XMLAttributeValueView Class Reference

A view into an attribute value. The class does not take the ownership of the data. More...

#include <XMLAttributeValueView.h>

Public Types
enum class	Type {   Null , SignedInteger , UnsignedInteger , Float ,   Double , StringView }
	Type of the value represented by the XMLAttributeValueView. More...

Public Member Functions
	XMLAttributeValueView ()=default
	Construct an uninitialized view of type Null. More...
	XMLAttributeValueView (const XMLAttributeValueView &)=default
	XMLAttributeValueView (XMLAttributeValueView &&)=default
XMLAttributeValueView &	operator= (const XMLAttributeValueView &)=default
XMLAttributeValueView &	operator= (XMLAttributeValueView &&)=default
	XMLAttributeValueView (bool value) noexcept
	Construct a view of type UnsignedInteger from the value. More...
	XMLAttributeValueView (short value) noexcept
	Construct a view of type SignedInteger from the value. More...
	XMLAttributeValueView (unsigned short value) noexcept
	Construct a view of type UnsignedInteger from the value. More...
	XMLAttributeValueView (int value) noexcept
	Construct a view of type SignedInteger from the value. More...
	XMLAttributeValueView (unsigned int value) noexcept
	Construct a view of type UnsignedInteger from the value. More...
	XMLAttributeValueView (long value) noexcept
	Construct a view of type SignedInteger from the value. More...
	XMLAttributeValueView (unsigned long value) noexcept
	Construct a view of type UnsignedInteger from the value. More...
	XMLAttributeValueView (long long value) noexcept
	Construct a view of type SignedInteger from the value. More...
	XMLAttributeValueView (unsigned long long value) noexcept
	Construct a view of type UnsignedInteger from the value. More...
	XMLAttributeValueView (float value) noexcept
	Construct a view of type Float from the value. More...
	XMLAttributeValueView (double value) noexcept
	Construct a view of type Double from the value. More...
	XMLAttributeValueView (const std::string_view &value) noexcept
	Construct a view of type StringView from the value. More...
Type	GetType () const noexcept
	Get the view type. More...
bool	IsNull () const noexcept
	Check if view is Null. More...
bool	IsSignedInteger () const noexcept
	Check if view has the SignedInteger type. More...
bool	IsUnsignedInteger () const noexcept
	Check if view has the UnsignedInteger type. More...
bool	IsFloat () const noexcept
	Check if view has the Float type. More...
bool	IsDouble () const noexcept
	Check if view has the Double type. More...
bool	IsStringView () const noexcept
	Check if view has the StringView type. More...
bool	TryGet (bool &value) const noexcept
	Try to get a boolean value from the view. More...
bool	TryGet (short &value) const noexcept
	Try to get a short value from the view. More...
bool	TryGet (unsigned short &value) const noexcept
	Try to get an unsigned short value from the view. More...
bool	TryGet (int &value) const noexcept
	Try to get an int value from the view. More...
bool	TryGet (unsigned int &value) const noexcept
	Try to get an unsigned int value from the view. More...
bool	TryGet (long &value) const noexcept
	Try to get a long value from the view. More...
bool	TryGet (unsigned long &value) const noexcept
	Try to get an unsigned long value from the view. More...
bool	TryGet (long long &value) const noexcept
	Try to get a long long value from the view. More...
bool	TryGet (unsigned long long &value) const noexcept
	Try to get an unsigned long long value from the view. More...
bool	TryGet (float &value) const noexcept
	Try to get a float value from the view. More...
bool	TryGet (double &value) const noexcept
	Try to get a double value from the view. More...
bool	TryGet (std::string_view &value) const noexcept
	Try to get a string_view value from the view. More...
template<typename T >
T	Get (T defaultValue={}) const noexcept
	Returns the value if there is a viable conversion, default value otherwise. More...
std::string	ToString () const
	Convert the view value to an UTF8 string. More...
wxString	ToWString () const
	Convert the view value to wxString. More...

Private Member Functions
template<typename ResultType >
bool	TryGetInteger (ResultType &value) const noexcept

Private Attributes
union {
int64_t   mInteger
double   mDouble
float   mFloat
struct {
const char *   Data
size_t   Length
}   mStringView
};
Type	mType { Type::Null }

Detailed Description

A view into an attribute value. The class does not take the ownership of the data.

