/// <summary>
/// Loads a header from the specified stream.
/// </summary>
/// <param name="stream">The input stream.</param>
/// <returns>A header loaded from the specified stream.</returns>
/// <exception cref="ArgumentNullException"><paramref name="stream"/> is <c>null</c>.</exception>
public virtual async Task <Header> LoadAsync(Stream stream)
{
if (stream == null)
{
throw new ArgumentNullException(nameof(stream));
}
// optimization: be one byte ahead when loading columns => only one I/O read per column
var buffer = new byte[HEADER_SIZE + 1];
int totalReadBytes = await stream.ReadAsync(buffer, 0, buffer.Length).ConfigureAwait(false);
BasicProperties headerProperties = ParseBasicProperties(buffer);
LoadColumnsResult loadColumnsResult = await LoadColumnsAsync(stream, buffer.Last()).ConfigureAwait(false);
totalReadBytes += loadColumnsResult.ReadBytes;
int bytesToSkip = headerProperties.HeaderSize - totalReadBytes;
if (bytesToSkip > 0)
{
// move to the end of the header
if (stream.CanSeek)
{
stream.Seek(bytesToSkip, SeekOrigin.Current);
}
else
{
// async read is more expensive then sync read so we use bigger buffer to reduce the number of I/O reads
const int MAX_SKIP_BUFFER_SIZE = 512;
byte[] skipBuffer = buffer;
if (bytesToSkip > buffer.Length)
{
skipBuffer = new byte[Math.Min(bytesToSkip, MAX_SKIP_BUFFER_SIZE)];
}
while (bytesToSkip > 0)
{
bytesToSkip -= await stream.ReadAsync(skipBuffer, 0, Math.Min(skipBuffer.Length, bytesToSkip)).ConfigureAwait(false);
}
}
}
return(CreateHeader(headerProperties, loadColumnsResult.Columns));
}
/// <summary>
/// Loads a header from the specified stream.
/// </summary>
/// <param name="stream">The input stream.</param>
/// <returns>A header loaded from the specified stream.</returns>
/// <exception cref="ArgumentNullException"><paramref name="stream"/> is <c>null</c>.</exception>
public virtual Header Load(Stream stream)
{
if (stream == null)
{
throw new ArgumentNullException(nameof(stream));
}
// optimization: be one byte ahead when loading columns => only one I/O read per column
var buffer = new byte[HEADER_SIZE + 1];
int totalReadBytes = stream.Read(buffer, 0, buffer.Length);
BasicProperties headerProperties = ParseBasicProperties(buffer);
LoadColumnsResult loadColumnsResult = LoadColumns(stream, buffer.Last());
totalReadBytes += loadColumnsResult.ReadBytes;
int bytesToSkip = headerProperties.HeaderSize - totalReadBytes;
if (bytesToSkip > 0)
{
// move to the end of the header
if (stream.CanSeek)
{
stream.Seek(bytesToSkip, SeekOrigin.Current);
}
else
{
while (bytesToSkip > 0)
{
bytesToSkip -= stream.Read(buffer, 0, Math.Min(buffer.Length, bytesToSkip));
}
}
}
return(CreateHeader(headerProperties, loadColumnsResult.Columns));
}
