class Convert

Convert-derived classes serve as bidirectional Value-Value converters. One direction is represented by Format method and usually converts the Value to the textual representation. Reverse direction is represented by the Scan method.

If the conversion is not possible (e.g. due to invalid textual representation), convert methods should return "ErrorValue" to indicate the problem.

virtual Value Format(const Value& q) const

Converts the Value. Default implementation uses Value::ToString to convert the Value.

virtual Value Scan(const Value& text) const

Converts the Value in reverse direction. Default implementation returns text (no conversion is performed).

virtual int Filter(int chr) const

Adjusts characters allowed in textual representation of Value.

Value operator()(const Value& q) const

Invokes the Format method. Helper functor-like syntax.

class ConvertDate : public Convert

Date Converter. Textual date format depends on actual regional settings.

Derived from Convert

ConvertDate(Date minval = Date::Low(), Date maxval = Date::High(), bool notnull = false)

Constructor.

~ConvertDate()

Default destructor.

ConvertDate& MinMax(Date _min, Date _max)

Sets the range of Dates allowed.

ConvertDate& Min(Date _min)

Sets minimal allowed Date.

ConvertDate& Max(Date _max)

Sets maximal allowed Date.

ConvertDate& NotNull(bool b = true)

Allows/disallows Null dates. (Null dates are represented by the empty text).

ConvertDate& NoNotNull()

Same as NotNull(false).

ConvertDate& Default(Date d)

When the text is empty, Scan returns this value.

Date GetMin() const

Returns minimal allowed date. This is maximum of value set by Min and default minimum (GetDefaultMin).

Date GetMax() const

Returns upper limit of allowed dates. This is minimum of value set by Max and default maximum (GetDefaultMax).

static Date GetDefaultMin()

Returns default minimum.

static Date GetDefaultMax()

Returns default maximum.

void SetDefaultMinMax(Date min, Date max)

Sets values for default minimum and maximum. Default values are Date::Low() and Date::Hight().

bool IsNotNull() const

class ConvertTime : public Convert

Time converter.

Derived from Convert

ConvertTime(Time minval = ToTime(Date::Low()), Time maxval = ToTime(Date::High()), bool notnull = false)

Constructor.

~ConvertTime()

Default destructor.

ConvertTime& MinMax(Time _min, Time _max)

Time limeits.

ConvertTime& Min(Time _min)

Sets lower limit.

ConvertTime& Max(Time _max)

Sets upper limit.

ConvertTime& NotNull(bool b = true)

Disallows empty Strings.

ConvertTime& NoNotNull()

Same as NotNull(false).

ConvertTime& Seconds(bool b = true)

If true (which is default), Format returns time with seconds.

ConvertTime& NoSeconds()

Same as Seconds(fale)

bool IsSeconds() const

Returns the value set by Seconds.,

ConvertTime& TimeAlways(bool b = true)

If active, Format always shows time, even if the Value is Date or is at midnight. Default is false.

bool IsTimeAlways() const

Returns the value set by TimeAlways.

ConvertTime& DayEnd(bool b = true)

If active, when Scan encounters date without time, it sets the time to 23:59:59. Default is false.

bool IsDayEnd() const

Returns the value set by DayEnd.

ConvertTime& Default(Time d)

Sets default time returned by Scan when input is empty.

Time GetMin() const

Returns minimal allowed time. This is maximum of value set by Min and default minimum (GetDefaultMin).

Time GetMax() const

Returns upper limit of allowed times. This is minimum of value set by Max and default maximum (GetDefaultMax).

static Time GetDefaultMin()

Returns Date::GetDefaultMin converted to Time.

static Time GetDefaultMax()

Returns Date::GetDefaultMax converted to Time.

bool IsNotNull() const

class ConvertDouble : public Convert

Floating point number converter.

Derived from Convert

ConvertDouble(double minval = -std::numeric_limits<double>::max(), double maxval = std::numeric_limits<double>::max(), bool notnull = false)

Constructor.

~ConvertDouble()

Default destructor.

ConvertDouble& Pattern(const char *p)

Formatting tag used for conversion to textual representation (includes standard printf formatting tags, see Format function for description). Default tag is %.10g. After setting a new pattern, ConvertDouble formats simple example number (Format(1.1)) and if it detects character ',' in resulting string, Filter method forces ',' to be used instead of '.' for decimal point.

ConvertDouble& MinMax(double _min, double _max)

Sets minimal and maximal allowed numbers.

ConvertDouble& Min(double _min)

Sets minimal allowed number.

ConvertDouble& Max(double _max)

Sets maximal allowed number.

ConvertDouble& NotNull(bool b = true)

Allows/disallows Nulls. (Nulls are represented by the empty text).

