1  /***********************************************************************
 2   * Copyright (c) 2021 Russell O'Connor, Jonas Nick                     *
 3   * Distributed under the MIT software license, see the accompanying    *
 4   * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
 5   ***********************************************************************/
 6  
 7  #ifndef SECP256K1_HSORT_H
 8  #define SECP256K1_HSORT_H
 9  
10  #include <stddef.h>
11  #include <string.h>
12  
13  /* In-place, iterative heapsort with an interface matching glibc's qsort_r. This
14   * is preferred over standard library implementations because they generally
15   * make no guarantee about being fast for malicious inputs.
16   * Remember that heapsort is unstable.
17   *
18   * In/Out: ptr: pointer to the array to sort. The contents of the array are
19   *              sorted in ascending order according to the comparison function.
20   * In:   count: number of elements in the array.
21   *        size: size in bytes of each element.
22   *         cmp: pointer to a comparison function that is called with two
23   *              arguments that point to the objects being compared. The cmp_data
24   *              argument of secp256k1_hsort is passed as third argument. The
25   *              function must return an integer less than, equal to, or greater
26   *              than zero if the first argument is considered to be respectively
27   *              less than, equal to, or greater than the second.
28   *    cmp_data: pointer passed as third argument to cmp.
29   */
30  static void secp256k1_hsort(void *ptr, size_t count, size_t size,
31                              int (*cmp)(const void *, const void *, void *),
32                              void *cmp_data);
33  #endif