/* Copyright (C) 1995, 1997, 1998 Aladdin Enterprises.  All rights reserved.
  
  This software is provided AS-IS with no warranty, either express or
  implied.
  
  This software is distributed under license and may not be copied,
  modified or distributed except as expressly authorized under the terms
  of the license contained in the file LICENSE in this distribution.
  
  For more information about licensing, please refer to
  http://www.ghostscript.com/licensing/. For information on
  commercial licensing, go to http://www.artifex.com/licensing/ or
  contact Artifex Software, Inc., 101 Lucas Valley Road #110,
  San Rafael, CA  94903, U.S.A., +1(415)492-9861.
*/

/* $Id: gxclfile.c,v 1.5 2002/02/21 22:24:53 giles Exp $ */
/* File-based command list implementation */
#include "stdio_.h"
#include "string_.h"
#include "unistd_.h"
#include "gserror.h"
#include "gserrors.h"
#include "gsmemory.h"
#include "gp.h"
#include "gxclio.h"

/* This is an implementation of the command list I/O interface */
/* that uses the file system for storage. */

/* ------ Open/close/unlink ------ */

int
clist_fopen(char fname[gp_file_name_sizeof], const char *fmode,
	    clist_file_ptr * pcf, gs_memory_t * mem, gs_memory_t *data_mem,
	    bool ok_to_compress)
{
    if (*fname == 0) {
	if (fmode[0] == 'r')
	    return_error(gs_error_invalidfileaccess);
	*pcf =
	    (clist_file_ptr) gp_open_scratch_file(gp_scratch_file_name_prefix,
						  fname, fmode);
    } else
	*pcf = gp_fopen(fname, fmode);
    if (*pcf == NULL) {
	eprintf1("Could not open the scratch file %s.\n", fname);
	return_error(gs_error_invalidfileaccess);
    }
    return 0;
}

int
clist_fclose(clist_file_ptr cf, const char *fname, bool delete)
{
    return (fclose((FILE *) cf) != 0 ? gs_note_error(gs_error_ioerror) :
	    delete ? clist_unlink(fname) :
	    0);
}

int
clist_unlink(const char *fname)
{
    return (unlink(fname) != 0 ? gs_note_error(gs_error_ioerror) : 0);
}

/* ------ Writing ------ */

long
clist_space_available(long requested)
{
    return requested;
}

int
clist_fwrite_chars(const void *data, uint len, clist_file_ptr cf)
{
    return fwrite(data, 1, len, (FILE *) cf);
}

/* ------ Reading ------ */

int
clist_fread_chars(void *data, uint len, clist_file_ptr cf)
{
    FILE *f = (FILE *) cf;
    byte *str = data;

    /* The typical implementation of fread */
    /* is extremely inefficient for small counts, */
    /* so we just use straight-line code instead. */
    switch (len) {
	default:
	    return fread(str, 1, len, f);
	case 8:
	    *str++ = (byte) getc(f);
	case 7:
	    *str++ = (byte) getc(f);
	case 6:
	    *str++ = (byte) getc(f);
	case 5:
	    *str++ = (byte) getc(f);
	case 4:
	    *str++ = (byte) getc(f);
	case 3:
	    *str++ = (byte) getc(f);
	case 2:
	    *str++ = (byte) getc(f);
	case 1:
	    *str = (byte) getc(f);
    }
    return len;
}

/* ------ Position/status ------ */

int
clist_set_memory_warning(clist_file_ptr cf, int bytes_left)
{
    return 0;			/* no-op */
}

int
clist_ferror_code(clist_file_ptr cf)
{
    return (ferror((FILE *) cf) ? gs_error_ioerror : 0);
}

long
clist_ftell(clist_file_ptr cf)
{
    return ftell((FILE *) cf);
}

void
clist_rewind(clist_file_ptr cf, bool discard_data, const char *fname)
{
    FILE *f = (FILE *) cf;

    if (discard_data) {
	/*
	 * The ANSI C stdio specification provides no operation for
	 * truncating a file at a given position, or even just for
	 * deleting its contents; we have to use a bizarre workaround to
	 * get the same effect.
	 */
	char fmode[4];

	/* Opening with "w" mode deletes the contents when closing. */
	freopen(fname, gp_fmode_wb, f);
	strcpy(fmode, "w+");
	strcat(fmode, gp_fmode_binary_suffix);
	freopen(fname, fmode, f);
    } else {
	rewind(f);
    }
}

int
clist_fseek(clist_file_ptr cf, long offset, int mode, const char *ignore_fname)
{
    return fseek((FILE *) cf, offset, mode);
}