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//===========================================================================

//

//      strncmp.cxx

//

//      ANSI standard strncmp() routine

//

//===========================================================================

//####ECOSGPLCOPYRIGHTBEGIN####

// -------------------------------------------

// This file is part of eCos, the Embedded Configurable Operating System.

// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.

//

// eCos is free software; you can redistribute it and/or modify it under

// the terms of the GNU General Public License as published by the Free

// Software Foundation; either version 2 or (at your option) any later version.

//

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// WARRANTY; without even the implied warranty of MERCHANTABILITY or

// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

// for more details.

//

// You should have received a copy of the GNU General Public License along

// with eCos; if not, write to the Free Software Foundation, Inc.,

// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.

//

// As a special exception, if other files instantiate templates or use macros

// or inline functions from this file, or you compile this file and link it

// with other works to produce a work based on this file, this file does not

// by itself cause the resulting work to be covered by the GNU General Public

// License. However the source code for this file must still be made available

// in accordance with section (3) of the GNU General Public License.

//

// This exception does not invalidate any other reasons why a work based on

// this file might be covered by the GNU General Public License.

//

// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.

// at http://sources.redhat.com/ecos/ecos-license/

// -------------------------------------------

//####ECOSGPLCOPYRIGHTEND####

//===========================================================================

//#####DESCRIPTIONBEGIN####

//

// Author(s):    jlarmour

// Contributors: 

// Date:         2000-04-14

// Purpose:     

// Description: 

// Usage:       

//

//####DESCRIPTIONEND####

//

//===========================================================================

// CONFIGURATION

#include <pkgconf/libc_string.h>   // Configuration header

// INCLUDES

#include <cyg/infra/cyg_type.h>    // Common type definitions

#include <cyg/infra/cyg_trac.h>    // Tracing support

#include <cyg/infra/cyg_ass.h>     // Assertion support

#include <string.h>                // Header for this file

#include <stddef.h>         // Compiler definitions such as size_t, NULL etc.

#include <cyg/libc/string/stringsupp.hxx> // Useful string function support and

                                          // prototypes

// EXPORTED SYMBOLS

externC int

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

    CYGBLD_ATTRIB_WEAK_ALIAS(__strncmp);

// FUNCTIONS

int

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

{

    int retval;

    CYG_REPORT_FUNCNAMETYPE( "__strncmp", "returning %d" );

    CYG_REPORT_FUNCARG3( "s1=%08x, s2=%08x, n=%d", s1, s2, n );

    if (n == 0)

    {

        CYG_REPORT_RETVAL( 0 );

        return 0;

    }

    CYG_CHECK_DATA_PTR( s1, "s1 is not a valid pointer!" );

    CYG_CHECK_DATA_PTR( s2, "s2 is not a valid pointer!" );

#if defined(CYGIMP_LIBC_STRING_PREFER_SMALL_TO_FAST) || defined(__OPTIMIZE_SIZE__)

    while (n-- != 0 && *s1 == *s2)

    {

        if (n == 0 || *s1 == '\0' || *s2 == '\0')

            break;

        s1++;

        s2++;

    }

    retval = (*(unsigned char *) s1) - (*(unsigned char *) s2);

    CYG_REPORT_RETVAL( retval );

    return retval;

#else

    const CYG_WORD *aligned_s1;

    const CYG_WORD *aligned_s2;

    // If s1 or s2 are unaligned, then compare bytes.

    if (CYG_LIBC_STR_UNALIGNED2 (s1, s2))

    {

        while (n-- != 0 && *s1 == *s2)

        {

            // If we've run out of bytes or hit a null, return zero

            // since we already know *s1 == *s2.

            if (n == 0 || *s1 == '\0')

                return 0;

            s1++;

            s2++;

        }

        retval = (*(unsigned char *) s1) - (*(unsigned char *) s2);

        CYG_REPORT_RETVAL( retval );

        return retval;

    } //if

    // If s1 and s2 are word-aligned, compare them a word at a time.

    aligned_s1 = (const CYG_WORD *)s1;

    aligned_s2 = (const CYG_WORD *)s2;

    while (n >= sizeof(CYG_WORD) && *aligned_s1 == *aligned_s2)

    {

        n -= sizeof (CYG_WORD);

        // If we've run out of bytes or hit a null, return zero

        // since we already know *aligned_s1 == *aligned_s2.

        if (n == 0 || CYG_LIBC_STR_DETECTNULL (*aligned_s1))

        {

            CYG_REPORT_RETVAL( 0 );

            return 0;

        } // if

        aligned_s1++;

        aligned_s2++;

    } // while

    // A difference was detected in last few bytes of s1, so search bytewise

    s1 = (const char *)aligned_s1;

    s2 = (const char *)aligned_s2;

    while (n-- > 0 && *s1 == *s2)

    {

        // If we've run out of bytes or hit a null, return zero

        // since we already know *s1 == *s2.

        if (n == 0 || *s1 == '\0')

        {

            CYG_REPORT_RETVAL( 0 );

            return 0;

        } // if

        s1++;

        s2++;

    } // while

    retval = (*(unsigned char *) s1) - (*(unsigned char *) s2);

    CYG_REPORT_RETVAL( retval );

    return retval;

#endif // not defined(CYGIMP_LIBC_STRING_PREFER_SMALL_TO_FAST) ||

       //     defined(__OPTIMIZE_SIZE__)

} // __strncmp()

// EOF strncmp.cxx