// * This makes emacs happy -*-Mode: C++;-*-
/****************************************************************************
* Copyright (c) 1998-2012,2014 Free Software Foundation, Inc. *
* *
* Permission is hereby granted, free of charge, to any person obtaining a *
* copy of this software and associated documentation files (the *
* "Software"), to deal in the Software without restriction, including *
* without limitation the rights to use, copy, modify, merge, publish, *
* distribute, distribute with modifications, sublicense, and/or sell *
* copies of the Software, and to permit persons to whom the Software is *
* furnished to do so, subject to the following conditions: *
* *
* The above copyright notice and this permission notice shall be included *
* in all copies or substantial portions of the Software. *
* *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS *
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF *
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. *
* IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, *
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR *
* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR *
* THE USE OR OTHER DEALINGS IN THE SOFTWARE. *
* *
* Except as contained in this notice, the name(s) of the above copyright *
* holders shall not be used in advertising or otherwise to promote the *
* sale, use or other dealings in this Software without prior written *
* authorization. *
****************************************************************************/

/****************************************************************************
* Author: Juergen Pfeifer, 1997 *
****************************************************************************/

// $Id: cursesf.h,v 1.32 2014/08/09 22:06:11 Adam.Jiang Exp $

#ifndef NCURSES_CURSESF_H_incl
#define NCURSES_CURSESF_H_incl 1

#include <cursesp.h>

#ifndef __EXT_QNX
#include <string.h>
#endif

extern "C" {
# include <form.h>
}
//
// -------------------------------------------------------------------------
// The abstract base class for buitin and user defined Fieldtypes.
// -------------------------------------------------------------------------
//
class NCURSES_IMPEXP NCursesFormField; // forward declaration

// Class to represent builtin field types as well as C++ written new
// fieldtypes (see classes UserDefineFieldType...
class NCURSES_IMPEXP NCursesFieldType
{
friend class NCursesFormField;

protected:
FIELDTYPE* fieldtype;

inline void OnError(int err) const THROW2(NCursesException const, NCursesFormException) {
if (err!=E_OK)
THROW(new NCursesFormException (err));
}

NCursesFieldType(FIELDTYPE *f) : fieldtype(f) {
}

virtual ~NCursesFieldType() {}

// Set the fields f fieldtype to this one.
virtual void set(NCursesFormField& f) = 0;

public:
NCursesFieldType()
: fieldtype(STATIC_CAST(FIELDTYPE*)(0))
{
}

NCursesFieldType& operator=(const NCursesFieldType& rhs)
{
if (this != &rhs) {
*this = rhs;
}
return *this;
}

NCursesFieldType(const NCursesFieldType& rhs)
: fieldtype(rhs.fieldtype)
{
}

};

//
// -------------------------------------------------------------------------
// The class representing a forms field, wrapping the lowlevel FIELD struct
// -------------------------------------------------------------------------
//
class NCURSES_IMPEXP NCursesFormField
{
friend class NCursesForm;

protected:
FIELD *field; // lowlevel structure
NCursesFieldType* ftype; // Associated field type

// Error handler
inline void OnError (int err) const THROW2(NCursesException const, NCursesFormException) {
if (err != E_OK)
THROW(new NCursesFormException (err));
}

public:
// Create a 'Null' field. Can be used to delimit a field list
NCursesFormField()
: field(STATIC_CAST(FIELD*)(0)),
ftype(STATIC_CAST(NCursesFieldType*)(0))
{
}

// Create a new field
NCursesFormField (int rows,
int ncols,
int first_row = 0,
int first_col = 0,
int offscreen_rows = 0,
int additional_buffers = 0)
: field(0),
ftype(STATIC_CAST(NCursesFieldType*)(0))
{
field = ::new_field(rows, ncols, first_row, first_col,
offscreen_rows, additional_buffers);
if (!field)
OnError(errno);
}

NCursesFormField& operator=(const NCursesFormField& rhs)
{
if (this != &rhs) {
*this = rhs;
}
return *this;
}

NCursesFormField(const NCursesFormField& rhs)
: field(rhs.field), ftype(rhs.ftype)
{
}

virtual ~NCursesFormField ();

// Duplicate the field at a new position
inline NCursesFormField* dup(int first_row, int first_col)
{
NCursesFormField* f = new NCursesFormField();
if (!f)
OnError(E_SYSTEM_ERROR);
else {
f->ftype = ftype;
f->field = ::dup_field(field,first_row,first_col);
if (!f->field)
OnError(errno);
}
return f;
}

