Benchmarks for pull requests for speeding up Base64 decoding in Data and NSData.

Tested on an iMac 12,2 mid-2011 with quad Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz running Ubuntu18.04 natively using FoundationBenchmarks package.

Base64Kit is used as control.

Base branch: DEVELOPMENT-SNAPSHOT-2020-05-11
PR for swift-decode1
PR for swift-decode2
PR for swift-decode3
Commit for swift-decode4

Base64Tests.base64DecodeShortSpeed	DEVELOPMENT-SNAPSHOT-2020-05-11	swift-decode1	difference		swift-decode2	difference		swift-decode3	difference		swift-decode4	difference		First to Last
NSData-decodeString	23027 ms	7300 ms	-15727 ms	-68%	5369 ms	-1931 ms	-26%	3344 ms	-2025 ms	-38%	3388 ms	44 ms	+1%	-19639 ms	-85%
NSData-decodeString - Ignore Unknown	23043 ms	7263 ms	-15780 ms	-68%	5365 ms	-1898 ms	-26%	3335 ms	-2030 ms	-38%	3420 ms	85 ms	+3%	-19623 ms	-85%
NSData-decodeData	29754 ms	28521 ms	-1233 ms	-4%	26157 ms	-2364 ms	-8%	3450 ms	-22707 ms	-87%	3467 ms	17 ms	+0%	-26287 ms	-88%
NSData-decodeData - Ignore Unknown	29707 ms	28582 ms	-1125 ms	-4%	26417 ms	-2165 ms	-8%	3374 ms	-23043 ms	-87%	3474 ms	100 ms	+3%	-26233 ms	-88%
Data-decodeString	23397 ms	7867 ms	-15530 ms	-66%	5935 ms	-1932 ms	-25%	3910 ms	-2025 ms	-34%	3328 ms	-582 ms	-15%	-20069 ms	-86%
Data-decodeString - Ignore Unknown	23415 ms	7853 ms	-15562 ms	-66%	5911 ms	-1942 ms	-25%	4039 ms	-1872 ms	-32%	3311 ms	-728 ms	-18%	-20104 ms	-86%
Data-decodeData	30564 ms	29275 ms	-1289 ms	-4%	26730 ms	-2545 ms	-9%	3913 ms	-22817 ms	-85%	3401 ms	-512 ms	-13%	-27163 ms	-89%
Data-decodeData - Ignore Unknown	30796 ms	29232 ms	-1564 ms	-5%	26706 ms	-2526 ms	-9%	3933 ms	-22773 ms	-85%	3344 ms	-589 ms	-15%	-27452 ms	-89%
Base64kit	3342 ms	3123 ms	-219 ms	-7%	3162 ms	39 ms	+1%	3086 ms	-76 ms	-2%	3249 ms	163 ms	+5%	-93 ms	-3%

Base64Tests.base64DecodeLongSpeed	DEVELOPMENT-SNAPSHOT-2020-05-11	swift-decode1	difference		swift-decode2	difference		swift-decode3	difference		swift-decode4	difference		First to Last
NSData-decodeString	56270 ms	14175 ms	-42095 ms	-75%	10433 ms	-3742 ms	-26%	5992 ms	-4441 ms	-43%	6127 ms	135 ms	+2%	-50143 ms	-89%
NSData-decodeString - Ignore Unknown	56259 ms	14170 ms	-42089 ms	-75%	10409 ms	-3761 ms	-27%	5984 ms	-4425 ms	-43%	6134 ms	150 ms	+3%	-50125 ms	-89%
NSData-decodeData	56869 ms	59053 ms	2184 ms	+4%	54378 ms	-4675 ms	-8%	5987 ms	-48391 ms	-89%	6131 ms	144 ms	+2%	-50738 ms	-89%
NSData-decodeData - Ignore Unknown	56750 ms	59010 ms	2260 ms	+4%	54399 ms	-4611 ms	-8%	6014 ms	-48385 ms	-89%	6127 ms	113 ms	+2%	-50623 ms	-89%
Data-decodeString	56458 ms	14349 ms	-42109 ms	-75%	10622 ms	-3727 ms	-26%	6209 ms	-4413 ms	-42%	6127 ms	-82 ms	-1%	-50331 ms	-89%
Data-decodeString - Ignore Unknown	56280 ms	14360 ms	-41920 ms	-74%	10601 ms	-3759 ms	-26%	6200 ms	-4401 ms	-42%	6138 ms	-62 ms	-1%	-50142 ms	-89%
Data-decodeData	56643 ms	59159 ms	2516 ms	+4%	54648 ms	-4511 ms	-8%	6189 ms	-48459 ms	-89%	6131 ms	-58 ms	-1%	-50512 ms	-89%
Data-decodeData - Ignore Unknown	56775 ms	59347 ms	2572 ms	+5%	54673 ms	-4674 ms	-8%	6189 ms	-48484 ms	-89%	6133 ms	-56 ms	-1%	-50642 ms	-89%
Base64kit	6323 ms	6478 ms	155 ms	+2%	6050 ms	-428 ms	-7%	6052 ms	2 ms	+0%	6311 ms	259 ms	+4%	-12 ms	0%