void GeohashNeighbors(GeoHashBits hash, GeoHashNeighbors neighbors)
{
neighbors.East = hash;
neighbors.West = hash;
neighbors.North = hash;
neighbors.South = hash;
neighbors.SouthEast = hash;
neighbors.SouthWest = hash;
neighbors.NorthEast = hash;
neighbors.NorthWest = hash;
geohash_move_x(neighbors.East, 1);
geohash_move_y(neighbors.East, 0);
geohash_move_x(neighbors.West, -1);
geohash_move_y(neighbors.West, 0);
geohash_move_x(neighbors.South, 0);
geohash_move_y(neighbors.South, -1);
geohash_move_x(neighbors.North, 0);
geohash_move_y(neighbors.North, 1);
geohash_move_x(neighbors.NorthWest, -1);
geohash_move_y(neighbors.NorthWest, 1);
geohash_move_x(neighbors.NorthEast, 1);
geohash_move_y(neighbors.NorthEast, 1);
geohash_move_x(neighbors.SouthEast, 1);
geohash_move_y(neighbors.SouthEast, -1);
geohash_move_x(neighbors.SouthWest, -1);
geohash_move_y(neighbors.SouthWest, -1);
}
int GeohashDecode(GeoHashRange longRange, GeoHashRange latRange, GeoHashBits hash, GeoHashArea area)
{
if (Hashiszero(hash) || Rangeiszero(latRange) ||
Rangeiszero(longRange))
{
return(0);
}
area.Hash = hash;
ushort step = hash.Step;
ulong hashSep = Deinterleave64(hash.Bits); /* hash = [LAT][LONG] */
double latScale = latRange.Max - latRange.Min;
double longScale = longRange.Max - longRange.Min;
ulong ilato = hashSep; /* get lat part of deinterleaved hash */
ulong ilono = hashSep >> 32; /* shift over to get long part of hash */
/* divide by 2**step.
* Then, for 0-1 coordinate, multiply times scale and add
* to the min to get the absolute coordinate. */
area.Latitude.Min =
latRange.Min + (ilato * 1.0 / (1ul << step)) * latScale;
area.Latitude.Max =
latRange.Min + ((ilato + 1) * 1.0 / (1ul << step)) * latScale;
area.Longitude.Min =
longRange.Min + (ilono * 1.0 / (1ul << step)) * longScale;
area.Longitude.Max =
longRange.Min + ((ilono + 1) * 1.0 / (1ul << step)) * longScale;
return(1);
}
void geohash_move_y(GeoHashBits hash, short d)
{
if (d == 0)
{
return;
}
ulong x = hash.Bits & 0xaaaaaaaaaaaaaaaaUL;
ulong y = hash.Bits & 0x5555555555555555UL;
ulong zz = 0xaaaaaaaaaaaaaaaaUL >> (64 - hash.Step * 2);
if (d > 0)
{
y = y + (zz + 1);
}
else
{
y = y | zz;
y = y - (zz + 1);
}
y &= (0x5555555555555555UL >> (64 - hash.Step * 2));
hash.Bits = (x | y);
}
void geohash_move_x(GeoHashBits hash, short d)
{
if (d == 0)
{
return;
}
ulong x = hash.Bits & 0xaaaaaaaaaaaaaaaaUL;
ulong y = hash.Bits & 0x5555555555555555UL;
ulong zz = 0x5555555555555555UL >> (64 - hash.Step * 2);
if (d > 0)
{
x = x + (zz + 1);
}
else
{
x = x | zz;
x = x - (zz + 1);
}
x &= (0xaaaaaaaaaaaaaaaaUL >> (64 - hash.Step * 2));
hash.Bits = (x | y);
}
public RedisGeoHash(double[] latlon)
{
LatLon = latlon;
var bits = new GeoHashBits();
var res = GeohashEncodeWgs84(Longitude, Latitude, RedisGeoHash.GeoStepMax, ref bits);
GeoHashBits = bits;
}
int GeohashDecodeToLongLatType(GeoHashBits hash, double[] xy)
{
GeoHashArea area = new GeoHashArea();
if (GeohashDecodeType(hash, area) == 0)
{
return(0);
}
return(GeohashDecodeAreaToLongLat(area, xy));
}
int GeohashEncode(GeoHashRange longRange, GeoHashRange latRange, double longitude, double latitude,
ushort step, ref GeoHashBits hash)
{
/* Check basic arguments sanity. */
if (step > 32 || step == 0 ||
Rangepiszero(latRange) || Rangepiszero(longRange))
{
return(0);
}
/* Return an error when trying to index outside the supported
* constraints. */
if (longitude > GeoLongMax)
{
return(0);
}
if (longitude < GeoLongMin)
{
return(0);
}
if (latitude > GeoLatMax)
{
return(0);
}
if (latitude < GeoLatMin)
{
return(0);
}
hash.Bits = 0;
hash.Step = step;
if (latitude < latRange.Min || latitude > latRange.Max ||
longitude < longRange.Min || longitude > longRange.Max)
{
return(0);
}
double latOffset =
(latitude - latRange.Min) / (latRange.Max - latRange.Min);
double longOffset =
(longitude - longRange.Min) / (longRange.Max - longRange.Min);
/* convert to fixed point based on the step size */
latOffset *= (1UL << step);
longOffset *= (1UL << step);
hash.Bits = Interleave64((uint)latOffset, (uint)longOffset);
return(1);
}
private bool Hashiszero(GeoHashBits r)
{
return(r.Bits == 0 && r.Step == 0);
}
int GeohashDecodeToLongLatWgs84(GeoHashBits hash, double[] xy)
{
return(GeohashDecodeToLongLatType(hash, xy));
}
int GeohashDecodeWgs84(GeoHashBits hash, GeoHashArea area)
{
return(GeohashDecodeType(hash, area));
}
int GeohashDecodeType(GeoHashBits hash, GeoHashArea area)
{
GeoHashRange[] r = new GeoHashRange[2];
GeohashGetCoordRange(ref r[0], ref r[1]);
return(GeohashDecode(r[0], r[1], hash, area));
}
public int GeohashEncodeWgs84(double longitude, double latitude, ushort step,
ref GeoHashBits hash)
{
return(GeohashEncodeType(longitude, latitude, step, ref hash));
}
int GeohashEncodeType(double longitude, double latitude, ushort step, ref GeoHashBits hash)
{
GeoHashRange[] r = new GeoHashRange[2];
GeohashGetCoordRange(ref r[0], ref r[1]);
return(GeohashEncode(r[0], r[1], longitude, latitude, step, ref hash));
}