// Link the field to a new location
inline NCursesFormField* link(int first_row, int first_col) {
NCursesFormField* f = new NCursesFormField();
if (!f)
OnError(E_SYSTEM_ERROR);
else {
f->ftype = ftype;
f->field = ::link_field(field,first_row,first_col);
if (!f->field)
OnError(errno);
}
return f;
}

// Get the lowlevel field representation
inline FIELD* get_field() const {
return field;
}

// Retrieve info about the field
inline void info(int& rows, int& ncols,
int& first_row, int& first_col,
int& offscreen_rows, int& additional_buffers) const {
OnError(::field_info(field, &rows, &ncols,
&first_row, &first_col,
&offscreen_rows, &additional_buffers));
}

// Retrieve info about the fields dynamic properties.
inline void dynamic_info(int& dynamic_rows, int& dynamic_cols,
int& max_growth) const {
OnError(::dynamic_field_info(field, &dynamic_rows, &dynamic_cols,
&max_growth));
}

// For a dynamic field you may set the maximum growth limit.
// A zero means unlimited growth.
inline void set_maximum_growth(int growth = 0) {
OnError(::set_max_field(field,growth));
}

// Move the field to a new position
inline void move(int row, int col) {
OnError(::move_field(field,row,col));
}

// Mark the field to start a new page
inline void new_page(bool pageFlag = FALSE) {
OnError(::set_new_page(field,pageFlag));
}

// Retrieve whether or not the field starts a new page.
inline bool is_new_page() const {
return ::new_page(field);
}

// Set the justification for the field
inline void set_justification(int just) {
OnError(::set_field_just(field,just));
}

// Retrieve the fields justification
inline int justification() const {
return ::field_just(field);
}
// Set the foreground attribute for the field
inline void set_foreground(chtype foreground) {
OnError(::set_field_fore(field,foreground));
}

// Retrieve the fields foreground attribute
inline chtype fore() const {
return ::field_fore(field);
}

// Set the background attribute for the field
inline void set_background(chtype background) {
OnError(::set_field_back(field,background));
}

// Retrieve the fields background attribute
inline chtype back() const {
return ::field_back(field);
}

// Set the padding character for the field
inline void set_pad_character(int padding) {
OnError(::set_field_pad(field, padding));
}

// Retrieve the fields padding character
inline int pad() const {
return ::field_pad(field);
}

// Switch on the fields options
inline void options_on (Field_Options opts) {
OnError (::field_opts_on (field, opts));
}

// Switch off the fields options
inline void options_off (Field_Options opts) {
OnError (::field_opts_off (field, opts));
}

// Retrieve the fields options
inline Field_Options options () const {
return ::field_opts (field);
}

// Set the fields options
inline void set_options (Field_Options opts) {
OnError (::set_field_opts (field, opts));
}

// Mark the field as changed
inline void set_changed(bool changeFlag = TRUE) {
OnError(::set_field_status(field,changeFlag));
}

// Test whether or not the field is marked as changed
inline bool changed() const {
return ::field_status(field);
}

// Return the index of the field in the field array of a form
// or -1 if the field is not associated to a form
inline int (index)() const {
return ::field_index(field);
}

// Store a value in a fields buffer. The default buffer is nr. 0
inline void set_value(const char *val, int buffer = 0) {
OnError(::set_field_buffer(field,buffer,val));
}

// Retrieve the value of a fields buffer. The default buffer is nr. 0
inline char* value(int buffer = 0) const {
return ::field_buffer(field,buffer);
}

// Set the validation type of the field.
inline void set_fieldtype(NCursesFieldType& f) {
ftype = &f;
f.set(*this); // A good friend may do that...
}

// Retrieve the validation type of the field.
inline NCursesFieldType* fieldtype() const {
return ftype;
}

};

// This are the built-in hook functions in this C++ binding. In C++ we use
// virtual member functions (see below On_..._Init and On_..._Termination)
// to provide this functionality in an object oriented manner.
extern "C" {
void _nc_xx_frm_init(FORM *);
void _nc_xx_frm_term(FORM *);
void _nc_xx_fld_init(FORM *);
void _nc_xx_fld_term(FORM *);
}

//
// -------------------------------------------------------------------------
// The class representing a form, wrapping the lowlevel FORM struct
// -------------------------------------------------------------------------
//
class NCURSES_IMPEXP NCursesForm : public NCursesPanel
{
protected:
FORM* form; // the lowlevel structure

private:
NCursesWindow* sub; // the subwindow object
bool b_sub_owner; // is this our own subwindow?
bool b_framed; // has the form a border?
bool b_autoDelete; // Delete fields when deleting form?

