Initial move from old twain-in-dotnet.

NTwain/MemoryManager.cs

@@ -0,0 +1,117 @@
+// The MIT License (MIT)
+// Copyright (c) 2013 Yin-Chun Wang
+//
+// Permission is hereby granted, free of charge, to any person obtaining a 
+// copy of this software and associated documentation files (the "Software"), 
+// to deal in the Software without restriction, including without limitation 
+// the rights to use, copy, modify, merge, publish, distribute, sublicense, 
+// and/or sell copies of the Software, and to permit persons to whom the 
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included 
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, 
+// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF 
+// OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+//
+
+using NTwain.Data;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Runtime.InteropServices;
+using System.Text;
+
+namespace NTwain
+{
+    /// <summary>
+    /// Provides methods for managing memory on data exchanged with twain sources.
+    /// </summary>
+    class MemoryManager
+    {
+        /// <summary>
+        /// Gets the global <see cref="MemoryManager"/> instance.
+        /// </summary>
+        public static readonly MemoryManager Global = new MemoryManager();
+
+        private MemoryManager() { }
+
+        /// <summary>
+        /// Updates the entry point used by TWAIN.
+        /// </summary>
+        /// <param name="entryPoint">The entry point.</param>
+        internal void UpdateEntryPoint(TWEntryPoint entryPoint)
+        {
+            _twain2Entry = entryPoint;
+        }
+
+        TWEntryPoint _twain2Entry;
+
+        public IntPtr MemAllocate(uint size)
+        {
+            if (_twain2Entry != null && _twain2Entry.AllocateFunction != null)
+            {
+                return _twain2Entry.AllocateFunction(size);
+            }
+            else
+            {
+                // 0x0040 is GPTR
+                return GlobalAlloc(0x0040, new UIntPtr(size));
+            }
+        }
+        public void MemFree(IntPtr handle)
+        {
+            if (_twain2Entry != null && _twain2Entry.FreeFunction != null)
+            {
+                _twain2Entry.FreeFunction(handle);
+            }
+            else
+            {
+                GlobalFree(handle);
+            }
+        }
+        public IntPtr MemLock(IntPtr handle)
+        {
+            if (_twain2Entry != null && _twain2Entry.LockFunction != null)
+            {
+                return _twain2Entry.LockFunction(handle);
+            }
+            else
+            {
+                return GlobalLock(handle);
+            }
+        }
+        public void MemUnlock(IntPtr handle)
+        {
+            if (_twain2Entry != null && _twain2Entry.UnlockFunction != null)
+            {
+                _twain2Entry.UnlockFunction(handle);
+            }
+            else
+            {
+                GlobalUnlock(handle);
+            }
+        }
+
+        #region old mem stuff for twain 1.x
+
+        [DllImport("kernel32", SetLastError = true, ExactSpelling = true)]
+        static extern IntPtr GlobalAlloc(uint uFlags, UIntPtr dwBytes);
+
+        [DllImport("kernel32", SetLastError = true, ExactSpelling = true)]
+        public static extern IntPtr GlobalFree(IntPtr hMem);
+
+        [DllImport("kernel32", SetLastError = true, ExactSpelling = true)]
+        public static extern IntPtr GlobalLock(IntPtr handle);
+
+        [DllImport("kernel32", SetLastError = true, ExactSpelling = true)]
+        [return: MarshalAs(UnmanagedType.Bool)]
+        public static extern bool GlobalUnlock(IntPtr handle);
+
+        #endregion
+    }
+}