//===========================================================================
//
//      strncpy.cxx
//
//      ANSI standard strncpy() routine
//
//===========================================================================
//####COPYRIGHTBEGIN####
//
// -------------------------------------------
// The contents of this file are subject to the Cygnus eCos Public License
// Version 1.0 (the "License"); you may not use this file except in
// compliance with the License.  You may obtain a copy of the License at
// http://sourceware.cygnus.com/ecos
// 
// Software distributed under the License is distributed on an "AS IS"
// basis, WITHOUT WARRANTY OF ANY KIND, either express or implied.  See the
// License for the specific language governing rights and limitations under
// the License.
// 
// The Original Code is eCos - Embedded Cygnus Operating System, released
// September 30, 1998.
// 
// The Initial Developer of the Original Code is Cygnus.  Portions created
// by Cygnus are Copyright (C) 1998 Cygnus Solutions.  All Rights Reserved.
// -------------------------------------------
//
//####COPYRIGHTEND####
//===========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s):   jlarmour
// Contributors:  jlarmour@cygnus.co.uk
// Date:        1998-02-13
// Purpose:     
// Description: 
// Usage:       
//
//####DESCRIPTIONEND####
//
//===========================================================================

// CONFIGURATION

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

// Include the C library?
#ifdef CYGPKG_LIBC     

// 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 "clibincl/stringsupp.hxx" // Useful string function support and
                                   // prototypes

// EXPORTED SYMBOLS

externC char *
strncpy( char *s1, const char *s2, size_t n ) \
    CYGPRI_LIBC_WEAK_ALIAS("_strncpy");

// FUNCTIONS

char *
_strncpy( char *s1, const char *s2, size_t n)
{
    CYG_REPORT_FUNCNAMETYPE( "_strncpy", "returning %08x" );
    CYG_REPORT_FUNCARG3( "s1=%08x, s2=%08x, n=%d", s1, s2, 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 *dscan;
    const char *sscan;
    
    dscan = s1;
    sscan = s2;
    while (n > 0)
    {
        --n;
        if ((*dscan++ = *sscan++) == '\0')
            break;
    }
    while (n-- > 0)
        *dscan++ = '\0';

    CYG_REPORT_RETVAL( s1 );
    
    return s1;
#else
    char *dst = s1;
    const char *src = s2;
    CYG_WORD *aligned_dst;
    const CYG_WORD *aligned_src;
    
    // If SRC or DEST is unaligned, then copy bytes.
    if (CYG_LIBC_STR_OPT_TOO_SMALL (n) || CYG_LIBC_STR_UNALIGNED2 (src, dst))
    {
        while (n > 0)
        {
            --n;
            if ((*dst++ = *src++) == '\0')
                break;
        }
        
        while (n -- > 0)
            *dst++ = '\0';
        
        CYG_REPORT_RETVAL( s1 );

        return s1;
    }
    
    aligned_dst = (CYG_WORD *)dst;
    aligned_src = (const CYG_WORD *)src;
    
    // SRC and DEST are both "CYG_WORD" aligned, try to do "CYG_WORD"
    // sized copies.
    while (n >= sizeof (CYG_WORD) && !CYG_LIBC_STR_DETECTNULL(*aligned_src))
    {
        n -= sizeof (CYG_WORD);
        *aligned_dst++ = *aligned_src++;
    }
    
    dst = (char *)aligned_dst;
    src = (const char *)aligned_src;
    
    while (n > 0)
    {
        --n;
        if ((*dst++ = *src++) == '\0')
            break;
    }
    
    while (n-- > 0)
        *dst++ = '\0';
    
    CYG_REPORT_RETVAL( s1 );

    return s1;
#endif // not defined(CYGIMP_LIBC_STRING_PREFER_SMALL_TO_FAST) ||
       //     defined(__OPTIMIZE_SIZE__)
} // _strncpy()

#endif // ifdef CYGPKG_LIBC     

// EOF strncpy.cxx