Audacity internally uses regular XML and an internal binary XML-like format. Binary format extends the possible XML types to support integers and floating point values, not just the string values.

This class represents the attribute value for both text and binary XML formats.

Class has a number of Get overloads, that allow to read the value with the required data type.

Integer-based types can be read from the view if it was initialized by an integer value or with a string_view that is a textual representation of an integer value. To avoid runtime data loss it is not possible to read an integer from the floating point values. Boundary checks are always performed. If the type is not large enough to store the value, Get fails.

Floating point values can be read from the view, if it is initialized using floating point, integer or a compatible string value. Conversion from Float to Double is forbidden.

String values can be read only if the view was created using a string_view. However there are ToString() and ToWString() methods that allow conversion from any type to string. Null type is represented by an empty string.

Definition at line 43 of file XMLAttributeValueView.h.

Member Enumeration Documentation

Type

enum class XMLAttributeValueView::Type

strong

Type of the value represented by the XMLAttributeValueView.

Enumerator
Null	The value is not initialized.
SignedInteger	The value is a signed integer.
UnsignedInteger	The value is an unsigned integer.
Float	The value is a single precision floating point value.
Double	The value is a double precision floating point value.
StringView	The value is a string_view.

Definition at line 47 of file XMLAttributeValueView.h.

   {
      Null, 
      SignedInteger, 
      UnsignedInteger, 
      Float, 
      Double, 
      StringView 
   };

Constructor & Destructor Documentation

XMLAttributeValueView() [1/15]

XMLAttributeValueView::XMLAttributeValueView ( )

default

Construct an uninitialized view of type Null.

XMLAttributeValueView() [2/15]

XMLAttributeValueView::XMLAttributeValueView ( const XMLAttributeValueView &  )

default

XMLAttributeValueView() [3/15]

XMLAttributeValueView::XMLAttributeValueView ( XMLAttributeValueView &&  )

default

XMLAttributeValueView() [4/15]

XMLAttributeValueView::XMLAttributeValueView ( bool  value )

explicitnoexcept

Construct a view of type UnsignedInteger from the value.

Definition at line 16 of file XMLAttributeValueView.cpp.

    : mInteger(value)
    , mType(Type::UnsignedInteger)
{
}

XMLAttributeValueView() [5/15]

XMLAttributeValueView::XMLAttributeValueView ( short  value )

explicitnoexcept

Construct a view of type SignedInteger from the value.

Definition at line 22 of file XMLAttributeValueView.cpp.

    : mInteger(value)
    , mType(Type::SignedInteger)
{
}

XMLAttributeValueView() [6/15]

XMLAttributeValueView::XMLAttributeValueView ( unsigned short  value )

explicitnoexcept

Construct a view of type UnsignedInteger from the value.

Definition at line 28 of file XMLAttributeValueView.cpp.

    : mInteger(value)
    , mType(Type::UnsignedInteger)
{
}

XMLAttributeValueView() [7/15]

XMLAttributeValueView::XMLAttributeValueView ( int  value )

explicitnoexcept

Construct a view of type SignedInteger from the value.

Definition at line 34 of file XMLAttributeValueView.cpp.

    : mInteger(value)
    , mType(Type::SignedInteger)
{
}

XMLAttributeValueView() [8/15]

XMLAttributeValueView::XMLAttributeValueView ( unsigned int  value )

explicitnoexcept

Construct a view of type UnsignedInteger from the value.

Definition at line 40 of file XMLAttributeValueView.cpp.

    : mInteger(value)
    , mType(Type::UnsignedInteger)
{
}

XMLAttributeValueView() [9/15]

XMLAttributeValueView::XMLAttributeValueView ( long  value )

explicitnoexcept

Construct a view of type SignedInteger from the value.

Definition at line 46 of file XMLAttributeValueView.cpp.

    : mInteger(value)
    , mType(Type::SignedInteger)
{
}

XMLAttributeValueView() [10/15]

XMLAttributeValueView::XMLAttributeValueView ( unsigned long  value )

explicitnoexcept

Construct a view of type UnsignedInteger from the value.

Definition at line 52 of file XMLAttributeValueView.cpp.

    : mInteger(value)
    , mType(Type::UnsignedInteger)
{
}

XMLAttributeValueView() [11/15]

XMLAttributeValueView::XMLAttributeValueView ( long long  value )

explicitnoexcept

Construct a view of type SignedInteger from the value.

