From b6a816f8b280f88b66d059a1bacf0dbb26702983 Mon Sep 17 00:00:00 2001
From: Tim Fischer <fischeti@iis.ee.ethz.ch>
Date: Thu, 3 Oct 2024 17:28:43 +0200
Subject: [PATCH] floogen: Support negative step sizes for connection ranges
 (#77)

* floogen(graph): Allow negative increments when specifying `range` in `connections`

* floogen(test): Extend tests with range tests

* docs: Update CHANGELOG
---
 CHANGELOG.md                |  1 +
 floogen/model/graph.py      | 33 +++++++++++++--------------------
 floogen/tests/graph_test.py | 27 +++++++++++++++++++++++++++
 3 files changed, 41 insertions(+), 20 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e9dddc2b..5826d6b0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -21,6 +21,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - The `data_width` and `user_width` fields for `protocols` are now also validated to be compatible with each other.
 - All the various `*Cfg`'s is now rendered by _FlooGen_, either in the `*_noc_pkg` or in the `*_noc` module itself.
 - Added support for single-AXI configuration networks.
+- Support for negative increments when specifying a `src_range` or `dst_range` in the `connections` schema.
 
 ### Changed
 
diff --git a/floogen/model/graph.py b/floogen/model/graph.py
index 3544e613..9a1caf5e 100644
--- a/floogen/model/graph.py
+++ b/floogen/model/graph.py
@@ -151,26 +151,19 @@ def get_link_edges(self, with_name=False):
     def get_nodes_from_range(self, node: str, rng: List[Tuple[int]]):
         """Return the nodes from the range."""
         nodes = []
-        match rng:
-            # 2D range
-            case [(start1, end1), (start2, end2)]:
-                for x in range(start1, end1 + 1):
-                    for y in range(start2, end2 + 1):
-                        node_name = f"{node}_{x}_{y}"
-                        if self.has_node(node_name):
-                            nodes.append(node_name)
-                        else:
-                            raise ValueError(f"Node {node_name} does not exist")
-            # 1D range
-            case [(start, end)]:
-                for i in range(start, end + 1):
-                    node_name = f"{node}_{i}"
-                    if self.has_node(node_name):
-                        nodes.append(node_name)
-                    else:
-                        raise ValueError(f"Node {node_name} does not exist")
-            case _:
-                raise NotImplementedError(f"Unsupported range {rng}")
+        if len(rng) == 0:
+            raise ValueError("Range is empty")
+        start, end = rng[0]
+        step = 1 if end > start else -1
+        for i in range(start, end + step, step):
+            if len (rng) == 1:
+                node_name = f"{node}_{i}"
+                if self.has_node(node_name):
+                    nodes.append(node_name)
+                else:
+                    raise ValueError(f"Node {node_name} does not exist")
+            else:
+                nodes.extend(self.get_nodes_from_range(f"{node}_{i}", rng[1:]))
         return nodes
 
     def get_nodes_from_idx(self, node: str, idx: List[int]):
diff --git a/floogen/tests/graph_test.py b/floogen/tests/graph_test.py
index b4533647..b5e07e6b 100644
--- a/floogen/tests/graph_test.py
+++ b/floogen/tests/graph_test.py
@@ -248,6 +248,33 @@ def test_get_nodes_from_range3(graph):
     nodes = graph.get_nodes_from_range("A", [(0, 3)])
     assert nodes == ["A_0", "A_1", "A_2", "A_3"]
 
+def test_get_nodes_from_range4(graph):
+    """Test getting all nodes from a range"""
+    graph.add_node("A_0", type="router")
+    graph.add_node("A_1", type="router")
+    graph.add_node("A_2", type="router")
+    graph.add_node("A_3", type="router")
+    nodes = graph.get_nodes_from_range("A", [(2, 1)])
+    assert nodes == ["A_2", "A_1"]
+
+def test_get_nodes_from_range_fail1(graph):
+    """Test getting all nodes from a range"""
+    graph.add_node("A_0", type="router")
+    graph.add_node("A_1", type="router")
+    graph.add_node("A_2", type="router")
+    graph.add_node("A_3", type="router")
+    with pytest.raises(ValueError):
+        graph.get_nodes_from_range("A", [(0, 1), (0, 1)])
+
+def test_get_nodes_from_range_fail2(graph):
+    """Test getting all nodes from a range"""
+    graph.add_node("A_0", type="router")
+    graph.add_node("A_1", type="router")
+    graph.add_node("A_2", type="router")
+    graph.add_node("A_3", type="router")
+    with pytest.raises(ValueError):
+        graph.get_nodes_from_range("A", [(0, 99)])
+
 
 def test_get_nodes_from_idx(graph):
     """Test getting all nodes from an index"""