wxWidgets/include/wx/valnum.h

/////////////////////////////////////////////////////////////////////////////
// Name:        wx/valnum.h
// Purpose:     Numeric validator classes.
// Author:      Vadim Zeitlin based on the submission of Fulvio Senore
// Created:     2010-11-06
// Copyright:   (c) 2010 wxWidgets team
//              (c) 2011 Vadim Zeitlin <vadim@wxwidgets.org>
// Licence:     wxWindows licence
/////////////////////////////////////////////////////////////////////////////

#ifndef _WX_VALNUM_H_
#define _WX_VALNUM_H_

#include "wx/defs.h"

#if wxUSE_VALIDATORS

#include "wx/validate.h"

#include <limits>

// Bit masks used for numeric validator styles.
enum wxNumValidatorStyle
{
    wxNUM_VAL_DEFAULT               = 0x0,
    wxNUM_VAL_THOUSANDS_SEPARATOR   = 0x1,
    wxNUM_VAL_ZERO_AS_BLANK         = 0x2,
    wxNUM_VAL_NO_TRAILING_ZEROES    = 0x4
};

// ----------------------------------------------------------------------------
// Base class for all numeric validators.
// ----------------------------------------------------------------------------

class WXDLLIMPEXP_CORE wxNumValidatorBase : public wxValidator
{
public:
    // Change the validator style. Usually it's specified during construction.
    void SetStyle(int style) { m_style = style; }


    // Override base class method to not do anything but always return success:
    // we don't need this as we do our validation on the fly here.
    virtual bool Validate(wxWindow * WXUNUSED(parent)) { return true; }

protected:
    wxNumValidatorBase(int style)
    {
        m_style = style;
    }

    wxNumValidatorBase(const wxNumValidatorBase& other)
    {
        m_style = other.m_style;
    }

    bool HasFlag(wxNumValidatorStyle style) const
    {
        return (m_style & style) != 0;
    }

    // Get the text entry of the associated control. Normally shouldn't ever
    // return NULL (and will assert if it does return it) but the caller should
    // still test the return value for safety.
    wxTextEntry *GetTextEntry() const;

    // Convert wxNUM_VAL_THOUSANDS_SEPARATOR and wxNUM_VAL_NO_TRAILING_ZEROES
    // bits of our style to the corresponding wxNumberFormatter::Style values.
    int GetFormatFlags() const;

    // Return true if pressing a '-' key is acceptable for the current control
    // contents and insertion point. This is meant to be called from the
    // derived class IsCharOk() implementation.
    bool IsMinusOk(const wxString& val, int pos) const;

    // Return the string which would result from inserting the given character
    // at the specified position.
    wxString GetValueAfterInsertingChar(wxString val, int pos, wxChar ch) const
    {
        val.insert(pos, ch);
        return val;
    }

private:
    // Check whether the specified character can be inserted in the control at
    // the given position in the string representing the current controls
    // contents.
    //
    // Notice that the base class checks for '-' itself so it's never passed to
    // this function.
    virtual bool IsCharOk(const wxString& val, int pos, wxChar ch) const = 0;

    // NormalizeString the contents of the string if it's a valid number, return
    // empty string otherwise.
    virtual wxString NormalizeString(const wxString& s) const = 0;


    // Event handlers.
    void OnChar(wxKeyEvent& event);
    void OnKillFocus(wxFocusEvent& event);


    // Determine the current insertion point and text in the associated control.
    void GetCurrentValueAndInsertionPoint(wxString& val, int& pos) const;


    // Combination of wxVAL_NUM_XXX values.
    int m_style;


    wxDECLARE_EVENT_TABLE();

    wxDECLARE_NO_ASSIGN_CLASS(wxNumValidatorBase);
};

namespace wxPrivate
{

// This is a helper class used by wxIntegerValidator and wxFloatingPointValidator
// below that implements Transfer{To,From}Window() adapted to the type of the
// variable.
//
// The template argument B is the name of the base class which must derive from
// wxNumValidatorBase and define LongestValueType type and {To,As}String()
// methods i.e. basically be one of wx{Integer,Number}ValidatorBase classes.
//
// The template argument T is just the type handled by the validator that will
// inherit from this one.
template <class B, typename T>
class wxNumValidator : public B
{
public:
    typedef B BaseValidator;
    typedef T ValueType;

    typedef typename BaseValidator::LongestValueType LongestValueType;

