private static List <EquivalenceClass> ComputeIgnoreCaseEquivalenceClasses(CharSetSolver solver, CultureInfo culture)
{
var ignoreCase = new Dictionary <char, EquivalenceClass>();
var sets = new List <EquivalenceClass>();
for (uint i = 65; i <= 0xFFFF; i++)
{
char C = (char)i;
char c = char.ToLower(C, culture);
if (c == C)
{
continue;
}
EquivalenceClass?ec;
if (!ignoreCase.TryGetValue(c, out ec))
{
ec = new EquivalenceClass(solver.CharConstraint(c));
ignoreCase[c] = ec;
sets.Add(ec);
}
ec._set = solver.Or(ec._set, solver.CharConstraint(C));
}
return(sets);
}
/// <summary>
/// Get the set of CI-equivalent characters to c.
/// This operation depends on culture for i, I, '\u0130', and '\u0131';
/// culture="" means InvariantCulture while culture=null means to use the current culture.
/// </summary>
public BDD Apply(char c, string?culture = null)
{
if (Volatile.Read(ref _cultureIndependentChars[c]) is BDD bdd)
{
return(bdd);
}
culture ??= CultureInfo.CurrentCulture.Name;
switch (c)
{
// Do not cache in _cultureIndependentChars values that are culture-dependent
case 'i':
return
(culture == string.Empty ? _i_Invariant :
IsTurkishAlphabet(culture) ? _i_Turkish :
_i_Default); // for all other cultures, case-sensitivity is the same as for en-US
case 'I':
return
(culture == string.Empty ? _i_Invariant :
IsTurkishAlphabet(culture) ? _I_Turkish : // different from 'i' above
_i_Default);
case Turkish_I_WithDot:
return
(culture == string.Empty ? _solver.CharConstraint(Turkish_I_WithDot) :
IsTurkishAlphabet(culture) ? _i_Turkish :
_i_Default);
case Turkish_i_WithoutDot:
return
(IsTurkishAlphabet(culture) ? _I_Turkish :
_solver.CharConstraint(Turkish_i_WithoutDot));
case 'k':
case 'K':
case KelvinSign:
Volatile.Write(ref _cultureIndependentChars[c], _solver.Or(_solver.Or(_solver.CharConstraint('k'), _solver.CharConstraint('K')), _solver.CharConstraint(KelvinSign)));
return(_cultureIndependentChars[c] !);
// Cache in _cultureIndependentChars entries that are culture-independent.
// BDDs are idempotent, so while we use volatile to ensure proper adherence
// to ECMA's memory model, we don't need Interlocked.CompareExchange.
case <= '\x7F':
// For ASCII range other than letters i, I, k, and K, the case-conversion is independent of culture and does
// not include case-insensitive-equivalent non-ASCII.
Volatile.Write(ref _cultureIndependentChars[c], _solver.Or(_solver.CharConstraint(char.ToLower(c)), _solver.CharConstraint(char.ToUpper(c))));
return(_cultureIndependentChars[c] !);
default:
// Bring in the full transfomation relation, but here it does not actually depend on culture
// so it is safe to store the result for c.
Volatile.Write(ref _cultureIndependentChars[c], Apply(_solver.CharConstraint(c)));
return(_cultureIndependentChars[c] !);
}
}
public IgnoreCaseTransformer(CharSetSolver solver)
{
_solver = solver;
_i_Invariant = solver.Or(_solver.CharConstraint('i'), solver.CharConstraint('I'));
_i_Default = solver.Or(_i_Invariant, solver.CharConstraint(Turkish_I_WithDot));
_i_Turkish = solver.Or(solver.CharConstraint('i'), solver.CharConstraint(Turkish_I_WithDot));
_I_Turkish = solver.Or(solver.CharConstraint('I'), solver.CharConstraint(Turkish_i_WithoutDot));
}