Sylpheed

/*

 * Sylpheed -- a GTK+ based, lightweight, and fast e-mail client

 * Copyright (C) 1999-2005 Hiroyuki Yamamoto

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

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

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

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

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

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

 */

#ifdef HAVE_CONFIG_H

#  include "config.h"

#endif

#include <glib.h>

#include <string.h>

#include <ctype.h>

#include "codeconv.h"

#include "base64.h"

#include "quoted-printable.h"

#define ENCODED_WORD_BEGIN        "=?"

#define ENCODED_WORD_END        "?="

/* Decodes headers based on RFC2045 and RFC2047. */

gchar *unmime_header(const gchar *encoded_str)

{

        const gchar *p = encoded_str;

        const gchar *eword_begin_p, *encoding_begin_p, *text_begin_p,

                    *eword_end_p;

        gchar charset[32];

        gchar encoding;

        gchar *conv_str;

        GString *outbuf;

        gchar *out_str;

        gsize out_len;

        outbuf = g_string_sized_new(strlen(encoded_str) * 2);

        while (*p != '\0') {

                gchar *decoded_text = NULL;

                gint len;

                eword_begin_p = strstr(p, ENCODED_WORD_BEGIN);

                if (!eword_begin_p) {

                        g_string_append(outbuf, p);

                        break;

                }

                encoding_begin_p = strchr(eword_begin_p + 2, '?');

                if (!encoding_begin_p) {

                        g_string_append(outbuf, p);

                        break;

                }

                text_begin_p = strchr(encoding_begin_p + 1, '?');

                if (!text_begin_p) {

                        g_string_append(outbuf, p);

                        break;

                }

                eword_end_p = strstr(text_begin_p + 1, ENCODED_WORD_END);

                if (!eword_end_p) {

                        g_string_append(outbuf, p);

                        break;

                }

                if (p == encoded_str) {

                        g_string_append_len(outbuf, p, eword_begin_p - p);

                        p = eword_begin_p;

                } else {

                        /* ignore spaces between encoded words */

                        const gchar *sp;

                        for (sp = p; sp < eword_begin_p; sp++) {

                                if (!g_ascii_isspace(*sp)) {

                                        g_string_append_len

                                                (outbuf, p, eword_begin_p - p);

                                        p = eword_begin_p;

                                        break;

                                }

                        }

                }

                len = MIN(sizeof(charset) - 1,

                          encoding_begin_p - (eword_begin_p + 2));

                memcpy(charset, eword_begin_p + 2, len);

                charset[len] = '\0';

                encoding = g_ascii_toupper(*(encoding_begin_p + 1));

                if (encoding == 'B') {

                        decoded_text = g_malloc

                                (eword_end_p - (text_begin_p + 1) + 1);

                        len = base64_decode((guchar *)decoded_text,

                                            text_begin_p + 1,

                                            eword_end_p - (text_begin_p + 1));

                        decoded_text[len] = '\0';

                } else if (encoding == 'Q') {

                        decoded_text = g_malloc

                                (eword_end_p - (text_begin_p + 1) + 1);

                        len = qp_decode_q_encoding

                                ((guchar *)decoded_text, text_begin_p + 1,

                                 eword_end_p - (text_begin_p + 1));

                } else {

                        g_string_append_len(outbuf, p, eword_end_p + 2 - p);

                        p = eword_end_p + 2;

                        continue;

                }

                /* convert to UTF-8 */

                conv_str = conv_codeset_strdup(decoded_text, charset, NULL);

                if (!conv_str)

                        conv_str = conv_utf8todisp(decoded_text, NULL);

                g_string_append(outbuf, conv_str);

                g_free(conv_str);

                g_free(decoded_text);

                p = eword_end_p + 2;

        }

        out_str = outbuf->str;

        out_len = outbuf->len;

        g_string_free(outbuf, FALSE);

        return g_realloc(out_str, out_len + 1);

}