/* -*- Mode: c; c-basic-offset: 4; indent-tabs-mode: t; tab-width: 8; -*- */

/* cairo - a vector graphics library with display and print output

 *

 * Copyright © 2005 Red Hat, Inc

 *

 * This library is free software; you can redistribute it and/or

 * modify it either under the terms of the GNU Lesser General Public

 * License version 2.1 as published by the Free Software Foundation

 * (the "LGPL") or, at your option, under the terms of the Mozilla

 * Public License Version 1.1 (the "MPL"). If you do not alter this

 * notice, a recipient may use your version of this file under either

 * the MPL or the LGPL.

 *

 * You should have received a copy of the LGPL along with this library

 * in the file COPYING-LGPL-2.1; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA

 * You should have received a copy of the MPL along with this library

 * in the file COPYING-MPL-1.1

 *

 * The contents of this file are subject to the Mozilla Public License

 * Version 1.1 (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.mozilla.org/MPL/

 *

 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY

 * OF ANY KIND, either express or implied. See the LGPL or the MPL for

 * the specific language governing rights and limitations.

 *

 * The Original Code is the cairo graphics library.

 *

 * The Initial Developer of the Original Code is Red Hat, Inc.

 *

 * Author(s):

 *  Kristian Høgsberg <krh@redhat.com>

 */

#include "cairoint.h"

#include "cairo-error-private.h"

#include "cairo-output-stream-private.h"

typedef struct _cairo_base85_stream {

    cairo_output_stream_t base;

    cairo_output_stream_t *output;

    unsigned char four_tuple[4];

    int pending;

} cairo_base85_stream_t;

static void

_expand_four_tuple_to_five (unsigned char four_tuple[4],

          unsigned char five_tuple[5],

          cairo_bool_t *all_zero)

{

    uint32_t value;

    int digit, i;

    value = (uint32_t)four_tuple[0] << 24 | four_tuple[1] << 16 | four_tuple[2] << 8 | four_tuple[3];

    if (all_zero)

  *all_zero = TRUE;

    for (i = 0; i < 5; i++) {

  digit = value % 85;

  if (digit != 0 && all_zero)

      *all_zero = FALSE;

  five_tuple[4-i] = digit + 33;

  value = value / 85;

    }

}

static cairo_status_t

_cairo_base85_stream_write (cairo_output_stream_t *base,

          const unsigned char   *data,

          unsigned int     length)

{

    cairo_base85_stream_t *stream = (cairo_base85_stream_t *) base;

    const unsigned char *ptr = data;

    unsigned char five_tuple[5];

    cairo_bool_t is_zero;

    while (length) {

  stream->four_tuple[stream->pending++] = *ptr++;

  length--;

  if (stream->pending == 4) {

      _expand_four_tuple_to_five (stream->four_tuple, five_tuple, &is_zero);

      if (is_zero)

    _cairo_output_stream_write (stream->output, "z", 1);

      else

    _cairo_output_stream_write (stream->output, five_tuple, 5);

      stream->pending = 0;

  }

    }

    return _cairo_output_stream_get_status (stream->output);

}

static cairo_status_t

_cairo_base85_stream_close (cairo_output_stream_t *base)

{

    cairo_base85_stream_t *stream = (cairo_base85_stream_t *) base;

    unsigned char five_tuple[5];

    if (stream->pending) {

  memset (stream->four_tuple + stream->pending, 0, 4 - stream->pending);

  _expand_four_tuple_to_five (stream->four_tuple, five_tuple, NULL);

  _cairo_output_stream_write (stream->output, five_tuple, stream->pending + 1);

    }

    return _cairo_output_stream_get_status (stream->output);

}

cairo_output_stream_t *

_cairo_base85_stream_create (cairo_output_stream_t *output)

{

    cairo_base85_stream_t *stream;

    if (output->status)

  return _cairo_output_stream_create_in_error (output->status);

    stream = _cairo_calloc (sizeof (cairo_base85_stream_t));

    if (unlikely (stream == NULL)) {

  _cairo_error_throw (CAIRO_STATUS_NO_MEMORY);

  return (cairo_output_stream_t *) &_cairo_output_stream_nil;

    }

    _cairo_output_stream_init (&stream->base,

             _cairo_base85_stream_write,

             NULL,

             _cairo_base85_stream_close);

    stream->output = output;

    stream->pending = 0;

    return &stream->base;

}