private long SearchFirst <T>(T value, IIndexedObjectComparer <T> c, long low, long high)
{
if (low > high)
{
return(-1);
}
while (true)
{
// If low is the same as high, we are either at the first value or at
// the position to insert the value,
if ((high - low) <= 4)
{
for (long i = low; i <= high; ++i)
{
file.Position = (i * 8);
long val = fileReader.ReadInt64();
int res = c.Compare(val, value);
if (res == 0)
{
return(i);
}
if (res > 0)
{
return(-(i + 1));
}
}
return(-(high + 2));
}
// The index half way between the low and high point
long mid = (low + high) >> 1;
// Reaf the middle value from the data file,
file.Position = (mid * 8);
long midVal = fileReader.ReadInt64();
// Compare it with the value
int res1 = c.Compare(midVal, value);
if (res1 < 0)
{
low = mid + 1;
}
else if (res1 > 0)
{
high = mid - 1;
}
else // if (res == 0)
{
high = mid;
}
}
}
private void SearchFirstAndLast <T>(T value, IIndexedObjectComparer <T> c, out long first, out long last)
{
long low = 0;
long high = Count - 1;
if (low > high)
{
first = -1;
last = -1;
return;
}
while (true)
{
// If low is the same as high, we are either at the first value or at
// the position to insert the value,
if ((high - low) <= 4)
{
first = SearchFirst(value, c, low, high);
last = SearchLast(value, c, low, high);
return;
}
// The index half way between the low and high point
long mid = (low + high) >> 1;
// Reaf the middle value from the data file,
file.Position = (mid * 8);
long midVal = fileReader.ReadInt64();
// Compare it with the value
int res = c.Compare(midVal, value);
if (res < 0)
{
low = mid + 1;
}
else if (res > 0)
{
high = mid - 1;
}
else // if (res == 0)
{
first = SearchFirst(value, c, low, high);
last = SearchLast(value, c, low, high);
return;
}
}
}
