source/libs/cairo/cairo-src/src/cairo-base64-stream.c

   1 /* -*- Mode: c; c-basic-offset: 4; indent-tabs-mode: t; tab-width: 8; -*- */
   2 /* cairo - a vector graphics library with display and print output
   3  *
   4  * Copyright © 2005-2007 Emmanuel Pacaud <emmanuel.pacaud@free.fr>
   5  * Copyright © 2009 Chris Wilson
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it either under the terms of the GNU Lesser General Public
   9  * License version 2.1 as published by the Free Software Foundation
  10  * (the "LGPL") or, at your option, under the terms of the Mozilla
  11  * Public License Version 1.1 (the "MPL"). If you do not alter this
  12  * notice, a recipient may use your version of this file under either
  13  * the MPL or the LGPL.
  14  *
  15  * You should have received a copy of the LGPL along with this library
  16  * in the file COPYING-LGPL-2.1; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA
  18  * You should have received a copy of the MPL along with this library
  19  * in the file COPYING-MPL-1.1
  20  *
  21  * The contents of this file are subject to the Mozilla Public License
  22  * Version 1.1 (the "License"); you may not use this file except in
  23  * compliance with the License. You may obtain a copy of the License at
  24  * http://www.mozilla.org/MPL/
  25  *
  26  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
  27  * OF ANY KIND, either express or implied. See the LGPL or the MPL for
  28  * the specific language governing rights and limitations.
  29  *
  30  * The Original Code is the cairo graphics library.
  31  *
  32  * The Initial Developer of the Original Code is Red Hat, Inc.
  33  *
  34  * Author(s):
  35  *      Kristian Høgsberg <krh@redhat.com>
  36  *      Chris Wilson <chris@chris-wilson.co.uk>
  37  */
  38
  39 #include "cairoint.h"
  40 #include "cairo-error-private.h"
  41 #include "cairo-output-stream-private.h"
  42
  43 typedef struct _cairo_base64_stream {
  44     cairo_output_stream_t base;
  45     cairo_output_stream_t *output;
  46     unsigned int in_mem;
  47     unsigned int trailing;
  48     unsigned char src[3];
  49 } cairo_base64_stream_t;
  50
  51 static char const base64_table[64] =
  52 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  53
  54 static cairo_status_t
  55 _cairo_base64_stream_write (cairo_output_stream_t *base,
  56                             const unsigned char   *data,
  57                             unsigned int           length)
  58 {
  59     cairo_base64_stream_t * stream = (cairo_base64_stream_t *) base;
  60     unsigned char *src = stream->src;
  61     unsigned int i;
  62
  63     if (stream->in_mem + length < 3) {
  64         for (i = 0; i < length; i++) {
  65             src[i + stream->in_mem] = *data++;
  66         }
  67         stream->in_mem += length;
  68         return CAIRO_STATUS_SUCCESS;
  69     }
  70
  71     do {
  72         unsigned char dst[4];
  73
  74         for (i = stream->in_mem; i < 3; i++) {
  75             src[i] = *data++;
  76             length--;
  77         }
  78         stream->in_mem = 0;
  79
  80         dst[0] = base64_table[src[0] >> 2];
  81         dst[1] = base64_table[(src[0] & 0x03) << 4 | src[1] >> 4];
  82         dst[2] = base64_table[(src[1] & 0x0f) << 2 | src[2] >> 6];
  83         dst[3] = base64_table[src[2] & 0xfc >> 2];
  84         /* Special case for the last missing bits */
  85         switch (stream->trailing) {
  86             case 2:
  87                 dst[2] = '=';
  88             case 1:
  89                 dst[3] = '=';
  90             default:
  91                 break;
  92         }
  93         _cairo_output_stream_write (stream->output, dst, 4);
  94     } while (length >= 3);
  95
  96     for (i = 0; i < length; i++) {
  97         src[i] = *data++;
  98     }
  99     stream->in_mem = length;
 100
 101     return _cairo_output_stream_get_status (stream->output);
 102 }
 103
 104 static cairo_status_t
 105 _cairo_base64_stream_close (cairo_output_stream_t *base)
 106 {
 107     cairo_base64_stream_t *stream = (cairo_base64_stream_t *) base;
 108     cairo_status_t status = CAIRO_STATUS_SUCCESS;
 109
 110     if (stream->in_mem > 0) {
 111         memset (stream->src + stream->in_mem, 0, 3 - stream->in_mem);
 112         stream->trailing = 3 - stream->in_mem;
 113         stream->in_mem = 3;
 114         status = _cairo_base64_stream_write (base, NULL, 0);
 115     }
 116
 117     return status;
 118 }
 119
 120 cairo_output_stream_t *
 121 _cairo_base64_stream_create (cairo_output_stream_t *output)
 122 {
 123     cairo_base64_stream_t *stream;
 124
 125     if (output->status)
 126         return _cairo_output_stream_create_in_error (output->status);
 127
 128     stream = malloc (sizeof (cairo_base64_stream_t));
 129     if (unlikely (stream == NULL)) {
 130         _cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
 131         return (cairo_output_stream_t *) &_cairo_output_stream_nil;
 132     }
 133
 134     _cairo_output_stream_init (&stream->base,
 135                                _cairo_base64_stream_write,
 136                                NULL,
 137                                _cairo_base64_stream_close);
 138
 139     stream->output = output;
 140     stream->in_mem = 0;
 141     stream->trailing = 0;
 142
 143     return &stream->base;
 144 }