Definition at line 58 of file XMLAttributeValueView.cpp.

    : mInteger(value)
    , mType(Type::SignedInteger)
{
}

XMLAttributeValueView() [12/15]

XMLAttributeValueView::XMLAttributeValueView ( unsigned long long  value )

explicitnoexcept

Construct a view of type UnsignedInteger from the value.

Definition at line 64 of file XMLAttributeValueView.cpp.

    : mInteger(value)
    , mType(Type::UnsignedInteger)
{
}

XMLAttributeValueView() [13/15]

XMLAttributeValueView::XMLAttributeValueView ( float  value )

explicitnoexcept

Construct a view of type Float from the value.

Definition at line 70 of file XMLAttributeValueView.cpp.

    : mFloat(value)
    , mType(Type::Float)
{
}

XMLAttributeValueView() [14/15]

XMLAttributeValueView::XMLAttributeValueView ( double  value )

explicitnoexcept

Construct a view of type Double from the value.

Definition at line 76 of file XMLAttributeValueView.cpp.

    : mDouble(value)
    , mType(Type::Double)
{
}

XMLAttributeValueView() [15/15]

XMLAttributeValueView::XMLAttributeValueView ( const std::string_view &  value )

explicitnoexcept

Construct a view of type StringView from the value.

Definition at line 82 of file XMLAttributeValueView.cpp.

    : mType(Type::StringView)
{
   mStringView.Data = value.data();
   mStringView.Length = value.length();
}

Member Function Documentation

Get()

template<typename T >

T XMLAttributeValueView::Get ( T  defaultValue = {} ) const

inlinenoexcept

Returns the value if there is a viable conversion, default value otherwise.

Definition at line 135 of file XMLAttributeValueView.h.

                          {}) const noexcept
   {
      // TryGet only modifies the value if conversion is possible,
      // so just reuse the defaultValue
      (void) TryGet(defaultValue);
      return defaultValue;
   }

GetType()

XMLAttributeValueView::Type XMLAttributeValueView::GetType ( ) const

noexcept

Get the view type.

Definition at line 90 of file XMLAttributeValueView.cpp.

{
   return mType;
}

References mType.

IsDouble()

bool XMLAttributeValueView::IsDouble ( ) const

noexcept

Check if view has the Double type.

Definition at line 115 of file XMLAttributeValueView.cpp.

{
   return mType == Type::Double;
}

References Double, and mType.

IsFloat()

bool XMLAttributeValueView::IsFloat ( ) const

noexcept

Check if view has the Float type.

Definition at line 110 of file XMLAttributeValueView.cpp.

{
   return mType == Type::Float;
}

References Float, and mType.

IsNull()

bool XMLAttributeValueView::IsNull ( ) const

noexcept

Check if view is Null.

Definition at line 95 of file XMLAttributeValueView.cpp.

{
   return mType == Type::Null;
}

References mType, and Null.

IsSignedInteger()

bool XMLAttributeValueView::IsSignedInteger ( ) const

noexcept

Check if view has the SignedInteger type.

Definition at line 100 of file XMLAttributeValueView.cpp.

{
   return mType == Type::SignedInteger;
}

References mType, and SignedInteger.

IsStringView()

bool XMLAttributeValueView::IsStringView ( ) const

noexcept

Check if view has the StringView type.

Definition at line 120 of file XMLAttributeValueView.cpp.

{
   return mType == Type::StringView;
}

References mType, and StringView.

IsUnsignedInteger()

bool XMLAttributeValueView::IsUnsignedInteger ( ) const

noexcept

Check if view has the UnsignedInteger type.

Definition at line 105 of file XMLAttributeValueView.cpp.

{
   return mType == Type::UnsignedInteger;
}

References mType, and UnsignedInteger.

operator=() [1/2]

XMLAttributeValueView & XMLAttributeValueView::operator= ( const XMLAttributeValueView &  )

default

operator=() [2/2]

XMLAttributeValueView & XMLAttributeValueView::operator= ( XMLAttributeValueView &&  )

default

ToString()

std::string XMLAttributeValueView::ToString

(

)

const

Convert the view value to an UTF8 string.

Definition at line 245 of file XMLAttributeValueView.cpp.

