50 lines
1.7 KiB
C++
50 lines
1.7 KiB
C++
/*
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* This file is free software: you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This file is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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* AP_OLC is based on INAV olc.c implemention, thanks @fiam and other contributors.
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*/
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#pragma once
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#include <stdint.h>
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typedef int32_t int32_t;
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static constexpr int32_t OLC_DEG_MULTIPLIER = 10000000; // 1e7
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class AP_OLC
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{
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public:
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// olc_encodes the given coordinates in lat and lon (deg * OLC_DEG_MULTIPLIER)
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// as an OLC code of the given length. It returns the number of characters
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// written to buf.
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static int olc_encode(int32_t lat, int32_t lon, size_t length, char *buf, size_t bufsize);
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private:
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static bool inited;
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// Initialized via init_constants()
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static int32_t grid_size;
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static int32_t initial_resolution;
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static void init_constants(void);
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static float compute_precision_for_length(int length);
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static int32_t adjust_latitude(int32_t lat, size_t code_len);
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static int32_t normalize_longitude(int32_t lon);
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static unsigned encode_pairs(uint32_t lat, uint32_t lon, size_t length, char *buf, size_t bufsize);
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static int encode_grid(uint32_t lat, uint32_t lon, size_t length,char *buf, size_t bufsize);
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};
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