61d88ec9c8
A flagset is a dynamic array where each bit of the array can be independently set/reset. It can be used for minor/major allocations or for other dynamically growing bitsets. Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
136 lines
3.1 KiB
C
136 lines
3.1 KiB
C
/*
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* shl - Flagset
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*
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* Copyright (c) 2013 David Herrmann <dh.herrmann@googlemail.com>
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files
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* (the "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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/*
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* A dynamic flagset implementation
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*/
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#ifndef SHL_FLAGSET_H
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#define SHL_FLAGSET_H
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#include <limits.h>
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#include <stdbool.h>
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#include <stddef.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include "shl_array.h"
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#include "shl_misc.h"
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static inline int shl_flagset_new(struct shl_array **out)
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{
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return shl_array_new(out, sizeof(unsigned long), 1);
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}
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static inline void shl_flagset_free(struct shl_array *arr)
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{
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return shl_array_free(arr);
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}
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static inline int shl_flagset_alloc(struct shl_array *arr, unsigned int *out)
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{
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static const unsigned long one = 1;
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unsigned int i, j;
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unsigned long *data;
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int ret;
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if (!arr)
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return -EINVAL;
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for (i = 0; i < arr->length; ++i) {
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data = SHL_ARRAY_AT(arr, unsigned long, i);
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for (j = 0; j < SHL_ULONG_BITS; ++j) {
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if (!(*data & (1UL << j))) {
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*data |= 1UL << j;
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*out = i * SHL_ULONG_BITS + j;
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return 0;
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}
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}
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}
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ret = shl_array_push(arr, &one);
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if (ret)
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return ret;
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*out = (arr->length - 1) * SHL_ULONG_BITS;
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return 0;
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}
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static inline int shl_flagset_reserve(struct shl_array *arr, unsigned int num)
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{
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int ret;
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unsigned int idx, off;
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unsigned long *data;
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if (!arr)
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return -EINVAL;
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idx = num / SHL_ULONG_BITS;
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off = num % SHL_ULONG_BITS;
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if (idx >= arr->length) {
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ret = shl_array_zresize(arr, idx + 1);
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if (ret)
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return ret;
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}
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data = SHL_ARRAY_AT(arr, unsigned long, idx);
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if (*data & (1UL << off))
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return -EEXIST;
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*data |= 1UL << off;
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return 0;
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}
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static inline int shl_flagset_set(struct shl_array *arr, unsigned int num)
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{
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int ret;
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ret = shl_flagset_reserve(arr, num);
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if (ret == -EEXIST)
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return 0;
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return ret;
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}
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static inline void shl_flagset_unset(struct shl_array *arr, unsigned int num)
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{
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unsigned int idx, off;
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unsigned long *data;
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if (!arr)
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return;
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idx = num / SHL_ULONG_BITS;
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off = num % SHL_ULONG_BITS;
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if (idx >= arr->length)
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return;
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data = SHL_ARRAY_AT(arr, unsigned long, idx);
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*data &= ~(1UL << off);
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}
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#endif /* SHL_FLAGSET_H */
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