LatinIME/native/jni/src/utils/ngram_utils.h

63 lines
1.7 KiB
C++

/*
* Copyright (C) 2014, The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef LATINIME_NGRAM_UTILS_H
#define LATINIME_NGRAM_UTILS_H
#include "defines.h"
namespace latinime {
enum class NgramType : int {
Unigram = 0,
Bigram = 1,
Trigram = 2,
NotANgramType = -1,
};
namespace AllNgramTypes {
// Use anonymous namespace to avoid ODR (One Definition Rule) violation.
namespace {
const NgramType ASCENDING[] = {
NgramType::Unigram, NgramType::Bigram, NgramType::Trigram
};
const NgramType DESCENDING[] = {
NgramType::Trigram, NgramType::Bigram, NgramType::Unigram
};
} // namespace
} // namespace AllNgramTypes
class NgramUtils final {
public:
static AK_FORCE_INLINE NgramType getNgramTypeFromWordCount(const int wordCount) {
// Max supported ngram is (MAX_PREV_WORD_COUNT_FOR_N_GRAM + 1)-gram.
if (wordCount <= 0 || wordCount > MAX_PREV_WORD_COUNT_FOR_N_GRAM + 1) {
return NgramType::NotANgramType;
}
// Convert word count to 0-origin enum value.
return static_cast<NgramType>(wordCount - 1);
}
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(NgramUtils);
};
}
#endif /* LATINIME_NGRAM_UTILS_H */