added an implemention of RFC2047 (support for character sets other than

1999-08-04  Robert Brady  <rwb197@ecs.soton.ac.uk>

	* camel/gmime-rfc2047.[ch]: added an implemention of RFC2047
	  (support for character sets other than US-ASCII in MIME
	  headers). Not actually called from anywhere yet.

svn path=/trunk/; revision=1075

2 files changed, 264 insertions, 0 deletions

diff --git a/camel/gmime-rfc2047.c b/camel/gmime-rfc2047.c
new file mode 100644
index 0000000000..2a90c1869e
--- /dev/null
+++ b/camel/gmime-rfc2047.c
@@ -0,0 +1,221 @@
+/* 
+ * gmime-rfc2047.c: implemention of RFC2047
+ *
+ * Copyright (C) 1999 Robert Brady <rwb197@ecs.soton.ac.uk>
+ *
+ * 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
+ *
+ */
+
+#include <stdio.h>
+#include <ctype.h>
+#include <unicode.h>
+#include <string.h>
+
+#include "gmime-rfc2047.h"
+
+#define NOT_RANKED -1
+
+/* base64 code from tin. This should be changed to use the base64 code Miguel comitted */
+
+const char base64_alphabet[64] =
+{
+	'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
+	'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
+	'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
+	'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/'};
+
+static unsigned char base64_rank[256];
+static int base64_rank_table_built;
+static void build_base64_rank_table (void);
+
+static int hexval(gchar c) {
+  if (isdigit(c)) return c-'0';
+  c = tolower(c);
+  return c - 'a' + 10;
+}
+
+static void decode_quoted(const gchar *text, gchar *to) {
+  while (*text) {
+    if (*text == '=') {
+      gchar a = hexval(text[1]);
+      gchar b = hexval(text[2]);
+      int c = (a << 4) + b;
+      *to = c;
+      to++;
+      text+=3;
+    } else if (*text == '_') {
+      *to = ' ';
+      to++;
+      text++;
+    } else {
+      *to = *text;
+      to++;
+      text++;
+    }
+  }
+  *to = 0;
+}
+
+static void decode_base64(const gchar *what,  gchar *where) {
+  unsigned short pattern = 0;
+  int bits = 0;
+  int delimiter = '=';
+  gchar x;
+  gchar *t = where;
+  int Q = 0;
+  while (*what != delimiter) {
+    x = base64_rank[(unsigned char)(*what++)];
+    if (x == NOT_RANKED)
+      continue;
+    pattern <<= 6;
+    pattern |= x;
+    bits += 6;
+    if (bits >= 8) {
+      x = (pattern >> (bits - 8)) & 0xff;
+      *t++ = x;
+      Q++;
+      bits -= 8;
+    }
+  }
+  *t = 0;
+}
+
+static void
+build_base64_rank_table (
+	void)
+{
+	int i;
+
+	if (!base64_rank_table_built) {
+		for (i = 0; i < 256; i++)
+			base64_rank[i] = NOT_RANKED;
+		for (i = 0; i < 64; i++)
+			base64_rank[(int) base64_alphabet[i]] = i;
+		base64_rank_table_built = 1;
+	}
+}
+
+gchar *gmime_rfc2047_decode(const gchar *data, const gchar *into_what) {
+  gchar buffer[4096] /* FIXME : constant sized buffer */, *b = buffer;
+
+  build_base64_rank_table();
+
+  while (*data) {
+
+    /* If we encounter an error we just break out of the loop and copy the rest
+     * of the text as-is */
+     
+    if (*data=='=') {
+      data++;
+      if (*data=='?') {
+	gchar *charset, *encoding, *text, *end;
+	gchar dc[4096];
+	charset = data+1;
+	encoding = strchr(charset, '?');
+
+	if (!encoding) break;
+	encoding++;
+        text = strchr(encoding, '?');
+	if (!text) break;
+	text++;
+	end = strstr(text, "?=");
+	if (!end) break;
+	end++;
+
+	*(encoding-1)=0;
+	*(text-1)=0;
+	*(end-1)=0;
+
+	if (strcasecmp(encoding, "q")==0) {
+	  decode_quoted(text, dc);
+	} else if (strcasecmp(encoding, "b")==0) {
+	  decode_base64(text, dc);
+	} else {
+	  /* What to do here? */
+	  break;
+	}
+
+	{
+	  int f;
+	  iconv_t i;
+	  const gchar *d2 = dc;
+	  int l = strlen(d2), l2 = 4000;
+
+	  i = unicode_iconv_open(into_what, charset);
+	  if (!i) 
+	     break;
+	   
+	  unicode_iconv(i, &d2, &l, &b, &l2);
+
+	  unicode_iconv_close(i);
+	  data = end;
+	}
+      }
+    }
+    else {
+      *b = *data;
+      b++;
+    }
+
+    data++;
+
+  }
+
+  while (*data) {
+    *b = *data;
+    b++;
+    data++;
+  }
+
+  *b = 0;
+
+  return g_strdup(buffer);
+}
+
+gchar *rfc2047_encode(const gchar *string, const gchar *charset) {
+  gchar buffer[4096] /* FIXME : constant sized buffer */;
+  gchar *b = buffer;
+  const gchar *s = string;
+  int not_ascii = 0, not_latin1 = 0;
+  while (*s) {
+    if (*s <= 20 || *s >= 0x7f || *s == '=') { not_ascii = 1; }
+    s++;
+  }
+  
+  if (!not_ascii) {
+    b += sprintf(b, "%s", string);
+  }
+  
+  else {
+    b += sprintf(b, "=?%s?Q?", charset);
+    s = string;
+    while (*s) {
+      if (*s == ' ') b += sprintf(b, "_");
+      else if (*s < 0x20 || *s >= 0x7f || *s == '=' || *s == '?' || *s == '_') {
+	b += sprintf(b, "=%2x", *s);
+      } else {
+	b += sprintf(b, "%c", *s);
+      }
+      s++;
+    }
+    b += sprintf(b, "?=");
+  }
+
+  *b = 0;
+
+  return g_strdup(buffer);
+}
diff --git a/camel/gmime-rfc2047.h b/camel/gmime-rfc2047.h
new file mode 100644
index 0000000000..bcc17896be
--- /dev/null
+++ b/camel/gmime-rfc2047.h
@@ -0,0 +1,43 @@
+#ifndef GMIME_RFC2047_H
+
+/* 
+ *
+ * Copyright (C) 1999 Robert Brady <rwb197@ecs.soton.ac.uk>
+ *
+ * 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
+ *
+ */
+
+#include <glib.h>
+
+gchar *gmime_rfc2047_decode(const gchar *text, const gchar* charset);
+gchar *gmime_rfc2047_encode(const gchar *text, const gchar* charset);
+
+/* 
+ * pass text and charset, (e.g. "UTF-8", or "ISO-8859-1"), and
+ * it will encode or decode text according to RFC2047
+ *
+ * You will need to link with libunicode for these.
+ *
+ * TODO : Make it so that if charset==NULL, the charset specified (either
+ *   implicitly or explicity) in the locale is used.
+ *
+ * TODO : Run torture tests and fix the buffer overruns in these functions.
+ *
+ * The caller will need to free the memory for the string.
+ */
+
+#endif