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106 lines
2.4 KiB
106 lines
2.4 KiB
/* |
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* Copyright (C) 2015 INRIA |
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* |
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* This file is subject to the terms and conditions of the GNU Lesser |
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* General Public License v2.1. See the file LICENSE in the top level |
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* directory for more details. |
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*/ |
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/** |
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* @defgroup sys_bitfield Bitfields |
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* @ingroup sys |
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* @brief Bitfields of arbitrary length |
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* @file |
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* @{ |
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* |
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* @brief bitfields operations on bitfields of arbitrary length |
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* |
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* @note Code taken mostly from |
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* <a href="http://stackoverflow.com/questions/1590893/error-trying-to-define-a-1-024-bit-128-byte-bit-field"> |
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* Stackoverflow, User Christoph</a> |
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* |
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* @author Oliver Hahm <oliver.hahm@inria.fr> |
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*/ |
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#ifndef BITFIELD_H |
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#define BITFIELD_H |
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#include <stdint.h> |
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#include <stdbool.h> |
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#include <stddef.h> |
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#ifdef __cplusplus |
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extern "C" { |
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#endif |
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/** |
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* @brief Declare a bitfield of a given size |
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* |
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* @note SIZE should be a constant expression. This avoids variable length |
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* arrays. |
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*/ |
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#define BITFIELD(NAME, SIZE) uint8_t NAME[((SIZE) + 7) / 8] |
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/** |
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* @brief Set the bit to 1 |
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* |
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* @param[in,out] field The bitfield |
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* @param[in] idx The number of the bit to set |
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*/ |
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static inline void bf_set(uint8_t field[], size_t idx) |
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{ |
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field[idx / 8] |= (1u << (idx % 8)); |
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} |
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/** |
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* @brief Clear the bit |
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* |
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* @param[in,out] field The bitfield |
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* @param[in] idx The number of the bit to clear |
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*/ |
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static inline void bf_unset(uint8_t field[], size_t idx) |
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{ |
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field[idx / 8] &= ~(1u << (idx % 8)); |
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} |
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/** |
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* @brief Toggle the bit |
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* |
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* @param[in,out] field The bitfield |
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* @param[in] idx The number of the bit to toggle |
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*/ |
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static inline void bf_toggle(uint8_t field[], size_t idx) |
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{ |
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field[idx / 8] ^= (1u << (idx % 8)); |
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} |
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/** |
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* @brief Check if the bet is set |
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* |
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* @param[in,out] field The bitfield |
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* @param[in] idx The number of the bit to check |
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*/ |
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static inline bool bf_isset(uint8_t field[], size_t idx) |
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{ |
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return (field[idx / 8] & (1u << (idx % 8))); |
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} |
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/** |
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* @brief Atomically get the number of an unset bit and set it |
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* |
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* This function can be used to record e.g., empty entries in an array. |
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* |
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* @param[in,out] field The bitfield |
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* @param[in] size The size of the bitfield |
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* |
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* @return number of bit that was set |
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* @return -1 if no bit was unset |
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*/ |
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int bf_get_unset(uint8_t field[], int size); |
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#ifdef __cplusplus |
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} |
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#endif |
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/** @} */ |
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#endif /* BITFIELD_H */
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