#ifndef CAFFE2_OPERATORS_TEXT_FILE_READER_UTILS_H
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#define CAFFE2_OPERATORS_TEXT_FILE_READER_UTILS_H
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#include <memory>
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#include <string>
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#include <vector>
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#include "caffe2/core/common.h"
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namespace caffe2 {
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struct CAFFE2_API Token {
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int startDelimId;
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const char* start;
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const char* end;
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};
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class CAFFE2_API TokenizedString {
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// holder for strings that have been modified
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std::vector<std::shared_ptr<std::string>> modifiedStrings_;
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std::vector<Token> tokens_;
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int lastDelim_;
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public:
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const std::vector<Token>& tokens() const {
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return tokens_;
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}
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int lastDelim() const {
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return lastDelim_;
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}
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friend class Tokenizer;
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};
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class CAFFE2_API Tokenizer {
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private:
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int startDelimId_;
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// state of the tokenizer
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std::string leftover_;
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// if we need to skip the first characters of the next batch because
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// e.g. an escape char that was the last character of the last batch.
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int toBeSkipped_;
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int delimTable_[256];
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const char escape_;
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public:
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Tokenizer(const std::vector<char>& delimiters, char escape);
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void reset();
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void next(char* start, char* end, TokenizedString& tokenized);
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};
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struct CAFFE2_API CharRange {
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char* start;
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char* end;
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};
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struct CAFFE2_API StringProvider {
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virtual void operator()(CharRange&) = 0;
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virtual void reset() = 0;
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virtual ~StringProvider() {}
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};
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class CAFFE2_API BufferedTokenizer {
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public:
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BufferedTokenizer(const Tokenizer& t, StringProvider* p, int numPasses = 1)
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: provider_(p), tokenizer_(t), tokenIndex_(0), numPasses_(numPasses) {}
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bool next(Token& token) {
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CharRange range;
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while (tokenIndex_ >= tokenized_.tokens().size()) {
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range.start = nullptr;
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while (range.start == nullptr && pass_ < numPasses_) {
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(*provider_)(range);
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if (range.start == nullptr) {
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++pass_;
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if (pass_ < numPasses_) {
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provider_->reset();
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tokenizer_.reset();
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}
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}
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}
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if (range.start == nullptr) {
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return false;
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}
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tokenizer_.next(range.start, range.end, tokenized_);
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tokenIndex_ = 0;
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}
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token = tokenized_.tokens()[tokenIndex_++];
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return true;
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};
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int endDelim() const {
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if (tokenIndex_ + 1 < tokenized_.tokens().size()) {
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return tokenized_.tokens()[tokenIndex_ + 1].startDelimId;
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}
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return tokenized_.lastDelim();
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}
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private:
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StringProvider* provider_;
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Tokenizer tokenizer_;
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TokenizedString tokenized_;
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int tokenIndex_;
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int numPasses_;
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int pass_{0};
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};
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class CAFFE2_API FileReader : public StringProvider {
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public:
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explicit FileReader(const std::string& path, size_t bufferSize = 65536);
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~FileReader();
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void operator()(CharRange& range) override;
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void reset() override;
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private:
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const size_t bufferSize_;
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int fd_;
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std::unique_ptr<char[]> buffer_;
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};
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} // namespace caffe2
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#endif // CAFFE2_OPERATORS_TEXT_FILE_READER_UTILS_H
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