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72 lines
2.5 KiB
72 lines
2.5 KiB
/* |
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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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#include <AP_HAL/AP_HAL.h> |
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#include <AP_HAL/AP_HAL_Boards.h> |
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#ifndef HAL_PLUSCODE_ENABLE |
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#define HAL_PLUSCODE_ENABLE !HAL_MINIMIZE_FEATURES && BOARD_FLASH_SIZE > 1024 |
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#endif |
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#if HAL_PLUSCODE_ENABLE |
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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 constexpr uint8_t SEPARATOR_CHAR = '+'; |
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static constexpr uint8_t SEPARATOR_POS = 8; |
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static constexpr uint8_t PADDING_CHAR = '0'; |
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static constexpr uint8_t ENCODING_BASE = 20; |
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static constexpr uint8_t PAIR_CODE_LEN = 10; |
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static constexpr uint8_t CODE_LEN_MAX = 15; |
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static constexpr uint8_t GRID_COLS = 4; |
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static constexpr uint8_t GRID_ROWS = ENCODING_BASE / GRID_COLS; |
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static constexpr int32_t OLC_DEG_MULTIPLIER = 10000000; // 1e7 |
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static constexpr int32_t LAT_MAX = 90 * OLC_DEG_MULTIPLIER; |
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static constexpr int32_t LON_MAX = 180 * OLC_DEG_MULTIPLIER; |
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static const int32_t initial_exponent; |
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// Work out the enclosing resolution (in degrees) for the grid algorithm. |
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static const int32_t grid_size; |
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// Work out the initial resolution |
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static const int32_t initial_resolution; |
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static constexpr char olc_alphabet[] = "23456789CFGHJMPQRVWX"; |
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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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#endif |