fileio.h

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/**********************************************************************
 * File:        fileio.h
 * Description: File I/O utilities.
 * Author:      Samuel Charron
 *
 * (C) Copyright 2013, Google Inc.
 * 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 TESSERACT_TRAINING_FILEIO_H_
#define TESSERACT_TRAINING_FILEIO_H_
 
#include <cstddef>
#include <cstdio>
#include <string>
 
#include <tesseract/genericvector.h>      // for GenericVector
#include <tesseract/platform.h>
#include <tesseract/strngs.h>             // for STRING
 
namespace tesseract {
 
// Reads a file as a vector of STRING.
// TODO: Use std::vector and std::string for LoadFileLinesToStrings.
inline bool LoadFileLinesToStrings(const char* filename,
                                   GenericVector<STRING>* lines) {
  GenericVector<char> data;
  if (!LoadDataFromFile(filename, &data)) {
    return false;
  }
  STRING lines_str(&data[0], data.size());
  lines_str.split('\n', lines);
  return true;
}
 
// A class to manipulate FILE*s.
class File {
 public:
  // Try to open the file 'filename' in mode 'mode'.
  // Stop the program if it cannot open it.
  static FILE* OpenOrDie(const std::string& filename, const std::string& mode);
  static FILE* Open(const std::string& filename, const std::string& mode);
 
  // Try to open the file 'filename' and to write 'str' in it.
  // Stop the program if it fails.
  static void WriteStringToFileOrDie(const std::string& str, const std::string& filename);
 
  // Return true if the file 'filename' is readable.
  static bool Readable(const std::string& filename);
 
  static bool ReadFileToString(const std::string& filename, std::string* out);
 
  // Helper methods
 
  // Concatenate file paths removing any extra intervening '/' symbols.
  static std::string JoinPath(const std::string& prefix, const std::string& suffix);
  // Delete a filename or all filenames matching a glob pattern.
  static bool Delete(const char* pathname);
  static bool DeleteMatchingFiles(const char* pattern);
};
 
// A class to manipulate Files for reading.
class InputBuffer {
 public:
  explicit InputBuffer(FILE* stream);
  // 'size' is ignored.
  InputBuffer(FILE* stream, size_t size);
 
  ~InputBuffer();
 
  // Read data until end-of-file.
  // The data is stored in '*out'.
  // Return false if an error occurs, true otherwise.
  bool Read(std::string* out);
 
  // Close the FILE* used by InputBuffer.
  // Return false if an error occurs, true otherwise.
  bool CloseFile();
 
 private:
  FILE* stream_;
};
 
// A class to manipulate Files for writing.
class OutputBuffer {
 public:
  explicit OutputBuffer(FILE* stream);
  // 'size' is ignored.
  OutputBuffer(FILE* stream, size_t size);
 
  ~OutputBuffer();
 
  // Write string 'str' to the open FILE*.
  void WriteString(const std::string& str);
 
  // Close the FILE* used by InputBuffer.
  // Return false if an error occurs, true otherwise.
  bool CloseFile();
 
 private:
  FILE* stream_;
};
 
}  // namespace tesseract
#endif  // TESSERACT_TRAINING_FILEIO_H_