void VP8IteratorReset(VP8EncIterator* const it) {
VP8Encoder* const enc = it->enc_;
VP8IteratorSetRow(it, 0);
VP8IteratorSetCountDown(it, enc->mb_w_ * enc->mb_h_); // default
InitTop(it);
memset(it->bit_count_, 0, sizeof(it->bit_count_));
it->do_trellis_ = 0;
}
int VP8IteratorNext(VP8EncIterator* const it) {
it->preds_ += 4;
it->mb_ += 1;
it->nz_ += 1;
it->y_top_ += 16;
it->uv_top_ += 16;
it->x_ += 1;
if (it->x_ == it->enc_->mb_w_) {
VP8IteratorSetRow(it, ++it->y_);
}
return (0 < --it->count_down_);
}
// initialize the job struct with some TODOs
static void InitSegmentJob(VP8Encoder* const enc, SegmentJob* const job,
int start_row, int end_row) {
WebPGetWorkerInterface()->Init(&job->worker);
job->worker.data1 = job;
job->worker.data2 = &job->it;
job->worker.hook = (WebPWorkerHook)DoSegmentsJob;
VP8IteratorInit(enc, &job->it);
VP8IteratorSetRow(&job->it, start_row);
VP8IteratorSetCountDown(&job->it, (end_row - start_row) * enc->mb_w_);
memset(job->alphas, 0, sizeof(job->alphas));
job->alpha = 0;
job->uv_alpha = 0;
// only one of both jobs can record the progress, since we don't
// expect the user's hook to be multi-thread safe
job->delta_progress = (start_row == 0) ? 20 : 0;
}