lsm/ntwain
1
0
Fork 0
mirror of https://github.com/soukoku/ntwain.git synced 2025-11-07 18:14:46 +08:00
Code Issues Actions Packages Projects Releases Wiki Activity

Missed one

Browse Source
This commit is contained in:
soukoku
2014-04-12 09:18:26 -04:00
parent 6a54b2a136
commit 2a72794eb2
1 changed files with 136 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

136
NTwain/Data/TypeReader.cs Normal file
View File

@@ -0,0 +1,136 @@
using NTwain.Values;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
namespace NTwain.Data
{
/// <summary>
/// Class to read common TWAIN values.
/// </summary>
public static class TypeReader
{
/// <summary>
/// Reads a TWAIN value.
/// </summary>
/// <param name="baseAddr">The base addr.</param>
/// <param name="offset">The offset.</param>
/// <param name="type">The TWAIN type.</param>
/// <returns></returns>
public static object ReadValue(IntPtr baseAddr, ref int offset, ItemType type)
{
object val = null;
switch (type)
{
case ItemType.Int8:
val = (sbyte)Marshal.ReadByte(baseAddr, offset);
break;
case ItemType.UInt8:
val = Marshal.ReadByte(baseAddr, offset);
break;
case ItemType.Bool:
case ItemType.UInt16:
val = (ushort)Marshal.ReadInt16(baseAddr, offset);
break;
case ItemType.Int16:
val = Marshal.ReadInt16(baseAddr, offset);
break;
case ItemType.UInt32:
val = (uint)Marshal.ReadInt32(baseAddr, offset);
break;
case ItemType.Int32:
val = Marshal.ReadInt32(baseAddr, offset);
break;
case ItemType.Fix32:
TWFix32 f32 = new TWFix32();
f32.Whole = Marshal.ReadInt16(baseAddr, offset);
f32.Fraction = (ushort)Marshal.ReadInt16(baseAddr, offset + 2);
val = f32;
break;
case ItemType.Frame:
TWFrame frame = new TWFrame();
frame.Left = (TWFix32)ReadValue(baseAddr, ref offset, ItemType.Fix32);
frame.Top = (TWFix32)ReadValue(baseAddr, ref offset, ItemType.Fix32);
frame.Right = (TWFix32)ReadValue(baseAddr, ref offset, ItemType.Fix32);
frame.Bottom = (TWFix32)ReadValue(baseAddr, ref offset, ItemType.Fix32);
return frame; // no need to update offset again after reading fix32
case ItemType.String128:
val = ReadString(baseAddr, offset, TwainConst.String128 - 2);
break;
case ItemType.String255:
val = ReadString(baseAddr, offset, TwainConst.String255 - 1);
break;
case ItemType.String32:
val = ReadString(baseAddr, offset, TwainConst.String32 - 2);
break;
case ItemType.String64:
val = ReadString(baseAddr, offset, TwainConst.String64 - 2);
break;
case ItemType.Handle:
val = new IntPtr(baseAddr.ToInt64() + offset);
break;
}
offset += GetItemTypeSize(type);
return val;
}
static string ReadString(IntPtr baseAddr, int offset, int maxLength)
{
// does this work cross-platform?
var val = Marshal.PtrToStringAnsi(new IntPtr(baseAddr.ToInt64() + offset));
if (val.Length > maxLength)
{
// bad source, whatever
}
return val;
//var sb = new StringBuilder(maxLength);
//byte bt;
//while (sb.Length < maxLength &&
// (bt = Marshal.ReadByte(baseAddr, offset++)) != 0)
//{
// sb.Append((char)bt);
//}
//return sb.ToString();
}
/// <summary>
/// Gets the byte size of the item type.
/// </summary>
/// <param name="type"></param>
/// <returns></returns>
public static int GetItemTypeSize(ItemType type)
{
switch (type)
{
case ItemType.Int8:
case ItemType.UInt8:
return 1;
case ItemType.UInt16:
case ItemType.Int16:
case ItemType.Bool:
return 2;
case ItemType.Int32:
case ItemType.UInt32:
case ItemType.Fix32:
return 4;
case ItemType.Frame:
return 16;
case ItemType.String32:
return TwainConst.String32;
case ItemType.String64:
return TwainConst.String64;
case ItemType.String128:
return TwainConst.String128;
case ItemType.String255:
return TwainConst.String255;
case ItemType.Handle:
return IntPtr.Size;
}
return 0;
}
}
}