60 lines
1.3 KiB
C
60 lines
1.3 KiB
C
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/* strncpy( char *, const char *, size_t )
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This file is part of the Public Domain C Library (PDCLib).
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Permission is granted to use, modify, and / or redistribute at will.
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*/
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#include <string.h>
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#ifndef REGTEST
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char * strncpy( char * s1, const char * s2, size_t n )
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{
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char * rc = s1;
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while ( n && ( *s1++ = *s2++ ) )
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{
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/* Cannot do "n--" in the conditional as size_t is unsigned and we have
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to check it again for >0 in the next loop below, so we must not risk
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underflow.
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*/
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--n;
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}
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/* Checking against 1 as we missed the last --n in the loop above. */
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while ( n-- > 1 )
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{
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*s1++ = '\0';
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}
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return rc;
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}
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#endif
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#ifdef TEST
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#include "_PDCLIB_test.h"
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int main( void )
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{
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char s[] = "xxxxxxx";
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TESTCASE( strncpy( s, "", 1 ) == s );
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TESTCASE( s[0] == '\0' );
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TESTCASE( s[1] == 'x' );
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TESTCASE( strncpy( s, abcde, 6 ) == s );
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TESTCASE( s[0] == 'a' );
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TESTCASE( s[4] == 'e' );
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TESTCASE( s[5] == '\0' );
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TESTCASE( s[6] == 'x' );
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TESTCASE( strncpy( s, abcde, 7 ) == s );
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TESTCASE( s[6] == '\0' );
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TESTCASE( strncpy( s, "xxxx", 3 ) == s );
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TESTCASE( s[0] == 'x' );
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TESTCASE( s[2] == 'x' );
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TESTCASE( s[3] == 'd' );
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return TEST_RESULTS;
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}
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#endif
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