Optimizations 2

[anatoly-kussul]

At this point I was just curious about how much further I can push it.
Feel free to close this PR if you feel like this is too much.

bench vs 4.2.0:

goos: linux
goarch: amd64
pkg: github.com/lithammer/shortuuid/v4
cpu: 12th Gen Intel(R) Core(TM) i5-12400F
                         │   v4.2.0    │                new2                 │
                         │   sec/op    │   sec/op     vs base                │
UUID-12                    123.3n ± 0%   101.5n ± 1%  -17.67% (p=0.000 n=10)
Encoding-12                44.42n ± 1%   30.43n ± 1%  -31.50% (p=0.000 n=10)
EncodingB57_MB-12          123.2n ± 4%   135.3n ± 1%   +9.91% (p=0.000 n=10)
EncodingB16-12             134.5n ± 0%   119.1n ± 0%  -11.42% (p=0.000 n=10)
EncodingB16_MB-12          327.0n ± 1%   189.4n ± 1%  -42.08% (p=0.000 n=10)
Decoding-12                173.9n ± 1%   164.4n ± 1%   -5.49% (p=0.000 n=10)
DecodingB16-12             206.0n ± 1%   193.6n ± 1%   -6.02% (p=0.000 n=10)
DecodingB16_MB-12          254.6n ± 1%   247.0n ± 2%   -3.00% (p=0.000 n=10)
NewWithAlphabet-12         387.2n ± 1%   383.8n ± 1%   -0.90% (p=0.024 n=10)
NewWithAlphabetB16-12      270.4n ± 1%   233.1n ± 0%  -13.83% (p=0.000 n=10)
NewWithAlphabetB16_MB-12   553.5n ± 0%   399.2n ± 1%  -27.88% (p=0.000 n=10)
NewWithNamespace-12        249.3n ± 1%   149.6n ± 1%  -40.00% (p=0.000 n=10)
NewWithNamespaceHttp-12    255.1n ± 3%   152.8n ± 1%  -40.11% (p=0.000 n=10)
NewWithNamespaceHttps-12   256.4n ± 2%   153.8n ± 1%  -40.04% (p=0.000 n=10)
geomean                    206.5n        162.9n       -21.08%

                         │    v4.2.0     │                 new2                 │
                         │     B/op      │    B/op     vs base                  │
UUID-12                     24.00 ± 0%     24.00 ± 0%        ~ (p=1.000 n=10) ¹
Encoding-12                 24.00 ± 0%     24.00 ± 0%        ~ (p=1.000 n=10) ¹
EncodingB57_MB-12           72.00 ± 0%     80.00 ± 0%  +11.11% (p=0.000 n=10)
EncodingB16-12              64.00 ± 0%     32.00 ± 0%  -50.00% (p=0.000 n=10)
EncodingB16_MB-12          480.00 ± 0%     96.00 ± 0%  -80.00% (p=0.000 n=10)
Decoding-12                 0.000 ± 0%     0.000 ± 0%        ~ (p=1.000 n=10) ¹
DecodingB16-12              0.000 ± 0%     0.000 ± 0%        ~ (p=1.000 n=10) ¹
DecodingB16_MB-12           0.000 ± 0%     0.000 ± 0%        ~ (p=1.000 n=10) ¹
NewWithAlphabet-12          264.0 ± 0%     264.0 ± 0%        ~ (p=1.000 n=10) ¹
NewWithAlphabetB16-12      128.00 ± 0%     96.00 ± 0%  -25.00% (p=0.000 n=10)
NewWithAlphabetB16_MB-12    544.0 ± 0%     160.0 ± 0%  -70.59% (p=0.000 n=10)
NewWithNamespace-12        200.00 ± 0%     24.00 ± 0%  -88.00% (p=0.000 n=10)
NewWithNamespaceHttp-12    208.00 ± 0%     24.00 ± 0%  -88.46% (p=0.000 n=10)
NewWithNamespaceHttps-12   224.00 ± 0%     24.00 ± 0%  -89.29% (p=0.000 n=10)
geomean                                ²               -51.82%                ²
¹ all samples are equal
² summaries must be >0 to compute geomean

