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108 lines
3.8 KiB
C
108 lines
3.8 KiB
C
/*
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*Copyright (c) 2013-2014, yinqiwen <yinqiwen@gmail.com>
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*All rights reserved.
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*
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*Redistribution and use in source and binary forms, with or without
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*modification, are permitted provided that the following conditions are met:
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*
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* * Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of Redis nor the names of its contributors may be used
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* to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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*THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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*AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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*IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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*ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
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*BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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*CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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*SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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*INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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*CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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*ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
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*THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef GEOHASH_H_
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#define GEOHASH_H_
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#include <stdint.h>
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#if defined(__cplusplus)
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extern "C"
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{
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#endif
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typedef enum
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{
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GEOHASH_NORTH = 0,
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GEOHASH_EAST,
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GEOHASH_WEST,
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GEOHASH_SOUTH,
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GEOHASH_SOUTH_WEST,
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GEOHASH_SOUTH_EAST,
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GEOHASH_NORT_WEST,
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GEOHASH_NORT_EAST
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} GeoDirection;
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typedef struct
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{
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uint64_t bits;
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uint8_t step;
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} GeoHashBits;
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typedef struct
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{
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double max;
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double min;
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} GeoHashRange;
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typedef struct
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{
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GeoHashBits hash;
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GeoHashRange latitude;
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GeoHashRange longitude;
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} GeoHashArea;
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typedef struct
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{
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GeoHashBits north;
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GeoHashBits east;
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GeoHashBits west;
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GeoHashBits south;
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GeoHashBits north_east;
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GeoHashBits south_east;
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GeoHashBits north_west;
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GeoHashBits south_west;
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} GeoHashNeighbors;
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/*
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* 0:success
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* -1:failed
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*/
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int geohash_encode(GeoHashRange lat_range, GeoHashRange lon_range, double latitude, double longitude, uint8_t step, GeoHashBits *hash);
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int geohash_decode(GeoHashRange lat_range, GeoHashRange lon_range, GeoHashBits hash, GeoHashArea *area);
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/*
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* Fast encode/decode version, more magic in implementation.
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*/
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int geohash_fast_encode(GeoHashRange lat_range, GeoHashRange lon_range, double latitude, double longitude, uint8_t step, GeoHashBits *hash);
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int geohash_fast_decode(GeoHashRange lat_range, GeoHashRange lon_range, GeoHashBits hash, GeoHashArea *area);
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int geohash_get_neighbors(GeoHashBits hash, GeoHashNeighbors *neighbors);
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int geohash_get_neighbor(GeoHashBits hash, GeoDirection direction, GeoHashBits *neighbor);
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GeoHashBits geohash_next_leftbottom(GeoHashBits bits);
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GeoHashBits geohash_next_rightbottom(GeoHashBits bits);
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GeoHashBits geohash_next_lefttop(GeoHashBits bits);
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GeoHashBits geohash_next_righttop(GeoHashBits bits);
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#if defined(__cplusplus)
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}
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#endif
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#endif /* GEOHASH_H_ */
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