ScaledIntegerNode Class Reference

An E57 element encoding a fixed point number. More...

List of all members.

Public Member Functions
	ScaledIntegerNode (ImageFile destImageFile, int64_t value, int64_t minimum, int64_t maximum, double scale=1.0, double offset=0.0)
	Create an E57 element for storing a fixed point number.
	ScaledIntegerNode (ImageFile destImageFile, int value, int64_t minimum, int64_t maximum, double scale=1.0, double offset=0.0)
	ScaledIntegerNode (ImageFile destImageFile, int value, int minimum, int maximum, double scale=1.0, double offset=0.0)
	ScaledIntegerNode (ImageFile destImageFile, double scaledValue, double scaledMinimum, double scaledMaximum, double scale=1.0, double offset=0.0)
	This second constructor create an E57 element for storing a fixed point number but does the scaling for you.
int64_t	rawValue () const
	Get raw unscaled integer value of element.
double	scaledValue () const
	Get scaled value of element.
int64_t	minimum () const
	Get the declared minimum that the raw value may take.
double	scaledMinimum () const
	Get the declared scaled minimum that the scaled value may take.
int64_t	maximum () const
	Get the declared maximum that the raw value may take.
double	scaledMaximum () const
	Get the declared scaled maximum that the scaled value may take.
double	scale () const
	Get declared scaling factor.
double	offset () const
	Get declared offset.
	operator Node () const
	Upcast a ScaledIntegerNode handle to a generic Node handle.
	ScaledIntegerNode (const Node &n)
	Downcast a generic Node handle to an ScaledIntegerNode handle.
bool	isRoot () const
	Is this a root node.
Node	parent () const
	Return parent of node, or self if a root node.
ustring	pathName () const
	Get absolute pathname of node.
ustring	elementName () const
	Get elementName string, that identifies the node in its parent..
ImageFile	destImageFile () const
	Get the ImageFile that was declared as the destination for the node when it was created.
bool	isAttached () const
	Has node been attached into the tree of an ImageFile.
void	dump (int indent=0, std::ostream &os=std::cout) const
	Diagnostic function to print internal state of object to output stream in an indented format.
void	checkInvariant (bool doRecurse=true, bool doUpcast=true)
	Check whether ScaledIntegerNode class invariant is true.

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Detailed Description

An E57 element encoding a fixed point number.

An ScaledIntegerNode is a terminal node (i.e. having no children) that holds a fixed point number encoded by an integer rawValue, a double precision floating point scale, an double precision floating point offset, and integer minimum/maximum bounds.

The minimum attribute may be a number in the interval [-2^63, 2^63). The maximum attribute may be a number in the interval [minimum, 2^63). The rawValue may be a number in the interval [minimum, maximum]. The scaledValue is a calculated double precision floating point number derived from: scaledValue = rawValue*scale + offset.

See Node class discussion for discussion of the common functions that StructureNode supports.

Class Invariant

A class invariant is a list of statements about an object that are always true before and after any operation on the object. An invariant is useful for testing correct operation of an implementation. Statements in an invariant can involve only externally visible state, or can refer to internal implementation-specific state that is not visible to the API user. The following C++ code checks externally visible state for consistancy and throws an exception if the invariant is violated:

void ScaledIntegerNode::checkInvariant(bool /*doRecurse*/, bool doUpcast) {
    // If destImageFile not open, can't test invariant (almost every call would throw)
    if (!destImageFile().isOpen())
        return;

    // If requested, call Node::checkInvariant
    if (doUpcast)
        static_cast<Node>(*this).checkInvariant(false, false);

    // If value is out of bounds
    if (rawValue() < minimum() || rawValue() > maximum())
       throw E57_EXCEPTION1(E57_ERROR_INVARIANCE_VIOLATION);

    // If scale is zero
    if (scale() == 0)
       throw E57_EXCEPTION1(E57_ERROR_INVARIANCE_VIOLATION);

    // If scaled value is not calculated correctly
    if (scaledValue() != rawValue() * scale() + offset())
       throw E57_EXCEPTION1(E57_ERROR_INVARIANCE_VIOLATION);
} // end ScaledIntegerNode::checkInvariant

See also:

Node