metadatatag.cs

对gif

// ==========================================================
// FreeImage 3 .NET wrapper
// Original FreeImage 3 functions and .NET compatible derived functions
//
// Design and implementation by
// - Jean-Philippe Goerke ([e-mail])
// - Carsten Klein ([e-mail])
//
// Contributors:
// - David Boland ([e-mail])
//
// Main reference : MSDN Knowlede Base
//
// This file is part of FreeImage 3
//
// COVERED CODE IS PROVIDED UNDER THIS LICENSE ON AN "AS IS" BASIS, WITHOUT WARRANTY
// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, WITHOUT LIMITATION, WARRANTIES
// THAT THE COVERED CODE IS FREE OF DEFECTS, MERCHANTABLE, FIT FOR A PARTICULAR PURPOSE
// OR NON-INFRINGING. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE COVERED
// CODE IS WITH YOU. SHOULD ANY COVERED CODE PROVE DEFECTIVE IN ANY RESPECT, YOU (NOT
// THE INITIAL DEVELOPER OR ANY OTHER CONTRIBUTOR) ASSUME THE COST OF ANY NECESSARY
// SERVICING, REPAIR OR CORRECTION. THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL
// PART OF THIS LICENSE. NO USE OF ANY COVERED CODE IS AUTHORIZED HEREUNDER EXCEPT UNDER
// THIS DISCLAIMER.
//
// Use at your own risk!
// ==========================================================

// ==========================================================
// CVS
// $Revision: 1.5 $
// $Date: 2008/07/25 07:30:13 $
// $Id: MetadataTag.cs,v 1.5 2008/07/25 07:30:13 cklein05 Exp $
// ==========================================================

using System;
using System.Text;
using System.Runtime.InteropServices;
using System.Collections.Generic;

namespace FreeImageAPI.Metadata
{
	/// <summary>
	/// Manages metadata objects and operations.
	/// </summary>
	public sealed class MetadataTag : IComparable, IComparable<MetadataTag>, ICloneable, IEquatable<MetadataTag>, IDisposable
	{
		/// <summary>
		/// The encapsulated FreeImage-tag.
		/// </summary>
		internal FITAG tag;
		/// <summary>
		/// The metadata model of <see cref="tag"/>.
		/// </summary>
		private FREE_IMAGE_MDMODEL model;
		/// <summary>
		/// Indicates whether this instance has already been disposed.
		/// </summary>
		private bool disposed = false;
		/// <summary>
		/// Indicates whether this instance was created by FreeImage or
		/// by the user.
		/// </summary>
		private bool selfCreated;
		/// <summary>
		/// List linking metadata-model and Type.
		/// </summary>
		private static readonly Dictionary<FREE_IMAGE_MDTYPE, Type> idList;
		/// <summary>
		/// List linking Type and metadata-model.
		/// </summary>
		private static readonly Dictionary<Type, FREE_IMAGE_MDTYPE> typeList;

		/// <summary>
		/// Initializes a new instance of this class.
		/// </summary>
		private MetadataTag()
		{
		}

		/// <summary>
		/// Initializes a new instance of this class.
		/// </summary>
		/// <param name="model">The new model the tag should be of.</param>
		public MetadataTag(FREE_IMAGE_MDMODEL model)
		{
			this.model = model;
			tag = FreeImage.CreateTag();
			selfCreated = true;

			if (model == FREE_IMAGE_MDMODEL.FIMD_XMP)
			{
				Key = "XMLPacket";
			}
		}

		/// <summary>
		/// Initializes a new instance of this class.
		/// </summary>
		/// <param name="tag">The <see cref="FITAG"/> to represent.</param>
		/// <param name="dib">The bitmap <paramref name="tag"/> was extracted from.</param>
		public MetadataTag(FITAG tag, FIBITMAP dib)
		{
			if (tag.IsNull)
			{
				throw new ArgumentNullException("tag");
			}
			if (dib.IsNull)
			{
				throw new ArgumentNullException("dib");
			}
			this.tag = tag;
			model = GetModel(dib, tag);
			selfCreated = false;

			if (model == FREE_IMAGE_MDMODEL.FIMD_XMP)
			{
				Key = "XMLPacket";
			}
		}

		/// <summary>
		/// Initializes a new instance of this class.
		/// </summary>
		/// <param name="tag">The <see cref="FITAG"/> to represent.</param>
		/// <param name="model">The model of <paramref name="tag"/>.</param>
		public MetadataTag(FITAG tag, FREE_IMAGE_MDMODEL model)
		{
			if (tag.IsNull)
			{
				throw new ArgumentNullException("tag");
			}
			this.tag = tag;
			this.model = model;
			selfCreated = false;

