Optimize skipNewlines scanning

[dduan]

Use local cursor/line counters in skipNewlines to reduce property writes, and tighten scanString loops by dropping redundant newline/dot checks during value and dotted-key scanning.

[github-actions]

Comparing results between 'main' and 'pull_request'

Host 'runnervmh13bl' with 4 'x86_64' processors with 15 GB memory, running:
#18~24.04.1-Ubuntu SMP Sat Jun 28 04:46:03 UTC 2025

TOMLDecoderBenchmarks

Decode toml.io example metrics

Time (wall clock): results within specified thresholds, fold down for details.

Time (wall clock) (μs) *	p0	p25	p50	p75	p90	p99	p100	Samples
main	70	71	71	73	80	94	155	6942
pull_request	70	71	71	73	79	96	143	6975
Δ	0	0	0	0	-1	2	-12	33
Improvement %	0	0	0	0	1	-2	8	33

Retains: results within specified thresholds, fold down for details.

Retains *	p0	p25	p50	p75	p90	p99	p100	Samples
main	624	624	624	625	625	625	625	6942
pull_request	624	624	624	624	624	624	624	6975
Δ	0	0	0	-1	-1	-1	-1	33
Improvement %	0	0	0	0	0	0	0	33

Parse toml.io example metrics

Time (wall clock): results within specified thresholds, fold down for details.

Time (wall clock) (ns) *	p0	p25	p50	p75	p90	p99	p100	Samples
main	6642	6835	6883	6943	7103	11335	48400	10000
pull_request	6462	6595	6643	6703	6835	9431	66343	10000
Δ	-180	-240	-240	-240	-268	-1904	17943	0
Improvement %	3	4	3	3	4	17	-37	0

Retains: results within specified thresholds, fold down for details.

Retains *	p0	p25	p50	p75	p90	p99	p100	Samples
main	8	9	9	9	9	9	9	10000
pull_request	8	9	9	9	9	9	9	10000
Δ	0	0	0	0	0	0	0	0
Improvement %	0	0	0	0	0	0	0	0

decode canada.toml metrics

Time (wall clock): results within specified thresholds, fold down for details.

Time (wall clock) (ms) *	p0	p25	p50	p75	p90	p99	p100	Samples
main	269	269	272	273	273	273	273	4
pull_request	267	267	268	268	268	268	268	4
Δ	-2	-2	-4	-5	-5	-5	-5	0
Improvement %	1	1	1	2	2	2	2	0

Retains: results within specified thresholds, fold down for details.

Retains (K) *	p0	p25	p50	p75	p90	p99	p100	Samples
main	1674	1674	1674	1674	1674	1674	1674	4
pull_request	1674	1674	1674	1674	1674	1674	1674	4
Δ	0	0	0	0	0	0	0	0
Improvement %	0	0	0	0	0	0	0	0

decode twitter.toml metrics

Time (wall clock): results within specified thresholds, fold down for details.

Time (wall clock) (μs) *	p0	p25	p50	p75	p90	p99	p100	Samples
main	9345	9404	9445	9478	9527	9708	9972	105
pull_request	9293	9355	9396	9445	9519	10117	10241	106
Δ	-52	-49	-49	-33	-8	409	269	1
Improvement %	1	1	1	0	0	-4	-3	1

Retains: results within specified thresholds, fold down for details.

Retains (K) *	p0	p25	p50	p75	p90	p99	p100	Samples
main	66	66	66	66	66	66	66	105
pull_request	66	66	66	66	66	66	66	106
Δ	0	0	0	0	0	0	0	1
Improvement %	0	0	0	0	0	0	0	1

parse canada.toml metrics

Time (wall clock): results within specified thresholds, fold down for details.

Time (wall clock) (ms) *	p0	p25	p50	p75	p90	p99	p100	Samples
main	17	18	18	19	19	20	20	55
pull_request	17	18	18	19	19	20	20	55
Δ	0	0	0	0	0	0	0	0
Improvement %	0	0	0	0	0	0	0	0

Retains: results within specified thresholds, fold down for details.

Retains *	p0	p25	p50	p75	p90	p99	p100	Samples
main	132	133	133	133	133	133	133	55
pull_request	132	133	133	133	133	133	133	55
Δ	0	0	0	0	0	0	0	0
Improvement %	0	0	0	0	0	0	0	0

parse twitter.toml metrics

Time (wall clock): results within specified thresholds, fold down for details.

Time (wall clock) (μs) *	p0	p25	p50	p75	p90	p99	p100	Samples
main	3036	3074	3084	3099	3129	3404	5039	318
pull_request	3064	3101	3115	3129	3154	3242	3607	315
Δ	28	27	31	30	25	-162	-1432	-3
Improvement %	-1	-1	-1	-1	-1	5	28	-3

Retains: results within specified thresholds, fold down for details.

Retains *	p0	p25	p50	p75	p90	p99	p100	Samples
main	1292	1293	1293	1293	1293	1293	1293	318
pull_request	1292	1293	1293	1293	1293	1293	1293	315
Δ	0	0	0	0	0	0	0	-3
Improvement %	0	0	0	0	0	0	0	-3