1 files changed, 45 insertions, 0 deletions
diff --git a/src/qmail-smtpc/qmailr_utils.c b/src/qmail-smtpc/qmailr_utils.c
index 177a356..deeff46 100644
--- a/src/qmail-smtpc/qmailr_utils.c
+++ b/src/qmail-smtpc/qmailr_utils.c
@@ -2,6 +2,9 @@
 
 #include <string.h>
 
+#include <skalibs/bitarray.h>
+#include <skalibs/stralloc.h>
+
 #include "qmailr.h"
 
 int qmailr_memcmp4 (void const *a, void const *b)
@@ -13,3 +16,45 @@ int qmailr_memcmp16 (void const *a, void const *b)
 {
   return memcmp(a, b, 16) ;
 }
+
+static inline int needsquoting (char const *s, size_t len)
+{
+  static unsigned char const badchar[32] =
+  {
+    0xff, 0xff, 0xff, 0xff,
+    0x05, 0x13, 0x00, 0x5c,
+    0x01, 0x00, 0x00, 0x38,
+    0x00, 0x00, 0x00, 0x80,
+    0xff, 0xff, 0xff, 0xff,
+    0xff, 0xff, 0xff, 0xff,
+    0xff, 0xff, 0xff, 0xff,
+    0xff, 0xff, 0xff, 0xff,
+  } ;
+  if (!len) return 1 ;
+  if (s[0] == '.' || s[len - 1] == '.') return 1 ;
+  for (size_t i = 0 ; i < len ; i++)
+  {
+    if (bitarray_peek(badchar, (unsigned char)s[i])) return 1 ;
+    if (i + 2 < len && s[i] == '.' && s[i+1] == '.') return 1 ;
+  }
+  return 0 ;
+}
+
+int qmailr_box_encode (char const *s, size_t len, stralloc *storage)
+{
+  if (needsquoting(s, len))
+  {
+    size_t j = storage->len ;
+    if (!stralloc_readyplus(storage, 2 + (len << 1))) return 0 ;
+    storage->s[j++] = '"' ;
+    for (size_t i = 0 ; i < len ; i++)
+    {
+      if (strchr("\"\\\r\n", s[i])) storage->s[j++] = '\\' ;
+      storage->s[j++] = s[i] ;
+    }
+    storage->s[j++] = '"' ;
+    storage->len = j ;
+  }
+  else if (!stralloc_catb(storage, s, len)) return 0 ;
+  return 1 ;
+}