1 files changed, 137 insertions, 0 deletions
diff --git a/common/sexp-parse.h b/common/sexp-parse.h
new file mode 100644
index 0000000..4f77f14
--- /dev/null
+++ b/common/sexp-parse.h
@@ -0,0 +1,137 @@
+/* sexp-parse.h - S-expression helper functions
+ * Copyright (C) 2002, 2003, 2007 Free Software Foundation, Inc.
+ *
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of either
+ *
+ *   - 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.
+ *
+ * or
+ *
+ *   - 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.
+ *
+ * or both in parallel, as here.
+ *
+ * This file 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, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef SEXP_PARSE_H
+#define SEXP_PARSE_H
+
+#include <gpg-error.h>
+
+
+/* Return the length of the next S-Exp part and update the pointer to
+   the first data byte.  0 is returned on error */
+static inline size_t
+snext (unsigned char const **buf)
+{
+  const unsigned char *s;
+  int n;
+
+  s = *buf;
+  for (n=0; *s && *s != ':' && (*s >= '0' && *s <= '9'); s++)
+    n = n*10 + (*s - '0');
+  if (!n || *s != ':')
+    return 0; /* we don't allow empty lengths */
+  *buf = s+1;
+  return n;
+}
+
+/* Skip over the S-Expression BUF points to and update BUF to point to
+   the character right behind.  DEPTH gives the initial number of open
+   lists and may be passed as a positive number to skip over the
+   remainder of an S-Expression if the current position is somewhere
+   in an S-Expression.  The function may return an error code if it
+   encounters an impossible condition.  */
+static inline gpg_error_t
+sskip (unsigned char const **buf, int *depth)
+{
+  const unsigned char *s = *buf;
+  size_t n;
+  int d = *depth;
+
+  while (d > 0)
+    {
+      if (*s == '(')
+        {
+          d++;
+          s++;
+        }
+      else if (*s == ')')
+        {
+          d--;
+          s++;
+        }
+      else
+        {
+          if (!d)
+            return gpg_error (GPG_ERR_INV_SEXP);
+          n = snext (&s);
+          if (!n)
+            return gpg_error (GPG_ERR_INV_SEXP);
+          s += n;
+        }
+    }
+  *buf = s;
+  *depth = d;
+  return 0;
+}
+
+
+/* Check whether the string at the address BUF points to matches
+   the token.  Return true on match and update BUF to point behind the
+   token.  Return false and do not update the buffer if it does not
+   match. */
+static inline int
+smatch (unsigned char const **buf, size_t buflen, const char *token)
+{
+  size_t toklen = strlen (token);
+
+  if (buflen != toklen || memcmp (*buf, token, toklen))
+    return 0;
+  *buf += toklen;
+  return 1;
+}
+
+/* Format VALUE for use as the length indicatior of an S-expression.
+   The caller needs to provide a buffer HELP_BUFFER wth a length of
+   HELP_BUFLEN.  The return value is a pointer into HELP_BUFFER with
+   the formatted length string.  The colon and a trailing nul are
+   appended.  HELP_BUFLEN must be at least 3 - a more useful value is
+   15.  If LENGTH is not NULL, the LENGTH of the resulting string
+   (excluding the terminating nul) is stored at that address. */
+static inline char *
+smklen (char *help_buffer, size_t help_buflen, size_t value, size_t *length)
+{
+  char *p = help_buffer + help_buflen;
+
+  if (help_buflen >= 3)
+    {
+      *--p = 0;
+      *--p = ':';
+      do
+        {
+          *--p = '0' + (value % 10);
+          value /= 10;
+        }
+      while (value && p > help_buffer);
+    }
+
+  if (length)
+    *length = (help_buffer + help_buflen) - p;
+  return p;
+}
+
+
+#endif /*SEXP_PARSE_H*/