public static MethodInfo GetHashMethod(EnumMatcherMode mode)
{
switch (mode)
{
case EnumMatcherMode.One: return(Methods.EnumHash1);
case EnumMatcherMode.Two: return(Methods.EnumHash2);
case EnumMatcherMode.Four: return(Methods.EnumHash4);
case EnumMatcherMode.Eight: return(Methods.EnumHash8);
case EnumMatcherMode.Sixteen: return(Methods.EnumHash16);
case EnumMatcherMode.ThirtyTwo: return(Methods.EnumHash32);
case EnumMatcherMode.SixtyFour: return(Methods.EnumHash64);
default: throw new Exception("Unexpected EnumMatcherMode: " + mode);
}
}
static bool MakeEnumMatcher(out Dictionary <string, object> enumLookup, out Dictionary <string, int> memberToBucket, out Dictionary <string, uint> memberToHash, out EnumMatcherMode bestMode)
{
var forType = typeof(EnumType);
var allValues = Enum.GetValues(forType);
enumLookup = allValues.Cast <EnumType>().ToDictionary(e => forType.GetEnumValueName(e), e => Convert.ChangeType(e, Enum.GetUnderlyingType(forType)));
var enumNames = enumLookup.Keys;
var allModes =
Enum.GetValues(typeof(EnumMatcherMode))
.Cast <EnumMatcherMode>()
.Where(m => m != EnumMatcherMode.None)
.OrderBy(o => (int)o)
.ToList();
foreach (var mode in allModes)
{
var mToH = new Dictionary <string, uint>();
var method = GetHashMethod(mode);
var buckets =
enumNames.GroupBy(
m =>
{
using (var str = new StringReader("\"" + m.JsonEscape(jsonp: false) + "\""))
{
str.Read(); // skip "
var ps = new object[] { str, (int)-1, (uint)0 };
method.Invoke(null, ps);
var bucket = (int)ps[1];
var hash = (uint)ps[2];
mToH[m] = hash;
return(bucket);
}
}
);
var collisions = buckets.Any(g => g.Count() > 1);
if (collisions)
{
continue;
}
memberToHash = mToH;
memberToBucket = buckets.ToDictionary(d => d.Single(), d => d.Key);
bestMode = mode;
return(true);
}
memberToHash = null;
memberToBucket = null;
bestMode = EnumMatcherMode.None;
return(false);
}
