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v261
src/basic/bitfield.h
74 строки
4 KB
Daan De Meyer
tree-wide: Introduce sd-forward.h and shared-forward.h headers
16 окт 2025, 18:00
16 окт 2025, 18:00
f102bc3
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/* SPDX-License-Identifier: LGPL-2.1-or-later */ #pragma once #include "basic-forward.h" /* Bit index (0-based) to mask of specified type. Assertion failure if index is out of range. */ #define _INDEX_TO_MASK(type, i, uniq) \ ({ \ int UNIQ_T(_i, uniq) = (i); \ assert(UNIQ_T(_i, uniq) >= 0); \ assert(UNIQ_T(_i, uniq) < (int)sizeof(type) * 8); \ ((type)1) << UNIQ_T(_i, uniq); \ }) #define INDEX_TO_MASK(type, i) \ ({ \ assert_cc(sizeof(type) <= sizeof(unsigned long long)); \ assert_cc(__builtin_choose_expr(__builtin_constant_p(i), i, 0) < (int)(sizeof(type) * 8)); \ __builtin_choose_expr(__builtin_constant_p(i), \ ((type)1) << (i), \ _INDEX_TO_MASK(type, i, UNIQ)); \ }) /* Builds a mask of specified type with multiple bits set. Note the result will not be constant, even if all * indexes are constant. */ #define INDEXES_TO_MASK(type, ...) \ UNIQ_INDEXES_TO_MASK(type, UNIQ, ##__VA_ARGS__) #define UNIQ_INDEXES_TO_MASK(type, uniq, ...) \ ({ \ typeof(type) UNIQ_T(_mask, uniq) = (type)0; \ int UNIQ_T(_i, uniq); \ FOREACH_ARGUMENT(UNIQ_T(_i, uniq), ##__VA_ARGS__) \ UNIQ_T(_mask, uniq) |= INDEX_TO_MASK(type, UNIQ_T(_i, uniq)); \ UNIQ_T(_mask, uniq); \ }) /* Same as the FLAG macros, but accept a 0-based bit index instead of a mask. Results in assertion failure if * index is out of range for the type. */ #define SET_BIT(bits, i) SET_FLAG(bits, INDEX_TO_MASK(typeof(bits), i), true) #define CLEAR_BIT(bits, i) SET_FLAG(bits, INDEX_TO_MASK(typeof(bits), i), false) #define BIT_SET(bits, i) FLAGS_SET(bits, INDEX_TO_MASK(typeof(bits), i)) /* As above, but accepts multiple indexes. Note the result will not be constant, even if all indexes are * constant. */ #define SET_BITS(bits, ...) SET_FLAG(bits, INDEXES_TO_MASK(typeof(bits), ##__VA_ARGS__), true) #define CLEAR_BITS(bits, ...) SET_FLAG(bits, INDEXES_TO_MASK(typeof(bits), ##__VA_ARGS__), false) #define BITS_SET(bits, ...) FLAGS_SET(bits, INDEXES_TO_MASK(typeof(bits), ##__VA_ARGS__)) /* Iterate through each set bit. Index is 0-based and type int. */ #define BIT_FOREACH(index, bits) _BIT_FOREACH(index, bits, UNIQ) #define _BIT_FOREACH(index, bits, uniq) \ for (int UNIQ_T(_last, uniq) = -1, index; \ (index = BIT_NEXT_SET(bits, UNIQ_T(_last, uniq))) >= 0; \ UNIQ_T(_last, uniq) = index) /* Find the next set bit after 0-based index 'prev'. Result is 0-based index of next set bit, or -1 if no * more bits are set. */ #define BIT_FIRST_SET(bits) BIT_NEXT_SET(bits, -1) #define BIT_NEXT_SET(bits, prev) \ UNIQ_BIT_NEXT_SET(bits, prev, UNIQ) #define UNIQ_BIT_NEXT_SET(bits, prev, uniq) \ ({ \ typeof(bits) UNIQ_T(_bits, uniq) = (bits); \ int UNIQ_T(_prev, uniq) = (prev); \ int UNIQ_T(_next, uniq); \ _BIT_NEXT_SET(UNIQ_T(_bits, uniq), \ UNIQ_T(_prev, uniq), \ UNIQ_T(_next, uniq)); \ }) #define _BIT_NEXT_SET(bits, prev, next) \ ((int)(prev + 1) == (int)sizeof(bits) * 8 \ ? -1 /* Prev index was msb. */ \ : ((next = __builtin_ffsll(((unsigned long long)(bits)) >> (prev + 1))) == 0 \ ? -1 /* No more bits set. */ \ : prev + next))