Add strtod

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@2541 42af7a65-404d-4744-a932-0658087f49c3

1 files changed, 228 insertions, 0 deletions

diff --git a/nuttx/lib/lib_strtod.c b/nuttx/lib/lib_strtod.c
new file mode 100755
index 000000000..777eb6ded
--- /dev/null
+++ b/nuttx/lib/lib_strtod.c
@@ -0,0 +1,228 @@
+/****************************************************************************
+ * lib/lib_strtod.c
+ *
+ * Convert string to double
+ *
+ * Copyright (C) 2002 Michael Ringgaard. All rights reserved.
+ * Copyright (C) 2006-2007 H. Peter Anvin.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the project nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <stdlib.h>
+#include <ctype.h>
+#include <errno.h>
+
+/****************************************************************************
+ * Pre-processor definitions
+ ****************************************************************************/
+
+/* These are predefined with GCC, but could be issues for other compilers. If
+ * not defined, an arbitrary big number is put in for now.  These should be
+ * added to nuttx/compiler for your compiler.
+ */
+
+#if !defined(__DBL_MIN_EXP__) || !defined(__DBL_MAX_EXP__)
+#  ifdef CONFIG_CPP_HAVE_WARNING
+#    warning "Size of exponent is unknown"
+#  endif
+#  undef  __DBL_MIN_EXP__
+#  define __DBL_MIN_EXP__ (-1021)
+#  undef  __DBL_MAX_EXP__
+#  define __DBL_MAX_EXP__ (1024)
+#endif
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+static inline int is_real(double x)
+{
+  const double_t infinite = 1.0/0.0;
+  return (x < infinite) && (x >= -infinite);
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/***************************************************(************************
+ * Name: strtod
+ *
+ * Description:
+ *   Convert a string to a double value
+ *
+ ****************************************************************************/
+
+double_t strtod(const char *str, char **endptr)
+{
+  double_t number;
+  int exponent;
+  int negative;
+  char *p = (char *) str;
+  double p10;
+  int n;
+  int num_digits;
+  int num_decimals;
+  const double_t infinite = 1.0/0.0;
+
+  /* Skip leading whitespace */
+
+  while (isspace(*p))
+    {
+      p++;
+    }
+
+  /* Handle optional sign */
+
+  negative = 0;
+  switch (*p)
+    {
+    case '-':
+      negative = 1; /* Fall through to increment position */
+    case '+':
+      p++;
+    }
+
+  number       = 0.;
+  exponent     = 0;
+  num_digits   = 0;
+  num_decimals = 0;
+
+  /* Process string of digits */
+
+  while (isdigit(*p))
+    {
+      number = number * 10. + (*p - '0');
+      p++;
+      num_digits++;
+    }
+
+  /* Process decimal part */
+
+  if (*p == '.')
+    {
+      p++;
+
+      while (isdigit(*p))
+      {
+        number = number * 10. + (*p - '0');
+        p++;
+        num_digits++;
+        num_decimals++;
+      }
+
+      exponent -= num_decimals;
+    }
+
+  if (num_digits == 0)
+    {
+      errno = ERANGE;
+      return 0.0;
+    }
+
+  /* Correct for sign */
+
+  if (negative)
+    {
+      number = -number;
+    }
+
+  /* Process an exponent string */
+
+  if (*p == 'e' || *p == 'E')
+    {
+      /* Handle optional sign */
+
+      negative = 0;
+      switch(*++p)
+        {
+        case '-':
+          negative = 1;   /* Fall through to increment pos */
+        case '+':
+          p++;
+        }
+
+      /* Process string of digits */
+
+      n = 0;
+      while (isdigit(*p))
+        {
+          n = n * 10 + (*p - '0');
+          p++;
+        }
+
+      if (negative)
+        {
+          exponent -= n;
+        }
+      else
+        {
+          exponent += n;
+        }
+    }
+
+  if (exponent < __DBL_MIN_EXP__ ||
+      exponent > __DBL_MAX_EXP__)
+    {
+      errno = ERANGE;
+      return infinite;
+    }
+
+  /* Scale the result */
+
+  p10 = 10.;
+  n = exponent;
+  if (n < 0) n = -n;
+  while (n)
+    {
+      if (n & 1)
+        {
+          if (exponent < 0)
+            {
+              number /= p10;
+            }
+          else
+            {
+              number *= p10;
+            }
+        }
+      n >>= 1;
+      p10 *= p10;
+    }
+
+  if (!is_real(number)) errno = ERANGE;
+  if (endptr) *endptr = p;
+
+  return number;
+}
+