/// <summary>
/// Compares the current content of this writer with another one.
/// </summary>
/// <exception cref="InvalidOperationException">Content is not available, the builder has been linked with another one.</exception>
public bool ContentEquals(BlobBuilder other)
{
if (!IsHead)
{
Throw.InvalidOperationBuilderAlreadyLinked();
}
if (ReferenceEquals(this, other))
{
return(true);
}
if (other == null)
{
return(false);
}
if (!other.IsHead)
{
Throw.InvalidOperationBuilderAlreadyLinked();
}
if (Count != other.Count)
{
return(false);
}
var leftEnumerator = GetChunks();
var rightEnumerator = other.GetChunks();
int leftStart = 0;
int rightStart = 0;
bool leftContinues = leftEnumerator.MoveNext();
bool rightContinues = rightEnumerator.MoveNext();
while (leftContinues && rightContinues)
{
Debug.Assert(leftStart == 0 || rightStart == 0);
var left = leftEnumerator.Current;
var right = rightEnumerator.Current;
int minLength = Math.Min(left.Length - leftStart, right.Length - rightStart);
if (!ByteSequenceComparer.Equals(left._buffer, leftStart, right._buffer, rightStart, minLength))
{
return(false);
}
leftStart += minLength;
rightStart += minLength;
// nothing remains in left chunk to compare:
if (leftStart == left.Length)
{
leftContinues = leftEnumerator.MoveNext();
leftStart = 0;
}
// nothing remains in left chunk to compare:
if (rightStart == right.Length)
{
rightContinues = rightEnumerator.MoveNext();
rightStart = 0;
}
}
return(leftContinues == rightContinues);
}
/// <exception cref="ArgumentNullException"><paramref name="suffix"/> is null.</exception>
/// <exception cref="InvalidOperationException">Builder is not writable, it has been linked with another one.</exception>
public void LinkSuffix(BlobBuilder suffix)
{
if (suffix == null)
{
throw new ArgumentNullException(nameof(suffix));
}
// TODO: consider copying data from right to left while there is space
if (!IsHead || !suffix.IsHead)
{
Throw.InvalidOperationBuilderAlreadyLinked();
}
// avoid chaining empty chunks:
if (suffix.Count == 0)
{
return;
}
bool isEmpty = Count == 0;
// swap buffers of the heads:
var suffixBuffer = suffix._buffer;
uint suffixLength = suffix._length;
int suffixPreviousLength = suffix.PreviousLength;
int oldSuffixLength = suffix.Length;
suffix._buffer = _buffer;
suffix._length = FrozenLength; // suffix is not a head anymore
_buffer = suffixBuffer;
_length = suffixLength;
PreviousLength += suffix.Length + suffixPreviousLength;
// Update the _previousLength of the suffix so that suffix.Count = suffix._previousLength + suffix.Length doesn't change.
// Note that the resulting previous length might be negative.
// The value is not used, other than for calculating the value of Count property.
suffix._previousLengthOrFrozenSuffixLengthDelta = suffixPreviousLength + oldSuffixLength - suffix.Length;
if (!isEmpty)
{
// First and last chunks:
//
// [First]->[]->[Last] <- [this] [SuffixFirst]->[]->[SuffixLast] <- [suffix]
// ^___________| ^_________________|
//
// Degenerate cases:
// this == First == Last and/or suffix == SuffixFirst == SuffixLast.
var first = FirstChunk;
var suffixFirst = suffix.FirstChunk;
var last = _nextOrPrevious;
var suffixLast = suffix._nextOrPrevious;
// Relink like so:
// [First]->[]->[Last] -> [suffix] -> [SuffixFirst]->[]->[SuffixLast] <- [this]
// ^_______________________________________________________|
_nextOrPrevious = suffixLast;
suffix._nextOrPrevious = (suffixFirst != suffix) ? suffixFirst : (first != this) ? first : suffix;
if (last != this)
{
last._nextOrPrevious = suffix;
}
if (suffixLast != suffix)
{
suffixLast._nextOrPrevious = (first != this) ? first : suffix;
}
}
CheckInvariants();
suffix.CheckInvariants();
}
// internal for testing
internal void ClearChunk()
{
_length = 0;
_previousLengthOrFrozenSuffixLengthDelta = 0;
_nextOrPrevious = this;
}