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Contents
package circular
// standard library container/ring package and "one slot open" technique
// as described at WP.
import (
"container/ring"
"errors"
)
// Buffer implements a circular buffer supporting both overflow-checked writes
// and unconditional, possibly overwriting, writes.
type Buffer struct {
start, end *ring.Ring
}
// NewBuffer constructs a new empty circular buffer.
func NewBuffer(size int) *Buffer {
r := ring.New(size + 1)
return &Buffer{r, r}
}
// ReadByte removes one byte from the buffer and returns it.
// ReadByte returns an error if the buffer is empty.
func (b *Buffer) ReadByte() (byte, error) {
if b.start == b.end {
return 0, errors.New("buffer empty")
}
c := b.start.Value.(byte)
b.start = b.start.Next()
return c, nil
}
// WriteByte puts byte c in the buffer there is room.
// WriteByte returns an error if the buffer is full.
func (b *Buffer) WriteByte(c byte) error {
if b.end.Next() == b.start {
return errors.New("buffer full")
}
b.end.Value = c
b.end = b.end.Next()
return nil
}
// Overwrite unconditionally puts byte c in the buffer. If the buffer was
// already full, c overwrites the oldest byte in the buffer.
func (b *Buffer) Overwrite(c byte) {
b.end.Value = c
b.end = b.end.Next()
if b.end == b.start {
b.start = b.start.Next()
}
}
// Reset puts the buffer in an empty state.
func (b *Buffer) Reset() {
b.start = b.end
}
Version data entries
122 entries across 122 versions & 1 rubygems