Initial revision

1 files changed, 96 insertions, 0 deletions

diff --git a/libc/stdlib/strtod.c b/libc/stdlib/strtod.c
new file mode 100644
index 000000000..0d3bb790a
--- /dev/null
+++ b/libc/stdlib/strtod.c
@@ -0,0 +1,96 @@
+/*
+ * strtod.c - This file is part of the libc-8086 package for ELKS,
+ * Copyright (C) 1995, 1996 Nat Friedman <ndf@linux.mit.edu>.
+ * 
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Library General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2 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
+ *  Library General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Library General Public
+ *  License along with this library; if not, write to the Free
+ *  Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+#include <stdlib.h>
+#include <ctype.h>
+
+float
+strtod(const char *nptr, char ** endptr)
+{
+  unsigned short negative;
+  float number;
+  float fp_part;
+  int exponent;
+  unsigned short exp_negative;
+
+  /* advance beyond any leading whitespace */
+  while (isspace(*nptr))
+    nptr++;
+
+  /* check for optional '+' or '-' */
+  negative=0;
+  if (*nptr=='-')
+    {
+      negative=1;
+      nptr++;
+    }
+  else
+    if (*nptr=='+')
+      nptr++;
+
+  number=0;
+  while (isdigit(*nptr))
+    {
+      number=number*10+(*nptr-'0');
+      nptr++;
+    }
+
+  if (*nptr=='.')
+    {
+      nptr++;
+      fp_part=0;
+      while (isdigit(*nptr))
+	{
+	  fp_part=fp_part/10.0 + (*nptr-'0')/10.0;
+	  nptr++;
+	}
+      number+=fp_part;
+    }
+
+  if (*nptr=='e' || *nptr=='E')
+    {
+      nptr++;
+      exp_negative=0;
+      if (*nptr=='-')
+	{
+	  exp_negative=1;
+	  nptr++;
+	}
+      else
+	if (*nptr=='+')
+	  nptr++;
+
+      exponent=0;
+      while (isdigit(*nptr))
+	{
+	  exponent=exponent*10+(*nptr-'0');
+	  exponent++;
+	}
+    }
+
+  while (exponent)
+    {
+      if (exp_negative)
+	number/=10;
+      else
+	number*=10;
+      exponent--;
+    }
+  return (negative ? -number:number);
+}