From 5322e66a121abd65a5c19f4bdada12851e7f5857 Mon Sep 17 00:00:00 2001 From: Than McIntosh Date: Thu, 11 May 2023 16:09:38 -0400 Subject: internal/coverage: implement conforming Seek method in slicereader Implement a real Seek() method in the slicereader helper (prior to this it had a simplified SeekTo function), so that slicereader's will satisfy the ReadSeeker interface (needed in a subsequent patch). Change-Id: I832e3ec1e34d0f8c6b5edf390470f6f943c6ece0 Reviewed-on: https://go-review.googlesource.com/c/go/+/495438 Run-TryBot: Than McIntosh TryBot-Result: Gopher Robot Reviewed-by: David Chase --- src/internal/coverage/slicereader/slicereader.go | 29 ++++++++++++++++++++++-- 1 file changed, 27 insertions(+), 2 deletions(-) (limited to 'src/internal/coverage/slicereader/slicereader.go') diff --git a/src/internal/coverage/slicereader/slicereader.go b/src/internal/coverage/slicereader/slicereader.go index 3d117bae37..d9f2a7eac4 100644 --- a/src/internal/coverage/slicereader/slicereader.go +++ b/src/internal/coverage/slicereader/slicereader.go @@ -6,6 +6,8 @@ package slicereader import ( "encoding/binary" + "fmt" + "io" "unsafe" ) @@ -38,8 +40,31 @@ func (r *Reader) Read(b []byte) (int, error) { return amt, nil } -func (r *Reader) SeekTo(off int64) { - r.off = off +func (r *Reader) Seek(offset int64, whence int) (ret int64, err error) { + switch whence { + case io.SeekStart: + if offset < 0 || offset > int64(len(r.b)) { + return 0, fmt.Errorf("invalid seek: new offset %d (out of range [0 %d]", offset, len(r.b)) + } + r.off = offset + return offset, nil + case io.SeekCurrent: + newoff := r.off + offset + if newoff < 0 || newoff > int64(len(r.b)) { + return 0, fmt.Errorf("invalid seek: new offset %d (out of range [0 %d]", newoff, len(r.b)) + } + r.off = newoff + return r.off, nil + case io.SeekEnd: + newoff := int64(len(r.b)) + offset + if newoff < 0 || newoff > int64(len(r.b)) { + return 0, fmt.Errorf("invalid seek: new offset %d (out of range [0 %d]", newoff, len(r.b)) + } + r.off = newoff + return r.off, nil + } + // other modes are not supported + return 0, fmt.Errorf("unsupported seek mode %d", whence) } func (r *Reader) Offset() int64 { -- cgit v1.3