From 3e884f5f3d42cbc4874a04da31dde10314b0cfad Mon Sep 17 00:00:00 2001
From: Runxi Yu
Date: Thu, 26 Mar 2026 09:17:14 +0000
Subject: format: Move commitgraph and packfile here

---
 format/packfile/ofs.go | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)
 create mode 100644 format/packfile/ofs.go

(limited to 'format/packfile/ofs.go')

diff --git a/format/packfile/ofs.go b/format/packfile/ofs.go
new file mode 100644
index 00000000..4992a506
--- /dev/null
+++ b/format/packfile/ofs.go
@@ -0,0 +1,26 @@
+package packfile
+
+import "fmt"
+
+// ParseOfsDeltaDistance parses one ofs-delta backward distance.
+func ParseOfsDeltaDistance(buf []byte) (uint64, int, error) {
+	if len(buf) == 0 {
+		return 0, 0, fmt.Errorf("packfile: malformed ofs-delta distance")
+	}
+
+	b := buf[0]
+	dist := uint64(b & 0x7f)
+
+	consumed := 1
+	for b&0x80 != 0 {
+		if consumed >= len(buf) {
+			return 0, 0, fmt.Errorf("packfile: malformed ofs-delta distance")
+		}
+
+		b = buf[consumed]
+		consumed++
+		dist = ((dist + 1) << 7) + uint64(b&0x7f)
+	}
+
+	return dist, consumed, nil
+}
-- 
cgit v1.3.1-10-gc9f91