private static long SeekTimeZoneFile(string hash)
{
var min = 1L;
var max = TimezoneFileReader.Count;
var converged = false;
while (true)
{
var mid = ((max - min) / 2) + min;
var midLine = TimezoneFileReader.GetLine(mid);
for (int i = 0; i < hash.Length; i++)
{
if (midLine[i] == '-')
{
return(mid);
}
if (midLine[i] > hash[i])
{
max = mid == max ? min : mid;
break;
}
if (midLine[i] < hash[i])
{
min = mid == min ? max : mid;
break;
}
if (i == 4)
{
return(mid);
}
if (min == mid)
{
min = max;
break;
}
}
if (min == max)
{
if (converged)
{
break;
}
converged = true;
}
}
return(0);
}
private static IEnumerable <int> GetTzDataLineNumbers(string geohash)
{
var seeked = SeekTimeZoneFile(geohash);
if (seeked == 0)
{
return(new List <int>());
}
long min = seeked, max = seeked;
var seekedGeohash = TimezoneFileReader.GetLine(seeked).Substring(0, 5);
while (true)
{
var prevGeohash = TimezoneFileReader.GetLine(min - 1).Substring(0, 5);
if (seekedGeohash == prevGeohash)
{
min--;
}
else
{
break;
}
}
while (true)
{
var nextGeohash = TimezoneFileReader.GetLine(max + 1).Substring(0, 5);
if (seekedGeohash == nextGeohash)
{
max++;
}
else
{
break;
}
}
var lineNumbers = new List <int>();
for (var i = min; i <= max; i++)
{
var lineNumber = int.Parse(TimezoneFileReader.GetLine(i).Substring(5));
lineNumbers.Add(lineNumber);
}
return(lineNumbers);
}
