C++ Code Examples for read input file

bool InputAudioFile::Read(size_t samples, int16_t* destination) {
  if (!fp_) {
    return false;
  }
  size_t samples_read = fread(destination, sizeof(int16_t), samples, fp_);
  if (samples_read < samples) {
    // Rewind and read the missing samples.
    rewind(fp_);
    size_t missing_samples = samples - samples_read;
    if (fread(destination + samples_read, sizeof(int16_t), missing_samples,
              fp_) < missing_samples) {
      // Could not read enough even after rewinding the file.
      return false;
    }
  }
  return true;
} 

static std::string
readInputTestFile( const char *path )
{
   FILE *file = fopen( path, "rb" );
   if ( !file )
      return std::string("");
   fseek( file, 0, SEEK_END );
   long size = ftell( file );
   fseek( file, 0, SEEK_SET );
   std::string text;
   char *buffer = new char[size+1];
   buffer[size] = 0;
   if ( fread( buffer, 1, size, file ) == (unsigned long)size )
      text = buffer;
   fclose( file );
   delete[] buffer;
   return text;
} 

void readLine(FILE *input, char *lineFromFile, int maxLength)
{
	// Variables...
	int stripPointer = 0;

	// Read line from file...
	memset(lineFromFile, 0, maxLength);
	fgets(lineFromFile, maxLength, input);

	// Clear the end-of-line stuff...
	stripPointer = strlen(lineFromFile) -1;
	while ((lineFromFile[stripPointer] == '\r') || (lineFromFile[stripPointer] == '\n') || (lineFromFile[stripPointer] == ' '))
	{
		lineFromFile[stripPointer] = 0;
		stripPointer--;
	}
} 

u64 file::read(std::string& input, u64 input_size /*= 0*/, u64 offset /*= 0*/) const
	{
		const auto path = m_path.string();
		std::ifstream ifs(path, std::ios::binary | std::ios::in);

		if (ifs.good())
		{
			if (offset > m_size)
				offset = 0;

			if ((input_size == 0) || (input_size + offset) > m_size)
				input_size = (m_size - offset);

			input.resize(static_cast<size_t>(input_size));
			ifs.seekg(offset, std::ios::beg);			
			ifs.read(&input[0], input.size());
			ifs.close();

			return ifs.gcount();
		}

		return 0;
	} 

void readInput(char* filePath) {
    
    ifstream fin;
    fin.open(filePath);
    
    string line;
    int counter = 0;
    
    while(getline(fin, line)) {
        
        counter = (counter + 1) % 3;
        if (counter == 1)
            imagePaths.push_back(line);
        else if (counter == 2) {
            Point leftEyeLoc = getCoordinates(line);
            leftEyeCoordinates.push_back(leftEyeLoc);
        }
        else { 

u64 file_util::read(const boost::filesystem::path& path, std::string& input, u64 input_size /*= 0*/, u64 offset /*= 0*/)
	{
		std::ifstream ifs(path.string(), std::ios::binary | std::ios::in | std::ios::ate);

		if (ifs.good())
		{
			const u64 size = ifs.tellg();
			if (offset > size)
				offset = 0;

			if ((input_size == 0) || (input_size + offset) > size)
				input_size = (size - offset);

			input.resize(static_cast<size_t>(input_size));
			ifs.seekg(offset, std::ios::beg);
			ifs.read(&input[0], input.size());
			ifs.close();

			return ifs.gcount();
		}

		return 0;
	} 

void read_input_file() {
    int a,b,c,i,j;
    int ar[10]={0,0,1,2,3,1,2,4,3,4};
    int br[10]={1,2,2,1,2,3,4,3,5,5};
    int cr[10]={16,13,10,4,9,12,14,7,20,4};
    FILE* input = fopen("mf.in","r");
    // read number of nodes and edges
    //fscanf(input,"%d %d",&n,&e);
    // initialize empty capacity matrix 
    for (i=0; i<6; i++) {
	for (j=0; j<6; j++) {
	    capacity[i][j] = 0;
	}
    }
    // read edge capacities
    for (i=0; i<10; i++) {
	//fscanf(input,"%d %d %d",&a,&b,&c);
	a=ar[i];b=br[i];c=cr[i];
	capacity[a][b] = c;
    }
    fclose(input);
} 

