adtools/clib2

/*
 * $Id: stdio_grow_file.c,v 1.8 2008-09-04 12:07:58 obarthel Exp $
 *
 * :ts=4
 *
 * Portable ISO 'C' (1994) runtime library for the Amiga computer
 * Copyright (c) 2002-2015 by Olaf Barthel <obarthel (at) gmx.net>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Neither the name of Olaf Barthel 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.
 */

#ifndef _STDIO_HEADERS_H
#include "stdio_headers.h"
#endif /* _STDIO_HEADERS_H */

/****************************************************************************/

/* The following is not part of the ISO 'C' (1994) standard. */

/****************************************************************************/

/* Seek to the end of a file, then add a certain number of 0 bytes. Note that
   this function will change the current file position! */
int
__grow_file_size(struct fd * fd,int num_bytes)
{
    unsigned char * aligned_buffer;
    unsigned char * buffer;
    struct FileHandle * fh;
    D_S(struct InfoData,id);
    LONG block_size;
    int bytes_written;
    int buffer_size;
    int size;
    LONG seek_position;
    off_t position;
    off_t current_position;
    int alignment_skip;
    int result = ERROR;

    assert( fd != NULL );

    D(("we have to grow the file by %ld bytes",num_bytes));

    block_size = 0;

    PROFILE_OFF();

    assert( FLAG_IS_CLEAR(fd->fd_Flags,FDF_STDIO) );

    fh = BADDR(fd->fd_File);
    if(fh != NULL && fh->fh_Type != NULL && DoPkt(fh->fh_Type,ACTION_DISK_INFO,MKBADDR(id),0,0,0,0))
        block_size = id->id_BytesPerBlock;

    PROFILE_ON();

    if(block_size < 512)
        block_size = 512;

    /* We have to fill up the file with zero bytes.
     * That data comes from a local buffer. How
     * large can we make it?
     */
    buffer_size = 8 * block_size;
    if(buffer_size > num_bytes)
        buffer_size = num_bytes;

    /* Allocate a little more memory than required to allow for
     * the buffer to be aligned to a cache line boundary.
     */
    buffer = malloc((size_t)buffer_size + (__cache_line_size-1));
    if(buffer == NULL)
    {
        SHOWMSG("not enough memory for write buffer");

        SetIoErr(ERROR_NO_FREE_STORE);
        goto out;
    }

    /* Align the buffer to a cache line boundary. */
    aligned_buffer = (unsigned char *)(((ULONG)(buffer + (__cache_line_size-1))) & ~(__cache_line_size-1));

    memset(aligned_buffer,0,(size_t)buffer_size);

    PROFILE_OFF();
    seek_position = Seek(fd->fd_File,0,OFFSET_END);
    PROFILE_ON();

    if(seek_position == SEEK_ERROR && IoErr() != OK)
    {
        SHOWMSG("could not move to the end of the file");
        goto out;
    }

    position = (off_t)seek_position;

    PROFILE_OFF();
    seek_position = Seek(fd->fd_File,0,OFFSET_CURRENT);
    PROFILE_ON();

    current_position = (off_t)seek_position;

    /* Try to make the first write access align the file position
     * to a block offset. Subsequent writes will then access the
     * file at positions that are multiples of the block size.
     */
    if(num_bytes > block_size && (current_position % block_size) != 0)
        alignment_skip = block_size - (current_position % block_size);
    else
        alignment_skip = 0;

    while(num_bytes > 0)
    {
        if(__check_abort_enabled)
            __check_abort();

        size = buffer_size;
        if(size > num_bytes)
            size = num_bytes;

        /* If possible, even out the block offset. */
        if(alignment_skip > 0 && size > alignment_skip)
            size = alignment_skip;

        alignment_skip = 0;

        PROFILE_OFF();
        bytes_written = Write(fd->fd_File,aligned_buffer,size);
        PROFILE_ON();

        if(bytes_written != size)
            goto out;

        num_bytes -= size;
    }

    SHOWMSG("all done.");

    result = OK;

 out:

    if(buffer != NULL)
        free(buffer);

    return(result);
}