Improved compatibility of Format String

[udaken]

BCL-Compatibility

The format of ZString has some incompatibility with BCL.
The main missing piece is the "Alignment Component".
There are also differences in the handling of whitespace and incorrect formatting.

Some of the cases are listed below.

Format String	String.Format	ZString.Format
Test("{0,10:X}{{0}}{1,-10:c}", Guid.NewGuid(), DateTime.Now.TimeOfDay.Negate());	Accept	throws FormatException
Test("{1,-1}{0,1}", Int64.MinValue, Int64.MaxValue);	"9223372036854775807-9223372036854775808"	"-1-1"
Test("{00 , 01 }, {01 ,02 }, {2 ,3 :D }, {3 ,4: X }", 2, 3, 5, 7)	Accept	throws FormatException
Test("}")	throws FormatException	throws IndexOutOfRangeException
Test("{ 0,0}, 9999")	throws FormatException	"9999"

I have added a test in CompositeFormatTest.cs that you can check out.

Performance

I've refactored the formatting parsing process.
As a side effect, it makes most of the parsing process about 20% faster. (compared to ver 2.2.0)

However, in the case of short format string (like x:{0}, y:{1}), Utf16PreparedFormat and Utf8PreparedFormat are about 20% slower.
I have optimized the PreparedFormat class, but Utf16PreparedFormat is still slow.

Format is acceptable because the impact is limited.

FormatBenchmark.cs

Method	FormatString	Mean	Error	StdDev	Ratio	RatioSD	Code Size	Gen 0	Gen 1	Gen 2	Allocated
Format_	This (...)orld. [62]	208.25 ns	2.284 ns	2.136 ns	1.00	0.00	3147 B	0.0181	-	-	152 B
FormatN	This (...)orld. [62]	166.63 ns	2.186 ns	2.045 ns	0.80	0.01	4172 B	0.0181	-	-	152 B
CreateUtf16PreparedFormat_	This (...)orld. [62]	303.47 ns	4.553 ns	4.259 ns	1.00	0.00	2796 B	0.0820	-	-	688 B
CreateUtf16PreparedFormatN	This (...)orld. [62]	297.62 ns	5.283 ns	4.942 ns	0.98	0.01	2030 B	0.0658	-	-	552 B
CreateUtf8PreparedFormat_	This (...)orld. [62]	300.89 ns	6.018 ns	5.629 ns	1.00	0.00	2799 B	0.0820	-	-	688 B
CreateUtf8PreparedFormatN	This (...)orld. [62]	338.32 ns	5.217 ns	4.880 ns	1.12	0.03	3430 B	0.0849	-	-	712 B
Utf16PreparedFormat_	This (...)orld. [62]	79.30 ns	1.162 ns	1.087 ns	1.00	0.00	2597 B	0.0181	-	-	152 B
Utf16PreparedFormatN	This (...)orld. [62]	96.11 ns	1.342 ns	1.255 ns	1.21	0.02	2188 B	0.0181	-	-	152 B
Utf8PreparedFormat_	This (...)orld. [62]	167.63 ns	2.481 ns	2.321 ns	1.00	0.00	2569 B	0.0181	-	-	152 B
Utf8PreparedFormatN	This (...)orld. [62]	137.85 ns	2.213 ns	2.070 ns	0.82	0.02	2356 B	0.0181	-	-	152 B
Utf16StringBuilderAppendFormat_	This (...)orld. [62]	216.73 ns	0.727 ns	0.680 ns	1.00	0.00	7425 B	-	-	-	-
Utf16StringBuilderAppendFormatN	This (...)orld. [62]	162.42 ns	1.610 ns	1.506 ns	0.75	0.01	7393 B	-	-	-	-
Utf8StringBuilderAppendFormat_	This (...)orld. [62]	245.23 ns	0.942 ns	0.835 ns	1.00	0.00	7856 B	-	-	-	-
Utf8StringBuilderAppendFormatN	This (...)orld. [62]	229.33 ns	0.944 ns	0.883 ns	0.93	0.00	10714 B	-	-	-	-
Format_	x:{0}, y:{1}	133.78 ns	1.151 ns	1.076 ns	1.00	0.00	3147 B	0.0057	-	-	48 B
FormatN	x:{0}, y:{1}	99.33 ns	1.070 ns	1.000 ns	0.74	0.01	4172 B	0.0057	-	-	48 B
CreateUtf16PreparedFormat_	x:{0}, y:{1}	206.94 ns	2.647 ns	2.476 ns	1.00	0.00	2796 B	0.0448	-	-	376 B
CreateUtf16PreparedFormatN	x:{0}, y:{1}	126.35 ns	2.426 ns	2.269 ns	0.61	0.01	2030 B	0.0372	-	-	312 B
CreateUtf8PreparedFormat_	x:{0}, y:{1}	203.51 ns	1.199 ns	1.122 ns	1.00	0.00	2799 B	0.0448	-	-	376 B
CreateUtf8PreparedFormatN	x:{0}, y:{1}	169.32 ns	2.718 ns	2.542 ns	0.83	0.01	3430 B	0.0420	-	-	352 B
Utf16PreparedFormat_	x:{0}, y:{1}	69.21 ns	0.898 ns	0.840 ns	1.00	0.00	2597 B	0.0057	-	-	48 B
Utf16PreparedFormatN	x:{0}, y:{1}	81.91 ns	1.049 ns	0.982 ns	1.18	0.02	2188 B	0.0057	-	-	48 B
Utf8PreparedFormat_	x:{0}, y:{1}	126.13 ns	0.971 ns	0.860 ns	1.00	0.00	2569 B	0.0057	-	-	48 B
Utf8PreparedFormatN	x:{0}, y:{1}	111.22 ns	0.655 ns	0.613 ns	0.88	0.01	2356 B	0.0057	-	-	48 B
Utf16StringBuilderAppendFormat_	x:{0}, y:{1}	144.91 ns	0.756 ns	0.707 ns	1.00	0.00	7276 B	-	-	-	-
Utf16StringBuilderAppendFormatN	x:{0}, y:{1}	102.43 ns	0.460 ns	0.431 ns	0.71	0.00	7393 B	-	-	-	-
Utf8StringBuilderAppendFormat_	x:{0}, y:{1}	175.73 ns	0.787 ns	0.736 ns	1.00	0.00	7856 B	-	-	-	-
Utf8StringBuilderAppendFormatN	x:{0}, y:{1}	147.53 ns	0.988 ns	0.876 ns	0.84	0.01	10549 B	-	-	-	-

