1 files changed, 71 insertions, 0 deletions
diff --git a/lib/xstrtod.c b/lib/xstrtod.c
new file mode 100644
index 0000000..6f861fb
--- /dev/null
+++ b/lib/xstrtod.c
@@ -0,0 +1,71 @@
+/* error-checking interface to strtod-like functions
+
+   Copyright (C) 1996, 1999-2000, 2003-2006, 2009-2022 Free Software
+   Foundation, Inc.
+
+   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 3 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, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Jim Meyering.  */
+
+#include <config.h>
+
+#include "xstrtod.h"
+
+#include <errno.h>
+#include <limits.h>
+#include <stdio.h>
+
+#if LONG
+# define XSTRTOD xstrtold
+# define DOUBLE long double
+#else
+# define XSTRTOD xstrtod
+# define DOUBLE double
+#endif
+
+/* An interface to a string-to-floating-point conversion function that
+   encapsulates all the error checking one should usually perform.
+   Like strtod/strtold, but stores the conversion in *RESULT,
+   and returns true upon successful conversion.
+   CONVERT specifies the conversion function, e.g., strtod itself.  */
+
+bool
+XSTRTOD (char const *str, char const **ptr, DOUBLE *result,
+         DOUBLE (*convert) (char const *, char **))
+{
+  DOUBLE val;
+  char *terminator;
+  bool ok = true;
+
+  errno = 0;
+  val = convert (str, &terminator);
+
+  /* Having a non-zero terminator is an error only when PTR is NULL. */
+  if (terminator == str || (ptr == NULL && *terminator != '\0'))
+    ok = false;
+  else
+    {
+      /* Allow underflow (in which case CONVERT returns zero),
+         but flag overflow as an error.  The user can decide
+         to use the limits in RESULT upon ERANGE.  */
+      if (val != 0 && errno == ERANGE)
+        ok = false;
+    }
+
+  if (ptr != NULL)
+    *ptr = terminator;
+
+  *result = val;
+  return ok;
+}