bool ResampleInputAudioFile::Read(size_t samples,
                                  int output_rate_hz,
                                  int16_t* destination) {
  const size_t samples_to_read = samples * file_rate_hz_ / output_rate_hz;
  RTC_CHECK_EQ(samples_to_read * output_rate_hz, samples * file_rate_hz_)
      << "Frame size and sample rates don't add up to an integer.";
  std::unique_ptr<int16_t[]> temp_destination(new int16_t[samples_to_read]);
  if (!InputAudioFile::Read(samples_to_read, temp_destination.get()))
    return false;
  resampler_.ResetIfNeeded(file_rate_hz_, output_rate_hz, 1);
  size_t output_length = 0;
  RTC_CHECK_EQ(resampler_.Push(temp_destination.get(), samples_to_read,
                               destination, samples, output_length),
               0);
  RTC_CHECK_EQ(samples, output_length);
  return true;
} 

static std::string readInputTestFile(const char *path) {
  FILE *file = fopen(path, "rb");
  if (!file)
    return std::string("");
  fseek(file, 0, SEEK_END);
  long size = ftell(file);
  fseek(file, 0, SEEK_SET);
  std::string text;
  char *buffer = new char[size + 1];
  buffer[size] = 0;
  if (fread(buffer, 1, size, file) == (unsigned long)size)
    text = buffer;
  fclose(file);
  delete[] buffer;
  return text;
} 

void DebugDumpGenerator::ReadAndDeinterleave(ResampleInputAudioFile* audio,
                                             int channels,
                                             const StreamConfig& config,
                                             float* const* buffer) {
  const size_t num_frames = config.num_frames();
  const int out_channels = config.num_channels();

  std::vector<int16_t> signal(channels * num_frames);

  audio->Read(num_frames * channels, &signal[0]);

  // We only allow reducing number of channels by discarding some channels.
  RTC_CHECK_LE(out_channels, channels);
  for (int channel = 0; channel < out_channels; ++channel) {
    for (size_t i = 0; i < num_frames; ++i) {
      buffer[channel][i] = S16ToFloat(signal[i * channels + channel]);
    }
  }
} 

static std::string readInputTestFile(const char *path) {
  FILE *file = fopen(path, "rb");
  if (!file)
    return std::string("");
  fseek(file, 0, SEEK_END);
  long size = ftell(file);
  fseek(file, 0, SEEK_SET);
  std::string text;
  char *buffer = new char[size + 1];
  buffer[size] = 0;
  if (fread(buffer, 1, size, file) == (unsigned long)size)
    text = buffer;
  fclose(file);
  delete[] buffer;
  return text;
} 

u64 file_component::read(std::string& input, u64 input_size /*= 0*/, u64 offset /*= 0*/) const
	{
		const auto path = m_path.string();
		std::ifstream ifs(path, std::ios::binary | std::ios::in);

		if (ifs.good())
		{
			if (offset > m_size)
				offset = 0;

			if ((input_size == 0) || (input_size + offset) > m_size)
				input_size = (m_size - offset);

			input.resize(static_cast<size_t>(input_size));
			ifs.seekg(offset, std::ios::beg);
			ifs.read(&input[0], input.size());
			ifs.close();

			return ifs.gcount();
		}

		return 0;
	} 

int FileInputStream::CopyingFileInputStream::Read(void* buffer, int size) {
  GOOGLE_CHECK(!is_closed_);

  int result;
  do {
    result = read(file_, buffer, size);
  } while (result < 0 && errno == EINTR);

  if (result < 0) {
    // Read error (not EOF).
    errno_ = errno;
  }

  return result;
} 

int FileInputStream::CopyingFileInputStream::Read(void* buffer, int size) {
  GOOGLE_CHECK(!is_closed_);

  int result;
  do {
    result = read(file_, buffer, size);
  } while (result < 0 && errno == EINTR);

