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Improve DateTime.ParseExact perf for invariant culture #82877

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merged 3 commits into from
Mar 3, 2023
Merged

Improve DateTime.ParseExact perf for invariant culture #82877

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73e1fe2
Improve DateTime parsing perf for invariant culture
stephentoub Mar 2, 2023
02377c5
Merge branch 'main' into dtinvariant
stephentoub Mar 2, 2023
5012178
Address PR feedback
stephentoub Mar 2, 2023
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2 changes: 1 addition & 1 deletion src/libraries/System.Private.CoreLib/src/System/Globalization/DateTimeFormatInfo.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -150,7 +150,7 @@ public sealed class DateTimeFormatInfo : IFormatProvider, ICloneable

private DateTimeFormatFlags formatFlags = DateTimeFormatFlags.NotInitialized;

private string CultureName => _name ??= _cultureData.CultureName;
internal string CultureName => _name ??= _cultureData.CultureName;

private CultureInfo Culture => _cultureInfo ??= CultureInfo.GetCultureInfo(CultureName);

Expand Down
229 changes: 179 additions & 50 deletions src/libraries/System.Private.CoreLib/src/System/Globalization/DateTimeParse.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@
// The .NET Foundation licenses this file to you under the MIT license.

using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.Runtime.CompilerServices;
using System.Text;
Expand Down Expand Up @@ -3299,25 +3300,56 @@ private static bool MatchAbbreviatedMonthName(ref __DTString str, DateTimeFormat
result = -1;
if (str.GetNext())
{
//
// Scan the month names (note that some calendars has 13 months) and find
// the matching month name which has the max string length.
// We need to do this because some cultures (e.g. "cs-CZ") which have
// abbreviated month names with the same prefix.
//
int monthsInYear = (dtfi.GetMonthName(13).Length == 0 ? 12 : 13);
for (int i = 1; i <= monthsInYear; i++)
if (dtfi.CultureName == "")
{
string searchStr = dtfi.GetAbbreviatedMonthName(i);
int matchStrLen = searchStr.Length;
if (dtfi.HasSpacesInMonthNames
? str.MatchSpecifiedWords(searchStr, false, ref matchStrLen)
: str.MatchSpecifiedWord(searchStr))
// Invariant data. Do a fast lookup on the known abbreviated month names.
ReadOnlySpan<char> span = str.Value.Slice(str.Index);
if (span.Length >= 3)
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{
if (matchStrLen > maxMatchStrLen)
uint m0 = span[0], m1 = span[1], m2 = span[2];
if ((m0 | m1 | m2) <= 0x7F)
{
maxMatchStrLen = matchStrLen;
result = i;
// Combine all the characters into a single uint, lowercased.
maxMatchStrLen = 3; // assume we'll successfully match
switch ((m0 << 16) | (m1 << 8) | m2 | 0x202020)
{
case 0x6a616e: /* 'jan' */ result = 1; break;
case 0x666562: /* 'feb' */ result = 2; break;
case 0x6d6172: /* 'mar' */ result = 3; break;
case 0x617072: /* 'apr' */ result = 4; break;
case 0x6d6179: /* 'may' */ result = 5; break;
case 0x6a756e: /* 'jun' */ result = 6; break;
case 0x6a756c: /* 'jul' */ result = 7; break;
case 0x617567: /* 'aug' */ result = 8; break;
case 0x736570: /* 'sep' */ result = 9; break;
case 0x6f6374: /* 'oct' */ result = 10; break;
case 0x6e6f76: /* 'nov' */ result = 11; break;
case 0x646563: /* 'dec' */ result = 12; break;
default: maxMatchStrLen = 0; break; // undo match assumption
}
}
}
}
else
{
// Scan the month names (note that some calendars has 13 months) and find
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Suggested change
// Scan the month names (note that some calendars has 13 months) and find
// Scan the month names (note that some calendars have 13 months) and find

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Thanks. These are both pre-existing. If I have to restart CI for some reason, I'll take the comment fixes.

// the matching month name which has the max string length.
// We need to do this because some cultures (e.g. "cs-CZ") which have
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Suggested change
// We need to do this because some cultures (e.g. "cs-CZ") which have
// We need to do this because some cultures (e.g. "cs-CZ") have

