/* Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You under the Apache License, Version 2.0

 * (the "License"); you may not use this file except in compliance with

 * the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

#include "apr_arch_file_io.h"

static apr_status_t setptr(apr_file_t *thefile, apr_off_t pos )

{

    apr_off_t newbufpos;

    apr_status_t rv;

    if (thefile->direction == 1) {

        rv = apr_file_flush_locked(thefile);

        if (rv) {

            return rv;

        }

        thefile->bufpos = thefile->direction = thefile->dataRead = 0;

    }

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

    if (newbufpos >= 0 && newbufpos <= thefile->dataRead) {

        thefile->bufpos = newbufpos;

        rv = APR_SUCCESS;

    }

    else {

        if (lseek(thefile->filedes, pos, SEEK_SET) != -1) {

            thefile->bufpos = thefile->dataRead = 0;

            thefile->filePtr = pos;

            rv = APR_SUCCESS;

        }

        else {

            rv = errno;

        }

    }

    return rv;

}

APR_DECLARE(apr_status_t) apr_file_seek(apr_file_t *thefile, apr_seek_where_t where, apr_off_t *offset)

{

    apr_off_t rv;

    thefile->eof_hit = 0;

    if (thefile->buffered) {

        int rc = EINVAL;

        apr_finfo_t finfo;

        file_lock(thefile);

        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_locked(&finfo, APR_FINFO_SIZE, thefile);

            if (rc == APR_SUCCESS)

                rc = setptr(thefile, finfo.size + *offset);

            break;

        }

        *offset = thefile->filePtr - thefile->dataRead + thefile->bufpos;

        file_unlock(thefile);

        return rc;

    }

    else {

        rv = lseek(thefile->filedes, *offset, where);

        if (rv == -1) {

            *offset = -1;

            return errno;

        }

        else {

            *offset = rv;

            return APR_SUCCESS;

        }

    }

}

apr_status_t apr_file_trunc(apr_file_t *fp, apr_off_t offset)

{

    if (fp->buffered) {

        int rc = 0;

        file_lock(fp);

        if (fp->direction == 1 && fp->bufpos != 0) {

            apr_off_t len = fp->filePtr + fp->bufpos;

            if (offset < len) {

                /* New file end fall below our write buffer limit.

                 * Figure out if and what needs to be flushed.

                 */

                apr_off_t off = len - offset;

                if (off >= 0 && off <= fp->bufpos)

                    fp->bufpos = fp->bufpos - (size_t)off;

                else

                    fp->bufpos = 0;

            }

            rc = apr_file_flush_locked(fp);

            /* Reset buffer positions for write mode */

            fp->bufpos = fp->direction = fp->dataRead = 0;

        }

        else if (fp->direction == 0) {

            /* Discard the read buffer, as we are about to reposition

             * ourselves to the end of file.

             */

            fp->bufpos = 0;

            fp->dataRead = 0;

        }

        file_unlock(fp);

        if (rc) {

            return rc;

        }

    }

    if (ftruncate(fp->filedes, offset) == -1) {

        return errno;

    }

    return apr_file_seek(fp, APR_SET, &offset);

}