In some locales signs and the exponent are not single character
tokens. Replace QLocaleData::numericToCLocale() with a tokenizer that
will cope with this. At the same time, cache the locale data needed in
support of that, so that we don't repeatedly recreate QString()
objects just to compare them against input tokens.
The caching class is inspired by Thiago's proposal for fixing the
performance, which also inspires the optimization of the C locale in
the tokenizer used here.
Add some testing that round-tripping numbers via strings works for the
locales with signs and exponents that use more than one character.
Task-number: QTBUG-107801
Change-Id: I9fd8409a371ed62ed969d9ebc8b09584e752f7fb
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
4931fe9b02