sl@0: /*
sl@0: * Copyright (c) 1997-2009 Nokia Corporation and/or its subsidiary(-ies).
sl@0: * All rights reserved.
sl@0: * This component and the accompanying materials are made available
sl@0: * under the terms of "Eclipse Public License v1.0"
sl@0: * which accompanies this distribution, and is available
sl@0: * at the URL "http://www.eclipse.org/legal/epl-v10.html".
sl@0: *
sl@0: * Initial Contributors:
sl@0: * Nokia Corporation - initial contribution.
sl@0: *
sl@0: * Contributors:
sl@0: *
sl@0: * Description:
sl@0: * FUNCTION
sl@0: * <<strncmp>>---character string compare
sl@0: * INDEX
sl@0: * strncmp
sl@0: * ANSI_SYNOPSIS
sl@0: * #include <string.h>
sl@0: * int strncmp(const char *<[a]>, const char * <[b]>, size_t <[length]>);
sl@0: * TRAD_SYNOPSIS
sl@0: * #include <string.h>
sl@0: * int strncmp(<[a]>, <[b]>, <[length]>)
sl@0: * char *<[a]>;
sl@0: * char *<[b]>;
sl@0: * size_t <[length]>
sl@0: * <<strncmp>> compares up to <[length]> characters
sl@0: * from the string at <[a]> to the string at <[b]>.
sl@0: * RETURNS
sl@0: * If <<*<[a]>>> sorts lexicographically after <<*<[b]>>>,
sl@0: * <<strncmp>> returns a number greater than zero.  If the two
sl@0: * strings are equivalent, <<strncmp>> returns zero.  If <<*<[a]>>>
sl@0: * sorts lexicographically before <<*<[b]>>>, <<strncmp>> returns a
sl@0: * number less than zero.
sl@0: * PORTABILITY
sl@0: * <<strncmp>> is ANSI C.
sl@0: * <<strncmp>> requires no supporting OS subroutines.
sl@0: * QUICKREF
sl@0: * strncmp ansi pure
sl@0: * 
sl@0: *
sl@0: */
sl@0: 
sl@0: 
sl@0: 
sl@0: #include <string.h>
sl@0: 
sl@0: /**
sl@0: Compare some characters of two strings.
sl@0: Compares the first num characters of string1 to the first num characters of string2.
sl@0: The comparison is performed character by character. 
sl@0: If a character that is not equal in both strings is found the function ends 
sl@0: and returns a value that determines which of them was greater.
sl@0: @return a value indicating the lexicographical relation between the strings.
sl@0: @param s1 Null-terminated string to compare 
sl@0: @param s2 Null-terminated string to compare. 
sl@0: @param n Maximum number of characters to compare.
sl@0: */
sl@0: EXPORT_C int 
sl@0: strncmp (const char *s1, const char *s2, size_t n)
sl@0: {
sl@0: 	const unsigned char* p1 = (const unsigned char*)s1;
sl@0: 	const unsigned char* p2 = (const unsigned char*)s2;
sl@0: 
sl@0: 	if (n == 0)
sl@0: 		return 0;
sl@0: 
sl@0: 	for (;;)
sl@0: 	{
sl@0: 		int c1 = *p1++;
sl@0: 		int d = c1 - *p2++;
sl@0: 		if (d != 0)
sl@0: 			return d;
sl@0: 		if (c1 == 0)
sl@0: 			return d;
sl@0: 		if (--n == 0)
sl@0: 			return d;
sl@0: 	}
sl@0: }