src/common/base64.c

   1 /*
   2  * Sylpheed -- a GTK+ based, lightweight, and fast e-mail client
   3  * Copyright (C) 1999-2012 Hiroyuki Yamamoto and the Claws Mail team
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 3 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  17  *
  18  */
  19
  20 #include <glib.h>
  21 #include <ctype.h>
  22 #include <string.h>
  23
  24 #include "base64.h"
  25 #include "utils.h"
  26
  27 static const gchar base64char[64] =
  28         "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  29
  30 static const signed char base64val[128] = {
  31         -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  32         -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  33         -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,
  34         52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1,
  35         -1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
  36         15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,
  37         -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
  38         41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1
  39 };
  40
  41 #define BASE64VAL(c)    (IS_ASCII(c) ? base64val[(gint) (c)] : -1)
  42
  43 void base64_encode(gchar *out, const guchar *in, gint inlen)
  44 {
  45         const guchar *inp = in;
  46         gchar *outp = out;
  47
  48         while (inlen >= 3) {
  49                 *outp++ = base64char[(inp[0] >> 2) & 0x3f];
  50                 *outp++ = base64char[((inp[0] & 0x03) << 4) |
  51                                      ((inp[1] >> 4) & 0x0f)];
  52                 *outp++ = base64char[((inp[1] & 0x0f) << 2) |
  53                                      ((inp[2] >> 6) & 0x03)];
  54                 *outp++ = base64char[inp[2] & 0x3f];
  55
  56                 inp += 3;
  57                 inlen -= 3;
  58         }
  59
  60         if (inlen > 0) {
  61                 *outp++ = base64char[(inp[0] >> 2) & 0x3f];
  62                 if (inlen == 1) {
  63                         *outp++ = base64char[(inp[0] & 0x03) << 4];
  64                         *outp++ = '=';
  65                 } else {
  66                         *outp++ = base64char[((inp[0] & 0x03) << 4) |
  67                                              ((inp[1] >> 4) & 0x0f)];
  68                         *outp++ = base64char[((inp[1] & 0x0f) << 2)];
  69                 }
  70                 *outp++ = '=';
  71         }
  72
  73         *outp = '\0';
  74 }
  75
  76 gint base64_decode(guchar *out, const gchar *in, gint inlen)
  77 {
  78         const gchar *inp = in;
  79         guchar *outp = out;
  80         gchar buf[4];
  81
  82         if (inlen < 0)
  83                 inlen = G_MAXINT;
  84
  85         while (inlen >= 4 && *inp != '\0') {
  86                 buf[0] = *inp++;
  87                 inlen--;
  88                 if (BASE64VAL(buf[0]) == -1) break;
  89
  90                 buf[1] = *inp++;
  91                 inlen--;
  92                 if (BASE64VAL(buf[1]) == -1) break;
  93
  94                 buf[2] = *inp++;
  95                 inlen--;
  96                 if (buf[2] != '=' && BASE64VAL(buf[2]) == -1) break;
  97
  98                 buf[3] = *inp++;
  99                 inlen--;
 100                 if (buf[3] != '=' && BASE64VAL(buf[3]) == -1) break;
 101
 102                 *outp++ = ((BASE64VAL(buf[0]) << 2) & 0xfc) |
 103                           ((BASE64VAL(buf[1]) >> 4) & 0x03);
 104                 if (buf[2] != '=') {
 105                         *outp++ = ((BASE64VAL(buf[1]) & 0x0f) << 4) |
 106                                   ((BASE64VAL(buf[2]) >> 2) & 0x0f);
 107                         if (buf[3] != '=') {
 108                                 *outp++ = ((BASE64VAL(buf[2]) & 0x03) << 6) |
 109                                            (BASE64VAL(buf[3]) & 0x3f);
 110                         }
 111                 }
 112         }
 113
 114         return outp - out;
 115 }
 116
 117 Base64Decoder *base64_decoder_new(void)
 118 {
 119         Base64Decoder *decoder;
 120
 121         decoder = g_new0(Base64Decoder, 1);
 122         return decoder;
 123 }
 124
 125 void base64_decoder_free(Base64Decoder *decoder)
 126 {
 127         g_free(decoder);
 128 }
 129
 130 gint base64_decoder_decode(Base64Decoder *decoder,
 131                            const gchar *in, guchar *out, gint inlen)
 132 {
 133         const gchar *in_end = in + inlen;
 134         gint len, total_len = 0;
 135         gboolean in_more = inlen > 0;
 136         gboolean got_eq = FALSE;
 137         gint buf_len;
 138         gchar buf[4];
 139
 140         cm_return_val_if_fail(decoder != NULL, -1);
 141         cm_return_val_if_fail(in != NULL, -1);
 142         cm_return_val_if_fail(out != NULL, -1);
 143
 144         /* Start with previous saved tail */
 145         buf_len = decoder->buf_len;
 146         memcpy(buf, decoder->buf, sizeof(buf));
 147
 148         while (in_more) {
 149                 while (buf_len < 4 && in_more) {
 150                         gchar c = *in;
 151
 152                         in++;
 153                         got_eq = (c == '=');
 154                         if (got_eq || BASE64VAL(c) >= 0)
 155                                 buf[buf_len++] = c;
 156                         in_more = (in < in_end) && !(got_eq && (buf_len == 4));
 157                 }
 158                 if (buf_len == 4) {
 159                         len = base64_decode(out, buf, 4);
 160                         out += len;
 161                         total_len += len;
 162                         buf_len = 0;
 163                 }
 164         }
 165         if (buf_len < 4) {
 166                 /* Save tail for next iteration call. It wll be ignored if ends here. */
 167                 decoder->buf_len = buf_len;
 168                 memcpy(decoder->buf, buf, buf_len);
 169         }
 170         return total_len;
 171 }