BenchmarkDotNet=v0.12.1, OS=Windows 10.0.19042
AMD Ryzen 7 3700X, 1 CPU, 16 logical and 8 physical cores
.NET Core SDK=3.1.302
  [Host]     : .NET Core 3.1.6 (CoreCLR 4.700.20.26901, CoreFX 4.700.20.31603), X64 RyuJIT
  DefaultJob : .NET Core 3.1.6 (CoreCLR 4.700.20.26901, CoreFX 4.700.20.31603), X64 RyuJIT

BuiltinTypesBenchmark.cs

Method	Mean	Error	StdDev	Ratio	Code Size	Gen 0	Gen 1	Gen 2	Allocated
Format_	2,871.2 ns	19.09 ns	17.86 ns	1.00	952 B	0.0648	-	-	560 B
FormatN	2,337.8 ns	15.88 ns	14.85 ns	0.81	952 B	0.0648	-	-	552 B
CreateUtf16PreparedFormat_	1,207.0 ns	17.42 ns	16.29 ns	1.00	200 B	0.3700	0.0038	-	3104 B
CreateUtf16PreparedFormatN	536.0 ns	8.16 ns	7.63 ns	0.44	159 B	0.1965	0.0010	-	1648 B
CreateUtf8PreparedFormat_	1,228.2 ns	19.72 ns	18.45 ns	1.00	203 B	0.3700	0.0038	-	3104 B
CreateUtf8PreparedFormatN	886.5 ns	10.00 ns	8.35 ns	0.72	194 B	0.2699	0.0019	-	2264 B
Utf16PreparedFormat_	2,349.2 ns	17.56 ns	16.42 ns	1.00	944 B	0.0648	-	-	560 B
Utf16PreparedFormatN	2,283.9 ns	18.38 ns	17.19 ns	0.97	944 B	0.0648	-	-	560 B
Utf8PreparedFormat_	1,575.2 ns	10.36 ns	9.69 ns	1.00	961 B	0.0591	-	-	504 B
Utf8PreparedFormatN	1,403.4 ns	11.02 ns	10.31 ns	0.89	961 B	0.0591	-	-	504 B
Utf16StringBuilderAppendFormat_	2,814.9 ns	10.21 ns	9.55 ns	1.00	4686 B	0.0076	-	-	72 B
Utf16StringBuilderAppendFormatN	2,274.3 ns	18.23 ns	16.16 ns	0.81	5571 B	0.0076	-	-	72 B
Utf8StringBuilderAppendFormat_	2,017.8 ns	16.70 ns	15.62 ns	1.00	5186 B	-	-	-	24 B
Utf8StringBuilderAppendFormatN	1,740.7 ns	10.89 ns	10.19 ns	0.86	6096 B	0.0019	-	-	24 B

[udaken]

The unit test passes, but I don't know why build-unity is failing.
(I have no knowledge of unity.)

[github-actions]

This PR is stale because it has been open 90 days with no activity. Remove stale label or comment or this will be closed in 7 days.

[udaken]

Hi @neuecc, I hope you will review this PR.

[neuecc]

sorry for delayed response.
Thanks!
This is well written and great achievement.