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

//

//      bsearch.cxx

//

//      ANSI standard binary search function defined in section 7.10.5.1

//      of the standard

//

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

//####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:         2000-04-30

// Purpose:     

// Description: 

// Usage:       

//

//####DESCRIPTIONEND####

//

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

// CONFIGURATION

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

// INCLUDES

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

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

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

#include <stdlib.h>                // Header for all stdlib functions

                                   // (like this one)

// TRACING

# if defined(CYGDBG_USE_TRACING) && \

     defined(CYGNUM_LIBC_BSEARCH_TRACE_LEVEL)

static int bsearch_trace = CYGNUM_LIBC_BSEARCH_TRACE_LEVEL;

#  define TL1 (0 < bsearch_trace)

# else

#  define TL1 (0)

# endif

// FUNCTIONS

externC void *

bsearch( const void *key, const void *base, size_t nmemb, size_t size,

         __bsearch_comparison_fn_t compar )

{

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

    CYG_REPORT_FUNCARG5( "key=%08x, base=%08x, nmemb=%d, size=%d, "

                         "compar=%08x", key, base, nmemb, size, compar );

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

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

    CYG_CHECK_FUNC_PTR( compar, "compar is not a valid function pointer!" );

    CYG_ADDRESS current;

    size_t lower = 0;

    size_t upper = nmemb;

    size_t index;

    int result;

    if (nmemb == 0 || size == 0)

    {

        CYG_TRACE2( TL1, "Warning! either nmemb (%d) or size (%d) is 0",

                    nmemb, size );

        CYG_REPORT_RETVAL( NULL );

        return NULL;

    } // if

    while (lower < upper)

    {

        index = (lower + upper) / 2;

        current = (CYG_ADDRESS) (((char *) base) + (index * size));

        CYG_TRACE2( TL1, "About to call comparison function with "

                    "key=%08x, current=%08x", key, current );

        result = compar (key, (void *) current);

        CYG_TRACE1( TL1, "Comparison function returned %d", result );

        if (result < 0)

            upper = index;

        else if (result > 0)

            lower = index + 1;

        else

        {

            CYG_REPORT_RETVAL( current );

            return (void *)current;

        } // else

    } // while

    CYG_REPORT_RETVAL( NULL );

    return NULL;

} // bsearch()

// EOF bsearch.cxx