mirror of
https://github.com/fluencelabs/redis
synced 2025-03-17 16:10:50 +00:00
Geo: sync faster decoding from krtm that synched from Ardb.
Instead of successive divisions in iteration the new code uses bitwise magic to interleave / deinterleave two 32bit values into a 64bit one. All tests still passing and is measurably faster, so worth it.
This commit is contained in:
antirez
parent
d308cadc8a
commit
4160bf0448
141
deps/geohash-int/geohash.c
vendored
141
deps/geohash-int/geohash.c
vendored
@ -44,6 +44,71 @@
|
||||
* -----------------
|
||||
*/
|
||||
|
||||
/* Interleave lower bits of x and y, so the bits of x
|
||||
* are in the even positions and bits from y in the odd;
|
||||
* x and y must initially be less than 2**32 (65536).
|
||||
* From: https://graphics.stanford.edu/~seander/bithacks.html#InterleaveBMN
|
||||
*/
|
||||
static inline uint64_t interleave64(uint32_t xlo, uint32_t ylo) {
|
||||
static const uint64_t B[] = {0x5555555555555555, 0x3333333333333333,
|
||||
0x0F0F0F0F0F0F0F0F, 0x00FF00FF00FF00FF,
|
||||
0x0000FFFF0000FFFF};
|
||||
static const unsigned int S[] = {1, 2, 4, 8, 16};
|
||||
|
||||
uint64_t x = xlo;
|
||||
uint64_t y = ylo;
|
||||
|
||||
x = (x | (x << S[4])) & B[4];
|
||||
y = (y | (y << S[4])) & B[4];
|
||||
|
||||
x = (x | (x << S[3])) & B[3];
|
||||
y = (y | (y << S[3])) & B[3];
|
||||
|
||||
x = (x | (x << S[2])) & B[2];
|
||||
y = (y | (y << S[2])) & B[2];
|
||||
|
||||
x = (x | (x << S[1])) & B[1];
|
||||
y = (y | (y << S[1])) & B[1];
|
||||
|
||||
x = (x | (x << S[0])) & B[0];
|
||||
y = (y | (y << S[0])) & B[0];
|
||||
|
||||
return x | (y << 1);
|
||||
}
|
||||
|
||||
/* reverse the interleave process
|
||||
* derived from http://stackoverflow.com/questions/4909263
|
||||
*/
|
||||
static inline uint64_t deinterleave64(uint64_t interleaved) {
|
||||
static const uint64_t B[] = {0x5555555555555555, 0x3333333333333333,
|
||||
0x0F0F0F0F0F0F0F0F, 0x00FF00FF00FF00FF,
|
||||
0x0000FFFF0000FFFF, 0x00000000FFFFFFFF};
|
||||
static const unsigned int S[] = {0, 1, 2, 4, 8, 16};
|
||||
|
||||
uint64_t x = interleaved;
|
||||
uint64_t y = interleaved >> 1;
|
||||
|
||||
x = (x | (x >> S[0])) & B[0];
|
||||
y = (y | (y >> S[0])) & B[0];
|
||||
|
||||
x = (x | (x >> S[1])) & B[1];
|
||||
y = (y | (y >> S[1])) & B[1];
|
||||
|
||||
x = (x | (x >> S[2])) & B[2];
|
||||
y = (y | (y >> S[2])) & B[2];
|
||||
|
||||
x = (x | (x >> S[3])) & B[3];
|
||||
y = (y | (y >> S[3])) & B[3];
|
||||
|
||||
x = (x | (x >> S[4])) & B[4];
|
||||
y = (y | (y >> S[4])) & B[4];
|
||||
|
||||
x = (x | (x >> S[5])) & B[5];
|
||||
y = (y | (y >> S[5])) & B[5];
|
||||
|
||||
return x | (y << 32);
|
||||
}
|
||||
|
||||
void geohashGetCoordRange(GeoHashRange *long_range, GeoHashRange *lat_range) {
|
||||
/* These are constraints from EPSG:900913 / EPSG:3785 / OSGEO:41001 */
|
||||
/* We can't geocode at the north/south pole. */
|
||||
@ -56,8 +121,6 @@ void geohashGetCoordRange(GeoHashRange *long_range, GeoHashRange *lat_range) {
|
||||
int geohashEncode(GeoHashRange *long_range, GeoHashRange *lat_range,
|
||||
double longitude, double latitude, uint8_t step,
|
||||
GeoHashBits *hash) {
|
||||
uint8_t i;
|
||||
|
||||
if (NULL == hash || step > 32 || step == 0 || RANGEPISZERO(lat_range) ||
|
||||
RANGEPISZERO(long_range)) {
|
||||
return 0;
|
||||
@ -71,29 +134,15 @@ int geohashEncode(GeoHashRange *long_range, GeoHashRange *lat_range,
|
||||
return 0;
|
||||
}
|
||||
|
||||
for (i = 0; i < step; i++) {
|
||||
uint8_t lat_bit, long_bit;
|
||||
double lat_offset =
|
||||
(latitude - lat_range->min) / (lat_range->max - lat_range->min);
|
||||
double long_offset =
|
||||
(longitude - long_range->min) / (long_range->max - long_range->min);
|
||||
|
||||
if (lat_range->max - latitude >= latitude - lat_range->min) {