NCursesFormField** my_fields; // The array of fields for this form

// This structure is used for the form's user data field to link the
// FORM* to the C++ object and to provide extra space for a user pointer.
typedef struct {
void* m_user; // the pointer for the user's data
const NCursesForm* m_back; // backward pointer to C++ object
const FORM* m_owner;
} UserHook;

// Get the backward pointer to the C++ object from a FORM
static inline NCursesForm* getHook(const FORM *f) {
UserHook* hook = reinterpret_cast<UserHook*>(::form_userptr(f));
assert(hook != 0 && hook->m_owner==f);
return const_cast<NCursesForm*>(hook->m_back);
}

friend void _nc_xx_frm_init(FORM *);
friend void _nc_xx_frm_term(FORM *);
friend void _nc_xx_fld_init(FORM *);
friend void _nc_xx_fld_term(FORM *);

// Calculate FIELD* array for the menu
FIELD** mapFields(NCursesFormField* nfields[]);

protected:
// internal routines
inline void set_user(void *user) {
UserHook* uptr = reinterpret_cast<UserHook*>(::form_userptr (form));
assert (uptr != 0 && uptr->m_back==this && uptr->m_owner==form);
uptr->m_user = user;
}

inline void *get_user() {
UserHook* uptr = reinterpret_cast<UserHook*>(::form_userptr (form));
assert (uptr != 0 && uptr->m_back==this && uptr->m_owner==form);
return uptr->m_user;
}

void InitForm (NCursesFormField* Fields[],
bool with_frame,
bool autoDeleteFields);

inline void OnError (int err) const THROW2(NCursesException const, NCursesFormException) {
if (err != E_OK)
THROW(new NCursesFormException (err));
}

// this wraps the form_driver call.
virtual int driver (int c) ;

// 'Internal' constructor, builds an object without association to a
// field array.
NCursesForm( int nlines,
int ncols,
int begin_y = 0,
int begin_x = 0)
: NCursesPanel(nlines, ncols, begin_y, begin_x),
form (STATIC_CAST(FORM*)(0)),
sub(0),
b_sub_owner(0),
b_framed(0),
b_autoDelete(0),
my_fields(0)
{
}

public:
// Create form for the default panel.
NCursesForm (NCursesFormField* Fields[],
bool with_frame=FALSE, // reserve space for a frame?
bool autoDelete_Fields=FALSE) // do automatic cleanup?
: NCursesPanel(),
form(0),
sub(0),
b_sub_owner(0),
b_framed(0),
b_autoDelete(0),
my_fields(0)
{
InitForm(Fields, with_frame, autoDelete_Fields);
}

// Create a form in a panel with the given position and size.
NCursesForm (NCursesFormField* Fields[],
int nlines,
int ncols,
int begin_y,
int begin_x,
bool with_frame=FALSE, // reserve space for a frame?
bool autoDelete_Fields=FALSE) // do automatic cleanup?
: NCursesPanel(nlines, ncols, begin_y, begin_x),
form(0),
sub(0),
b_sub_owner(0),
b_framed(0),
b_autoDelete(0),
my_fields(0)
{
InitForm(Fields, with_frame, autoDelete_Fields);
}

NCursesForm& operator=(const NCursesForm& rhs)
{
if (this != &rhs) {
*this = rhs;
NCursesPanel::operator=(rhs);
}
return *this;
}

NCursesForm(const NCursesForm& rhs)
: NCursesPanel(rhs),
form(rhs.form),
sub(rhs.sub),
b_sub_owner(rhs.b_sub_owner),
b_framed(rhs.b_framed),
b_autoDelete(rhs.b_autoDelete),
my_fields(rhs.my_fields)
{
}

virtual ~NCursesForm();

// Set the default attributes for the form
virtual void setDefaultAttributes();

// Retrieve current field of the form.
inline NCursesFormField* current_field() const {
return my_fields[::field_index(::current_field(form))];
}

// Set the forms subwindow
void setSubWindow(NCursesWindow& sub);

// Set these fields for the form
inline void setFields(NCursesFormField* Fields[]) {
OnError(::set_form_fields(form,mapFields(Fields)));
}

