strncmp.c

Nucleus Common Library for Integrator using ARM Developer Suite

/*************************************************************************
*
*               Copyright Mentor Graphics Corporation 2002
*                         All Rights Reserved.
*
* THIS WORK CONTAINS TRADE SECRET AND PROPRIETARY INFORMATION WHICH IS
* THE PROPERTY OF MENTOR GRAPHICS CORPORATION OR ITS LICENSORS AND IS
* SUBJECT TO LICENSE TERMS.
*
*************************************************************************/

/*************************************************************************
* FILE NAME                                     VERSION
*
*       strncmp.c                               Nucleus Common Library 1.1
*
* DESCRIPTION
*
*       This file contains the implementation of NCL_strcmp.
*
* DATA STRUCTURES
*
*       None.
*
* FUNCTIONS
*
*       NCL_strcmp
*
* DEPENDENCIES
*
*       ncl.h
*       string.h
*       nucleus.h
*
************************************************************************/

#define NU_NCL_SOURCE_FILE

#include "ncl\inc\ncl.h"
#include "ncl\inc\string.h"
#include "plus\nucleus.h"                                /* MMU Support */

/*************************************************************************
*
*   FUNCTION
*
*       NCL_strncmp
*
*   DESCRIPTION
*
*       Lexigraphically compare at most n characters from the incoming
*       2 arguments and return an integer greater than, equal to, or
*       less than 0 according to whether s1 is greater than, equal to,
*       or less than s2.
*
*   INPUTS
*
*       s1                  String to compare
*       s2                  String to compare
*       n                   The most chars that will be compared
*
*   OUTPUTS
*
*       int                 0 means s1 == s2;
*                           -1 means s1 < s2;
*                           1 means s1 > s2
*
*************************************************************************/

int NCL_strncmp(register const char *s1, register const char *s2,
                 register size_t n)
{
    while ((n > 0) && (*s1 == *s2) && (*s1))
        ++s1, ++s2, --n;

    if (n == 0)
    {
        return 0;
    }

    return ((int)(unsigned char)*s1) - ((int)(unsigned char)*s2);
}