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/* cairo_output_stream.c: Output stream abstraction
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 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 cairo_output_stream.c as distributed with 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-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 = 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);
}
/* Mark end of base85 data */
_cairo_output_stream_printf (stream->output, "~>");
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 = malloc (sizeof (cairo_base85_stream_t));
if (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,
_cairo_base85_stream_close);
stream->output = output;
stream->pending = 0;
return &stream->base;
}
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