Some more unverified tw_info reads ideas.

soukoku · Apr 11, 2023 · 2fd5f05 · 2fd5f05
1 parent fa88dd4
commit 2fd5f05
Show file tree

Hide file tree

Showing 3 changed files with 15 additions and 5 deletions.
diff --git a/src/NTwain/Data/TWAINH_EXTRAS.cs b/src/NTwain/Data/TWAINH_EXTRAS.cs
@@ -1040,8 +1040,9 @@ public unsafe TValue ReadNonPointerData<TValue>() where TValue : struct
     /// </summary>
     /// <param name="memMgr"></param>
     /// <param name="index">If item is an array specify which string to read</param>
+    /// <param name="lengthHint">Pass a value if you know how long it should be.</param>
     /// <returns></returns>
-    public unsafe string? ReadHandleString(IMemoryManager memMgr, int index = 0)
+    public unsafe string? ReadHandleString(IMemoryManager memMgr, int index = 0, int lengthHint = -1)
     {
       if (index < 0 || index >= NumItems || !IsDataAPointer) return default;
 
@@ -1053,7 +1054,7 @@ public unsafe TValue ReadNonPointerData<TValue>() where TValue : struct
       if (NumItems == 1)
       {
         // if 1, item is already the pointer to the string
-        value = LockAndReadNullTerminatedString(memMgr, itemAsPtr);
+        value = LockAndReadNullTerminatedString(memMgr, itemAsPtr, lengthHint);
       }
       else
       {
@@ -1062,17 +1063,17 @@ public unsafe TValue ReadNonPointerData<TValue>() where TValue : struct
         lockPtr += (IntPtr.Size * index);
         // is this even correct? I hope it is
         var subItemPtr = Marshal.PtrToStructure<IntPtr>(lockPtr);
-        value = LockAndReadNullTerminatedString(memMgr, subItemPtr);
+        value = LockAndReadNullTerminatedString(memMgr, subItemPtr, lengthHint);
         memMgr.Unlock(itemAsPtr);
       }
       return value;
     }
 
-    private string? LockAndReadNullTerminatedString(IMemoryManager memMgr, IntPtr data)
+    private string? LockAndReadNullTerminatedString(IMemoryManager memMgr, IntPtr data, int lengthHint = -1)
     {
       var lockPtr = memMgr.Lock(data);
       // yolo as ansi, should work in most cases
-      var value = Marshal.PtrToStringAnsi(lockPtr);
+      var value = lengthHint > 0 ? Marshal.PtrToStringAnsi(lockPtr, lengthHint) : Marshal.PtrToStringAnsi(lockPtr);
       memMgr.Unlock(data);
       return value;
     }

diff --git a/src/NTwain/Data/ValueReader.cs b/src/NTwain/Data/ValueReader.cs
@@ -439,6 +439,9 @@ public static TValue ReadTWTYData<TValue>(this IntPtr intptr, TWTY type, int ite
         default:
           throw new NotSupportedException($"Unsupported item type {type} for reading.");
         // TODO: verify if needs to read int32 for small types
+        case TWTY.HANDLE:
+          intptr += IntPtr.Size * itemIndex;
+          return MarshalTo<TValue>(intptr);
         case TWTY.INT8:
           intptr += 1 * itemIndex;
           if (isEnum)

diff --git a/src/NTwain/Data/ValueWriter.cs b/src/NTwain/Data/ValueWriter.cs
@@ -548,6 +548,8 @@ static TWTY GetItemType<TValue>() where TValue : struct
       if (type == typeof(TW_STR128)) return TWTY.STR128;
       if (type == typeof(TW_STR255)) return TWTY.STR255;
       if (type == typeof(TW_FRAME)) return TWTY.FRAME;
+      if (type == typeof(IntPtr)) return TWTY.HANDLE;
+      if (type == typeof(UIntPtr)) return TWTY.HANDLE;
 
       if (type.IsEnum)
       {
@@ -579,6 +581,10 @@ static void WriteContainerData<TValue>(IntPtr intptr, TWTY type, TValue value, i
         default:
           throw new NotSupportedException($"Unsupported item type {type} for writing.");
         // TODO: for small types needs to fill whole int32 before writing?
+        case TWTY.HANDLE:
+          intptr += IntPtr.Size * itemIndex;
+          Marshal.StructureToPtr(value, intptr, false);
+          break;
         case TWTY.INT8:
           intptr += 1 * itemIndex;
           //int intval = Convert.ToSByte(value);