			if (model == FREE_IMAGE_MDMODEL.FIMD_XMP)
			{
				Key = "XMLPacket";
			}
		}

		static MetadataTag()
		{
			idList = new Dictionary<FREE_IMAGE_MDTYPE, Type>();
			idList.Add(FREE_IMAGE_MDTYPE.FIDT_BYTE, typeof(byte));
			idList.Add(FREE_IMAGE_MDTYPE.FIDT_SHORT, typeof(ushort));
			idList.Add(FREE_IMAGE_MDTYPE.FIDT_LONG, typeof(uint));
			idList.Add(FREE_IMAGE_MDTYPE.FIDT_RATIONAL, typeof(FIURational));
			idList.Add(FREE_IMAGE_MDTYPE.FIDT_SBYTE, typeof(sbyte));
			idList.Add(FREE_IMAGE_MDTYPE.FIDT_UNDEFINED, typeof(byte));
			idList.Add(FREE_IMAGE_MDTYPE.FIDT_SSHORT, typeof(short));
			idList.Add(FREE_IMAGE_MDTYPE.FIDT_SLONG, typeof(int));
			idList.Add(FREE_IMAGE_MDTYPE.FIDT_SRATIONAL, typeof(FIRational));
			idList.Add(FREE_IMAGE_MDTYPE.FIDT_FLOAT, typeof(float));
			idList.Add(FREE_IMAGE_MDTYPE.FIDT_DOUBLE, typeof(double));
			idList.Add(FREE_IMAGE_MDTYPE.FIDT_IFD, typeof(uint));
			idList.Add(FREE_IMAGE_MDTYPE.FIDT_PALETTE, typeof(RGBQUAD));

			typeList = new Dictionary<Type, FREE_IMAGE_MDTYPE>();
			typeList.Add(typeof(ushort), FREE_IMAGE_MDTYPE.FIDT_SHORT);
			typeList.Add(typeof(ushort[]), FREE_IMAGE_MDTYPE.FIDT_SHORT);
			typeList.Add(typeof(string), FREE_IMAGE_MDTYPE.FIDT_ASCII);
			typeList.Add(typeof(uint), FREE_IMAGE_MDTYPE.FIDT_LONG);
			typeList.Add(typeof(uint[]), FREE_IMAGE_MDTYPE.FIDT_LONG);
			typeList.Add(typeof(FIURational), FREE_IMAGE_MDTYPE.FIDT_RATIONAL);
			typeList.Add(typeof(FIURational[]), FREE_IMAGE_MDTYPE.FIDT_RATIONAL);
			typeList.Add(typeof(sbyte), FREE_IMAGE_MDTYPE.FIDT_SBYTE);
			typeList.Add(typeof(sbyte[]), FREE_IMAGE_MDTYPE.FIDT_SBYTE);
			typeList.Add(typeof(byte), FREE_IMAGE_MDTYPE.FIDT_UNDEFINED);
			typeList.Add(typeof(byte[]), FREE_IMAGE_MDTYPE.FIDT_UNDEFINED);
			typeList.Add(typeof(short), FREE_IMAGE_MDTYPE.FIDT_SSHORT);
			typeList.Add(typeof(short[]), FREE_IMAGE_MDTYPE.FIDT_SSHORT);
			typeList.Add(typeof(int), FREE_IMAGE_MDTYPE.FIDT_SLONG);
			typeList.Add(typeof(int[]), FREE_IMAGE_MDTYPE.FIDT_SLONG);
			typeList.Add(typeof(FIRational), FREE_IMAGE_MDTYPE.FIDT_SRATIONAL);
			typeList.Add(typeof(FIRational[]), FREE_IMAGE_MDTYPE.FIDT_SRATIONAL);
			typeList.Add(typeof(float), FREE_IMAGE_MDTYPE.FIDT_FLOAT);
			typeList.Add(typeof(float[]), FREE_IMAGE_MDTYPE.FIDT_FLOAT);
			typeList.Add(typeof(double), FREE_IMAGE_MDTYPE.FIDT_DOUBLE);
			typeList.Add(typeof(double[]), FREE_IMAGE_MDTYPE.FIDT_DOUBLE);
			typeList.Add(typeof(RGBQUAD), FREE_IMAGE_MDTYPE.FIDT_PALETTE);
			typeList.Add(typeof(RGBQUAD[]), FREE_IMAGE_MDTYPE.FIDT_PALETTE);
		}

		/// <summary>
		/// Releases all resources used by the instance.
		/// </summary>
		~MetadataTag()
		{
			Dispose();
		}

