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/**
* slibc — Yet another C library
* Copyright © 2015 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 first occurrence of a byte in a memory segment.
*
* @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 first occurrence of `c`,
* `NULL` if none were found.
*/
void* memchr(const void* segment, int c, size_t size)
{
char* s = segment;
while (size--)
if (*s++ == c)
return s - 1;
return NULL;
}
/**
* Find the first occurrence of a byte in a memory segment.
* The memory segment must be known to contain the sought after byte.
*
* This is a GNU-compliant slibc extension.
*
* @param segment The memory segment to search.
* @param c The sought after character.
* @return Pointer to the first occurrence of `c`.
*/
void* rawmemchr(const void* segment, int c)
{
char* s = segment;
for (;;)
if (*s++ == c)
return s - 1;
}
/**
* 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.
*/
void* memrchr(const void* segment, int c, size_t size)
{
char* s = segment;
while (size--)
if (s[size] == c)
return s + size;
return NULL;
}
/**
* Find the first occurrence of a byte in a string.
*
* `s = strchr(s, 0)` is a faster alternative to
* `s = s + strlen(s)`.
*
* @param string The string to search.
* The terminating NUL character is
* considered a part of the string.
* @param c The sought after character.
* @return Pointer to the first occurrence of `c`,
* `NULL` if none were found.
*/
char* strchr(const char* string, int c)
{
for (;;)
if (*string == c)
return string;
else if (!*string++)
return NULL;
}
/* TODO Ensure that `s = strchr(s, 0)` is faster than `s = s + strlen(s)`. */
/**
* Find the first occurrence of a byte in a string, or
* if there is no such byte, the end of the string.
*
* This is a GNU-compliant slibc extension.
*
* @param string The string to search.
* The terminating NUL character is
* considered a part of the string.
* @param c The sought after character.
* @return Pointer to the first occurrence of `c`,
* Pointer to the terminating NUL character
* if none were found.
*/
char* strchrnul(const char* string, int c)
{
for (;; string++)
if (*string == c)
return string;
else if (!*string)
return string;
}
/**
* Find the last occurrence of a byte in a string.
*
* For improved performace, use `memrchr` instead of
* this function if you already know the length of the
* string.
*
* @param string The string to search.
* The terminating NUL character is
* considered a part of the string.
* @param c The sought after character.
* @return Pointer to the last occurrence of `c`,
* `NULL` if none were found.
*/
char* strrchr(const char* string, int c)
{
char* r = NULL;
for (;;)
if (*string == c)
r = string;
else if (!*string++)
return r;
}
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