/*

* Copyright (c) 1997-2009 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:

* FUNCTION

* <<strncmp>>---character string compare

* INDEX

* strncmp

* ANSI_SYNOPSIS

* #include <string.h>

* int strncmp(const char *<[a]>, const char * <[b]>, size_t <[length]>);

* TRAD_SYNOPSIS

* #include <string.h>

* int strncmp(<[a]>, <[b]>, <[length]>)

* char *<[a]>;

* char *<[b]>;

* size_t <[length]>

* <<strncmp>> compares up to <[length]> characters

* from the string at <[a]> to the string at <[b]>.

* RETURNS

* If <<*<[a]>>> sorts lexicographically after <<*<[b]>>>,

* <<strncmp>> returns a number greater than zero.  If the two

* strings are equivalent, <<strncmp>> returns zero.  If <<*<[a]>>>

* sorts lexicographically before <<*<[b]>>>, <<strncmp>> returns a

* number less than zero.

* PORTABILITY

* <<strncmp>> is ANSI C.

* <<strncmp>> requires no supporting OS subroutines.

* QUICKREF

* strncmp ansi pure

* 

*

*/

#include <string.h>

/**

Compare some characters of two strings.

Compares the first num characters of string1 to the first num characters of string2.

The comparison is performed character by character. 

If a character that is not equal in both strings is found the function ends 

and returns a value that determines which of them was greater.

@return a value indicating the lexicographical relation between the strings.

@param s1 Null-terminated string to compare 

@param s2 Null-terminated string to compare. 

@param n Maximum number of characters to compare.

*/

EXPORT_C int 

strncmp (const char *s1, const char *s2, size_t n)

{

	const unsigned char* p1 = (const unsigned char*)s1;

	const unsigned char* p2 = (const unsigned char*)s2;

	if (n == 0)

		return 0;

	for (;;)

	{

		int c1 = *p1++;

		int d = c1 - *p2++;

		if (d != 0)

			return d;

		if (c1 == 0)

			return d;

		if (--n == 0)

			return d;

	}

}