Functions: Multi Function

This adds the `MultiFunction` type and some smallish utility types that it uses.
A `MultiFunction` encapsulates a function that is optimized for throughput by
always processing many elements at once.

This is an important part of the new particle system, because it allows us to
execute user generated node trees for many particles efficiently.

Reviewers: brecht

Differential Revision: https://developer.blender.org/D8030

1 files changed, 155 insertions, 0 deletions

diff --git a/source/blender/functions/FN_multi_function_param_type.hh b/source/blender/functions/FN_multi_function_param_type.hh
new file mode 100644
index 00000000000..bd31a793b21
--- /dev/null
+++ b/source/blender/functions/FN_multi_function_param_type.hh
@@ -0,0 +1,155 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __FN_MULTI_FUNCTION_PARAM_TYPE_HH__
+#define __FN_MULTI_FUNCTION_PARAM_TYPE_HH__
+
+/** \file
+ * \ingroup fn
+ *
+ * A multi-function has an arbitrary amount of parameters. Every parameter belongs to one of three
+ * interface types:
+ * - Input: An input parameter is readonly inside the function. The values have to be provided by
+ *     the caller.
+ * - Output: An output parameter has to be initialized by the function. However, the caller
+ *     provides the memory where the data has to be constructed.
+ * - Mutable: A mutable parameter can be considered to be an input and output. The caller has to
+ *     initialize the data, but the function is allowed to modify it.
+ *
+ * Furthermore, every parameter has a MFDataType that describes what kind of data is being passed
+ * around.
+ */
+
+#include "FN_multi_function_data_type.hh"
+
+namespace blender {
+namespace fn {
+
+class MFParamType {
+ public:
+  enum InterfaceType {
+    Input,
+    Output,
+    Mutable,
+  };
+
+  enum Category {
+    SingleInput,
+    VectorInput,
+    SingleOutput,
+    VectorOutput,
+    SingleMutable,
+    VectorMutable,
+  };
+
+ private:
+  InterfaceType m_interface_type;
+  MFDataType m_data_type;
+
+ public:
+  MFParamType(InterfaceType interface_type, MFDataType data_type)
+      : m_interface_type(interface_type), m_data_type(data_type)
+  {
+  }
+
+  static MFParamType ForSingleInput(const CPPType &type)
+  {
+    return MFParamType(InterfaceType::Input, MFDataType::ForSingle(type));
+  }
+
+  static MFParamType ForVectorInput(const CPPType &base_type)
+  {
+    return MFParamType(InterfaceType::Input, MFDataType::ForVector(base_type));
+  }
+
+  static MFParamType ForSingleOutput(const CPPType &type)
+  {
+    return MFParamType(InterfaceType::Output, MFDataType::ForSingle(type));
+  }
+
+  static MFParamType ForVectorOutput(const CPPType &base_type)
+  {
+    return MFParamType(InterfaceType::Output, MFDataType::ForVector(base_type));
+  }
+
+  static MFParamType ForMutableSingle(const CPPType &type)
+  {
+    return MFParamType(InterfaceType::Mutable, MFDataType::ForSingle(type));
+  }
+
+  static MFParamType ForMutableVector(const CPPType &base_type)
+  {
+    return MFParamType(InterfaceType::Mutable, MFDataType::ForVector(base_type));
+  }
+
+  MFDataType data_type() const
+  {
+    return m_data_type;
+  }
+
+  InterfaceType interface_type() const
+  {
+    return m_interface_type;
+  }
+
+  Category category() const
+  {
+    switch (m_data_type.category()) {
+      case MFDataType::Single: {
+        switch (m_interface_type) {
+          case Input:
+            return SingleInput;
+          case Output:
+            return SingleOutput;
+          case Mutable:
+            return SingleMutable;
+        }
+        break;
+      }
+      case MFDataType::Vector: {
+        switch (m_interface_type) {
+          case Input:
+            return VectorInput;
+          case Output:
+            return VectorOutput;
+          case Mutable:
+            return VectorMutable;
+        }
+        break;
+      }
+    }
+    BLI_assert(false);
+    return SingleInput;
+  }
+
+  friend bool operator==(const MFParamType &a, const MFParamType &b);
+  friend bool operator!=(const MFParamType &a, const MFParamType &b);
+};
+
+inline bool operator==(const MFParamType &a, const MFParamType &b)
+{
+  return a.m_interface_type == b.m_interface_type && a.m_data_type == b.m_data_type;
+}
+
+inline bool operator!=(const MFParamType &a, const MFParamType &b)
+{
+  return !(a == b);
+}
+
+}  // namespace fn
+}  // namespace blender
+
+#endif /* __FN_MULTI_FUNCTION_PARAM_TYPE_HH__ */