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text_file_reader_utils.cc
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text_file_reader_utils.cc
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#include "caffe2/operators/text_file_reader_utils.h"
#include <fcntl.h>
#include <cerrno>
#include <cstring>
#include <sstream>
namespace caffe2 {
Tokenizer::Tokenizer(const std::vector<char>& delims, char escape)
: escape_(escape) {
reset();
std::memset(delimTable_, 0, sizeof(delimTable_));
for (int i = 0; i < delims.size(); ++i) {
delimTable_[(unsigned char)delims.at(i)] = i + 1;
}
}
void Tokenizer::reset() {
toBeSkipped_ = 0;
startDelimId_ = 0;
leftover_.clear();
}
void Tokenizer::next(char* start, char* end, TokenizedString& tokenized) {
tokenized.modifiedStrings_.clear();
tokenized.tokens_.clear();
char* currentStart = start;
std::string* copied = nullptr;
if (!leftover_.empty()) {
tokenized.modifiedStrings_.emplace_back(std::make_shared<std::string>());
copied = tokenized.modifiedStrings_.back().get();
*copied = std::move(leftover_);
}
char* ch;
for (ch = start + toBeSkipped_; ch < end; ++ch) {
if (*ch == escape_) {
if (!copied) {
tokenized.modifiedStrings_.emplace_back(std::make_shared<std::string>());
copied = tokenized.modifiedStrings_.back().get();
}
copied->append(currentStart, ch);
currentStart = ch + 1;
// skip next character, since it's escaped
++ch;
continue;
}
int newDelimId = delimTable_[(unsigned char)*ch];
if (newDelimId > 0) {
// found delimiter
tokenized.tokens_.emplace_back();
auto& token = tokenized.tokens_.back();
token.startDelimId = startDelimId_;
if (copied) {
copied->append(currentStart, ch);
const char* c_str = copied->data();
token.start = c_str;
token.end = c_str + copied->size();
} else {
token.start = currentStart;
token.end = ch;
}
currentStart = ch + 1;
copied = nullptr;
startDelimId_ = newDelimId - 1;
}
}
tokenized.lastDelim_ = startDelimId_;
toBeSkipped_ = ch - end;
if (copied) {
copied->append(currentStart, end);
leftover_ = std::move(*copied);
} else {
leftover_.assign(currentStart, end);
}
}
FileReader::FileReader(const std::string& path, size_t bufferSize)
: bufferSize_(bufferSize), buffer_(new char[bufferSize]) {
fd_ = open(path.c_str(), O_RDONLY, 0777);
if (fd_ < 0) {
throw std::runtime_error(
"Error opening file for reading: " + std::string(std::strerror(errno)) +
" Path=" + path);
}
}
void FileReader::reset() {
if (lseek(fd_, 0, SEEK_SET) == -1) {
throw std::runtime_error(
"Error reseting file cursor: " + std::string(std::strerror(errno)));
}
}
FileReader::~FileReader() {
if (fd_ >= 0) {
close(fd_);
}
}
void FileReader::operator()(CharRange& range) {
char* buffer = buffer_.get();
auto numRead = read(fd_, buffer, bufferSize_);
if (numRead == -1) {
throw std::runtime_error(
"Error reading file: " + std::string(std::strerror(errno)));
}
if (numRead == 0) {
range.start = nullptr;
range.end = nullptr;
return;
}
range.start = buffer;
range.end = buffer + numRead;
}
}