// Remove the form from the screen
inline void unpost (void) {
OnError (::unpost_form (form));
}

// Post the form to the screen if flag is true, unpost it otherwise
inline void post(bool flag = TRUE) {
OnError (flag ? ::post_form(form) : ::unpost_form (form));
}

// Decorations
inline void frame(const char *title=NULL, const char* btitle=NULL) {
if (b_framed)
NCursesPanel::frame(title,btitle);
else
OnError(E_SYSTEM_ERROR);
}

inline void boldframe(const char *title=NULL, const char* btitle=NULL) {
if (b_framed)
NCursesPanel::boldframe(title,btitle);
else
OnError(E_SYSTEM_ERROR);
}

inline void label(const char *topLabel, const char *bottomLabel) {
if (b_framed)
NCursesPanel::label(topLabel,bottomLabel);
else
OnError(E_SYSTEM_ERROR);
}

// -----
// Hooks
// -----

// Called after the form gets repositioned in its window.
// This is especially true if the form is posted.
virtual void On_Form_Init();

// Called before the form gets repositioned in its window.
// This is especially true if the form is unposted.
virtual void On_Form_Termination();

// Called after the field became the current field
virtual void On_Field_Init(NCursesFormField& field);

// Called before this field is left as current field.
virtual void On_Field_Termination(NCursesFormField& field);

// Calculate required window size for the form.
void scale(int& rows, int& ncols) const {
OnError(::scale_form(form,&rows,&ncols));
}

// Retrieve number of fields in the form.
int count() const {
return ::field_count(form);
}

// Make the page the current page of the form.
void set_page(int pageNum) {
OnError(::set_form_page(form, pageNum));
}

// Retrieve current page number
int page() const {
return ::form_page(form);
}

// Switch on the forms options
inline void options_on (Form_Options opts) {
OnError (::form_opts_on (form, opts));
}

// Switch off the forms options
inline void options_off (Form_Options opts) {
OnError (::form_opts_off (form, opts));
}

// Retrieve the forms options
inline Form_Options options () const {
return ::form_opts (form);
}

// Set the forms options
inline void set_options (Form_Options opts) {
OnError (::set_form_opts (form, opts));
}

// Are there more data in the current field after the data shown
inline bool data_ahead() const {
return ::data_ahead(form);
}

// Are there more data in the current field before the data shown
inline bool data_behind() const {
return ::data_behind(form);
}

// Position the cursor to the current field
inline void position_cursor () {
OnError (::pos_form_cursor (form));
}
// Set the current field
inline void set_current(NCursesFormField& F) {
OnError (::set_current_field(form, F.field));
}

// Provide a default key virtualization. Translate the keyboard
// code c into a form request code.
// The default implementation provides a hopefully straightforward
// mapping for the most common keystrokes and form requests.
virtual int virtualize(int c);

// Operators
inline NCursesFormField* operator[](int i) const {
if ( (i < 0) || (i >= ::field_count (form)) )
OnError (E_BAD_ARGUMENT);
return my_fields[i];
}

// Perform the menu's operation
// Return the field where you left the form.
virtual NCursesFormField* operator()(void);

// Exception handlers. The default is a Beep.
virtual void On_Request_Denied(int c) const;
virtual void On_Invalid_Field(int c) const;
virtual void On_Unknown_Command(int c) const;

};

//
// -------------------------------------------------------------------------
// This is the typical C++ typesafe way to allow to attach
// user data to a field of a form. Its assumed that the user
// data belongs to some class T. Use T as template argument
// to create a UserField.
// -------------------------------------------------------------------------
template<class T> class NCURSES_IMPEXP NCursesUserField : public NCursesFormField
{
public:
NCursesUserField (int rows,
int ncols,
int first_row = 0,
int first_col = 0,
const T* p_UserData = STATIC_CAST(T*)(0),
int offscreen_rows = 0,
int additional_buffers = 0)
: NCursesFormField (rows, ncols,
first_row, first_col,
offscreen_rows, additional_buffers) {
if (field)
OnError(::set_field_userptr(field, STATIC_CAST(void *)(p_UserData)));
}

virtual ~NCursesUserField() {};

inline const T* UserData (void) const {
return reinterpret_cast<const T*>(::field_userptr (field));
}

