Class FString: Add toFloat(), toDouble() and setNumber(...) for floating point values

doc/TODO

@@ -21,7 +21,6 @@ Missing Features
 ---------------------------------------
 
 - Multiple lines support for FLabel
-- long double to FString + FString to long double
 - Add a window switcher on the right side of the status bar
 - Add a scrolling area with on-demand scroll bars for FButtonGroup
 

src/fobject.h

@@ -27,6 +27,7 @@ typedef signed short sInt16;
 typedef signed int   sInt32;
 typedef int64_t      sInt64;
 
+typedef long double  lDouble;
 
 //----------------------------------------------------------------------
 // class FObject

src/fstring.cpp

@@ -1017,6 +1017,30 @@ uLong FString::toULong() const
   return num;
 }
 
+//----------------------------------------------------------------------
+double FString::toDouble() const
+{
+  wchar_t* p;
+  register double ret;
+
+  if ( ! this->string || ! *this->string )
+    throw std::invalid_argument ("null value");
+
+  ret = wcstod(this->string, &p);
+
+  if ( p != 0 && *p != '\0' )
+    throw std::invalid_argument ("no valid floating point value");
+
+  if ( errno == ERANGE )
+  {
+    if ( ret >= HUGE_VAL || ret <= -HUGE_VAL )
+      throw std::out_of_range ("overflow");
+    if ( ret == 0.0l )
+      throw std::out_of_range ("underflow");
+  }
+  return ret;
+}
+
 //----------------------------------------------------------------------
 FString FString::ltrim() const
 {
@@ -1212,6 +1236,34 @@ FString& FString::setNumber (uLong num)
   return *this;
 }
 
+//----------------------------------------------------------------------
+FString& FString::setNumber (lDouble num, int precision)
+{
+  register wchar_t *s;
+  wchar_t format[20];  // = "%.<precision>Lg"
+
+  s = &format[0];
+  *s++ = L'%';
+  *s++ = L'.';
+
+  if ( precision > 99 )
+    precision = 99;
+
+  if ( precision >= 10 )
+  {
+    *s++ = precision / 10 + L'0';
+    *s++ = precision % 10 + L'0';
+  }
+  else
+    *s++ = precision + L'0';
+
+  *s++ = L'L';
+  *s++ = L'g';
+  *s   = L'\0';
+
+  return sprintf(format, num);
+}
+
 //----------------------------------------------------------------------
 FString& FString::setFormatedNumber (long num, char separator)
 {

src/fstring.h

@@ -11,6 +11,7 @@
 #include <cassert>
 #include <cerrno>  // for read errno
 #include <climits>
+#include <cmath>
 #include <cstdarg> // need for va_list, va_start and va_end
 #include <cstdio>  // need for vsprintf
 #include <cstring>
@@ -44,6 +45,8 @@ typedef signed short sInt16;
 typedef signed int   sInt32;
 typedef int64_t      sInt64;
 
+typedef long double  lDouble;
+
 
 //----------------------------------------------------------------------
 // class FString
@@ -119,6 +122,8 @@ class FString
    uInt     toUInt()    const;
    long     toLong()    const;
    uLong    toULong()   const;
+   float    toFloat()   const;
+   double   toDouble()  const;
 
    FString  ltrim() const;
    FString  rtrim() const;
@@ -145,6 +150,9 @@ class FString
    FString& setNumber (uInt);
    FString& setNumber (long);
    FString& setNumber (uLong);
+   FString& setNumber (float, int precision=8);
+   FString& setNumber (double, int precision=11);
+   FString& setNumber (lDouble, int precision=11);
 
    FString& setFormatedNumber (sInt16, char separator='.');
    FString& setFormatedNumber (uInt16, char separator='.');
@@ -327,6 +335,10 @@ inline int FString::toInt() const
 inline uInt FString::toUInt() const
 { return uInt( toULong() ); }
 
+//----------------------------------------------------------------------
+inline float FString::toFloat() const
+{ return float( toDouble() ); }
+
 //----------------------------------------------------------------------
 inline std::vector<FString> FString::split (std::wstring& s)
 { return split(FString(s)); }
@@ -367,6 +379,14 @@ inline FString& FString::setNumber (int num)
 inline FString& FString::setNumber (uInt num)
 { return setNumber (uLong(num)); }
 