  if (result < 0) {
    // Read error (not EOF).
    errno_ = errno;
  }

  return result;
} 

int FileInputStream::CopyingFileInputStream::Read(void* buffer, int size) {
  GOOGLE_CHECK(!is_closed_);

  int result;
  do {
    result = read(file_, buffer, size);
  } while (result < 0 && errno == EINTR);

  if (result < 0) {
    // Read error (not EOF).
    errno_ = errno;
  }

  return result;
} 

int FileInputStream::CopyingFileInputStream::Read(void* buffer, int size) {
  GOOGLE_CHECK(!is_closed_);

  int result;
  do {
    result = read(file_, buffer, size);
  } while (result < 0 && errno == EINTR);

  if (result < 0) {
    // Read error (not EOF).
    errno_ = errno;
  }

  return result;
} 

int FileInputStream::CopyingFileInputStream::Read(void* buffer, int size) {
  GOOGLE_CHECK(!is_closed_);

  int result;
  do {
    result = read(file_, buffer, size);
  } while (result < 0 && errno == EINTR);

  if (result < 0) {
    // Read error (not EOF).
    errno_ = errno;
  }

  return result;
} 

int FileInputStream::CopyingFileInputStream::Read(void* buffer, int size) {
  GOOGLE_CHECK(!is_closed_);

  int result;
  do {
    result = read(file_, buffer, size);
  } while (result < 0 && errno == EINTR);

  if (result < 0) {
    // Read error (not EOF).
    errno_ = errno;
  }

  return result;
} 

void
bufferedReadPixels (InputFile::Data* ifd, int scanLine1, int scanLine2)
{
    //
    // bufferedReadPixels reads each row of tiles that intersect the
    // scan-line range (scanLine1 to scanLine2). The previous row of
    // tiles is cached in order to prevent redundent tile reads when
    // accessing scanlines sequentially.
    //

    int minY = std::min (scanLine1, scanLine2);
    int maxY = std::max (scanLine1, scanLine2);

    if (minY < ifd->minY || maxY >  ifd->maxY)
    {
        throw Iex::ArgExc ("Tried to read scan line outside "
			   "the image file's data window.");
    }

    //
    // The minimum and maximum y tile coordinates that intersect this
    // scanline range
    //

    int minDy = (minY - ifd->minY) / ifd->tFile->tileYSize();
    int maxDy = (maxY - ifd->minY) / ifd->tFile->tileYSize();

    //
    // Figure out which one is first in the file so we can read without seeking
    //

    int yStart, yEnd, yStep;

    if (ifd->lineOrder == DECREASING_Y)
    {
        yStart = maxDy;
        yEnd = minDy - 1;
        yStep = -1;
    }
    else
    { 

int FileInputStream::CopyingFileInputStream::Read(void* buffer, int size) {
  GOOGLE_CHECK(!is_closed_);

  int result;
  do {
    result = read(file_, buffer, size);
  } while (result < 0 && errno == EINTR);

  if (result < 0) {
    // Read error (not EOF).
    errno_ = errno;
  }

  return result;
} 

int FileInputStream::CopyingFileInputStream::Read(void* buffer, int size) {
  GOOGLE_CHECK(!is_closed_);

  int result;
  do {
    result = read(file_, buffer, size);
  } while (result < 0 && errno == EINTR);

  if (result < 0) {
    // Read error (not EOF).
    errno_ = errno;
  }

  return result;
} 

void MultiLevelPartition::read(const std::string &inputFileName) {
	std::ifstream file;
	file.open(inputFileName);
	if (file.is_open()) {
		std::string line;
		getline(file, line);

		count numLevels = std::stoi(line);
		numCells = std::vector<count>(numLevels);
		for (index i = 0; i < numLevels; ++i) {
			std::getline(file, line);
			numCells[i] = std::stoi(line);
		}

		computeBitmap();

		std::getline(file, line);
		count numVertices = std::stoi(line);

		cellNumbers = std::vector<pv>(numVertices);
		for (index i = 0; i < numVertices; ++i) {
			std::getline(file, line);
			cellNumbers[i] = std::stoull(line);
		}
	}
}