    // FIXME-VC6: This compiler fails to compile the assert below with a
    // nonsensical error C2248: "'LongestValueType' : cannot access protected
    // typedef declared in class 'wxIntegerValidatorBase'" so just disable the
    // check for it.
#ifndef __VISUALC6__
    wxCOMPILE_TIME_ASSERT
    (
        sizeof(ValueType) <= sizeof(LongestValueType),
        UnsupportedType
    );
#endif // __VISUALC6__

    void SetMin(ValueType min)
    {
        this->DoSetMin(min);
    }

    void SetMax(ValueType max)
    {
        this->DoSetMax(max);
    }

    void SetRange(ValueType min, ValueType max)
    {
        SetMin(min);
        SetMax(max);
    }

    virtual bool TransferToWindow()
    {
        if ( m_value )
        {
            wxTextEntry * const control = BaseValidator::GetTextEntry();
            if ( !control )
                return false;

            control->SetValue(NormalizeValue(*m_value));
        }

        return true;
    }

    virtual bool TransferFromWindow()
    {
        if ( m_value )
        {
            wxTextEntry * const control = BaseValidator::GetTextEntry();
            if ( !control )
                return false;

            const wxString s(control->GetValue());
            LongestValueType value;
            if ( s.empty() && BaseValidator::HasFlag(wxNUM_VAL_ZERO_AS_BLANK) )
                value = 0;
            else if ( !BaseValidator::FromString(s, &value) )
                return false;

            if ( !this->IsInRange(value) )
                return false;

            *m_value = static_cast<ValueType>(value);
        }

        return true;
    }

protected:
    wxNumValidator(ValueType *value, int style)
        : BaseValidator(style),
          m_value(value)
    {
    }

    // Implement wxNumValidatorBase virtual method which is the same for
    // both integer and floating point numbers.
    virtual wxString NormalizeString(const wxString& s) const
    {
        LongestValueType value;
        return BaseValidator::FromString(s, &value) ? NormalizeValue(value)
                                                    : wxString();
    }

private:
    // Just a helper which is a common part of TransferToWindow() and
    // NormalizeString(): returns string representation of a number honouring
    // wxNUM_VAL_ZERO_AS_BLANK flag.
    wxString NormalizeValue(LongestValueType value) const
    {
        wxString s;
        if ( value != 0 || !BaseValidator::HasFlag(wxNUM_VAL_ZERO_AS_BLANK) )
            s = this->ToString(value);

        return s;
    }


    ValueType * const m_value;

    wxDECLARE_NO_ASSIGN_CLASS(wxNumValidator);
};

} // namespace wxPrivate

// ----------------------------------------------------------------------------
// Validators for integer numbers.
// ----------------------------------------------------------------------------

// Base class for integer numbers validator. This class contains all non
// type-dependent code of wxIntegerValidator<> and always works with values of
// type LongestValueType. It is not meant to be used directly, please use
// wxIntegerValidator<> only instead.
class WXDLLIMPEXP_CORE wxIntegerValidatorBase : public wxNumValidatorBase
{
protected:
    // Define the type we use here, it should be the maximal-sized integer type
    // we support to make it possible to base wxIntegerValidator<> for any type
    // on it.
#ifdef wxLongLong_t
    typedef wxLongLong_t LongestValueType;
#else
    typedef long LongestValueType;
#endif

    wxIntegerValidatorBase(int style)
        : wxNumValidatorBase(style)
    {
        wxASSERT_MSG( !(style & wxNUM_VAL_NO_TRAILING_ZEROES),
                      "This style doesn't make sense for integers." );
    }

    wxIntegerValidatorBase(const wxIntegerValidatorBase& other)
        : wxNumValidatorBase(other)
    {
        m_min = other.m_min;
        m_max = other.m_max;
    }

    // Provide methods for wxNumValidator use.
    wxString ToString(LongestValueType value) const;
    static bool FromString(const wxString& s, LongestValueType *value);

    void DoSetMin(LongestValueType min) { m_min = min; }
    void DoSetMax(LongestValueType max) { m_max = max; }

    bool IsInRange(LongestValueType value) const
    {
        return m_min <= value && value <= m_max;
    }

    // Implement wxNumValidatorBase pure virtual method.
    virtual bool IsCharOk(const wxString& val, int pos, wxChar ch) const;

private:
    // Minimal and maximal values accepted (inclusive).
    LongestValueType m_min, m_max;

    wxDECLARE_NO_ASSIGN_CLASS(wxIntegerValidatorBase);
};

// Validator for integer numbers. It can actually work with any integer type
// (short, int or long and long long if supported) and their unsigned versions
// as well.
template <typename T>
class wxIntegerValidator
    : public wxPrivate::wxNumValidator<wxIntegerValidatorBase, T>
{
public:
    typedef T ValueType;

    typedef
        wxPrivate::wxNumValidator<wxIntegerValidatorBase, T> Base;

