2.3-InternetRadio/nutos/nut/crt/fread.c

/*
 * Copyright (C) 2001-2003 by egnite Software GmbH. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * For additional information see http://www.ethernut.de/
 *
 */

/*
 * $Log$
 * Revision 1.3  2009/01/17 15:37:52  haraldkipp
 * Added some NUTASSERT macros to check function parameters.
 *
 * Revision 1.2  2004/04/15 10:23:24  haraldkipp
 * Distinguish between read error and end of file
 *
 * Revision 1.1.1.1  2003/05/09 14:40:27  haraldkipp
 * Initial using 3.2.1
 *
 * Revision 1.1  2003/02/04 17:49:05  harald
 * *** empty log message ***
 *
 */


#include "nut_io.h"

#include <sys/nutdebug.h>
#include <io.h>

/*!
 * \addtogroup xgCrtStdio
 */
/*@{*/

/*!
 * \brief Read data from a stream.
 *
 * \param buffer Pointer to the buffer that receives the data.
 * \param size   Item size in bytes.
 * \param count  Maximum number of items to read.
 * \param stream Pointer to a previously opened stream.
 *
 * \return The number of full items read, which may be less then the
 *         specified number.
 *
 * \warning The function will not check, if the stream pointer points
 *          to a valid stream.
 */
size_t fread(void *buffer, size_t size, size_t count, FILE * stream)
{
    size_t rc;
    size_t nu = 0;

    NUTASSERT(stream != NULL);
    NUTASSERT(buffer != NULL);
    if (size > 1)
        count *= size;
    if (stream->iob_flags & _IOUNG) {
        stream->iob_flags &= ~_IOUNG;
        *((char *) buffer) = (char) stream->iob_unget;
        buffer = ((char *) buffer) + 1;
        count--;
        nu++;
    }
    rc = (size_t) _read(stream->iob_fd, buffer, count);
    if (rc == 0) {
        stream->iob_flags |= _IOEOF;
    }
    else if(rc == (size_t)-1) {
        stream->iob_flags |= _IOERR;
        rc = 0;
    }
    rc += nu;
    if (size > 1) {
        rc /= size;
    }
    return rc;
}

/*@}*/