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#include "rewriter/katakana_promotion_rewriter.h"
#include "base/util.h"
#include "converter/segments.h"
#include "protocol/commands.pb.h"
#include "request/conversion_request.h"
#include "transliteration/transliteration.h"
namespace mozc {
namespace {
bool MaybePromoteKatakana(Segment *segment) {
if (segment->meta_candidates_size() <= transliteration::FULL_KATAKANA) {
return false;
}
const Segment::Candidate &katakana_candidate =
segment->meta_candidate(transliteration::FULL_KATAKANA);
const string &katakana_value = katakana_candidate.value;
if (!Util::IsScriptType(katakana_value, Util::KATAKANA)) {
return false;
}
constexpr size_t kMaxRankForKatakana = 5;
for (size_t i = 0;
i < std::min(segment->candidates_size(), kMaxRankForKatakana);
++i) {
if (segment->candidate(i).value == katakana_value) {
// No need to promote or insert.
return false;
}
}
Segment::Candidate insert_candidate = katakana_candidate;
size_t index = kMaxRankForKatakana;
for (; index < segment->candidates_size(); ++index) {
if (segment->candidate(index).value == katakana_value) {
break;
}
}
const size_t insert_pos =
std::min(kMaxRankForKatakana, segment->candidates_size());
if (index < segment->candidates_size()) {
const Segment::Candidate insert_candidate = segment->candidate(index);
*(segment->insert_candidate(insert_pos)) = insert_candidate;
} else {
*(segment->insert_candidate(insert_pos)) = katakana_candidate;
}
return true;
}
} // namespace
KatakanaPromotionRewriter::KatakanaPromotionRewriter() = default;
KatakanaPromotionRewriter::~KatakanaPromotionRewriter() = default;
int KatakanaPromotionRewriter::capability(
const ConversionRequest &request) const {
if (request.request().mixed_conversion()) {
return RewriterInterface::ALL;
} else {
// Desktop version has a keybind to select katakana.
return RewriterInterface::NOT_AVAILABLE;
}
}
bool KatakanaPromotionRewriter::Rewrite(const ConversionRequest &request,
Segments *segments) const {
bool modified = false;
for (size_t i = 0; i < segments->conversion_segments_size(); ++i) {
modified |= MaybePromoteKatakana(segments->mutable_conversion_segment(i));
}
return modified;
}
} // namespace mozc