From c62c5544fa23378843a3383a9dcd4494e5ea33bc Mon Sep 17 00:00:00 2001
From: Runxi Yu
Date: Fri, 6 Mar 2026 11:54:21 +0800
Subject: format/commitgraph: Split into ./read and ./

---
 format/commitgraph/read/edges.go | 48 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)
 create mode 100644 format/commitgraph/read/edges.go

(limited to 'format/commitgraph/read/edges.go')

diff --git a/format/commitgraph/read/edges.go b/format/commitgraph/read/edges.go
new file mode 100644
index 00000000..de8bab60
--- /dev/null
+++ b/format/commitgraph/read/edges.go
@@ -0,0 +1,48 @@
+package read
+
+import (
+	"encoding/binary"
+
+	"codeberg.org/lindenii/furgit/format/commitgraph"
+	"codeberg.org/lindenii/furgit/internal/intconv"
+)
+
+func (reader *Reader) decodeExtraEdgeList(layer *layer, edgeStart uint32) ([]Position, error) {
+	if len(layer.chunkExtraEdges) == 0 {
+		return nil, &ErrMalformed{Path: layer.path, Reason: "missing EDGE chunk"}
+	}
+
+	out := make([]Position, 0)
+
+	cur := edgeStart
+	for {
+		off64 := uint64(cur) * 4
+
+		off, err := intconv.Uint64ToInt(off64)
+		if err != nil {
+			return nil, err
+		}
+
+		if off+4 > len(layer.chunkExtraEdges) {
+			return nil, &ErrMalformed{Path: layer.path, Reason: "EDGE index out of range"}
+		}
+
+		word := binary.BigEndian.Uint32(layer.chunkExtraEdges[off : off+4])
+		parentGlobal := word & commitgraph.ParentLastMask
+
+		parentPos, err := reader.globalToPosition(parentGlobal)
+		if err != nil {
+			return nil, err
+		}
+
+		out = append(out, parentPos)
+
+		if word&commitgraph.ParentExtraMask != 0 {
+			break
+		}
+
+		cur++
+	}
+
+	return out, nil
+}
-- 
cgit v1.3.1-10-gc9f91