text: // Copyright (c) 2016 Google Inc.
  //
  // Permission is hereby granted, free of charge, to any person obtaining a
  // copy of this software and/or associated documentation files (the
  // "Materials"), to deal in the Materials without restriction, including
  // without limitation the rights to use, copy, modify, merge, publish,
  // distribute, sublicense, and/or sell copies of the Materials, and to
  // permit persons to whom the Materials are furnished to do so, subject to
  // the following conditions:
  //
  // The above copyright notice and this permission notice shall be included
  // in all copies or substantial portions of the Materials.
  //
  // MODIFICATIONS TO THIS FILE MAY MEAN IT NO LONGER ACCURATELY REFLECTS
  // KHRONOS STANDARDS. THE UNMODIFIED, NORMATIVE VERSIONS OF KHRONOS
  // SPECIFICATIONS AND HEADER INFORMATION ARE LOCATED AT
  //    https://www.khronos.org/registry/
  //
  // THE MATERIALS ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
  // IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
  // CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  // TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  // MATERIALS OR THE USE OR OTHER DEALINGS IN THE MATERIALS.
  
  #ifndef LIBSPIRV_TOOLS_IO_H_
  #define LIBSPIRV_TOOLS_IO_H_
  
  #include <cstdint>
  #include <cstdio>
  #include <vector>
  
  // Appends the content from the file named as |filename| to |data|, assuming
  // each element in the file is of type |T|. The file is opened with the given
  // |mode|. If |filename| is nullptr or "-", reads from the standard input. If
  // any error occurs, writes error messages to standard error and returns false.
  template <typename T>
  bool ReadFile(const char* filename, const char* mode, std::vector<T>* data) {
    const int buf_size = 1024;
    const bool use_file = filename && strcmp("-", filename);
    if (FILE* fp = (use_file ? fopen(filename, mode) : stdin)) {
      T buf[buf_size];
      while (size_t len = fread(buf, sizeof(T), buf_size, fp)) {
        data->insert(data->end(), buf, buf + len);
      }
      if (ftell(fp) == -1L) {
        if (ferror(fp)) {
          fprintf(stderr, "error: error reading file '%s'\n", filename);
          return false;
        }
      } else {
        if (sizeof(T) != 1 && (ftell(fp) % sizeof(T))) {
          fprintf(stderr, "error: corrupted word found in file '%s'\n", filename);
          return false;
        }
      }
      if (use_file) fclose(fp);
    } else {
      fprintf(stderr, "error: file does not exist '%s'\n", filename);
      return false;
    }
    return true;
  }
  
  // Writes the given |data| into the file named as |filename| using the given
  // |mode|, assuming |data| is an array of |count| elements of type |T|. If
  // |filename| is nullptr or "-", writes to standard output. If any error occurs,
  // returns false and outputs error message to standard error.
  template <typename T>
  bool WriteFile(const char* filename, const char* mode, const T* data,
                 size_t count) {
    const bool use_stdout =
        !filename || (filename[0] == '-' && filename[1] == '\0');
    if (FILE* fp = (use_stdout ? stdout : fopen(filename, mode))) {
      size_t written = fwrite(data, sizeof(T), count, fp);
      if (count != written) {
        fprintf(stderr, "error: could not write to file '%s'\n", filename);
        return false;
      }
      if (!use_stdout) fclose(fp);
    } else {
      fprintf(stderr, "error: could not open file '%s'\n", filename);
      return false;
    }
    return true;
  }
  
  #endif  // LIBSPIRV_TOOLS_IO_H_
  