audk/StdLib/LibC/String/Concatenation.c

84 lines
3.1 KiB
C

/** @file
Concatenation Functions for <string.h>.
Copyright (c) 2010, Intel Corporation. All rights reserved.<BR>
This program and the accompanying materials are licensed and made available under
the terms and conditions of the BSD License that accompanies this distribution.
The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php.
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#include <Uefi.h>
#include <Library/BaseLib.h>
#include <LibConfig.h>
#include <string.h>
/** The strcat function appends a copy of the string pointed to by s2
(including the terminating null character) to the end of the string pointed
to by s1. The initial character of s2 overwrites the null character at the
end of s1. If copying takes place between objects that overlap, the
behavior is undefined.
@return The strcat function returns the value of s1.
**/
char *
strcat(char * __restrict s1, const char * __restrict s2)
{
return AsciiStrCat( s1, s2);
}
/** The strncat function appends not more than n characters (a null character
and characters that follow it are not appended) from the array pointed to
by s2 to the end of the string pointed to by s1. The initial character of
s2 overwrites the null character at the end of s1. A terminating null
character is always appended to the result. If copying takes place
between objects that overlap, the behavior is undefined.
@return The strncat function returns the value of s1.
**/
char *
strncat(char * __restrict s1, const char * __restrict s2, size_t n)
{
return AsciiStrnCat( s1, s2, n);
}
/** The strncatX function appends not more than n characters (a null character
and characters that follow it are not appended) from the array pointed to
by s2 to the end of the string pointed to by s1. The initial character of
s2 overwrites the null character at the end of s1. The result is always
terminated with a null character. If copying takes place between objects
that overlap, the behavior is undefined.
strncatX exists because normal strncat does not indicate if the operation
was terminated because of exhausting n or reaching the end of s2.
@return The strncatX function returns 0 if the operation was terminated
because it reached the end of s1. Otherwise, a non-zero value is
returned indicating how many characters remain in s1.
**/
int
strncatX(char * __restrict s1, const char * __restrict s2, size_t n)
{
int NumLeft;
// Find s1's terminating NUL
for( ; n != 0; --n) {
if( *s1++ == '\0') break;
}
// Now copy *s2 into s1, overwriting s1's terminating NUL
for( --s1; n != 0; --n) {
if((*s1++ = *s2++) == '\0') break;
}
NumLeft = (int)n;
// Guarantee that s1 is NUL terminated.
*--s1 = '\0';
return NumLeft; // Zero if we ran out of buffer ( strlen(s1) < strlen(s2) )
}