inline virtual void setUserData(const T* p_UserData) {
if (field)
OnError (::set_field_userptr (field, STATIC_CAST(void *)(p_UserData)));
}
};
//
// -------------------------------------------------------------------------
// The same mechanism is used to attach user data to a form
// -------------------------------------------------------------------------
//
template<class T> class NCURSES_IMPEXP NCursesUserForm : public NCursesForm
{
protected:
// 'Internal' constructor, builds an object without association to a
// field array.
NCursesUserForm( int nlines,
int ncols,
int begin_y = 0,
int begin_x = 0,
const T* p_UserData = STATIC_CAST(T*)(0))
: NCursesForm(nlines,ncols,begin_y,begin_x) {
if (form)
set_user (const_cast<void *>(reinterpret_cast<const void*>
(p_UserData)));
}

public:
NCursesUserForm (NCursesFormField* Fields[],
const T* p_UserData = STATIC_CAST(T*)(0),
bool with_frame=FALSE,
bool autoDelete_Fields=FALSE)
: NCursesForm (Fields, with_frame, autoDelete_Fields) {
if (form)
set_user (const_cast<void *>(reinterpret_cast<const void*>(p_UserData)));
};

NCursesUserForm (NCursesFormField* Fields[],
int nlines,
int ncols,
int begin_y = 0,
int begin_x = 0,
const T* p_UserData = STATIC_CAST(T*)(0),
bool with_frame=FALSE,
bool autoDelete_Fields=FALSE)
: NCursesForm (Fields, nlines, ncols, begin_y, begin_x,
with_frame, autoDelete_Fields) {
if (form)
set_user (const_cast<void *>(reinterpret_cast<const void*>
(p_UserData)));
};

virtual ~NCursesUserForm() {
};

inline T* UserData (void) {
return reinterpret_cast<T*>(get_user ());
};

inline virtual void setUserData (const T* p_UserData) {
if (form)
set_user (const_cast<void *>(reinterpret_cast<const void*>(p_UserData)));
}

};
//
// -------------------------------------------------------------------------
// Builtin Fieldtypes
// -------------------------------------------------------------------------
//
class NCURSES_IMPEXP Alpha_Field : public NCursesFieldType
{
private:
int min_field_width;

void set(NCursesFormField& f) {
OnError(::set_field_type(f.get_field(),fieldtype,min_field_width));
}

public:
Alpha_Field(int width)
: NCursesFieldType(TYPE_ALPHA),
min_field_width(width) {
}
};

class NCURSES_IMPEXP Alphanumeric_Field : public NCursesFieldType
{
private:
int min_field_width;

void set(NCursesFormField& f) {
OnError(::set_field_type(f.get_field(),fieldtype,min_field_width));
}

public:
Alphanumeric_Field(int width)
: NCursesFieldType(TYPE_ALNUM),
min_field_width(width) {
}
};

class NCURSES_IMPEXP Integer_Field : public NCursesFieldType
{
private:
int precision;
long lower_limit, upper_limit;

void set(NCursesFormField& f) {
OnError(::set_field_type(f.get_field(),fieldtype,
precision,lower_limit,upper_limit));
}

public:
Integer_Field(int prec, long low=0L, long high=0L)
: NCursesFieldType(TYPE_INTEGER),
precision(prec), lower_limit(low), upper_limit(high) {
}
};

class NCURSES_IMPEXP Numeric_Field : public NCursesFieldType
{
private:
int precision;
double lower_limit, upper_limit;

void set(NCursesFormField& f) {
OnError(::set_field_type(f.get_field(),fieldtype,
precision,lower_limit,upper_limit));
}

public:
Numeric_Field(int prec, double low=0.0, double high=0.0)
: NCursesFieldType(TYPE_NUMERIC),
precision(prec), lower_limit(low), upper_limit(high) {
}
};

class NCURSES_IMPEXP Regular_Expression_Field : public NCursesFieldType
{
private:
char* regex;

void set(NCursesFormField& f) {
OnError(::set_field_type(f.get_field(),fieldtype,regex));
}

void copy_regex(const char *source)
{
regex = new char[1 + ::strlen(source)];
(::strcpy)(regex, source);
}

public:
Regular_Expression_Field(const char *expr)
: NCursesFieldType(TYPE_REGEXP),
regex(NULL)
{
copy_regex(expr);
}

Regular_Expression_Field& operator=(const Regular_Expression_Field& rhs)
{
if (this != &rhs) {
*this = rhs;
copy_regex(rhs.regex);
NCursesFieldType::operator=(rhs);
}
return *this;
}

