status-go/vendor/github.com/anacrolix/missinggo/rle.go

47 lines
1.1 KiB
Go

package missinggo
// A RunLengthEncoder counts successive duplicate elements and emits the
// element and the run length when the element changes or the encoder is
// flushed.
type RunLengthEncoder interface {
// Add a series of identical elements to the stream.
Append(element interface{}, count uint64)
// Emit the current element and its count if non-zero without waiting for
// the element to change.
Flush()
}
type runLengthEncoder struct {
eachRun func(element interface{}, count uint64)
element interface{}
count uint64
}
// Creates a new RunLengthEncoder. eachRun is called when an element and its
// count is emitted, per the RunLengthEncoder interface.
func NewRunLengthEncoder(eachRun func(element interface{}, count uint64)) RunLengthEncoder {
return &runLengthEncoder{
eachRun: eachRun,
}
}
func (me *runLengthEncoder) Append(element interface{}, count uint64) {
if element == me.element {
me.count += count
return
}
if me.count != 0 {
me.eachRun(me.element, me.count)
}
me.count = count
me.element = element
}
func (me *runLengthEncoder) Flush() {
if me.count == 0 {
return
}
me.eachRun(me.element, me.count)
me.count = 0
}