public override Array GetArray(Type leafType, int depth, out string[] heads)
{
// The only type that must be forwarded to impl is the complex class, as the impl stores this class.
// The only types that must _not_ be forwarded are any object types (impl is an IMathLink, and therefore cannot handle them).
// Every type other than Complex could be handled by the base implementation here, but it is likely that the wrapped link
// is a NativeLink, which can handle many primitive types (those that are native in the MathLink C API) in a
// very efficient way, so we want to forward these.
if (leafType == ComplexType || Utils.IsTrulyPrimitive(leafType))
{
return(impl.GetArray(leafType, depth, out heads));
}
else
{
return(base.GetArray(leafType, depth, out heads));
}
}
// Can read any kind of array, except for jagged arrays that are multidimensional at the beginning, like [][,]
// (jagged at start like [,][] or [,...][][] is OK, but only if we know the type, not for an Array slot). Recall
// that mixed array types are read backwards, so [][,] is a 2-deep array of element type [] (i.e., it is multidimensional
// at the start, not the end). One more limitation: For an Array argument slot, if the incoming array is 3-deep or deeper,
// it must be rectangular, not jagged.
// We know the incoming expression has head List.
internal static Array readArbitraryArray(IMathLink ml, Type t)
{
int len;
if (t == typeof(Array))
{
ExpressionType leafExprType;
Type leafType;
// For the Array type, we have no clue about how the leaf elements will be read. Thus we need to peek into
// the incoming data to decide what type it is.
int depth = determineIncomingArrayDepth(ml);
ILinkMark mark = ml.CreateMark();
ILoopbackLink loop = null;
try {
if (depth == 1)
{
len = ml.CheckFunction("List");
if (len == 0)
{
throw new MathLinkException(MathLinkException.MLE_EMPTY_ARRAY);
}
leafExprType = ml.GetNextExpressionType();
ml.SeekMark(mark);
leafType = netTypeFromExpressionType(leafExprType, ml);
// Fail if data could only be read as Expr. This means that we cannot pass a list of arbitrary expressions
// to an arg slot typed as Array. It would have to be typed as Expr[]. We make this choice to provide
// more meaningful error reporting for the cases where the array has bogus data in it. We assume that
// this convenience outweighs the very rare cases where a programmer would want to pass an array of exprs
// for an Array slot (they could always create the array separately and pass it as an object reference).
if (leafType == typeof(Expr))
{
if (leafExprType == ExpressionType.Complex)
{
throw new MathLinkException(MathLinkException.MLE_NO_COMPLEX);
}
else
{
throw new MathLinkException(MathLinkException.MLE_BAD_ARRAY);
}
}
return((Array)ml.GetArray(leafType, 1));
}
else if (depth == 2)
{
// The loopback link is just a utility for quickly reading expressions off the link (via TransferExpression).
// Nothing is ever read back off the loopback link.
loop = MathLinkFactory.CreateLoopbackLink();
// Determine if the array is rectangular or jagged.
len = ml.CheckFunction("List");
bool isJagged = false;
bool foundLeafType = false;
// This next assignment is strictly for the compiler. The value will never be used
// unless it is set to an actual value below. We have an existing function that will get
// the leafExprType of the incoming array (getLeafExprType()), but we also need to check if the array
// is jagged here, so we will do both tasks at once and save a little time.
leafExprType = ExpressionType.Integer;
int lenAtLevel2 = ml.CheckFunction("List");
if (lenAtLevel2 > 0)
{
leafExprType = ml.GetNextExpressionType();
foundLeafType = true;
}
// peel off all the elements in the first sublist.
for (int j = 0; j < lenAtLevel2; j++)
{
loop.TransferExpression(ml);
}
// For each remaining sublist, check its length and peel off its members. At this point, though, we
// cannot be guaranteed that all elements are lists (or, at least, guaranteed that it is an error
// if they are not). They could be Null if the array is jagged: {{1, 2}, Null}.
for (int i = 1; i < len; i++)
{
ExpressionType nextExprType = ml.GetNextExpressionType();
if (nextExprType == ExpressionType.Object)
{
isJagged = true;
// OK to have null as an element in a jagged array.
if (ml.GetObject() != null)
{
throw new MathLinkException(MathLinkException.MLE_BAD_ARRAY_SHAPE);
}
}
else if (nextExprType == ExpressionType.Function)
{
int thisLength = ml.CheckFunction("List");
if (!foundLeafType && thisLength > 0)
{
leafExprType = ml.GetNextExpressionType();
foundLeafType = true;
}
if (thisLength != lenAtLevel2)
{
isJagged = true;
break;
}
else
{
for (int j = 0; j < thisLength; j++)
{
loop.TransferExpression(ml);
}
}
}
else
{
throw new MathLinkException(MathLinkException.MLE_BAD_ARRAY_DEPTH);
}
}
// If the array is empty we cannot create a .NET array for it, as there is no type info for the array we are creating.
if (!foundLeafType)
{
throw new MathLinkException(MathLinkException.MLE_EMPTY_ARRAY);
}
leafType = netTypeFromExpressionType(leafExprType, ml);
ml.SeekMark(mark);
if (isJagged)
{
ml.CheckFunction("List");
Array result = Array.CreateInstance(Array.CreateInstance(leafType, 0).GetType(), len);
for (int i = 0; i < len; i++)
{
// Have to check if elements are lists or Null.
ExpressionType nextExprType = ml.GetNextExpressionType();
if (nextExprType == ExpressionType.Function)
{
result.SetValue(ml.GetArray(leafType, 1), i);
}
else
{
string sym = ml.GetSymbol();
if (sym != "Null")
{
throw new MathLinkException(MathLinkException.MLE_BAD_ARRAY_SHAPE);
}
result.SetValue(null, i);
}
}
return(result);
}
else
{
return(ml.GetArray(leafType, 2));
}
}
else
{
// For an Array argument slot, we only support passing >2-deep rectangular arrays, not jagged.
for (int i = 0; i < depth; i++)
{
ml.CheckFunction("List");
}
leafExprType = ml.GetNextExpressionType();
leafType = netTypeFromExpressionType(leafExprType, ml);
ml.SeekMark(mark);
return(ml.GetArray(leafType, depth));
}
} finally {
if (loop != null)
{
loop.Close();
}
ml.DestroyMark(mark);
}
}
else
{
// We have the actual array shape encoded in the type. Either [], [,..], or array-of-arrays: [][]....
int arrayRank = t.GetArrayRank();
Type elementType = t.GetElementType();
if (elementType.IsArray)
{
if (arrayRank > 1)
{
// Don't support multidimensional array at start of jagged array: [][,]. Recall that mixed array types
// are read backwards, so [][,] is a 2-deep array of element type [].
throw new MathLinkException(MathLinkException.MLE_MULTIDIM_ARRAY_OF_ARRAY);
}
len = ml.CheckFunction("List");
Array result = Array.CreateInstance(elementType, len);
for (int i = 0; i < len; i++)
{
ExpressionType nextExprType = ml.GetNextExpressionType();
if (nextExprType == ExpressionType.Function)
{
result.SetValue(readArbitraryArray(ml, elementType), i);
}
else
{
string sym = ml.GetSymbol();
if (sym != "Null")
{
throw new MathLinkException(MathLinkException.MLE_BAD_ARRAY_SHAPE);
}
result.SetValue(null, i);
}
}
return(result);
}
else if (elementType == typeof(Array))
{
// Don't support Array[].
throw new MathLinkException(MathLinkException.MLE_ARRAY_OF_ARRAYCLASS);
}
else
{
return(ml.GetArray(elementType, arrayRank));
}
}
}