format: Move commitgraph and packfile here

1 files changed, 33 insertions, 0 deletions

diff --git a/format/packfile/ingest/entry_header.go b/format/packfile/ingest/entry_header.go
new file mode 100644
index 00000000..c74fdc16
--- /dev/null
+++ b/format/packfile/ingest/entry_header.go
@@ -0,0 +1,33 @@
+package ingest
+
+import (
+	"codeberg.org/lindenii/furgit/internal/intconv"
+	objecttype "codeberg.org/lindenii/furgit/object/type"
+)
+
+// encodePackEntryHeader encodes one non-delta packed entry header.
+func encodePackEntryHeader(ty objecttype.Type, size int64) []byte {
+	var out [16]byte
+
+	n := 0
+
+	s, err := intconv.Int64ToUint64(size)
+	if err != nil {
+		panic(err)
+	}
+
+	c := (uint8(ty) << 4) | byte(s&0x0f)
+
+	s >>= 4
+	for s != 0 {
+		out[n] = c | 0x80
+		n++
+		c = byte(s & 0x7f)
+		s >>= 7
+	}
+
+	out[n] = c
+	n++
+
+	return append([]byte(nil), out[:n]...)
+}