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