// abbreviated month names with the same prefix.
int monthsInYear = (dtfi.GetMonthName(13).Length == 0 ? 12 : 13);
for (int i = 1; i <= monthsInYear; i++)
{
string searchStr = dtfi.GetAbbreviatedMonthName(i);
int matchStrLen = searchStr.Length;
if (dtfi.HasSpacesInMonthNames
? str.MatchSpecifiedWords(searchStr, false, ref matchStrLen)
: str.MatchSpecifiedWord(searchStr))
{
if (matchStrLen > maxMatchStrLen)
{
maxMatchStrLen = matchStrLen;
result = i;
}
}
}
}
Expand Down Expand Up @@ -3370,25 +3402,54 @@ private static bool MatchMonthName(ref __DTString str, DateTimeFormatInfo dtfi,
result = -1;
if (str.GetNext())
{
//
// Scan the month names (note that some calendars has 13 months) and find
// the matching month name which has the max string length.
// We need to do this because some cultures (e.g. "vi-VN") which have
// month names with the same prefix.
//
int monthsInYear = (dtfi.GetMonthName(13).Length == 0 ? 12 : 13);
for (int i = 1; i <= monthsInYear; i++)
if (dtfi.CultureName == "")
{
string searchStr = dtfi.GetMonthName(i);
int matchStrLen = searchStr.Length;
if (dtfi.HasSpacesInMonthNames
? str.MatchSpecifiedWords(searchStr, false, ref matchStrLen)
: str.MatchSpecifiedWord(searchStr))
// Invariant data. Do a fast lookup on the known month names.
ReadOnlySpan<char> span = str.Value.Slice(str.Index);
if (span.Length >= 3)
{
if (matchStrLen > maxMatchStrLen)
uint m0 = span[0], m1 = span[1], m2 = span[2];
if ((m0 | m1 | m2) <= 0x7F)
{
maxMatchStrLen = matchStrLen;
result = i;
// Combine all the characters into a single uint, lowercased.
switch ((m0 << 16) | (m1 << 8) | m2 | 0x202020)
{
case 0x6a616e: /* 'jan' */ SetIfStartsWith(span, "January", 1, ref result, ref maxMatchStrLen); break;
case 0x666562: /* 'feb' */ SetIfStartsWith(span, "February", 2, ref result, ref maxMatchStrLen); break;
case 0x6d6172: /* 'mar' */ SetIfStartsWith(span, "March", 3, ref result, ref maxMatchStrLen); break;
case 0x617072: /* 'apr' */ SetIfStartsWith(span, "April", 4, ref result, ref maxMatchStrLen); break;
case 0x6d6179: /* 'may' */ SetIfStartsWith(span, "May", 5, ref result, ref maxMatchStrLen); break;
case 0x6a756e: /* 'jun' */ SetIfStartsWith(span, "June", 6, ref result, ref maxMatchStrLen); break;
case 0x6a756c: /* 'jul' */ SetIfStartsWith(span, "July", 7, ref result, ref maxMatchStrLen); break;
case 0x617567: /* 'aug' */ SetIfStartsWith(span, "August", 8, ref result, ref maxMatchStrLen); break;
case 0x736570: /* 'sep' */ SetIfStartsWith(span, "September", 9, ref result, ref maxMatchStrLen); break;
case 0x6f6374: /* 'oct' */ SetIfStartsWith(span, "October", 10, ref result, ref maxMatchStrLen); break;
case 0x6e6f76: /* 'nov' */ SetIfStartsWith(span, "November", 11, ref result, ref maxMatchStrLen); break;
case 0x646563: /* 'dec' */ SetIfStartsWith(span, "December", 12, ref result, ref maxMatchStrLen); break;
}
}
}
}
else
{
// Scan the month names (note that some calendars has 13 months) and find
// the matching month name which has the max string length.
// We need to do this because some cultures (e.g. "vi-VN") which have
// month names with the same prefix.
int monthsInYear = (dtfi.GetMonthName(13).Length == 0 ? 12 : 13);
for (int i = 1; i <= monthsInYear; i++)
{
string searchStr = dtfi.GetMonthName(i);
int matchStrLen = searchStr.Length;
if (dtfi.HasSpacesInMonthNames
? str.MatchSpecifiedWords(searchStr, false, ref matchStrLen)
: str.MatchSpecifiedWord(searchStr))
{
if (matchStrLen > maxMatchStrLen)
{
maxMatchStrLen = matchStrLen;
result = i;
}
}
}
}
Expand Down Expand Up @@ -3442,18 +3503,46 @@ private static bool MatchAbbreviatedDayName(ref __DTString str, DateTimeFormatIn
result = -1;
if (str.GetNext())
{
for (DayOfWeek i = DayOfWeek.Sunday; i <= DayOfWeek.Saturday; i++)
if (dtfi.CultureName == "")
{
string searchStr = dtfi.GetAbbreviatedDayName(i);
int matchStrLen = searchStr.Length;
if (dtfi.HasSpacesInDayNames
? str.MatchSpecifiedWords(searchStr, false, ref matchStrLen)
: str.MatchSpecifiedWord(searchStr))
// Invariant data. Do a fast lookup on the known abbreviated day names.
ReadOnlySpan<char> span = str.Value.Slice(str.Index);
