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SequenceReader performance; elide bounds checks and book-keeping #82765

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SequenceReader performance; elide bounds checks and book-keeping #82765

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580a164
SequenceReader; elide bounds checks by using ref-oriented approach
mgravell Feb 28, 2023
dfe7241
net6-: don't forget to increment _consumedAtStartOfCurrentSpan
mgravell Feb 28, 2023
481b49c
- don't use the Unsafe or MemoryMarshal evilness
mgravell Mar 1, 2023
a5bf93d
in search, avoid copying out the T value
mgravell Mar 1, 2023
836bc9c
drop unused method
mgravell Mar 1, 2023
4e8d89c
reinstate next position; needed to avoid double-fetch in GetNextSpan
mgravell Mar 1, 2023
f359dd0
use better API to get first span in ResetReader
mgravell Mar 1, 2023
454315e
simplify Position getter
mgravell Mar 1, 2023
d001302
move reset logic to constructor; use constructor in ResetReader
mgravell Mar 1, 2023
4ba4be6
always track consumed span when moving to next, even for single segment
mgravell Mar 1, 2023
ec519f7
for single-segment cases, length is trivial; record length at EOF; up…
mgravell Mar 1, 2023
f6d17c4
use named parameter to clarify meaning
mgravell Mar 1, 2023
7a17388
explicit types (IDE0008)
mgravell Mar 1, 2023
4781155
- fix increment bug at end of single-segment buffers
mgravell Mar 2, 2023
e49b863
simplify advance further
mgravell Mar 2, 2023
11a7b46
remove debug-check from AssertValidPosition() to make the compiler ha…
mgravell Mar 2, 2023
570d221
TryPeek/TryRead: avoid bounds check by hoisting into locals
mgravell Mar 2, 2023
c1c6d59
nit: use local for the addition too (cuts a `mov` from the JIT output)
mgravell Mar 2, 2023
594f879
test fixes
mgravell Mar 2, 2023
892a9e7
Advance: don't short-circuit (we expect both sides to pass)
mgravell Mar 3, 2023
eeb4bff
work around JIT regressions
mgravell Mar 3, 2023
0412ab1
nit: TryGetNextBuffer - defer updating result; empty segments are v.rare
mgravell Mar 7, 2023
e825679
Fix two rebase errors
jozkee Aug 17, 2023
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use better API to get first span in ResetReader
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@mgravell @jozkee
mgravell authored and jozkee committed Aug 11, 2023
commit f359dd02cd85a5c44909b21c9d4391d15febd508
11 changes: 5 additions & 6 deletions src/libraries/System.Memory/src/System/Buffers/SequenceReader.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -246,14 +246,13 @@ private void ResetReader()
var position = _sequence.Start;
_currentPositionObject = position.GetObject();
_currentPositionInteger = position.GetInteger();
_consumedAtStartOfCurrentSpan = 0;
_sequence.TryGetBuffer(position, out var memory, out var next);
_nextPositionObject = next.GetObject();
_nextPositionInteger = next.GetInteger();
_currentSpan = memory.Span;
_sequence.GetFirstSpan(out _currentSpan, out position);
_nextPositionObject = position.GetObject();
_nextPositionInteger = position.GetInteger();
_currentSpanIndex = 0;
_consumedAtStartOfCurrentSpan = 0;
if (_currentSpan.IsEmpty && !_sequence.IsSingleSegment)
{
{ // edge-case; multi-segment with zero-length as first
GetNextSpan();
}
}
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