From bd9ca0ee6f4645d31335d63d35d3b495afa32cc5 Mon Sep 17 00:00:00 2001
From: Runxi Yu
Date: Fri, 6 Mar 2026 10:57:15 +0800
Subject: format/commitgraph: Split layer files

---
 format/commitgraph/layer_pos.go | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)
 create mode 100644 format/commitgraph/layer_pos.go

(limited to 'format/commitgraph/layer_pos.go')

diff --git a/format/commitgraph/layer_pos.go b/format/commitgraph/layer_pos.go
new file mode 100644
index 00000000..3b82c433
--- /dev/null
+++ b/format/commitgraph/layer_pos.go
@@ -0,0 +1,21 @@
+package commitgraph
+
+import "codeberg.org/lindenii/furgit/internal/intconv"
+
+func (reader *Reader) layerByPosition(pos Position) (*layer, error) {
+	graphIdx, err := intconv.Uint64ToInt(uint64(pos.Graph))
+	if err != nil {
+		return nil, err
+	}
+
+	if graphIdx < 0 || graphIdx >= len(reader.layers) {
+		return nil, &ErrPositionOutOfRange{Pos: pos}
+	}
+
+	layer := &reader.layers[graphIdx]
+	if pos.Index >= layer.numCommits {
+		return nil, &ErrPositionOutOfRange{Pos: pos}
+	}
+
+	return layer, nil
+}
-- 
cgit v1.3.1-10-gc9f91