seek.c

Apache V2.0.15 Alpha For Linuxhttpd-2_0_15-alpha.tar.Z

/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2000-2001 The Apache Software Foundation.  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. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact [e-mail].
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

#include "win32/fileio.h"
#include "apr_file_io.h"
#include <errno.h>
#include <string.h>

static apr_status_t setptr(apr_file_t *thefile, unsigned long pos )
{
    long newbufpos;
    DWORD rc;

    if (thefile->direction == 1) {
        apr_file_flush(thefile);
        thefile->bufpos = thefile->direction = thefile->dataRead = 0;
    }

    newbufpos = pos - (thefile->filePtr - thefile->dataRead);

    if (newbufpos >= 0 && newbufpos <= thefile->dataRead) {
        thefile->bufpos = newbufpos;
        rc = 0;
    } else {
        rc = SetFilePointer(thefile->filehand, pos, NULL, FILE_BEGIN);

        if ( rc == 0xFFFFFFFF )
            rc = apr_get_os_error();
        else
            rc = thefile->bufpos = thefile->dataRead = 0;
    }

    return rc;
}



APR_DECLARE(apr_status_t) apr_file_seek(apr_file_t *thefile, apr_seek_where_t where, apr_off_t *offset)
{
    DWORD howmove;
    DWORD rv;

    if (thefile->buffered) {
        int rc = APR_EINVAL;
        apr_finfo_t finfo;

        switch (where) {
        case APR_SET:
            rc = setptr(thefile, *offset);
            break;

        case APR_CUR:
            rc = setptr(thefile, thefile->filePtr - thefile->dataRead + thefile->bufpos + *offset);
            break;

        case APR_END:
            rc = apr_file_info_get(&finfo, APR_FINFO_SIZE, thefile);
            if (rc == APR_SUCCESS && (finfo.valid & APR_FINFO_SIZE))
                rc = setptr(thefile, finfo.size - *offset);
            break;
        }

        *offset = thefile->filePtr + thefile->bufpos;
        return rc;
    } else {
        switch(where) {
        case APR_SET: {
            howmove = FILE_BEGIN;
            break;
        }
        case APR_CUR: {
            howmove = FILE_CURRENT;
            break;
        }
        case APR_END: {
            howmove = FILE_END;
            break;
        }
        }

        rv = SetFilePointer(thefile->filehand, *offset, NULL, howmove);
        if (rv == -1) {
            *offset = -1;
            return apr_get_os_error();
        }
        else {
            *offset = rv;
            return APR_SUCCESS;
        }
    }
}