src/port/strnlen.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * strnlen.c
   4  *              Fallback implementation of strnlen().
   5  *
   6  *
   7  * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
   8  * Portions Copyright (c) 1994, Regents of the University of California
   9  *
  10  * IDENTIFICATION
  11  *        src/port/strnlen.c
  12  *
  13  *-------------------------------------------------------------------------
  14  */
  15
  16 #include "c.h"
  17
  18 /*
  19  * Implementation of posix' strnlen for systems where it's not available.
  20  *
  21  * Returns the number of characters before a null-byte in the string pointed
  22  * to by str, unless there's no null-byte before maxlen. In the latter case
  23  * maxlen is returned.
  24  */
  25 size_t
  26 strnlen(const char *str, size_t maxlen)
  27 {
  28         const char *p = str;
  29
  30         while (maxlen-- > 0 && *p)
  31                 p++;
  32         return p - str;
  33 }