1 files changed, 33 insertions, 0 deletions

diff --git a/format/delta/apply/apply.go b/format/delta/apply/apply.go
index f9f2fbaf..cd53f837 100644
--- a/format/delta/apply/apply.go
+++ b/format/delta/apply/apply.go
@@ -6,101 +6,129 @@ import "fmt"
 // Apply applies one Git delta instruction stream to base.
 func Apply(base, delta []byte) ([]byte, error) {
 	pos := 0
+
 	srcSize, err := readVarint(delta, &pos)
 	if err != nil {
 		return nil, err
 	}
+
 	dstSize, err := readVarint(delta, &pos)
 	if err != nil {
 		return nil, err
 	}
+
 	if srcSize != len(base) {
 		return nil, fmt.Errorf("format/delta/apply: delta source size mismatch: got %d want %d", srcSize, len(base))
 	}
 
 	out := make([]byte, dstSize)
 	outPos := 0
+
 	for pos < len(delta) {
 		op := delta[pos]
 		pos++
+
+		//nolint:nestif
 		if op&0x80 != 0 {
 			off := 0
+
 			if op&0x01 != 0 {
 				if pos >= len(delta) {
 					return nil, fmt.Errorf("format/delta/apply: malformed delta copy offset")
 				}
+
 				off |= int(delta[pos])
 				pos++
 			}
+
 			if op&0x02 != 0 {
 				if pos >= len(delta) {
 					return nil, fmt.Errorf("format/delta/apply: malformed delta copy offset")
 				}
+
 				off |= int(delta[pos]) << 8
 				pos++
 			}
+
 			if op&0x04 != 0 {
 				if pos >= len(delta) {
 					return nil, fmt.Errorf("format/delta/apply: malformed delta copy offset")
 				}
+
 				off |= int(delta[pos]) << 16
 				pos++
 			}
+
 			if op&0x08 != 0 {
 				if pos >= len(delta) {
 					return nil, fmt.Errorf("format/delta/apply: malformed delta copy offset")
 				}
+
 				off |= int(delta[pos]) << 24
 				pos++
 			}
 
 			n := 0
+
 			if op&0x10 != 0 {
 				if pos >= len(delta) {
 					return nil, fmt.Errorf("format/delta/apply: malformed delta copy size")
 				}
+
 				n |= int(delta[pos])
 				pos++
 			}
+
 			if op&0x20 != 0 {
 				if pos >= len(delta) {
 					return nil, fmt.Errorf("format/delta/apply: malformed delta copy size")
 				}
+
 				n |= int(delta[pos]) << 8
 				pos++
 			}
+
 			if op&0x40 != 0 {
 				if pos >= len(delta) {
 					return nil, fmt.Errorf("format/delta/apply: malformed delta copy size")
 				}
+
 				n |= int(delta[pos]) << 16
 				pos++
 			}
+
 			if n == 0 {
 				n = 0x10000
 			}
+
 			if off < 0 || n < 0 || off+n > len(base) || outPos+n > len(out) {
 				return nil, fmt.Errorf("format/delta/apply: delta copy out of bounds")
 			}
+
 			copy(out[outPos:outPos+n], base[off:off+n])
 			outPos += n
+
 			continue
 		}
 
 		if op == 0 {
 			return nil, fmt.Errorf("format/delta/apply: invalid delta opcode 0")
 		}
+
 		n := int(op)
 		if pos+n > len(delta) || outPos+n > len(out) {
 			return nil, fmt.Errorf("format/delta/apply: delta insert out of bounds")
 		}
+
 		copy(out[outPos:outPos+n], delta[pos:pos+n])
 		outPos += n
 		pos += n
 	}
+
 	if outPos != len(out) {
 		return nil, fmt.Errorf("format/delta/apply: delta output size mismatch: got %d want %d", outPos, len(out))
 	}
+
 	return out, nil
 }
 
@@ -108,20 +136,25 @@ func Apply(base, delta []byte) ([]byte, error) {
 func readVarint(buf []byte, pos *int) (int, error) {
 	value := 0
 	shift := uint(0)
+
 	for {
 		if *pos >= len(buf) {
 			return 0, fmt.Errorf("format/delta/apply: malformed delta varint")
 		}
+
 		b := buf[*pos]
 		*pos++
+
 		value |= int(b&0x7f) << shift
 		if b&0x80 == 0 {
 			break
 		}
+
 		shift += 7
 		if shift > 63 {
 			return 0, fmt.Errorf("format/delta/apply: delta varint overflow")
 		}
 	}
+
 	return value, nil
 }