|
||||
lat_bit = 0;
|
||||
lat_range->max = (lat_range->max + lat_range->min) / 2;
|
||||
} else {
|
||||
lat_bit = 1;
|
||||
lat_range->min = (lat_range->max + lat_range->min) / 2;
|
||||
}
|
||||
if (long_range->max - longitude >= longitude - long_range->min) {
|
||||
long_bit = 0;
|
||||
long_range->max = (long_range->max + long_range->min) / 2;
|
||||
} else {
|
||||
long_bit = 1;
|
||||
long_range->min = (long_range->max + long_range->min) / 2;
|
||||
}
|
||||
|
||||
hash->bits <<= 1;
|
||||
hash->bits += long_bit;
|
||||
hash->bits <<= 1;
|
||||
hash->bits += lat_bit;
|
||||
}
|
||||
/* convert to fixed point based on the step size */
|
||||
lat_offset *= (1 << step);
|
||||
long_offset *= (1 << step);
|
||||
hash->bits = interleave64(lat_offset, long_offset);
|
||||
return 1;
|
||||
}
|
||||
|
||||
@ -108,45 +157,35 @@ int geohashEncodeWGS84(double longitude, double latitude, uint8_t step,
|
||||
return geohashEncodeType(longitude, latitude, step, hash);
|
||||
}
|
||||
|
||||
static inline uint8_t get_bit(uint64_t bits, uint8_t pos) {
|
||||
return (bits >> pos) & 0x01;
|
||||
}
|
||||
|
||||
int geohashDecode(const GeoHashRange long_range, const GeoHashRange lat_range,
|
||||
const GeoHashBits hash, GeoHashArea *area) {
|
||||
uint8_t i;
|
||||
|
||||
if (HASHISZERO(hash) || NULL == area || RANGEISZERO(lat_range) ||
|
||||
RANGEISZERO(long_range)) {
|
||||
return 0;
|
||||
}
|
||||
|
||||
area->hash = hash;
|
||||
area->longitude.min = long_range.min;
|
||||
area->longitude.max = long_range.max;
|
||||
area->latitude.min = lat_range.min;
|
||||
area->latitude.max = lat_range.max;
|
||||
uint8_t step = hash.step;
|
||||
uint64_t hash_sep = deinterleave64(hash.bits); /* hash = [LAT][LONG] */
|
||||
|
||||
for (i = 0; i < hash.step; i++) {
|
||||
uint8_t lat_bit, long_bit;
|
||||
double lat_scale = lat_range.max - lat_range.min;
|
||||
double long_scale = long_range.max - long_range.min;
|
||||
|
||||
long_bit = get_bit(hash.bits, (hash.step - i) * 2 - 1);
|
||||
lat_bit = get_bit(hash.bits, (hash.step - i) * 2 - 2);
|
||||
uint32_t ilato = hash_sep; /* get lat part of deinterleaved hash */
|
||||
uint32_t ilono = hash_sep >> 32; /* shift over to get long part of hash */
|
||||
|
||||
if (lat_bit == 0) {
|
||||
area->latitude.max = (area->latitude.max + area->latitude.min) / 2;
|
||||
} else {
|
||||
area->latitude.min = (area->latitude.max + area->latitude.min) / 2;
|
||||
}
|
||||
/* 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 =
|
||||
lat_range.min + (ilato * 1.0 / (1ull << step)) * lat_scale;
|
||||
area->latitude.max =
|
||||
lat_range.min + ((ilato + 1) * 1.0 / (1ull << step)) * lat_scale;
|
||||
area->longitude.min =
|
||||
long_range.min + (ilono * 1.0 / (1ull << step)) * long_scale;
|
||||
area->longitude.max =
|
||||
long_range.min + ((ilono + 1) * 1.0 / (1ull << step)) * long_scale;
|
||||
|
||||
if (long_bit == 0) {
|
||||
area->longitude.max =
|
||||
(area->longitude.max + area->longitude.min) / 2;
|
||||
} else {
|
||||
area->longitude.min =
|
||||
(area->longitude.max + area->longitude.min) / 2;
|
||||
}
|
||||
}
|
||||
return 1;
|
||||
}
|
||||
|
||||
|
||||
@ -164,7 +164,7 @@ double extractDistanceOrReply(redisClient *c, robj **argv,
|
||||
* than "5.2144992818115 meters away." We provide 4 digits after the dot
|
||||
* so that the returned value is decently accurate even when the unit is
|
||||
* the kilometer. */
|
||||
inline void addReplyDoubleDistance(redisClient *c, double d) {
|
||||
void addReplyDoubleDistance(redisClient *c, double d) {
|
||||
char dbuf[128];
|
||||
int dlen = snprintf(dbuf, sizeof(dbuf), "%.4f", d);
|
||||
addReplyBulkCBuffer(c, dbuf, dlen);
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user