helos1/libc/strncmp.c

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2021-10-10 14:39:17 +08:00
/* strncmp( const char *, const char *, size_t )
This file is part of the Public Domain C Library (PDCLib).
Permission is granted to use, modify, and / or redistribute at will.
*/
#include <string.h>
#ifndef REGTEST
int strncmp( const char * s1, const char * s2, size_t n )
{
while ( n && *s1 && ( *s1 == *s2 ) )
{
++s1;
++s2;
--n;
}
if ( n == 0 )
{
return 0;
}
else
{
return ( *( unsigned char * )s1 - * ( unsigned char * )s2 );
}
}
#endif
#ifdef TEST
#include "_PDCLIB_test.h"
int main( void )
{
char cmpabcde[] = "abcde\0f";
char cmpabcd_[] = "abcde\xfc";
char empty[] = "";
char x[] = "x";
TESTCASE( strncmp( abcde, cmpabcde, 5 ) == 0 );
TESTCASE( strncmp( abcde, cmpabcde, 10 ) == 0 );
TESTCASE( strncmp( abcde, abcdx, 5 ) < 0 );
TESTCASE( strncmp( abcdx, abcde, 5 ) > 0 );
TESTCASE( strncmp( empty, abcde, 5 ) < 0 );
TESTCASE( strncmp( abcde, empty, 5 ) > 0 );
TESTCASE( strncmp( abcde, abcdx, 4 ) == 0 );
TESTCASE( strncmp( abcde, x, 0 ) == 0 );
TESTCASE( strncmp( abcde, x, 1 ) < 0 );
TESTCASE( strncmp( abcde, cmpabcd_, 10 ) < 0 );
return TEST_RESULTS;
}
#endif