path: root/src/string/mem/memrchr.c

/**
 * slibc — Yet another C library
 * Copyright © 2015, 2016  Mattias Andrée (maandree@member.fsf.org)
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#include <string.h>


# pragma GCC diagnostic ignored "-Wdiscarded-qualifiers"



/**
 * Find the last occurrence of a byte in a memory segment.
 * 
 * For improved performace, use this function instead
 * of `strrchr` if you already know the length of the
 * string.
 * 
 * @param   segment  The memory segment to search.
 * @param   c        The sought after character.
 * @param   size     The size of the memory segment.
 * @return           Pointer to the last occurrence of `c`,
 *                   `NULL` if none were found.
 * 
 * @since  Always.
 */
void* (memrchr)(const void* segment, int c, size_t size)
{
  char* s = segment;
  while (size--)
    if (s[size] == c)
      return s + size;
  return NULL;
}