1 /* GStreamer

     2  * Copyright (C) <2007> Mike Smith <msmith@xiph.org>

     3  *

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

     5  * modify it under the terms of the GNU Library General Public

     6  * License as published by the Free Software Foundation; either

     7  * version 2 of the License, or (at your option) any later version.

     8  *

     9  * This library is distributed in the hope that it will be useful,

    10  * but WITHOUT ANY WARRANTY; without even the implied warranty of

    11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

    12  * Library General Public License for more details.

    13  *

    14  * You should have received a copy of the GNU Library General Public

    15  * License along with this library; if not, write to the

    16  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,

    17  * Boston, MA 02111-1307, USA.

    18  */

    19 

    20 /**

    21  * SECTION:gstrtspbase64

    22  * @short_description: Helper functions to handle Base64

    23  *

    24  * Last reviewed on 2007-07-24 (0.10.14)

    25  */

    26 

    27 #ifdef HAVE_CONFIG_H

    28 #include "config.h"

    29 #endif

    30 

    31 #include <string.h>

    32 

    33 #include "gstrtspbase64.h"

    34 

    35 static char base64table[64] = {

    36   'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O',

    37   'P',

    38   'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e',

    39   'f',

    40   'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u',

    41   'v',

    42   'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/'

    43 };

    44 

    45 /**

    46  * gst_rtsp_base64_encode:

    47  * @data: the binary data to encode

    48  * @len: the length of @data

    49  *

    50  * Encode a sequence of binary data into its Base-64 stringified representation.

    51  *

    52  * Returns: a newly allocated, zero-terminated Base-64 encoded string

    53  * representing @data.

    54  */

    55 /* This isn't efficient, but it doesn't need to be */

    56 #ifdef __SYMBIAN32__

    57 EXPORT_C

    58 #endif

    59 

    60 gchar *

    61 gst_rtsp_base64_encode (const gchar * data, gsize len)

    62 {

    63   gchar *out = g_malloc (len * 4 / 3 + 4);

    64   gchar *result = out;

    65   int chunk;

    66 

    67   while (len > 0) {

    68     chunk = (len > 3) ? 3 : len;

    69     *out++ = base64table[(*data & 0xFC) >> 2];

    70     *out++ = base64table[((*data & 0x03) << 4) | ((*(data + 1) & 0xF0) >> 4)];

    71     switch (chunk) {

    72       case 3:

    73         *out++ =

    74             base64table[((*(data + 1) & 0x0F) << 2) | ((*(data +

    75                         2) & 0xC0) >> 6)];

    76         *out++ = base64table[(*(data + 2)) & 0x3F];

    77         break;

    78       case 2:

    79         *out++ = base64table[((*(data + 1) & 0x0F) << 2)];

    80         *out++ = '=';

    81         break;

    82       case 1:

    83         *out++ = '=';

    84         *out++ = '=';

    85         break;

    86     }

    87     data += chunk;

    88     len -= chunk;

    89   }

    90   *out = 0;

    91 

    92   return result;

    93 }

    94 

    95 /**

    96  * gst_rtsp_base64_decode_ip:

    97  * @data: the base64 encoded data

    98  * @len: location for output length or NULL

    99  *

   100  * Decode the base64 string pointed to by @data in-place. When @len is not #NULL

   101  * it will contain the length of the decoded data.

   102  */

   103 void

   104 gst_rtsp_base64_decode_ip (gchar * data, gsize * len)

   105 {

   106   char dtable[256];

   107   int i, j, k = 0, n = strlen (data);

   108 

   109   for (i = 0; i < 255; i++)

   110     dtable[i] = 0x80;

   111   for (i = 'A'; i <= 'Z'; i++)

   112     dtable[i] = 0 + (i - 'A');

   113   for (i = 'a'; i <= 'z'; i++)

   114     dtable[i] = 26 + (i - 'a');

   115   for (i = '0'; i <= '9'; i++)

   116     dtable[i] = 52 + (i - '0');

   117   dtable['+'] = 62;

   118   dtable['/'] = 63;

   119   dtable['='] = 0;

   120 

   121   for (j = 0; j < n; j += 4) {

   122     char a[4], b[4];

   123 

   124     for (i = 0; i < 4; i++) {

   125       int c = data[i + j];

   126 

   127       if (dtable[c] & 0x80) {

   128         if (len)

   129           *len = 0;

   130         return;

   131       }

   132       a[i] = (char) c;

   133       b[i] = (char) dtable[c];

   134     }

   135     data[k++] = (b[0] << 2) | (b[1] >> 4);

   136     data[k++] = (b[1] << 4) | (b[2] >> 2);

   137     data[k++] = (b[2] << 6) | b[3];

   138     i = a[2] == '=' ? 1 : (a[3] == '=' ? 2 : 3);

   139     if (i < 3) {

   140       data[k] = 0;

   141       if (len)

   142         *len = k;

   143       return;

   144     }

   145   }

   146   data[k] = 0;

   147   if (len)

   148     *len = k;

   149   return;

   150 }