static void Stat3Get_(FuncContext fctx, int argc, Mem[] argv)
{
int n = Vdbe.Value_Int(argv[1]);
Stat3Accum p = (Stat3Accum)Vdbe.Value_Blob(argv[0]);
Debug.Assert(p != null);
if (p.a.length <= n)
{
return;
}
switch (argc)
{
case 2: Vdbe.Result_Int64(fctx, p.a[n].Rowid); break;
case 3: Vdbe.Result_Int64(fctx, p.a[n].Eq); break;
case 4: Vdbe.Result_Int64(fctx, p.a[n].Lt); break;
default: Vdbe.Result_Int64(fctx, p.a[n].DLt); break;
}
}
static void Stat3Init_(FuncContext fctx, int argc, Mem[][] argv)
{
tRowcnt rows = (tRowcnt)Vdbe.Value_Int64(argv[0]);
int maxSamples = Vdbe.Value_Int(argv[1]);
int n = maxSamples;
Stat3Accum p = new Stat3Accum
{
a = new array_t <Stat3Accum.Stat3Sample>(new Stat3Accum.Stat3Sample[n]),
Rows = rows,
MaxSamples = maxSamples,
PSamples = (uint)(rows / (maxSamples / 3 + 1) + 1),
};
if (p == null)
{
Vdbe.Result_ErrorNoMem(fctx);
return;
}
SysEx.Randomness(-1, p.Prn);
Vdbe.Result_Blob(fctx, p, -1, C._free);
}
static void Stat3Init_(FuncContext fctx, int argc, Mem[][] argv)
{
tRowcnt rows = (tRowcnt)Vdbe.Value_Int64(argv[0]);
int maxSamples = Vdbe.Value_Int(argv[1]);
int n = maxSamples;
Stat3Accum p = new Stat3Accum
{
a = new array_t<Stat3Accum.Stat3Sample>(new Stat3Accum.Stat3Sample[n]),
Rows = rows,
MaxSamples = maxSamples,
PSamples = (uint)(rows / (maxSamples / 3 + 1) + 1),
};
if (p == null)
{
Vdbe.Result_ErrorNoMem(fctx);
return;
}
SysEx.Randomness(-1, p.Prn);
Vdbe.Result_Blob(fctx, p, -1, C._free);
}
static void Stat3Push_(FuncContext fctx, int argc, Mem[] argv)
{
tRowcnt eq = (tRowcnt)Vdbe.Value_Int64(argv[0]);
if (eq == 0)
{
return;
}
tRowcnt lt = (tRowcnt)Vdbe.Value_Int64(argv[1]);
tRowcnt dLt = (tRowcnt)Vdbe.Value_Int64(argv[2]);
long rowid = Vdbe.Value_Int64(argv[3]);
Stat3Accum p = (Stat3Accum)Vdbe.Value_Blob(argv[4]);
bool isPSample = false;
bool doInsert = false;
int min = p.Min;
uint h = p.Prn = p.Prn * 1103515245 + 12345;
if ((lt / p.PSamples) != ((eq + lt) / p.PSamples))
{
doInsert = isPSample = true;
}
else if (p.a.length < p.MaxSamples)
{
doInsert = true;
}
else if (eq > p.a[min].Eq || (eq == p.a[min].Eq && h > p.a[min].Hash))
{
doInsert = true;
}
if (!doInsert)
{
return;
}
Stat3Accum.Stat3Sample sample;
if (p.a.length == p.MaxSamples)
{
Debug.Assert(p.a.length - min - 1 >= 0);
C._memmove(p.a[min], p.a[min + 1], sizeof(p.a[0]) * (p.a.length - min - 1));
sample = p.a[p.a.length - 1];
}
else
{
sample = p.a[p.a.length++];
}
sample.Rowid = rowid;
sample.Eq = eq;
sample.Lt = lt;
sample.DLt = dLt;
sample.Hash = h;
sample.IsPSample = isPSample;
// Find the new minimum
if (p.a.length == p.MaxSamples)
{
int sampleIdx = 0; sample = p.a[sampleIdx];
int i = 0;
while (sample.IsPSample)
{
i++;
sampleIdx++; sample = p.a[sampleIdx];
Debug.Assert(i < p.a.length);
}
eq = sample.Eq;
h = sample.Hash;
min = i;
for (i++, sampleIdx++; i < p.a.length; i++, sampleIdx++)
{
sample = p.a[sampleIdx];
if (sample.IsPSample)
{
continue;
}
if (sample.Eq < eq || (sample.Eq == eq && sample.Hash < h))
{
min = i;
eq = sample.Eq;
h = sample.Hash;
}
}
p.Min = min;
}
}