                         │    v4.2.0    │                 new2                 │
                         │  allocs/op   │ allocs/op   vs base                  │
UUID-12                    1.000 ± 0%     1.000 ± 0%        ~ (p=1.000 n=10) ¹
Encoding-12                1.000 ± 0%     1.000 ± 0%        ~ (p=1.000 n=10) ¹
EncodingB57_MB-12          2.000 ± 0%     1.000 ± 0%  -50.00% (p=0.000 n=10)
EncodingB16-12             2.000 ± 0%     1.000 ± 0%  -50.00% (p=0.000 n=10)
EncodingB16_MB-12          4.000 ± 0%     1.000 ± 0%  -75.00% (p=0.000 n=10)
Decoding-12                0.000 ± 0%     0.000 ± 0%        ~ (p=1.000 n=10) ¹
DecodingB16-12             0.000 ± 0%     0.000 ± 0%        ~ (p=1.000 n=10) ¹
DecodingB16_MB-12          0.000 ± 0%     0.000 ± 0%        ~ (p=1.000 n=10) ¹
NewWithAlphabet-12         2.000 ± 0%     2.000 ± 0%        ~ (p=1.000 n=10) ¹
NewWithAlphabetB16-12      3.000 ± 0%     2.000 ± 0%  -33.33% (p=0.000 n=10)
NewWithAlphabetB16_MB-12   5.000 ± 0%     2.000 ± 0%  -60.00% (p=0.000 n=10)
NewWithNamespace-12        5.000 ± 0%     1.000 ± 0%  -80.00% (p=0.000 n=10)
NewWithNamespaceHttp-12    5.000 ± 0%     1.000 ± 0%  -80.00% (p=0.000 n=10)
NewWithNamespaceHttps-12   5.000 ± 0%     1.000 ± 0%  -80.00% (p=0.000 n=10)
geomean                               ²               -47.13%                ²
¹ all samples are equal
² summaries must be >0 to compute geomean

bench vs #63

goos: linux
goarch: amd64
pkg: github.com/lithammer/shortuuid/v4
cpu: 12th Gen Intel(R) Core(TM) i5-12400F
                         │     new     │                new2                 │
                         │   sec/op    │   sec/op     vs base                │
UUID-12                    119.6n ± 0%   101.5n ± 1%  -15.09% (p=0.000 n=10)
Encoding-12                42.32n ± 0%   30.43n ± 1%  -28.10% (p=0.000 n=10)
EncodingB57_MB-12          116.5n ± 2%   135.3n ± 1%  +16.13% (p=0.000 n=10)
EncodingB16-12             151.9n ± 0%   119.1n ± 0%  -21.59% (p=0.000 n=10)
EncodingB16_MB-12          191.2n ± 2%   189.4n ± 1%        ~ (p=0.469 n=10)
Decoding-12                167.4n ± 1%   164.4n ± 1%   -1.76% (p=0.000 n=10)
DecodingB16-12             200.0n ± 1%   193.6n ± 1%   -3.20% (p=0.000 n=10)
DecodingB16_MB-12          249.9n ± 2%   247.0n ± 2%   -1.16% (p=0.001 n=10)
NewWithAlphabet-12         381.0n ± 2%   383.8n ± 1%        ~ (p=0.110 n=10)
NewWithAlphabetB16-12      293.6n ± 1%   233.1n ± 0%  -20.62% (p=0.000 n=10)
NewWithAlphabetB16_MB-12   403.5n ± 1%   399.2n ± 1%   -1.07% (p=0.003 n=10)
NewWithNamespace-12        166.3n ± 1%   149.6n ± 1%  -10.07% (p=0.000 n=10)
NewWithNamespaceHttp-12    169.8n ± 1%   152.8n ± 1%  -10.04% (p=0.000 n=10)
NewWithNamespaceHttps-12   167.4n ± 1%   153.8n ± 1%   -8.13% (p=0.000 n=10)
geomean                    177.4n        162.9n        -8.15%

