SI-9332 Iterator.span exhausts leading iterator #4530
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Since the leading and trailing iterators returned by span share the underlying iterator, the leading iterator must flag when it is exhausted (when the span predicate fails) since the trailing iterator will advance the underlying iterator. It would also be possible to leave the failing element in the leading lookahead buffer, where it would forever fail the predicate, but that entails evaluating the predicate twice, on both enqueue and dequeue.
The queue is only used when the prefix is drained by finish. Since a finished flag has been introduced, distinguish between the drained state and using the underlying (buffered) iterator.
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LGTM! What a selfish iterator :) |
lrytz
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May 28, 2015
SI-9332 Iterator.span exhausts leading iterator
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Since the leading and trailing iterators returned by span
share the underlying iterator, the leading iterator must
flag when it is exhausted (when the span predicate fails)
since the trailing iterator will advance the underlying
iterator.
It would also be possible to leave the failing element in
the leading lookahead buffer, where it would forever fail
the predicate, but that entails evaluating the predicate
twice, on both enqueue and dequeue.