Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

stop allocating on every byte read (for CIDs and varints) #220

Merged
merged 2 commits into from Sep 7, 2021
Merged

stop allocating on every byte read (for CIDs and varints) #220

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
f79e90b
avoid allocating on every byte read
mvdan Sep 7, 2021
3c1c62a
avoid another alloc per read byte
mvdan Sep 7, 2021
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Jump to
Jump to file
Failed to load files.
Diff view
Diff view
29 changes: 16 additions & 13 deletions v2/internal/io/converter.go
View file
Open in desktop
Expand Up @@ -17,15 +17,21 @@ var (
type (
readerPlusByte struct {
io.Reader

byteBuf [1]byte // escapes via io.Reader.Read; preallocate
}

readSeekerPlusByte struct {
io.ReadSeeker

byteBuf [1]byte // escapes via io.Reader.Read; preallocate
}

discardingReadSeekerPlusByte struct {
io.Reader
offset int64

byteBuf [1]byte // escapes via io.Reader.Read; preallocate
}

ByteReadSeeker interface {
Expand All @@ -43,15 +49,15 @@ func ToByteReader(r io.Reader) io.ByteReader {
if br, ok := r.(io.ByteReader); ok {
return br
}
return &readerPlusByte{r}
return &readerPlusByte{Reader: r}
}

func ToByteReadSeeker(r io.Reader) ByteReadSeeker {
if brs, ok := r.(ByteReadSeeker); ok {
return brs
}
if rs, ok := r.(io.ReadSeeker); ok {
return &readSeekerPlusByte{rs}
return &readSeekerPlusByte{ReadSeeker: rs}
}
return &discardingReadSeekerPlusByte{Reader: r}
}
Expand All @@ -63,16 +69,19 @@ func ToReaderAt(rs io.ReadSeeker) io.ReaderAt {
return &readSeekerAt{rs: rs}
}

func (rb readerPlusByte) ReadByte() (byte, error) {
return readByte(rb)
func (rb *readerPlusByte) ReadByte() (byte, error) {
_, err := io.ReadFull(rb, rb.byteBuf[:])
return rb.byteBuf[0], err
}

func (rsb readSeekerPlusByte) ReadByte() (byte, error) {
return readByte(rsb)
func (rsb *readSeekerPlusByte) ReadByte() (byte, error) {
_, err := io.ReadFull(rsb, rsb.byteBuf[:])
return rsb.byteBuf[0], err
}

func (drsb *discardingReadSeekerPlusByte) ReadByte() (byte, error) {
return readByte(drsb)
_, err := io.ReadFull(drsb, drsb.byteBuf[:])
return drsb.byteBuf[0], err
}

func (drsb *discardingReadSeekerPlusByte) Read(p []byte) (read int, err error) {
Expand All @@ -98,12 +107,6 @@ func (drsb *discardingReadSeekerPlusByte) Seek(offset int64, whence int) (int64,
}
}

func readByte(r io.Reader) (byte, error) {
var p [1]byte
_, err := io.ReadFull(r, p[:])
return p[0], err
}

func (rsa *readSeekerAt) ReadAt(p []byte, off int64) (n int, err error) {
rsa.mu.Lock()
defer rsa.mu.Unlock()
Expand Down