                         │     new      │                new2                 │
                         │     B/op     │    B/op     vs base                 │
UUID-12                    24.00 ± 0%     24.00 ± 0%       ~ (p=1.000 n=10) ¹
Encoding-12                24.00 ± 0%     24.00 ± 0%       ~ (p=1.000 n=10) ¹
EncodingB57_MB-12          80.00 ± 0%     80.00 ± 0%       ~ (p=1.000 n=10) ¹
EncodingB16-12             32.00 ± 0%     32.00 ± 0%       ~ (p=1.000 n=10) ¹
EncodingB16_MB-12          96.00 ± 0%     96.00 ± 0%       ~ (p=1.000 n=10) ¹
Decoding-12                0.000 ± 0%     0.000 ± 0%       ~ (p=1.000 n=10) ¹
DecodingB16-12             0.000 ± 0%     0.000 ± 0%       ~ (p=1.000 n=10) ¹
DecodingB16_MB-12          0.000 ± 0%     0.000 ± 0%       ~ (p=1.000 n=10) ¹
NewWithAlphabet-12         264.0 ± 0%     264.0 ± 0%       ~ (p=1.000 n=10) ¹
NewWithAlphabetB16-12      96.00 ± 0%     96.00 ± 0%       ~ (p=1.000 n=10) ¹
NewWithAlphabetB16_MB-12   160.0 ± 0%     160.0 ± 0%       ~ (p=1.000 n=10) ¹
NewWithNamespace-12        24.00 ± 0%     24.00 ± 0%       ~ (p=1.000 n=10) ¹
NewWithNamespaceHttp-12    24.00 ± 0%     24.00 ± 0%       ~ (p=1.000 n=10) ¹
NewWithNamespaceHttps-12   24.00 ± 0%     24.00 ± 0%       ~ (p=1.000 n=10) ¹
geomean                               ²               +0.00%                ²
¹ all samples are equal
² summaries must be >0 to compute geomean

                         │     new      │                new2                 │
                         │  allocs/op   │ allocs/op   vs base                 │
UUID-12                    1.000 ± 0%     1.000 ± 0%       ~ (p=1.000 n=10) ¹
Encoding-12                1.000 ± 0%     1.000 ± 0%       ~ (p=1.000 n=10) ¹
EncodingB57_MB-12          1.000 ± 0%     1.000 ± 0%       ~ (p=1.000 n=10) ¹
EncodingB16-12             1.000 ± 0%     1.000 ± 0%       ~ (p=1.000 n=10) ¹
EncodingB16_MB-12          1.000 ± 0%     1.000 ± 0%       ~ (p=1.000 n=10) ¹
Decoding-12                0.000 ± 0%     0.000 ± 0%       ~ (p=1.000 n=10) ¹
DecodingB16-12             0.000 ± 0%     0.000 ± 0%       ~ (p=1.000 n=10) ¹
DecodingB16_MB-12          0.000 ± 0%     0.000 ± 0%       ~ (p=1.000 n=10) ¹
NewWithAlphabet-12         2.000 ± 0%     2.000 ± 0%       ~ (p=1.000 n=10) ¹
NewWithAlphabetB16-12      2.000 ± 0%     2.000 ± 0%       ~ (p=1.000 n=10) ¹
NewWithAlphabetB16_MB-12   2.000 ± 0%     2.000 ± 0%       ~ (p=1.000 n=10) ¹
NewWithNamespace-12        1.000 ± 0%     1.000 ± 0%       ~ (p=1.000 n=10) ¹
NewWithNamespaceHttp-12    1.000 ± 0%     1.000 ± 0%       ~ (p=1.000 n=10) ¹
NewWithNamespaceHttps-12   1.000 ± 0%     1.000 ± 0%       ~ (p=1.000 n=10) ¹
geomean                               ²               +0.00%                ²
¹ all samples are equal
² summaries must be >0 to compute geomean