/// <summary>
/// Read values of type <see cref="TiffFieldType.SLong"/> from the specified tag.
/// </summary>
/// <param name="tag">The tag to read.</param>
/// <param name="sizeLimit">The maximum number of values to read.</param>
/// <param name="cancellationToken">The <see cref="CancellationToken"/> that fires if the user want to stop the current task.</param>
/// <returns>A <see cref="ValueTask{TiffValueCollection}"/> that completes when the values are read and return the read values.</returns>
public ValueTask <TiffValueCollection <int> > ReadSLongFieldAsync(TiffTag tag, int sizeLimit, CancellationToken cancellationToken = default)
{
if (Reader is null)
{
throw new InvalidOperationException();
}
if (ImageFileDirectory is null)
{
throw new InvalidOperationException();
}
TiffImageFileDirectoryEntry entry = ImageFileDirectory.FindEntry(tag);
if (entry.Tag == TiffTag.None)
{
return(new ValueTask <TiffValueCollection <int> >(TiffValueCollection.Empty <int>()));
}
return(Reader.ReadSLongFieldAsync(entry, sizeLimit, cancellationToken: cancellationToken));
}
/// <summary>
/// Read values of type <see cref="TiffFieldType.Long"/> from the specified tag.
/// </summary>
/// <param name="tag">The tag to read.</param>
/// <param name="sizeLimit">The maximum number of values to read.</param>
/// <returns>The values read.</returns>
public TiffValueCollection <uint> ReadLongField(TiffTag tag, int sizeLimit)
{
if (Reader is null)
{
throw new InvalidOperationException();
}
if (ImageFileDirectory is null)
{
throw new InvalidOperationException();
}
TiffImageFileDirectoryEntry entry = ImageFileDirectory.FindEntry(tag);
if (entry.Tag == TiffTag.None)
{
return(TiffValueCollection.Empty <uint>());
}
return(Reader.ReadLongField(entry, sizeLimit));
}
/// <summary>
/// Read values of type <see cref="TiffFieldType.ASCII"/> from the specified tag.
/// </summary>
/// <param name="tag">The tag to read.</param>
/// <returns>The values read.</returns>
public TiffValueCollection <string> ReadASCIIField(TiffTag tag)
{
if (Reader is null)
{
throw new InvalidOperationException();
}
if (ImageFileDirectory is null)
{
throw new InvalidOperationException();
}
TiffImageFileDirectoryEntry entry = ImageFileDirectory.FindEntry(tag);
if (entry.Tag == TiffTag.None)
{
return(TiffValueCollection.Empty <string>());
}
return(Reader.ReadASCIIField(entry));
}
internal async Task <TiffStreamRegion> WriteAlignedValues(TiffValueCollection <string> values, CancellationToken cancellationToken)
{
EnsureNotDisposed();
cancellationToken.ThrowIfCancellationRequested();
Debug.Assert(_writer != null);
long position = await AlignToWordBoundaryAsync(cancellationToken).ConfigureAwait(false);
int maxByteCount = 0;
foreach (string item in values)
{
maxByteCount = Math.Max(maxByteCount, Encoding.ASCII.GetMaxByteCount(item.Length));
}
long offset = position;
int bytesWritten = 0;
byte[] buffer = ArrayPool <byte> .Shared.Rent(maxByteCount + 1);
try
{
foreach (string item in values)
{
int length = Encoding.ASCII.GetBytes(item, 0, item.Length, buffer, 0);
buffer[length] = 0;
await _writer !.WriteAsync(offset, new ArraySegment <byte>(buffer, 0, length + 1), cancellationToken).ConfigureAwait(false);
offset += length + 1;
AdvancePosition(length + 1);
bytesWritten += length + 1;
}
}
finally
{
ArrayPool <byte> .Shared.Return(buffer);
}
return(new TiffStreamRegion(position, bytesWritten));
}
static async Task <uint?> TransformValueTaskAsync(ValueTask <TiffValueCollection <uint> > valueTask)
{
TiffValueCollection <uint> result = await valueTask.ConfigureAwait(false);
return(result.IsEmpty ? default(uint?) : result.GetFirstOrDefault());
}
static async Task <TiffStreamOffset> TransformValueTaskAsync(ValueTask <TiffValueCollection <TiffStreamOffset> > valueTask)
{
TiffValueCollection <TiffStreamOffset> result = await valueTask.ConfigureAwait(false);
return(result.GetFirstOrDefault());
}
private static TiffValueCollection <string> ParseASCIIArray(ReadOnlySpan <byte> buffer)
{
int startIndex = 0;
int count = buffer.Length;
if (count == 0)
{
return(TiffValueCollection.Empty <string>());
}
// Find the null terminator of the first string.
int endIndex = startIndex + count - 1;
int nullIndex = endIndex + 1;
for (int i = startIndex; i <= endIndex; i++)
{
if (buffer[i] == 0)
{
nullIndex = i;
break;
}
}
string firstValue = EncodingASCIIGetString(buffer.Slice(startIndex, nullIndex - startIndex));
if (nullIndex >= endIndex)
{
return(TiffValueCollection.Single(firstValue));
}
// Find the count of all strings.
startIndex = nullIndex + 1;
int strCount = 1;
for (int i = startIndex; i <= endIndex; i++)
{
if (buffer[i] == 0)
{
strCount++;
}
}
if (buffer[endIndex] != 0)
{
strCount++;
}
// Read all strings.
string[] values = new string[strCount];
values[0] = firstValue;
int index = 1;
for (int i = startIndex; i <= endIndex; i++)
{
if (buffer[i] == 0)
{
values[index] = EncodingASCIIGetString(buffer.Slice(startIndex, i - startIndex));
index++;
startIndex = i + 1;
}
}
if (buffer[endIndex] != 0)
{
values[index] = EncodingASCIIGetString(buffer.Slice(startIndex, endIndex - startIndex + 1));
}
return(TiffValueCollection.UnsafeWrap(values));
}
static async Task <TiffRational[]> TransformValueTaskAsync(ValueTask <TiffValueCollection <TiffRational> > valueTask)
{
TiffValueCollection <TiffRational> result = await valueTask.ConfigureAwait(false);
return(result.GetOrCreateArray());
}
static async Task <TiffInkSet> TransformValueTaskAsync(ValueTask <TiffValueCollection <ushort> > valueTask)
{
TiffValueCollection <ushort> result = await valueTask.ConfigureAwait(false);
return(result.IsEmpty ? TiffInkSet.CMYK : (TiffInkSet)result.GetFirstOrDefault());
}
static async Task <TiffT4Options> TransformValueTaskAsync(ValueTask <TiffValueCollection <uint> > valueTask)
{
TiffValueCollection <uint> result = await valueTask.ConfigureAwait(false);
return(result.IsEmpty ? TiffT4Options.None : (TiffT4Options)result.GetFirstOrDefault());
}
static async Task <TiffPredictor> TransformValueTaskAsync(ValueTask <TiffValueCollection <ushort> > valueTask)
{
TiffValueCollection <ushort> result = await valueTask.ConfigureAwait(false);
return(result.IsEmpty ? TiffPredictor.None : (TiffPredictor)result.GetFirstOrDefault());
}