if (span.Length >= 3)
{
if (matchStrLen > maxMatchStrLen)
uint d0 = span[0], d1 = span[1], d2 = span[2];
if ((d0 | d1 | d2) <= 0x7F)
{
maxMatchStrLen = matchStrLen;
result = (int)i;
// Combine all the characters into a single uint, lowercased.
maxMatchStrLen = 3; // assume we'll successfully match
switch ((d0 << 16) | (d1 << 8) | d2 | 0x202020)
{
case 0x73756E /* 'sun' */: result = 0; break;
case 0x6d6f6e /* 'mon' */: result = 1; break;
case 0x747565 /* 'tue' */: result = 2; break;
case 0x776564 /* 'wed' */: result = 3; break;
case 0x746875 /* 'thu' */: result = 4; break;
case 0x667269 /* 'fri' */: result = 5; break;
case 0x736174 /* 'sat' */: result = 6; break;
default: maxMatchStrLen = 0; break; // undo match assumption
}
}
}
}
else
{
for (DayOfWeek i = DayOfWeek.Sunday; i <= DayOfWeek.Saturday; i++)
{
string searchStr = dtfi.GetAbbreviatedDayName(i);
int matchStrLen = searchStr.Length;
if (dtfi.HasSpacesInDayNames
? str.MatchSpecifiedWords(searchStr, false, ref matchStrLen)
: str.MatchSpecifiedWord(searchStr))
{
if (matchStrLen > maxMatchStrLen)
{
maxMatchStrLen = matchStrLen;
result = (int)i;
}
}
}
}
Expand Down Expand Up @@ -3481,18 +3570,44 @@ private static bool MatchDayName(ref __DTString str, DateTimeFormatInfo dtfi, sc
result = -1;
if (str.GetNext())
{
for (DayOfWeek i = DayOfWeek.Sunday; i <= DayOfWeek.Saturday; i++)
if (dtfi.CultureName == "")
{
string searchStr = dtfi.GetDayName(i);
int matchStrLen = searchStr.Length;
if (dtfi.HasSpacesInDayNames
? str.MatchSpecifiedWords(searchStr, false, ref matchStrLen)
: str.MatchSpecifiedWord(searchStr))
// Invariant data. Do a fast lookup on the known day names.
ReadOnlySpan<char> span = str.Value.Slice(str.Index);
if (span.Length >= 3)
{
if (matchStrLen > maxMatchStrLen)
uint d0 = span[0], d1 = span[1], d2 = span[2];
if ((d0 | d1 | d2) <= 0x7F)
{
maxMatchStrLen = matchStrLen;
result = (int)i;
// Combine all the characters into a single uint, lowercased.
switch ((d0 << 16) | (d1 << 8) | d2 | 0x202020)
{
case 0x73756E /* 'sun' */: SetIfStartsWith(span, "Sunday", 0, ref result, ref maxMatchStrLen); break;
case 0x6d6f6e /* 'mon' */: SetIfStartsWith(span, "Monday", 1, ref result, ref maxMatchStrLen); break;
case 0x747565 /* 'tue' */: SetIfStartsWith(span, "Tuesday", 2, ref result, ref maxMatchStrLen); break;
case 0x776564 /* 'wed' */: SetIfStartsWith(span, "Wednesday", 3, ref result, ref maxMatchStrLen); break;
case 0x746875 /* 'thu' */: SetIfStartsWith(span, "Thursday", 4, ref result, ref maxMatchStrLen); break;
case 0x667269 /* 'fri' */: SetIfStartsWith(span, "Friday", 5, ref result, ref maxMatchStrLen); break;
case 0x736174 /* 'sat' */: SetIfStartsWith(span, "Saturday", 6, ref result, ref maxMatchStrLen); break;
}
}
}
}
else
{
for (DayOfWeek i = DayOfWeek.Sunday; i <= DayOfWeek.Saturday; i++)
{
string searchStr = dtfi.GetDayName(i);
int matchStrLen = searchStr.Length;
if (dtfi.HasSpacesInDayNames
? str.MatchSpecifiedWords(searchStr, false, ref matchStrLen)
: str.MatchSpecifiedWord(searchStr))
{
if (matchStrLen > maxMatchStrLen)
{
maxMatchStrLen = matchStrLen;
result = (int)i;
}
}
}
}
Expand All @@ -3505,6 +3620,20 @@ private static bool MatchDayName(ref __DTString str, DateTimeFormatInfo dtfi, sc
return false;
}

/// <summary>
/// Sets <paramref name="result"/> to <paramref name="matchResult"/> and <paramref name="maxMatchStrLen"/> to <paramref name="match"/>'s Length
/// if <paramref name="span"/> starts with <paramref name="match"/> with an ordinal ignore-case comparison.
/// </summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)] // exposes StartsWith to constant `match`
private static void SetIfStartsWith(ReadOnlySpan<char> span, [ConstantExpected] string match, int matchResult, scoped ref int result, ref int maxMatchStrLen)
{
if (span.StartsWith(match, StringComparison.OrdinalIgnoreCase))
{
result = matchResult;
maxMatchStrLen = match.Length;
}
}

/*=================================MatchEraName==================================
**Action: Parse era name from string starting at str.Index.
**Returns: An era value.
Expand Down