{
   switch (mType)
   {
   case XMLAttributeValueView::Type::Null:
      return {};
   case XMLAttributeValueView::Type::SignedInteger:
      return std::to_string(mInteger);
   case XMLAttributeValueView::Type::UnsignedInteger:
      return std::to_string(static_cast<uint64_t>(mInteger));
   case XMLAttributeValueView::Type::Float:
      return std::to_string(mFloat);
   case XMLAttributeValueView::Type::Double:
      return std::to_string(mDouble);
   case XMLAttributeValueView::Type::StringView:
      return std::string(mStringView.Data, mStringView.Length);
   }
 
   return {};
}

References Double, Float, mDouble, mFloat, mInteger, mStringView, mType, Null, SignedInteger, StringView, and UnsignedInteger.

ToWString()

wxString XMLAttributeValueView::ToWString

(

)

const

Convert the view value to wxString.

Definition at line 266 of file XMLAttributeValueView.cpp.

{
   switch (mType)
   {
   case XMLAttributeValueView::Type::Null:
      return {};
   case XMLAttributeValueView::Type::SignedInteger:
      return wxString() << mInteger;
   case XMLAttributeValueView::Type::UnsignedInteger:
      return wxString() << static_cast<uint64_t>(mInteger);
   case XMLAttributeValueView::Type::Float:
      return wxString() << mFloat;
   case XMLAttributeValueView::Type::Double:
      return wxString() << mDouble;
   case XMLAttributeValueView::Type::StringView:
      return wxString::FromUTF8(mStringView.Data, mStringView.Length);
   }
 
   return {};
}

References Double, Float, mDouble, mFloat, mInteger, mStringView, mType, Null, SignedInteger, StringView, and UnsignedInteger.

Referenced by Track::HandleCommonXMLAttribute().

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TryGet() [1/12]

bool XMLAttributeValueView::TryGet ( bool &  value ) const

noexcept

Try to get a boolean value from the view.

Definition at line 125 of file XMLAttributeValueView.cpp.

{
   return TryGetInteger(value);
}

Referenced by Track::HandleCommonXMLAttribute(), PlayableTrack::HandleXMLAttribute(), SelectedRegion::HandleXMLAttribute(), WaveformAppearance::HandleXMLAttribute(), WaveColorAttachment::HandleXMLAttribute(), and ChannelView::HandleXMLAttribute().

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TryGet() [2/12]

bool XMLAttributeValueView::TryGet ( double &  value ) const

noexcept

Try to get a double value from the view.

Definition at line 200 of file XMLAttributeValueView.cpp.

{
   if (mType == Type::Float)
   {
      value = mFloat;
      return true;
   }
   else if (mType == Type::Double)
   {
      value = mDouble;
      return true;
   }
   else if (mType == Type::SignedInteger || mType == Type::UnsignedInteger)
   {
      value = mInteger;
      return true;
   }
   else if (mType == Type::StringView)
   {
      const char* end = mStringView.Data + mStringView.Length;
 
      double tempValue = {};
 
      const auto result = FromChars(mStringView.Data, end, tempValue);
 
      if (result.ec == std::errc() && result.ptr == end)
      {
         value = tempValue;
         return true;
      }
   }
 
   return false;
}

References details::end(), and FromChars().

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TryGet() [3/12]

bool XMLAttributeValueView::TryGet ( float &  value ) const

noexcept

Try to get a float value from the view.

Definition at line 170 of file XMLAttributeValueView.cpp.

{
   if (mType == Type::Float)
   {
      value = mFloat;
      return true;
   }
   else if (mType == Type::SignedInteger || mType == Type::UnsignedInteger)
   {
      value = mInteger;
      return true;
   }
   else if (mType == Type::StringView)
   {
      const char* end = mStringView.Data + mStringView.Length;
 
      float tempValue = {};
 
      const auto result = FromChars(mStringView.Data, end, tempValue);
 
      if (result.ec == std::errc() && result.ptr == end)
      {
         value = tempValue;
         return true;
      }
   }
 
   return false;
}

References details::end(), and FromChars().

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TryGet() [4/12]

bool XMLAttributeValueView::TryGet ( int &  value ) const

noexcept

Try to get an int value from the view.

Definition at line 140 of file XMLAttributeValueView.cpp.

{
   return TryGetInteger(value);
}

TryGet() [5/12]

bool XMLAttributeValueView::TryGet ( long &  value ) const

noexcept

Try to get a long value from the view.

