instead.")]
        IList<Box> ISuperBox.Children
        {
            get { return RootBoxes; }
        }

        [Obsolete("Use the BaseMedia class instead.")]
        IEnumerator<Box> IEnumerable<Box>.GetEnumerator()
        {
            return RootBoxes.GetEnumerator();
        }

        [Obsolete("Use the BaseMedia class instead.")]
        System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
        {
            return RootBoxes.GetEnumerator();
        }
    }
}