TLA  Line data    Source code

       1                 : /*-------------------------------------------------------------------------
       2                 :  *
       3                 :  * qunique.h
       4                 :  *      inline array unique functions
       5                 :  * Portions Copyright (c) 2019-2023, PostgreSQL Global Development Group
       6                 :  *
       7                 :  * IDENTIFICATION
       8                 :  *      src/include/lib/qunique.h
       9                 :  *-------------------------------------------------------------------------
      10                 :  */
      11                 : 
      12                 : #ifndef QUNIQUE_H
      13                 : #define QUNIQUE_H
      14                 : 
      15                 : /*
      16                 :  * Remove duplicates from a pre-sorted array, according to a user-supplied
      17                 :  * comparator.  Usually the array should have been sorted with qsort() using
      18                 :  * the same arguments.  Return the new size.
      19                 :  */
      20                 : static inline size_t
      21 CBC      180787 : qunique(void *array, size_t elements, size_t width,
      22                 :         int (*compare) (const void *, const void *))
      23                 : {
      24          180787 :     char       *bytes = (char *) array;
      25                 :     size_t      i,
      26                 :                 j;
      27                 : 
      28          180787 :     if (elements <= 1)
      29            5095 :         return elements;
      30                 : 
      31         4210521 :     for (i = 1, j = 0; i < elements; ++i)
      32                 :     {
      33         4034829 :         if (compare(bytes + i * width, bytes + j * width) != 0 &&
      34                 :             ++j != i)
      35         1974596 :             memcpy(bytes + j * width, bytes + i * width, width);
      36                 :     }
      37                 : 
      38          175692 :     return j + 1;
      39                 : }
      40                 : 
      41                 : /*
      42                 :  * Like qunique(), but takes a comparator with an extra user data argument
      43                 :  * which is passed through, for compatibility with qsort_arg().
      44                 :  */
      45                 : static inline size_t
      46         1628755 : qunique_arg(void *array, size_t elements, size_t width,
      47                 :             int (*compare) (const void *, const void *, void *),
      48                 :             void *arg)
      49                 : {
      50         1628755 :     char       *bytes = (char *) array;
      51                 :     size_t      i,
      52                 :                 j;
      53                 : 
      54         1628755 :     if (elements <= 1)
      55 UBC           0 :         return elements;
      56                 : 
      57 CBC    29828406 :     for (i = 1, j = 0; i < elements; ++i)
      58                 :     {
      59        28199651 :         if (compare(bytes + i * width, bytes + j * width, arg) != 0 &&
      60                 :             ++j != i)
      61         1845107 :             memcpy(bytes + j * width, bytes + i * width, width);
      62                 :     }
      63                 : 
      64         1628755 :     return j + 1;
      65                 : }
      66                 : 
      67                 : #endif                          /* QUNIQUE_H */