    // Ctor for an integer validator.
    //
    // Sets the range appropriately for the type, including setting 0 as the
    // minimal value for the unsigned types.
    wxIntegerValidator(ValueType *value = NULL, int style = wxNUM_VAL_DEFAULT)
        : Base(value, style)
    {
        this->DoSetMin(std::numeric_limits<ValueType>::min());
        this->DoSetMax(std::numeric_limits<ValueType>::max());
    }

    virtual wxObject *Clone() const { return new wxIntegerValidator(*this); }

private:
    wxDECLARE_NO_ASSIGN_CLASS(wxIntegerValidator);
};

// Helper function for creating integer validators which allows to avoid
// explicitly specifying the type as it deduces it from its parameter.
template <typename T>
inline wxIntegerValidator<T>
wxMakeIntegerValidator(T *value, int style = wxNUM_VAL_DEFAULT)
{
    return wxIntegerValidator<T>(value, style);
}

// ----------------------------------------------------------------------------
// Validators for floating point numbers.
// ----------------------------------------------------------------------------

// Similar to wxIntegerValidatorBase, this class is not meant to be used
// directly, only wxFloatingPointValidator<> should be used in the user code.
class WXDLLIMPEXP_CORE wxFloatingPointValidatorBase : public wxNumValidatorBase
{
public:
    // Set precision i.e. the number of digits shown (and accepted on input)
    // after the decimal point. By default this is set to the maximal precision
    // supported by the type handled by the validator.
    void SetPrecision(unsigned precision) { m_precision = precision; }

protected:
    // Notice that we can't use "long double" here because it's not supported
    // by wxNumberFormatter yet, so restrict ourselves to just double (and
    // float).
    typedef double LongestValueType;

    wxFloatingPointValidatorBase(int style)
        : wxNumValidatorBase(style)
    {
    }

    wxFloatingPointValidatorBase(const wxFloatingPointValidatorBase& other)
        : wxNumValidatorBase(other)
    {
        m_precision = other.m_precision;

        m_min = other.m_min;
        m_max = other.m_max;
    }

    // Provide methods for wxNumValidator use.
    wxString ToString(LongestValueType value) const;
    static bool FromString(const wxString& s, LongestValueType *value);

    void DoSetMin(LongestValueType min) { m_min = min; }
    void DoSetMax(LongestValueType max) { m_max = max; }

    bool IsInRange(LongestValueType value) const
    {
        return m_min <= value && value <= m_max;
    }

    // Implement wxNumValidatorBase pure virtual method.
    virtual bool IsCharOk(const wxString& val, int pos, wxChar ch) const;

private:
    // Maximum number of decimals digits after the decimal separator.
    unsigned m_precision;

    // Minimal and maximal values accepted (inclusive).
    LongestValueType m_min, m_max;

    wxDECLARE_NO_ASSIGN_CLASS(wxFloatingPointValidatorBase);
};

// Validator for floating point numbers. It can be used with float, double or
// long double values.
template <typename T>
class wxFloatingPointValidator
    : public wxPrivate::wxNumValidator<wxFloatingPointValidatorBase, T>
{
public:
    typedef T ValueType;
    typedef wxPrivate::wxNumValidator<wxFloatingPointValidatorBase, T> Base;

    // Ctor using implicit (maximal) precision for this type.
    wxFloatingPointValidator(ValueType *value = NULL,
                             int style = wxNUM_VAL_DEFAULT)
        : Base(value, style)
    {
        DoSetMinMax();

        this->SetPrecision(std::numeric_limits<ValueType>::digits10);
    }

    // Ctor specifying an explicit precision.
    wxFloatingPointValidator(int precision,
                      ValueType *value = NULL,
                      int style = wxNUM_VAL_DEFAULT)
        : Base(value, style)
    {
        DoSetMinMax();

        this->SetPrecision(precision);
    }

    virtual wxObject *Clone() const
    {
        return new wxFloatingPointValidator(*this);
    }

private:
    void DoSetMinMax()
    {
        // NB: Do not use min(), it's not the smallest representable value for
        //     the floating point types but rather the smallest representable
        //     positive value.
        this->DoSetMin(-std::numeric_limits<ValueType>::max());
        this->DoSetMax( std::numeric_limits<ValueType>::max());
    }
};

// Helper similar to wxMakeIntValidator().
//
// NB: Unfortunately we can't just have a wxMakeNumericValidator() which would
//     return either wxIntegerValidator<> or wxFloatingPointValidator<> so we
//     do need two different functions.
template <typename T>
inline wxFloatingPointValidator<T>
wxMakeFloatingPointValidator(T *value, int style = wxNUM_VAL_DEFAULT)
{
    return wxFloatingPointValidator<T>(value, style);
}

template <typename T>
inline wxFloatingPointValidator<T>
wxMakeFloatingPointValidator(int precision, T *value, int style = wxNUM_VAL_DEFAULT)
{
    return wxFloatingPointValidator<T>(precision, value, style);
}

#endif // wxUSE_VALIDATORS

#endif // _WX_VALNUM_H_