Line data    Source code

       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * qunique.h
       4             :  *      inline array unique functions
       5             :  * Portions Copyright (c) 2019-2024, 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      292808 : qunique(void *array, size_t elements, size_t width,
      22             :         int (*compare) (const void *, const void *))
      23             : {
      24      292808 :     char       *bytes = (char *) array;
      25             :     size_t      i,
      26             :                 j;
      27             : 
      28      292808 :     if (elements <= 1)
      29        2114 :         return elements;
      30             : 
      31     9800694 :     for (i = 1, j = 0; i < elements; ++i)
      32             :     {
      33     9510000 :         if (compare(bytes + i * width, bytes + j * width) != 0 &&
      34             :             ++j != i)
      35     4972758 :             memcpy(bytes + j * width, bytes + i * width, width);
      36             :     }
      37             : 
      38      290694 :     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     4581344 : qunique_arg(void *array, size_t elements, size_t width,
      47             :             int (*compare) (const void *, const void *, void *),
      48             :             void *arg)
      49             : {
      50     4581344 :     char       *bytes = (char *) array;
      51             :     size_t      i,
      52             :                 j;
      53             : 
      54     4581344 :     if (elements <= 1)
      55           0 :         return elements;
      56             : 
      57   213187282 :     for (i = 1, j = 0; i < elements; ++i)
      58             :     {
      59   208605938 :         if (compare(bytes + i * width, bytes + j * width, arg) != 0 &&
      60             :             ++j != i)
      61    30474726 :             memcpy(bytes + j * width, bytes + i * width, width);
      62             :     }
      63             : 
      64     4581344 :     return j + 1;
      65             : }
      66             : 
      67             : #endif                          /* QUNIQUE_H */