public static MethodInfo GetHashMethod(MemberMatcherMode mode)
{
switch (mode)
{
case MemberMatcherMode.One: return(Methods.MemberHash1);
case MemberMatcherMode.Two: return(Methods.MemberHash2);
case MemberMatcherMode.Four: return(Methods.MemberHash4);
case MemberMatcherMode.Eight: return(Methods.MemberHash8);
case MemberMatcherMode.Sixteen: return(Methods.MemberHash16);
case MemberMatcherMode.ThirtyTwo: return(Methods.MemberHash32);
case MemberMatcherMode.SixtyFour: return(Methods.MemberHash64);
default: throw new Exception("Unexpected MemberMatcherMode: " + mode);
}
}
static bool MakeMemberMatcher(out Dictionary <string, MemberInfo> memberLookup, out Dictionary <string, int> memberToBucket, out Dictionary <string, uint> memberToHash, out MemberMatcherMode bestMode)
{
var forType = typeof(ForType);
var fields = forType.GetFields(BindingFlags.DeclaredOnly | BindingFlags.Instance | BindingFlags.Public);
var props = forType.GetProperties(BindingFlags.DeclaredOnly | BindingFlags.Instance | BindingFlags.Public).Where(p => p.SetMethod != null);
var members = fields.Cast <MemberInfo>().Concat(props.Cast <MemberInfo>());
memberLookup = members.ToDictionary(m => m.GetSerializationName(), m => m);
var memberNames = memberLookup.Keys;
var allModes =
Enum.GetValues(typeof(MemberMatcherMode))
.Cast <MemberMatcherMode>()
.Where(m => m != MemberMatcherMode.None)
.OrderBy(o => (int)o)
.ToList();
foreach (var mode in allModes)
{
var mToH = new Dictionary <string, uint>();
var method = GetHashMethod(mode);
var buckets =
memberNames.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 = MemberMatcherMode.None;
return(false);
}
