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53 lines
1.7 KiB
53 lines
1.7 KiB
/* |
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* Copyright (C) 2020 Siddharth B Purohit |
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* |
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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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#include "CANIface.h" |
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bool AP_HAL::CANFrame::priorityHigherThan(const CANFrame& rhs) const |
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{ |
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const uint32_t clean_id = id & MaskExtID; |
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const uint32_t rhs_clean_id = rhs.id & MaskExtID; |
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/* |
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* STD vs EXT - if 11 most significant bits are the same, EXT loses. |
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*/ |
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const bool ext = id & FlagEFF; |
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const bool rhs_ext = rhs.id & FlagEFF; |
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if (ext != rhs_ext) { |
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const uint32_t arb11 = ext ? (clean_id >> 18) : clean_id; |
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const uint32_t rhs_arb11 = rhs_ext ? (rhs_clean_id >> 18) : rhs_clean_id; |
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if (arb11 != rhs_arb11) { |
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return arb11 < rhs_arb11; |
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} else { |
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return rhs_ext; |
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} |
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} |
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/* |
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* RTR vs Data frame - if frame identifiers and frame types are the same, RTR loses. |
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*/ |
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const bool rtr = id & FlagRTR; |
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const bool rhs_rtr = rhs.id & FlagRTR; |
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if (clean_id == rhs_clean_id && rtr != rhs_rtr) { |
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return rhs_rtr; |
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} |
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/* |
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* Plain ID arbitration - greater value loses. |
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*/ |
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return clean_id < rhs_clean_id; |
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}
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