From 015adfc69e63e46c7823524032636faa99106c1f Mon Sep 17 00:00:00 2001
From: Patrick Lehmann <Patrick.Lehmann@plc2.de>
Date: Wed, 6 Jan 2021 11:20:42 +0100
Subject: Implemented a decorator to pre-calculate enum position to enum
 literal name lookups.

---
 pyGHDL/libghdl/_decorator.py     | 33 +++++++++++++++++++++++
 pyGHDL/libghdl/_types.py         | 18 +++++++++++++
 pyGHDL/libghdl/utils/__init__.py | 57 ++++++++++++++--------------------------
 3 files changed, 70 insertions(+), 38 deletions(-)
 create mode 100644 pyGHDL/libghdl/_decorator.py
 create mode 100644 pyGHDL/libghdl/_types.py

(limited to 'pyGHDL')

diff --git a/pyGHDL/libghdl/_decorator.py b/pyGHDL/libghdl/_decorator.py
new file mode 100644
index 000000000..01863381a
--- /dev/null
+++ b/pyGHDL/libghdl/_decorator.py
@@ -0,0 +1,33 @@
+from functools import wraps
+from typing import Callable, List
+
+from pydecor import export
+
+
+@export
+def EnumLookupTable(cls) -> Callable:
+    """
+    Decorator to precalculate a enum lookup table (LUT) for enum position to
+    enum literal name.
+
+    .. todo:: Make compatible to chained decorators
+
+    :param cls: Enumerator class for which a LUT shall be pre-calculated.
+    """
+    def decorator(func) -> Callable:
+        def gen() -> List[str]:
+            d = [e for e in dir(cls) if e[0] != "_"]
+            res = [None] * len(d)
+            for e in d:
+                res[getattr(cls, e)] = e
+            return res
+
+        __lut = gen()
+
+        def wrapper(id: int) -> str:
+            # function that replaces the placeholder function
+            return __lut[id]
+
+        return wrapper
+
+    return decorator
diff --git a/pyGHDL/libghdl/_types.py b/pyGHDL/libghdl/_types.py
new file mode 100644
index 000000000..2a486a15b
--- /dev/null
+++ b/pyGHDL/libghdl/_types.py
@@ -0,0 +1,18 @@
+from typing import TypeVar
+
+__all__ = [
+	'ErrorIndex',
+	'MessageIdWarnings',
+	'NameId',
+	'SourceFileEntry',
+	'Iir',
+	'IirKind'
+]
+
+ErrorIndex =  TypeVar('ErrorIndex', bound=int)
+MessageIdWarnings = TypeVar('MessageIdWarnings', bound=int)
+NameId = TypeVar('NameId', bound=int)
+SourceFileEntry = TypeVar('SourceFileEntry', bound=int)
+
+Iir = TypeVar('Iir', bound=int)
+IirKind = TypeVar('IirKind', bound=int)
diff --git a/pyGHDL/libghdl/utils/__init__.py b/pyGHDL/libghdl/utils/__init__.py
index a98b6c963..3b64e7698 100644
--- a/pyGHDL/libghdl/utils/__init__.py
+++ b/pyGHDL/libghdl/utils/__init__.py
@@ -37,6 +37,8 @@ from typing import List, Any, Generator
 
 from pydecor import export
 
+from pyGHDL.libghdl._decorator import EnumLookupTable
+from pyGHDL.libghdl._types import NameId
 import pyGHDL.libghdl.name_table as name_table
 import pyGHDL.libghdl.files_map as files_map
 import pyGHDL.libghdl.vhdl.nodes as nodes
@@ -46,54 +48,33 @@ import pyGHDL.libghdl.vhdl.flists as flists
 
 
 @export
-def name_image(nameid) -> str:
-    """Lookup a :obj:`nameid` and return its string."""
-    return name_table.Get_Name_Ptr(nameid).decode("utf-8")
+def name_image(NameId: NameId) -> str:
+    """Lookup a :obj:`NameId` and return its string."""
+    return name_table.Get_Name_Ptr(NameId)
 
 
-def _build_enum_image(cls) -> List[str]:
-    """Create a lookup table for enumeration values to literal names."""
-    d = [e for e in dir(cls) if e[0] != "_"]
-    res = [None] * len(d)
-    for e in d:
-        res[getattr(cls, e)] = e
-    return res
+#@export # FIXME: see above
+@EnumLookupTable(nodes_meta.fields)
+def fields_image(idx: int) -> str:
+    """String representation of Nodes_Meta.fields :obj:`idx`."""
 
 
-_fields_image = _build_enum_image(nodes_meta.fields)
+#@export # FIXME: see above
+@EnumLookupTable(nodes.Iir_Kind)
+def kind_image(k: int) -> str:
+    """String representation of Nodes.Iir_Kind :obj:`k`."""
 
 
-@export
-def fields_image(idx) -> str:
-    """String representation of field :obj:`idx`."""
-    return _fields_image[idx]
-
-
-_kind_image = _build_enum_image(nodes.Iir_Kind)
-
-
-@export
-def kind_image(k) -> str:
-    """String representation of Iir_Kind :obj:`k`."""
-    return _kind_image[k]
-
-
-_types_image = _build_enum_image(nodes_meta.types)
-
-
-@export
-def types_image(t) -> str:
+#@export # FIXME: see above
+@EnumLookupTable(nodes_meta.types)
+def types_image(t: int) -> str:
     """String representation of Nodes_Meta.Types :obj:`t`."""
-    return _types_image[t]
 
 
-_attr_image = _build_enum_image(nodes_meta.Attr)
-
-
-@export
-def attr_image(a) -> str:
+#@export # FIXME: see above
+@EnumLookupTable(nodes_meta.Attr)
+def attr_image(a: int) -> str:
     """String representation of Nodes_Meta.Attr :obj:`a`."""
-    return _attr_image[a]
 
 
 @export
-- 
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