text: /* -*- Mode: c; c-basic-offset: 4; indent-tabs-mode: t; tab-width: 8; -*- */
  /* cairo-wasm - a vector graphics library with display and print output
   *
   * Copyright © 2005-2007 Emmanuel Pacaud <emmanuel.pacaud@free.fr>
   * Copyright © 2009 Chris Wilson
   *
   * 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-wasm graphics library.
   *
   * The Initial Developer of the Original Code is Red Hat, Inc.
   *
   * Author(s):
   *	Kristian Høgsberg <krh@redhat.com>
   *	Chris Wilson <chris@chris-wilson.co.uk>
   */
  
  #include "cairoint.h"
  #include "cairo-error-private.h"
  #include "cairo-output-stream-private.h"
  
  typedef struct _cairo_base64_stream {
      cairo_output_stream_t base;
      cairo_output_stream_t *output;
      unsigned int in_mem;
      unsigned int trailing;
      unsigned char src[3];
  } cairo_base64_stream_t;
  
  static char const base64_table[64] =
  "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  
  static cairo_status_t
  _cairo_base64_stream_write (cairo_output_stream_t *base,
  			    const unsigned char	  *data,
  			    unsigned int	   length)
  {
      cairo_base64_stream_t * stream = (cairo_base64_stream_t *) base;
      unsigned char *src = stream->src;
      unsigned int i;
  
      if (stream->in_mem + length < 3) {
  	for (i = 0; i < length; i++) {
  	    src[i + stream->in_mem] = *data++;
  	}
  	stream->in_mem += length;
  	return CAIRO_STATUS_SUCCESS;
      }
  
      do {
  	unsigned char dst[4];
  
  	for (i = stream->in_mem; i < 3; i++) {
  	    src[i] = *data++;
  	    length--;
  	}
  	stream->in_mem = 0;
  
  	dst[0] = base64_table[src[0] >> 2];
  	dst[1] = base64_table[(src[0] & 0x03) << 4 | src[1] >> 4];
  	dst[2] = base64_table[(src[1] & 0x0f) << 2 | src[2] >> 6];
  	dst[3] = base64_table[src[2] & 0xfc >> 2];
  	/* Special case for the last missing bits */
  	switch (stream->trailing) {
  	    case 2:
  		dst[2] = '=';
  		/* fall through */
  	    case 1:
  		dst[3] = '=';
  	    default:
  		break;
  	}
  	_cairo_output_stream_write (stream->output, dst, 4);
      } while (length >= 3);
  
      for (i = 0; i < length; i++) {
  	src[i] = *data++;
      }
      stream->in_mem = length;
  
      return _cairo_output_stream_get_status (stream->output);
  }
  
  static cairo_status_t
  _cairo_base64_stream_close (cairo_output_stream_t *base)
  {
      cairo_base64_stream_t *stream = (cairo_base64_stream_t *) base;
      cairo_status_t status = CAIRO_STATUS_SUCCESS;
  
      if (stream->in_mem > 0) {
  	memset (stream->src + stream->in_mem, 0, 3 - stream->in_mem);
  	stream->trailing = 3 - stream->in_mem;
  	stream->in_mem = 3;
  	status = _cairo_base64_stream_write (base, NULL, 0);
      }
  
      return status;
  }
  
  cairo_output_stream_t *
  _cairo_base64_stream_create (cairo_output_stream_t *output)
  {
      cairo_base64_stream_t *stream;
  
      if (output->status)
  	return _cairo_output_stream_create_in_error (output->status);
  
      stream = _cairo_malloc (sizeof (cairo_base64_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_base64_stream_write,
  			       NULL,
  			       _cairo_base64_stream_close);
  
      stream->output = output;
      stream->in_mem = 0;
      stream->trailing = 0;
  
      return &stream->base;
  }
  