ConvertDouble& NoNotNull()

Equivalent to NotNull(false).

double GetMin() const

double GetMax() const

bool IsNotNull() const

struct ConvertFloat : public ConvertDouble

This helper class changes precision of double->text conversion to 7 digits to reflect the precision of float type.

static double GetDefaultMin()

Returns the minimal number representable by float.

static double GetDefaultMax()

Returns the maximal number representable by float.

ConvertFloat(double minval = GetDefaultMin(), double maxval = GetDefaultMax(), bool notnull = false)

minval maxval notnull .

class ConvertInt : public Convert

Integer converter.

Derived from Convert

ConvertInt(int minval = -INT_MAX, int maxval = INT_MAX, bool notnull = false)

Constructor.

~ConvertInt()

Default destructor.

ConvertInt& MinMax(int _min, int _max)

Sets minimal and maximal allowed numbers.

ConvertInt& Min(int _min)

Sets minimal allowed number.

ConvertInt& Max(int _max)

Sets maximal allowed number.

ConvertInt& NotNull(bool b = true)

Allows/disallows Nulls. (Nulls are represented by the empty text).

ConvertInt& NoNotNull()

Equivalent to NotNull(false).

int GetMin() const

int GetMax() const

bool IsNotNull() const

class ConvertString : public Convert

String "converter". Of course, String already is textual representation of itself, the real purpose of this class is to introduce constraints of String value.

Derived from Convert

ConvertString(int maxlen = INT_MAX, bool notnull = false)

Constructor.

~ConvertString()

Default destructor.

ConvertString& MaxLen(int _maxlen)

Sets maximum length of String allowed.

int GetMaxLength() const

ConvertString& NotNull(bool b = true)

Disallows empty Strings.

ConvertString& NoNotNull()

Same as NotNull(false).

bool IsNotNull() const

ConvertString& TrimLeft(bool b = true)

ConvertString& TrimRight(bool b = true)

ConvertString& TrimBoth(bool b = true)

Whitechars on the left/right/both side(s) are removed before checking count of characters or nullness.

bool IsTrimLeft() const

bool IsTrimRight() const

Checks whether TrimLeft or TrimRight (or both) is active.

class FormatConvert : public Convert

This unidirectional Convert class (only Format direction implemented) converts single Value or ValueArray using Format function and specified formatter pattern.

Derived from Convert

void SetFormat(const char *fmt)

Sets formatting pattern.

class JoinConvert : public Convert

This unidirectional Convert class (only Format direction is implemented) converts ValueArray using a set of other Convert instances. Resulting textual representation is created by joining a set of defined elements - some of them static texts, others referring to elements of input ValueArray, converted using specified Convert.

Derived from Convert

JoinConvert& Add(const char *text)

Adds static text to the list of elements.

JoinConvert& Add(int pos, const Convert& cv)

Add element referring to input value, to be converted using specified Convert.

JoinConvert& Add(int pos)

Add element referring to input value, to be converted using default Convert.

JoinConvert& Add(const Convert& cv)

Add element referring to input value, to be converted using specified Convert. Index of input element is the index of previous input element plus 1.

JoinConvert& Add()

Add element referring to input value, to be converted using default Convert. Index of input element is the index of previous input element plus 1.

Standard converts are simple global functions returning a constant reference to the single global variable representing the particular Convert class. Following table lists names of these functions and respective constructors of Convert classes used to create global variable:

const Convert& StdConvert()

Convert

const ConvertInt& StdConvertInt()

ConvertInt

const ConvertInt& StdConvertIntNotNull()

ConvertInt(-INT_MAX, INT_MAX, true)

const ConvertDouble& StdConvertDouble()

ConvertDouble

const ConvertDouble& StdConvertDoubleNotNull()

ConvertDouble(-DOUBLE_NULL_LIM, DOUBLE_NULL_LIM, true)

const ConvertDate& StdConvertDate()

ConvertDate

const ConvertDate& StdConvertDateNotNull()

ConvertDate(Date(0, 0, 0), Date(3000, 12, 31), true)

const ConvertTime& StdConvertTime()

ConvertTime

const ConvertTime& StdConvertTimeNotNull()

ConvertTime(Null, Null, true)

const ConvertString& StdConvertString()

ConvertString

const ConvertString& StdConvertStringNotNull()

ConvertString(INT_MAX, true)

template <typename F, typename S, class R>

const auto& LambdaConvert(F format, S scan, R filter)

template <typename F, typename S>

const auto& LambdaConvert(F format, S scan)

template <typename F>

const auto& LambdaConvert(F format)

Returns a reference to a static Convert instance that has Format/Scan/Filter defined as lambda expressions.

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