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

//

//      strncat.cxx

//

//      ANSI standard strncat() 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.

//

// eCos is distributed in the hope that it will be useful, but WITHOUT ANY

// 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 char *

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

    CYGBLD_ATTRIB_WEAK_ALIAS(__strncat);

// FUNCTIONS

char *

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

{

    CYG_REPORT_FUNCNAMETYPE( "__strncat", "returning %08x" );

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

    if (n)

    {

        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__)

    char *s = s1;

    while (*s1)

        s1++;

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

    {

        if (n == 0)

            *s1 = '\0';

    }

    CYG_REPORT_RETVAL( s );

    return s;

#else

    char *s = s1;

    // Skip over the data in s1 as quickly as possible.

    if (!CYG_LIBC_STR_UNALIGNED (s1))

    {

        CYG_WORD *aligned_s1 = (CYG_WORD *)s1;

        while (!CYG_LIBC_STR_DETECTNULL (*aligned_s1))

            aligned_s1++;

        s1 = (char *)aligned_s1;

    }

    while (*s1)

        s1++;

    // s1 now points to the its trailing null character, now copy

    // up to N bytes from S2 into S1 stopping if a NULL is encountered

    // in S2.

    // 

    // It is not safe to use strncpy here since it copies EXACTLY N

    // characters, NULL padding if necessary.

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

    {

        if (n == 0)

            *s1 = '\0';

    }

    CYG_REPORT_RETVAL( s );

    return s;

#endif // not defined(CYGIMP_LIBC_STRING_PREFER_SMALL_TO_FAST) ||

       //     defined(__OPTIMIZE_SIZE__)

} // __strncat()

// EOF strncat.cxx