Definition at line 150 of file XMLAttributeValueView.cpp.

{
   return TryGetInteger(value);
}

TryGet() [6/12]

bool XMLAttributeValueView::TryGet ( long long &  value ) const

noexcept

Try to get a long long value from the view.

Definition at line 160 of file XMLAttributeValueView.cpp.

{
   return TryGetInteger(value);
}

TryGet() [7/12]

bool XMLAttributeValueView::TryGet ( short &  value ) const

noexcept

Try to get a short value from the view.

Definition at line 130 of file XMLAttributeValueView.cpp.

{
   return TryGetInteger(value);
}

TryGet() [8/12]

bool XMLAttributeValueView::TryGet ( std::string_view &  value ) const

noexcept

Try to get a string_view value from the view.

Definition at line 235 of file XMLAttributeValueView.cpp.

{
   if (mType != Type::StringView)
      return false;
 
   value = std::string_view(mStringView.Data, mStringView.Length);
 
   return true;
}

TryGet() [9/12]

bool XMLAttributeValueView::TryGet ( unsigned int &  value ) const

noexcept

Try to get an unsigned int value from the view.

Definition at line 145 of file XMLAttributeValueView.cpp.

{
   return TryGetInteger(value);
}

TryGet() [10/12]

bool XMLAttributeValueView::TryGet ( unsigned long &  value ) const

noexcept

Try to get an unsigned long value from the view.

Definition at line 155 of file XMLAttributeValueView.cpp.

{
   return TryGetInteger(value);
}

TryGet() [11/12]

bool XMLAttributeValueView::TryGet ( unsigned long long &  value ) const

noexcept

Try to get an unsigned long long value from the view.

Definition at line 165 of file XMLAttributeValueView.cpp.

{
   return TryGetInteger(value);
}

TryGet() [12/12]

bool XMLAttributeValueView::TryGet ( unsigned short &  value ) const

noexcept

Try to get an unsigned short value from the view.

Definition at line 135 of file XMLAttributeValueView.cpp.

{
   return TryGetInteger(value);
}

TryGetInteger()

template<typename ResultType >

bool XMLAttributeValueView::TryGetInteger ( ResultType &  value ) const

privatenoexcept

Definition at line 318 of file XMLAttributeValueView.cpp.

{
   static_assert(std::is_integral_v<ResultType>);
 
   if (mType == Type::SignedInteger)
   {
      return CheckInteger(value, mInteger);
   }
   else if (mType == Type::UnsignedInteger)
   {
      return CheckInteger(value, static_cast<uint64_t>(mInteger));
   }
   else if (mType == Type::StringView)
   {
      const char* end = mStringView.Data + mStringView.Length;
 
      ResultType tempValue = {};
 
      const auto result = FromChars(mStringView.Data, end, tempValue);
 
      if (result.ec == std::errc() && result.ptr == end)
      {
         value = tempValue;
         return true;
      }
   }
 
   return false;
}

References CheckInteger(), details::end(), and FromChars().

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Member Data Documentation

union { ... } XMLAttributeValueView::@139

Data

const char* XMLAttributeValueView::Data

Definition at line 160 of file XMLAttributeValueView.h.

Length

size_t XMLAttributeValueView::Length

Definition at line 161 of file XMLAttributeValueView.h.

mDouble

double XMLAttributeValueView::mDouble

Definition at line 155 of file XMLAttributeValueView.h.

Referenced by ToString(), and ToWString().

mFloat

float XMLAttributeValueView::mFloat

Definition at line 156 of file XMLAttributeValueView.h.

Referenced by ToString(), and ToWString().

mInteger

int64_t XMLAttributeValueView::mInteger

Definition at line 154 of file XMLAttributeValueView.h.

Referenced by ToString(), and ToWString().

struct { ... } XMLAttributeValueView::mStringView

Referenced by ToString(), and ToWString().

mType

Type XMLAttributeValueView::mType { Type::Null }

private

Definition at line 165 of file XMLAttributeValueView.h.

Referenced by GetType(), IsDouble(), IsFloat(), IsNull(), IsSignedInteger(), IsStringView(), IsUnsignedInteger(), ToString(), and ToWString().

---

The documentation for this class was generated from the following files:

• XMLAttributeValueView.h
• XMLAttributeValueView.cpp