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binaryserializer.go
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/
binaryserializer.go
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package binaryserializer
import (
"encoding/binary"
"io"
"github.com/pkg/errors"
)
// maxItems is the number of buffers to keep in the free
// list to use for binary serialization and deserialization.
const maxItems = 1024
// Borrow returns a byte slice from the free list with a length of 8. A new
// buffer is allocated if there are not any available on the free list.
func Borrow() []byte {
var buf []byte
select {
case buf = <-binaryFreeList:
default:
buf = make([]byte, 8)
}
return buf[:8]
}
// Return puts the provided byte slice back on the free list. The buffer MUST
// have been obtained via the Borrow function and therefore have a cap of 8.
func Return(buf []byte) {
select {
case binaryFreeList <- buf:
default:
// Let it go to the garbage collector.
}
}
// Uint8 reads a single byte from the provided reader using a buffer from the
// free list and returns it as a uint8.
func Uint8(r io.Reader) (uint8, error) {
buf := Borrow()[:1]
if _, err := io.ReadFull(r, buf); err != nil {
Return(buf)
return 0, errors.WithStack(err)
}
rv := buf[0]
Return(buf)
return rv, nil
}
// Uint16 reads two bytes from the provided reader using a buffer from the
// free list, converts it to a number using the provided byte order, and returns
// the resulting uint16.
func Uint16(r io.Reader) (uint16, error) {
buf := Borrow()[:2]
if _, err := io.ReadFull(r, buf); err != nil {
Return(buf)
return 0, errors.WithStack(err)
}
rv := binary.LittleEndian.Uint16(buf)
Return(buf)
return rv, nil
}
// Uint32 reads four bytes from the provided reader using a buffer from the
// free list, converts it to a number using the provided byte order, and returns
// the resulting uint32.
func Uint32(r io.Reader) (uint32, error) {
buf := Borrow()[:4]
if _, err := io.ReadFull(r, buf); err != nil {
Return(buf)
return 0, errors.WithStack(err)
}
rv := binary.LittleEndian.Uint32(buf)
Return(buf)
return rv, nil
}
// Uint64 reads eight bytes from the provided reader using a buffer from the
// free list, converts it to a number using the provided byte order, and returns
// the resulting uint64.
func Uint64(r io.Reader) (uint64, error) {
buf := Borrow()[:8]
if _, err := io.ReadFull(r, buf); err != nil {
Return(buf)
return 0, errors.WithStack(err)
}
rv := binary.LittleEndian.Uint64(buf)
Return(buf)
return rv, nil
}
// PutUint8 copies the provided uint8 into a buffer from the free list and
// writes the resulting byte to the given writer.
func PutUint8(w io.Writer, val uint8) error {
buf := Borrow()[:1]
buf[0] = val
_, err := w.Write(buf)
Return(buf)
return errors.WithStack(err)
}
// PutUint16 serializes the provided uint16 using the given byte order into a
// buffer from the free list and writes the resulting two bytes to the given
// writer.
func PutUint16(w io.Writer, val uint16) error {
buf := Borrow()[:2]
binary.LittleEndian.PutUint16(buf, val)
_, err := w.Write(buf)
Return(buf)
return errors.WithStack(err)
}
// PutUint32 serializes the provided uint32 using the given byte order into a
// buffer from the free list and writes the resulting four bytes to the given
// writer.
func PutUint32(w io.Writer, val uint32) error {
var buf [4]byte
binary.LittleEndian.PutUint32(buf[:], val)
_, err := w.Write(buf[:])
return errors.WithStack(err)
}
// PutUint64 serializes the provided uint64 using the given byte order into a
// buffer from the free list and writes the resulting eight bytes to the given
// writer.
func PutUint64(w io.Writer, val uint64) error {
var buf [8]byte
binary.LittleEndian.PutUint64(buf[:], val)
_, err := w.Write(buf[:])
return errors.WithStack(err)
}
// binaryFreeList provides a free list of buffers to use for serializing and
// deserializing primitive integer values to and from io.Readers and io.Writers.
//
// It defines a concurrent safe free list of byte slices (up to the
// maximum number defined by the maxItems constant) that have a
// cap of 8 (thus it supports up to a uint64). It is used to provide temporary
// buffers for serializing and deserializing primitive numbers to and from their
// binary encoding in order to greatly reduce the number of allocations
// required.
//
// For convenience, functions are provided for each of the primitive unsigned
// integers that automatically obtain a buffer from the free list, perform the
// necessary binary conversion, read from or write to the given io.Reader or
// io.Writer, and return the buffer to the free list.
var binaryFreeList = make(chan []byte, maxItems)