ceph/src/spdk/include/spdk/bit_array.h

   1 /*-
   2  *   BSD LICENSE
   3  *
   4  *   Copyright (c) Intel Corporation.
   5  *   All rights reserved.
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   7  *   Redistribution and use in source and binary forms, with or without
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  10  *
  11  *     * Redistributions of source code must retain the above copyright
  12  *       notice, this list of conditions and the following disclaimer.
  13  *     * Redistributions in binary form must reproduce the above copyright
  14  *       notice, this list of conditions and the following disclaimer in
  15  *       the documentation and/or other materials provided with the
  16  *       distribution.
  17  *     * Neither the name of Intel Corporation nor the names of its
  18  *       contributors may be used to endorse or promote products derived
  19  *       from this software without specific prior written permission.
  20  *
  21  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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  31  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  */
  33
  34 /** \file
  35  * Bit array data structure
  36  */
  37
  38 #ifndef SPDK_BIT_ARRAY_H
  39 #define SPDK_BIT_ARRAY_H
  40
  41 #include "spdk/stdinc.h"
  42
  43 #ifdef __cplusplus
  44 extern "C" {
  45 #endif
  46
  47 /**
  48  * Variable-length bit array.
  49  */
  50 struct spdk_bit_array;
  51
  52 /**
  53  * Return the number of bits that a bit array is currently sized to hold.
  54  *
  55  * \param ba Bit array to query.
  56  *
  57  * \return the number of bits.
  58  */
  59 uint32_t spdk_bit_array_capacity(const struct spdk_bit_array *ba);
  60
  61 /**
  62  * Create a bit array.
  63  *
  64  * \param num_bits Number of bits that the bit array is sized to hold.
  65  *
  66  * All bits in the array will be cleared.
  67  *
  68  * \return a pointer to the new bit array.
  69  */
  70 struct spdk_bit_array *spdk_bit_array_create(uint32_t num_bits);
  71
  72 /**
  73  * Free a bit array and set the pointer to NULL.
  74  *
  75  * \param bap Bit array to free.
  76  */
  77 void spdk_bit_array_free(struct spdk_bit_array **bap);
  78
  79 /**
  80  * Create or resize a bit array.
  81  *
  82  * To create a new bit array, pass a pointer to a spdk_bit_array pointer that is
  83  * NULL for bap.
  84  *
  85  * The bit array will be sized to hold at least num_bits.
  86  *
  87  * If num_bits is smaller than the previous size of the bit array,
  88  * any data beyond the new num_bits size will be cleared.
  89  *
  90  * If num_bits is larger than the previous size of the bit array,
  91  * any data beyond the old num_bits size will be cleared.
  92  *
  93  * \param bap Bit array to create/resize.
  94  * \param num_bits Number of bits that the bit array is sized to hold.
  95  *
  96  * \return 0 on success, negative errno on failure.
  97  */
  98 int spdk_bit_array_resize(struct spdk_bit_array **bap, uint32_t num_bits);
  99
 100 /**
 101  * Get the value of a bit from the bit array.
 102  *
 103  * If bit_index is beyond the end of the current size of the bit array, this
 104  * function will return false (i.e. bits beyond the end of the array are implicitly 0).
 105  *
 106  * \param ba Bit array to query.
 107  * \param bit_index The index of a bit to query.
 108  *
 109  * \return the value of a bit from the bit array on success, or false on failure.
 110  */
 111 bool spdk_bit_array_get(const struct spdk_bit_array *ba, uint32_t bit_index);
 112
 113 /**
 114  * Set (to 1) a bit in the bit array.
 115  *
 116  * If bit_index is beyond the end of the bit array, this function will return -EINVAL.
 117  *
 118  * \param ba Bit array to set a bit.
 119  * \param bit_index The index of a bit to set.
 120  *
 121  * \return 0 on success, negative errno on failure.
 122  */
 123 int spdk_bit_array_set(struct spdk_bit_array *ba, uint32_t bit_index);
 124
 125 /**
 126  * Clear (to 0) a bit in the bit array.
 127  *
 128  * If bit_index is beyond the end of the bit array, no action is taken. Bits
 129  * beyond the end of the bit array are implicitly 0.
 130  *
 131  * \param ba Bit array to clear a bit.
 132  * \param bit_index The index of a bit to clear.
 133  */
 134 void spdk_bit_array_clear(struct spdk_bit_array *ba, uint32_t bit_index);
 135
 136 /**
 137  * Find the index of the first set bit in the array.
 138  *
 139  * \param ba The bit array to search.
 140  * \param start_bit_index The bit index from which to start searching (0 to start
 141  * from the beginning of the array).
 142  *
 143  * \return the index of the first set bit. If no bits are set, returns UINT32_MAX.
 144  */
 145 uint32_t spdk_bit_array_find_first_set(const struct spdk_bit_array *ba, uint32_t start_bit_index);
 146
 147 /**
 148  * Find the index of the first cleared bit in the array.
 149  *
 150  * \param ba The bit array to search.
 151  * \param start_bit_index The bit index from which to start searching (0 to start
 152  * from the beginning of the array).
 153  *
 154  * \return the index of the first cleared bit. If no bits are cleared, returns UINT32_MAX.
 155  */
 156 uint32_t spdk_bit_array_find_first_clear(const struct spdk_bit_array *ba, uint32_t start_bit_index);
 157
 158 /**
 159  * Count the number of set bits in the array.
 160  *
 161  * \param ba The bit array to search.
 162  *
 163  * \return the number of bits set in the array.
 164  */
 165 uint32_t spdk_bit_array_count_set(const struct spdk_bit_array *ba);
 166
 167 /**
 168  * Count the number of cleared bits in the array.
 169  *
 170  * \param ba The bit array to search.
 171  *
 172  * \return the number of bits cleared in the array.
 173  */
 174 uint32_t spdk_bit_array_count_clear(const struct spdk_bit_array *ba);
 175
 176 /**
 177  * Store bitmask from bit array.
 178  *
 179  * \param ba Bit array.
 180  * \param mask Destination mask. Mask and bit array capacity must be equal.
 181  */
 182 void spdk_bit_array_store_mask(const struct spdk_bit_array *ba, void *mask);
 183
 184 /**
 185  * Load bitmask to bit array.
 186  *
 187  * \param ba Bit array.
 188  * \param mask Source mask. Mask and bit array capacity must be equal.
 189  */
 190 void spdk_bit_array_load_mask(struct spdk_bit_array *ba, const void *mask);
 191
 192 /**
 193  * Clear (to 0) bit array bitmask.
 194  *
 195  * \param ba Bit array.
 196  */
 197 void spdk_bit_array_clear_mask(struct spdk_bit_array *ba);
 198
 199 #ifdef __cplusplus
 200 }
 201 #endif
 202
 203 #endif