+//----------------------------------------------------------------------
+inline FString& FString::setNumber (float num, int precision)
+{ return setNumber (lDouble(num), precision); }
+
+//----------------------------------------------------------------------
+inline FString& FString::setNumber (double num, int precision)
+{ return setNumber (lDouble(num), precision); }
+
 //----------------------------------------------------------------------
 inline FString& FString::setFormatedNumber (sInt16 num, char separator)
 { return setFormatedNumber (long(num), separator); }

test/calculator.cpp

@@ -14,7 +14,7 @@
 #include "fdialog.h"
 #include "fmessagebox.h"
 
-const long double PI = 3.141592653589793238L;
+const lDouble PI = 3.141592653589793238L;
 
 //----------------------------------------------------------------------
 // class Button
@@ -129,7 +129,7 @@ class Calc : public FDialog
      NUM_OF_BUTTONS
    };
 
-   long double a, b;
+   lDouble a, b;
    uInt    max_char;
    int     last_key;
    char    infix_operator;
@@ -139,7 +139,7 @@ class Calc : public FDialog
 
    struct stack_data
    {
-     long double term;
+     lDouble term;
      char infix_operator;
    };
 
@@ -151,7 +151,7 @@ class Calc : public FDialog
    virtual void draw();
    bool isDataEntryKey(int);
    bool isOperatorKey(int);
-   void setDisplay (long double);
+   void setDisplay (lDouble);
    void setInfixOperator(char);
    void clearInfixOperator();
    void calcInfixOperator();
@@ -400,7 +400,7 @@ bool Calc::isOperatorKey(int key)
 }
 
 //----------------------------------------------------------------------
-void Calc::setDisplay (long double d)
+void Calc::setDisplay (lDouble d)
 {
   char buffer[32];
   snprintf (buffer, sizeof(buffer), "%31.11Lg", d);
@@ -535,7 +535,7 @@ void Calc::onClose (FCloseEvent* event)
 void Calc::cb_buttonClicked (FWidget*, void* data_ptr)
 {
   int key;
-  long double* x;
+  lDouble* x;
 
   using namespace std;
 
@@ -907,7 +907,7 @@ void Calc::cb_buttonClicked (FWidget*, void* data_ptr)
   if ( ! input.isEmpty() )
   {
     if ( isDataEntryKey(key) )
-      *x = atof(input.c_str());
+      *x = input.toDouble();
     else
     {
       // remove trailing zeros

test/fstring.cpp

@@ -1,5 +1,7 @@
 // fstring.cpp
 
+#include <iomanip>
+
 #include <langinfo.h>
 #include <term.h>
 #include <unistd.h>
@@ -116,21 +118,37 @@ int main (int, char**)
             << formatStr.sprintf("sqrt(%d) = %d", 16, 4)
             << std::endl;
 
-  FString ulong_str = "123456789";
-  uLong ulong_num = ulong_str.toULong();
+  uLong ulong_num = FString("123456789").toULong();
   std::cout << "   toULong:  " << ulong_num << std::endl;
 
-  FString long_str = "-9876543210";
-  long long_num = long_str.toLong();
+  long long_num = FString("-9876543210").toLong();
   std::cout << "    toLong: " << long_num << std::endl;
 
-  FString num1, num2;
+  setlocale(LC_NUMERIC, "C");
+  try
+  {
+    double double_num = FString("2.7182818284590452353").toDouble();
+    std::cout << "  toDouble:  " << std::setprecision(11)
+                                 << double_num << std::endl;
+  }
+  catch (const std::invalid_argument& ex)
+  {
+    std::cerr << "Invalid argument: " << ex.what() << std::endl;
+  }
+  catch (const std::out_of_range& ex)
+  {
+    std::cerr << "Out of range: " << ex.what() << std::endl;
+  }
+  FString num1, num2, num3;
   num1.setNumber(137);
   num2.setNumber(-512);
+  num3.setNumber(3.141592653589793238L, 12);
   std::cout << " setNumber:  "
             << num1 << " (unsigned)"    << std::endl;
   std::cout << " setNumber: "
             << num2 << " (signed)"      << std::endl;
+  std::cout << " setNumber:  "
+            << num3 << " (long double)" << std::endl;
 
   FString fnum1, fnum2;
   fnum1.setFormatedNumber(0xffffffffffffffff, '\'');