/// <summary>
/// Gets country code from an IPv4 address.
/// </summary>
private string getCountryCodeIPv4(IPAddress addr)
{
// Get IP address as unsigned 32-bit
byte[] bytes = addr.GetAddressBytes();
UInt32 val = 0;
for (int i = 0; i != bytes.Length; ++i)
{
val <<= 8;
val += bytes[i];
}
// Find largest RangeFirst that's not greater than value
// Binary search on ranges sorted by their first values
int bottom = 0;
int top = ip4Ranges.Length - 1;
int middle = top >> 1;
while (top >= bottom)
{
if (ip4Ranges[middle].RangeFirst == val)
{
break;
}
if (ip4Ranges[middle].RangeFirst > val)
{
top = middle - 1;
}
else
{
bottom = middle + 1;
}
middle = (bottom + top) >> 1;
}
// We're looking for equal or nearest smaller
while (middle > 0 && ip4Ranges[middle].RangeFirst > val)
{
--middle;
}
IPv4Range range = ip4Ranges[middle];
// We just have a larger one: no country
if (range.RangeFirst > val)
{
return(GetNoCountry());
}
// We're actually within range: return that country
if (range.RangeFirst <= val && range.RangeLast >= val)
{
return(countries[range.CountryId]);
}
// No country
return(GetNoCountry());
}
/// <summary>
/// Serializes IP range data in binary form.
/// </summary>
public void WriteBin(BinaryWriter bw)
{
// Number of ranges
UInt32 count = (UInt32)ip4Ranges.Length;
bw.Write(count);
// Write each range
for (UInt32 i = 0; i != count; ++i)
{
IPv4Range range = ip4Ranges[i];
bw.Write(range.RangeFirst);
bw.Write(range.RangeLast);
bw.Write(range.CountryId);
}
}
/// <summary>
/// Reads IPv4 range file; returns sorted array, with contiguous same-country ranges merged.
/// </summary>
private IPv4Range[] loadIp4(StreamReader sr)
{
// Reserve
List <IPv4Range> res = new List <IPv4Range>(180000);
// Parse file
string line;
while ((line = sr.ReadLine()) != null)
{
if (line == string.Empty || line.StartsWith("#"))
{
continue;
}
string[] parts = getParts(line);
UInt32 first = UInt32.Parse(parts[0]);
UInt32 last = UInt32.Parse(parts[1]);
string country = parts[5];
byte countryId = getCountryId(country);
res.Add(new IPv4Range {
RangeFirst = first, RangeLast = last, CountryId = countryId
});
}
// Sort by range starts
res.Sort((a, b) => a.RangeFirst.CompareTo(b.RangeFirst));
// Eliminate duplicates
List <IPv4Range> cpy = new List <IPv4Range>(res.Count);
cpy.Add(res[0]);
for (int i = 1; i < res.Count; ++i)
{
IPv4Range curr = res[i];
IPv4Range prev = cpy[cpy.Count - 1];
// Current range is contiguous to previous one; same country too
if (curr.CountryId == prev.CountryId && curr.RangeFirst == prev.RangeLast + 1)
{
prev.RangeLast = curr.RangeLast;
cpy[cpy.Count - 1] = prev;
}
// Nop, add new item
else
{
cpy.Add(curr);
}
}
// Return redcued array (with contiguous country ranges merged)
return(cpy.ToArray());
}