Regular_Expression_Field(const Regular_Expression_Field& rhs)
: NCursesFieldType(rhs),
regex(NULL)
{
copy_regex(rhs.regex);
}

~Regular_Expression_Field() {
delete[] regex;
}
};

class NCURSES_IMPEXP Enumeration_Field : public NCursesFieldType
{
private:
const char** list;
int case_sensitive;
int non_unique_matches;

void set(NCursesFormField& f) {
OnError(::set_field_type(f.get_field(),fieldtype,
list,case_sensitive,non_unique_matches));
}
public:
Enumeration_Field(const char* enums[],
bool case_sens=FALSE,
bool non_unique=FALSE)
: NCursesFieldType(TYPE_ENUM),
list(enums),
case_sensitive(case_sens ? -1 : 0),
non_unique_matches(non_unique ? -1 : 0) {
}

Enumeration_Field& operator=(const Enumeration_Field& rhs)
{
if (this != &rhs) {
*this = rhs;
NCursesFieldType::operator=(rhs);
}
return *this;
}

Enumeration_Field(const Enumeration_Field& rhs)
: NCursesFieldType(rhs),
list(rhs.list),
case_sensitive(rhs.case_sensitive),
non_unique_matches(rhs.non_unique_matches)
{
}
};

class NCURSES_IMPEXP IPV4_Address_Field : public NCursesFieldType
{
private:
void set(NCursesFormField& f) {
OnError(::set_field_type(f.get_field(),fieldtype));
}

public:
IPV4_Address_Field() : NCursesFieldType(TYPE_IPV4) {
}
};

extern "C" {
bool _nc_xx_fld_fcheck(FIELD *, const void*);
bool _nc_xx_fld_ccheck(int c, const void *);
void* _nc_xx_fld_makearg(va_list*);
}

//
// -------------------------------------------------------------------------
// Abstract base class for User-Defined Fieldtypes
// -------------------------------------------------------------------------
//
class NCURSES_IMPEXP UserDefinedFieldType : public NCursesFieldType
{
friend class UDF_Init; // Internal helper to set up statics
private:
// For all C++ defined fieldtypes we need only one generic lowlevel
// FIELDTYPE* element.
static FIELDTYPE* generic_fieldtype;

protected:
// This are the functions required by the low level libforms functions
// to construct a fieldtype.
friend bool _nc_xx_fld_fcheck(FIELD *, const void*);
friend bool _nc_xx_fld_ccheck(int c, const void *);
friend void* _nc_xx_fld_makearg(va_list*);

void set(NCursesFormField& f) {
OnError(::set_field_type(f.get_field(),fieldtype,&f));
}

protected:
// Redefine this function to do a field validation. The argument
// is a reference to the field you should validate.
virtual bool field_check(NCursesFormField& f) = 0;

// Redefine this function to do a character validation. The argument
// is the character to be validated.
virtual bool char_check (int c) = 0;

public:
UserDefinedFieldType() : NCursesFieldType(generic_fieldtype) {
}
};

extern "C" {
bool _nc_xx_next_choice(FIELD*, const void *);
bool _nc_xx_prev_choice(FIELD*, const void *);
}

//
// -------------------------------------------------------------------------
// Abstract base class for User-Defined Fieldtypes with Choice functions
// -------------------------------------------------------------------------
//
class NCURSES_IMPEXP UserDefinedFieldType_With_Choice : public UserDefinedFieldType
{
friend class UDF_Init; // Internal helper to set up statics
private:
// For all C++ defined fieldtypes with choice functions we need only one
// generic lowlevel FIELDTYPE* element.
static FIELDTYPE* generic_fieldtype_with_choice;

// This are the functions required by the low level libforms functions
// to construct a fieldtype with choice functions.
friend bool _nc_xx_next_choice(FIELD*, const void *);
friend bool _nc_xx_prev_choice(FIELD*, const void *);

protected:
// Redefine this function to do the retrieval of the next choice value.
// The argument is a reference to the field tobe examined.
virtual bool next (NCursesFormField& f) = 0;

// Redefine this function to do the retrieval of the previous choice value.
// The argument is a reference to the field tobe examined.
virtual bool previous(NCursesFormField& f) = 0;

public:
UserDefinedFieldType_With_Choice() {
fieldtype = generic_fieldtype_with_choice;
}
};

#endif /* NCURSES_CURSESF_H_incl */