		/// <summary>
		/// Determines whether two specified <see cref="MetadataTag"/> objects have the same value.
		/// </summary>
		/// <param name="left">A <see cref="MetadataTag"/> or a null reference (<b>Nothing</b> in Visual Basic).</param>
		/// <param name="right">A <see cref="MetadataTag"/> or a null reference (<b>Nothing</b> in Visual Basic).</param>
		/// <returns>
		/// <b>true</b> if the value of left is the same as the value of right; otherwise, <b>false</b>.
		/// </returns>
		public static bool operator ==(MetadataTag left, MetadataTag right)
		{
			// Check whether both are null
			if (Object.ReferenceEquals(left, null) && Object.ReferenceEquals(right, null))
			{
				return true;
			}
			// Check whether only one is null
			if (Object.ReferenceEquals(left, null) || Object.ReferenceEquals(right, null))
			{
				return false;
			}
			left.CheckDisposed();
			right.CheckDisposed();
			// Check all properties
			if ((left.Key != right.Key) ||
				(left.ID != right.ID) ||
				(left.Description != right.Description) ||
				(left.Count != right.Count) ||
				(left.Length != right.Length) ||
				(left.Model != right.Model) ||
				(left.Type != right.Type))
			{
				return false;
			}
			if (left.Length == 0)
			{
				return true;
			}
			IntPtr ptr1 = FreeImage.GetTagValue(left.tag);
			IntPtr ptr2 = FreeImage.GetTagValue(right.tag);
			return FreeImage.CompareMemory(ptr1, ptr2, left.Length);
		}

		/// <summary>
		/// Determines whether two specified <see cref="MetadataTag"/> objects have different values.
		/// </summary>
		/// <param name="left">A <see cref="MetadataTag"/> or a null reference (<b>Nothing</b> in Visual Basic).</param>
		/// <param name="right">A <see cref="MetadataTag"/> or a null reference (<b>Nothing</b> in Visual Basic).</param>
		/// <returns>
		/// true if the value of left is different from the value of right; otherwise, <b>false</b>.
		/// </returns>
		public static bool operator !=(MetadataTag left, MetadataTag right)
		{
			return !(left == right);
		}

		/// <summary>
		/// Extracts the value of a <see cref="MetadataTag"/> instance to a <see cref="FITAG"/> handle.
		/// </summary>
		/// <param name="value">A <see cref="MetadataTag"/> instance.</param>
		/// <returns>A new instance of <see cref="FITAG"/> initialized to <paramref name="value"/>.</returns>
		public static implicit operator FITAG(MetadataTag value)
		{
			return value.tag;
		}

		private static FREE_IMAGE_MDMODEL GetModel(FIBITMAP dib, FITAG tag)
		{
			FITAG value;
			foreach (FREE_IMAGE_MDMODEL model in FreeImage.FREE_IMAGE_MDMODELS)
			{
				FIMETADATA mData = FreeImage.FindFirstMetadata(model, dib, out value);
				if (mData.IsNull)
				{
					continue;
				}
				try
				{
					do
					{
						if (value == tag)
						{
							return model;
						}
					}
					while (FreeImage.FindNextMetadata(mData, out value));
				}
				finally
				{
					if (!mData.IsNull)
					{
						FreeImage.FindCloseMetadata(mData);
					}
				}
			}
			throw new ArgumentException("'tag' is no metadata object of 'dib'");
		}

		/// <summary>
		/// Gets the model of the metadata.
		/// </summary>
		public FREE_IMAGE_MDMODEL Model
		{
			get { CheckDisposed(); return model; }
		}

		/// <summary>
		/// Gets or sets the key of the metadata.
		/// </summary>
		public string Key
		{
			get { CheckDisposed(); return FreeImage.GetTagKey(tag); }
			set
			{
				CheckDisposed();
				if ((model != FREE_IMAGE_MDMODEL.FIMD_XMP) || (value == "XMLPacket"))
				{
					FreeImage.SetTagKey(tag, value);
				}
			}
		}

		/// <summary>
		/// Gets or sets the description of the metadata.
		/// </summary>
		public string Description
		{
			get { CheckDisposed(); return FreeImage.GetTagDescription(tag); }
			set { CheckDisposed(); FreeImage.SetTagDescription(tag, value); }
		}

		/// <summary>
		/// Gets or sets the ID of the metadata.
		/// </summary>
		public ushort ID
		{
			get { CheckDisposed(); return FreeImage.GetTagID(tag); }
			set { CheckDisposed(); FreeImage.SetTagID(tag, value); }
		}

		/// <summary>
		/// Gets the type of the metadata.
		/// </summary>
		public FREE_IMAGE_MDTYPE Type
		{
			get { CheckDisposed(); return FreeImage.GetTagType(tag); }
			private set { FreeImage.SetTagType(tag, value); }
		}

		/// <summary>
		/// Gets the number of elements the metadata object contains.
		/// </summary>
		public uint Count
		{
			get { CheckDisposed(); return Type == FREE_IMAGE_MDTYPE.FIDT_ASCII ? FreeImage.GetTagCount(tag) - 1 : FreeImage.GetTagCount(tag); }
			private set { FreeImage.SetTagCount(tag, value); }
		}

		/// <summary>
		/// Gets the length of the value in bytes.
		/// </summary>
		public uint Length
		{
			get { CheckDisposed(); return Type == FREE_IMAGE_MDTYPE.FIDT_ASCII ? FreeImage.GetTagLength(tag) - 1 : FreeImage.GetTagLength(tag); }
			private set { FreeImage.SetTagLength(tag, value); }
		}