Flexible bytes buffer

Package flexbuf provides bytes buffer implementing many data access and manipulation interfaces.

io.Writer
io.WriterAt
io.ByteWriter
io.WriterTo
io.StringWriter
io.Reader
io.ByteReader
io.ReaderAt
io.ReaderFrom
io.Seeker
io.Closer
fmt.Stringer

Additionally, flexbuf provides Truncate(size int64) error method to make it almost a drop in replacement for os.File.

Installation

go get github.com/rzajac/flexbuf

Examples

buf := &flexbuf.Buffer{}

_, _ = buf.Write([]byte{0, 1, 2, 3})
_, _ = buf.Seek(-2, io.SeekEnd)
_, _ = buf.Write([]byte{4, 5})
_, _ = buf.Seek(0, io.SeekStart)

data, _ := ioutil.ReadAll(buf)
fmt.Println(data)

// Output: [0 1 4 5]

How is it different from bytes.Buffer?

The bytes.Buffer always reads from current offset and writes to the end of the buffer, flexbuf behaves more like a file it reads and writes at current offset. Also bytes.Buffer doesn't implement interfaces:

• io.WriterAt
• io.ReaderAt
• io.Seeker
• io.Closer

or methods:

• Truncate

Can I use flexbuf.Buffer as a replacement for os.File?

It depends. Even though flexbuf.Buffer probably implements all the methods you need to use it as a replacement for os.File there are some minor differences:

• Truncate method does not return os.PathError instances.
• WriteAt will not return error when used on an instance created with flexbuf.New(flexbuf.Append) or flexbuf.With(myBuf, flexbuf.Append).

Benchmarks

Some benchmarks between flexbuf.Buffer and bytes.Buffer:

BenchmarkWrite/flexbuf-12          124060         11014 ns/op       32768 B/op           1 allocs/op
BenchmarkWrite/bytes-12            101112         11767 ns/op       32768 B/op           1 allocs/op
BenchmarkWriteByte/flexbuf-12    38088462          31.2 ns/op           1 B/op           1 allocs/op
BenchmarkWriteByte/bytes-12      15355932          76.9 ns/op          64 B/op           1 allocs/op
BenchmarkWriteString/flexbuf-12  18013146          63.8 ns/op          16 B/op           1 allocs/op
BenchmarkWriteString/bytes-12    12852244          88.3 ns/op          64 B/op           1 allocs/op
BenchmarkReadFrom/flexbuf-12        27813         43573 ns/op      129024 B/op           7 allocs/op
BenchmarkReadFrom/bytes-12          27439         43440 ns/op      129024 B/op           7 allocs/op

License

BSD-2-Clause