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* Copyright (C) 2017 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
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* See the License for the specific language governing permissions and
* limitations under the License.
// Inference code for the text classification model.
#include <memory>
#include <set>
#include <string>
#include <vector>
#include "feature-processor.h"
#include "model-executor.h"
#include "model_generated.h"
#include "strip-unpaired-brackets.h"
#include "types.h"
#include "util/memory/mmap.h"
#include "util/utf8/unilib.h"
namespace libtextclassifier2 {
// A text processing model that provides text classification, annotation,
// selection suggestion for various types.
// NOTE: This class is not thread-safe.
class TextClassifier {
static std::unique_ptr<TextClassifier> FromUnownedBuffer(const char* buffer,
int size);
// Takes ownership of the mmap.
static std::unique_ptr<TextClassifier> FromScopedMmap(
std::unique_ptr<ScopedMmap>* mmap);
static std::unique_ptr<TextClassifier> FromFileDescriptor(int fd, int offset,
int size);
static std::unique_ptr<TextClassifier> FromFileDescriptor(int fd);
static std::unique_ptr<TextClassifier> FromPath(const std::string& path);
// Returns true if the model is ready for use.
bool IsInitialized() { return initialized_; }
// Runs inference for given a context and current selection (i.e. index
// of the first and one past last selected characters (utf8 codepoint
// offsets)). Returns the indices (utf8 codepoint offsets) of the selection
// beginning character and one past selection end character.
// Returns the original click_indices if an error occurs.
// NOTE: The selection indices are passed in and returned in terms of
// UTF8 codepoints (not bytes).
// Requires that the model is a smart selection model.
CodepointSpan SuggestSelection(const std::string& context,
CodepointSpan click_indices) const;
// Classifies the selected text given the context string.
// Returns an empty result if an error occurs.
std::vector<std::pair<std::string, float>> ClassifyText(
const std::string& context, CodepointSpan selection_indices) const;
// Annotates given input text. The annotations should cover the whole input
// context except for whitespaces, and are sorted by their position in the
// context string.
std::vector<AnnotatedSpan> Annotate(const std::string& context) const;
// Constructs and initializes text classifier from given model.
// Takes ownership of 'mmap', and thus owns the buffer that backs 'model'.
TextClassifier(std::unique_ptr<ScopedMmap>* mmap, const Model* model)
: model_(model), mmap_(std::move(*mmap)), unilib_(new UniLib()) {
// Constructs, validates and initializes text classifier from given model.
// Does not own the buffer that backs 'model'.
explicit TextClassifier(const Model* model)
: model_(model), unilib_(new UniLib()) {
// Checks that model contains all required fields, and initializes internal
// datastructures.
void ValidateAndInitialize();
// Initializes regular expressions for the regex model.
void InitializeRegexModel();
// Groups the tokens into chunks. A chunk is a token span that should be the
// suggested selection when any of its contained tokens is clicked. The chunks
// are non-overlapping and are sorted by their position in the context string.
// "num_tokens" is the total number of tokens available (as this method does
// not need the actual vector of tokens).
// "span_of_interest" is a span of all the tokens that could be clicked.
// The resulting chunks all have to overlap with it and they cover this span
// completely. The first and last chunk might extend beyond it.
// The chunks vector is cleared before filling.
bool Chunk(int num_tokens, const TokenSpan& span_of_interest,
const CachedFeatures& cached_features,
std::vector<TokenSpan>* chunks) const;
// Collection name for other.
const std::string kOtherCollection = "other";
// Collection name for phone.
const std::string kPhoneCollection = "phone";
const Model* model_;
std::unique_ptr<ModelExecutor> selection_executor_;
std::unique_ptr<ModelExecutor> classification_executor_;
std::unique_ptr<EmbeddingExecutor> embedding_executor_;
std::unique_ptr<FeatureProcessor> selection_feature_processor_;
std::unique_ptr<FeatureProcessor> classification_feature_processor_;
struct CompiledRegexPattern {
std::string collection_name;
std::unique_ptr<UniLib::RegexPattern> pattern;
std::unique_ptr<ScopedMmap> mmap_;
bool initialized_ = false;
std::vector<CompiledRegexPattern> regex_patterns_;
std::unique_ptr<UniLib> unilib_;
// Interprets the buffer as a Model flatbuffer and returns it for reading.
const Model* ViewModel(const void* buffer, int size);
} // namespace libtextclassifier2