/* Copyright (C) 1995, 1997, 1998 Aladdin Enterprises.  All rights reserved.
  
  This file is part of AFPL Ghostscript.
  
  AFPL Ghostscript is distributed with NO WARRANTY OF ANY KIND.  No author or
  distributor accepts any responsibility for the consequences of using it, or
  for whether it serves any particular purpose or works at all, unless he or
  she says so in writing.  Refer to the Aladdin Free Public License (the
  "License") for full details.
  
  Every copy of AFPL Ghostscript must include a copy of the License, normally
  in a plain ASCII text file named PUBLIC.  The License grants you the right
  to copy, modify and redistribute AFPL Ghostscript, but only under certain
  conditions described in the License.  Among other things, the License
  requires that the copyright notice and this notice be preserved on all
  copies.
*/

/*$Id$ */
/* 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);
}