1 files changed, 143 insertions, 0 deletions
diff --git a/libmailutils/filter/dq.c b/libmailutils/filter/dq.c
new file mode 100644
index 000000000..d3bb18523
--- /dev/null
+++ b/libmailutils/filter/dq.c
@@ -0,0 +1,143 @@
+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 2011-2012, 2014-2017 Free Software Foundation, Inc.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General
+   Public License along with this library.  If not, see 
+   <http://www.gnu.org/licenses/>. */
+
+/* Doble-quote escaping filter.
+   In encode mode, escapes each occurrence of double-quote and backslash
+   by prefixing it with backslash.
+   In decode mode, removes backslash prefixes.
+*/
+   
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+#include <stdlib.h>
+#include <string.h>
+#include <mailutils/errno.h>
+#include <mailutils/filter.h>
+#include <mailutils/wordsplit.h>
+#include <mailutils/cctype.h>
+
+/* Move min(isize,osize) bytes from iptr to optr, replacing each
+   escapable control character with its escape sequence. */
+static enum mu_filter_result
+_dq_encoder (void *xd MU_ARG_UNUSED,
+	     enum mu_filter_command cmd,
+	     struct mu_filter_io *iobuf)
+{
+  size_t i, j;
+  const unsigned char *iptr;
+  size_t isize;
+  char *optr;
+  size_t osize;
+  
+  switch (cmd)
+    {
+    case mu_filter_init:
+    case mu_filter_done:
+      return mu_filter_ok;
+    default:
+      break;
+    }
+  
+  iptr = (const unsigned char *) iobuf->input;
+  isize = iobuf->isize;
+  optr = iobuf->output;
+  osize = iobuf->osize;
+
+  for (i = j = 0; i < isize && j < osize; i++)
+    {
+      unsigned char c = *iptr++;
+
+      if (strchr ("\\\"", c))
+	{
+	  if (j + 1 == osize)
+	    {
+	      if (i == 0)
+		{
+		  iobuf->osize = 2;
+		  return mu_filter_moreoutput;
+		}
+	      break;
+	    }
+	  else
+	    {
+	      optr[j++] = '\\';
+	      optr[j++] = c;
+	    }
+	}
+      else
+	optr[j++] = c;
+    }
+  iobuf->isize = i;
+  iobuf->osize = j;
+  return mu_filter_ok;
+}
+
+/* Move min(isize,osize) bytes from iptr to optr, replacing each escape
+   sequence with its ASCII code. */
+static enum mu_filter_result
+_dq_decoder (void *xd MU_ARG_UNUSED,
+	     enum mu_filter_command cmd,
+	     struct mu_filter_io *iobuf)
+{
+  size_t i, j;
+  const unsigned char *iptr;
+  size_t isize;
+  char *optr;
+  size_t osize;
+  
+  switch (cmd)
+    {
+    case mu_filter_init:
+    case mu_filter_done:
+      return mu_filter_ok;
+    default:
+      break;
+    }
+  
+  iptr = (const unsigned char *) iobuf->input;
+  isize = iobuf->isize;
+  optr = iobuf->output;
+  osize = iobuf->osize;
+
+  for (i = j = 0; i < isize && j < osize; i++)
+    {
+      unsigned char c = *iptr++;
+      if (c == '\\')
+	{
+	  if (i + 1 == isize)
+	    break;
+	  optr[j++] = *iptr++;
+	}
+      else
+	optr[j++] = c;
+    }
+
+  iobuf->isize = i;
+  iobuf->osize = j;
+  return mu_filter_ok;
+}
+
+static struct _mu_filter_record _dq_filter = {
+  "dq",
+  NULL,
+  _dq_encoder,
+  _dq_decoder,
+};
+
+mu_filter_record_t mu_dq_filter = &_dq_filter;
+