A Data_Component provides a common, virtual interface for all HiRISE Observation data blocks. More...

#include <Data_Component.hh>

Inheritance diagram for Data_Component:

[legend]

Collaboration diagram for Data_Component:

Public Member Functions
	Data_Component (const char *names=NULL, unsigned int size=0, const Index offsets=NULL, const Index indexed_arrays[][2]=NULL, Data_Order order=Data_Block::MSB)
	Constructs a Data_Component using component specifications. More...

	Data_Component (const Data_Component &component, bool data_duplicate=true)
	Copy constructor. More...

Data_Component &	operator= (const Data_Component &component)
	Assignment operator. More...

virtual	~Data_Component ()
	Destructor. More...

virtual std::string	id () const
	Gets the identification of this component. More...

virtual const char *	name () const =0
	Gets the name of the component. More...

const char *	name (Index element) const
	Gets the name of a component Element. More...

virtual u_int_32	get (Index element, Index index=0) const
	Gets a value from a data Element or array entry of the component. More...

virtual Data_Component &	put (const u_int_32 value, Index element, Index index=0)
	Puts a value into a data Element or array entry of the component. More...

virtual idaeim::PVL::Aggregate *	PVL () const =0
	Produces an exhausitive PVL (Parameter Value Language) rendition of the component contents. More...

virtual std::ostream &	print (std::ostream &stream=std::cout, bool verbose=false) const =0
	Prints a detailed description of the component structure and contents. More...

std::ostream &	print_element (const Index element, int format=DECIMAL, std::ostream &stream=std::cout, int width=0) const
	Prints an Element description. More...

std::ostream &	print_element (const Index element, std::ostream &stream) const
	Prints an Element description. More...

std::ostream &	print_element_location (const Index element, std::ostream &stream=std::cout) const
	Prints the location of an Element in the component. More...

unsigned int	element_location_print_width (Index element) const
	Gets the width of the Element location printing fields. More...

unsigned int	name_field_width () const
	Gets the width of the Element name printing field. More...

Data_Component &	name_field_width (unsigned int width)
	Sets the width of the Element name field for printing. More...

virtual bool	is_valid () const =0
	Tests if the component data is valid. More...

Data_Block &	data (void *const block)
	Overrides the base Data_Block::data to reset Local_Data. More...

Data_Block &	attach (void *const block, unsigned int size)
	Attaches a new block of data to the component. More...

Data_Component &	resize (unsigned int size)
	Resizes the block of local data storage. More...

unsigned char *	data () const
	Gets a pointer to the current component storage. More...

unsigned int	local_data ()
	Gets the size of the local data storage area. More...

u_int_16	internet_checksum () const
	Calculates the Internet Checksum as per RFC 1071. More...

Public Member Functions inherited from Data_Block
	Data_Block ()

	Data_Block (void const data, const Index offsets, Index total_elements=0, const Index *array_counts=NULL, bool native_order=true)

	Data_Block (void *const data, const Value_List &offsets, const Value_List &array_counts, bool native_order=true)

	Data_Block (void *const data, const Value_List &offsets, bool native_order=true)

	Data_Block (void const data, const Index offsets, Index total_elements, const Index *array_counts, Data_Order data_order)

	Data_Block (void *const data, const Value_List &offsets, const Value_List &array_counts, Data_Order data_order)

	Data_Block (void const data, const Index offsets, Index total_elements, Data_Order data_order)

	Data_Block (void const data, const Index offsets, Data_Order data_order)

	Data_Block (void *const data, const Value_List &offsets, Data_Order data_order)

	Data_Block (void const data, const Index offsets, const Index indexed_counts[][2], Data_Order data_order)

	Data_Block (const Data_Block &data_block)

Data_Block &	operator= (const Data_Block &data_block)

virtual	~Data_Block ()

bool	native () const

Data_Block &	native (bool native_order)

Data_Order	data_order () const

Data_Block &	data_order (Data_Order order)

unsigned char *	data () const

Index	size () const

Value_List	element_offsets_list () const

Index *	element_offsets ()

bool	element_offsets (const Value_List &offsets)

bool	element_offsets (const Index *offsets, Index total_elements=NO_INDEX)

bool	element_sizes (const Value_List &sizes)

bool	element_sizes (const Index *sizes, Index total_elements=NO_INDEX)

Index	offset_of (Index element) const

bool	offset_of (Index element, Index offset)

bool	insert_element (Index offset, Index size, Index array_count=1)

Data_Block &	delete_element (Index element)

Data_Block &	shift_offsets (int amount)

Index	elements () const

Index	size_of (Index element) const

bool	size_of (Index element, Index size)

Index	value_size_of (Index element) const

Data_Block &	value_size_of (Index element, Index size)

Index	index_of (Index offset) const

Value_List	array_counts_list () const

Index *	array_counts ()

Data_Block &	array_counts (const Value_List &counts, Index begin=0)

Data_Block &	array_counts (const Index *counts, Index begin=0, Index end=NO_INDEX)

Data_Block &	array_indexed_counts (const Index indexed_counts[][2], Index total_counts=NO_INDEX)

Data_Block &	array_offset_counts (const Index offset_counts[][2], Index total_counts=NO_INDEX)

Index	count_of (Index element) const

Data_Block &	count_of (Index element, Index count)

bool	reset_counts (bool unconditional=true, Index begin=0, Index end=NO_INDEX)

const Data_Block &	get (T &value, const Index element, const Index index=0) const

const Data_Block &	get (T &value, const Index element, const Index index=0) const

T	get (const Index element, const Index index=0) const

T	get (const Index element, const Index index=0) const

Data_Block &	put (T &value, const Index element, const Index index=0)

Data_Block &	put (T &value, const Index element, const Index index=0)

const Data_Block &	get (T *array, const Index element, Index count=0) const

const Data_Block &	get (T *array, const Index element, Index count=0) const

Data_Block &	put (T *array, const Index element, Index count=0)

Data_Block &	put (T *array, const Index element, Index count=0)

std::istream &	input (std::istream &stream)

std::ostream &	output (std::ostream &stream) const

std::ostream &	print (std::ostream &stream=std::cout) const

Static Public Attributes
static const char *const	ID
	Class identification name with source code version and date. More...

static const int	DECIMAL = 0
	Format specifier. More...

static const int	HEX = -1

static const int	BOOLEAN = -2

static const char	PATHNAME_DELIMITER = FILESYSTEM_PATHNAME_DELIMITER
	Host filesystem pathname delimiter. More...

static const int	UTC_SECONDS_PRECISION = SECONDS_PRECISION
	UTC seconds precision (digits after the decimal point). More...

static const char	SUBSECONDS_DELIMITER = ':'
	Delimits subseconds from seconds in clock count representations. More...

static const char *const	SPICE_METAKERNEL_VARIABLE
	The name of the environment variable for the SPICE metakernel pathname. More...

static const char *const	DEFAULT_SPICE_METAKERNEL
	The default SPICE metakernal pathname. More...

static const int	MRO_CLOCK_ID = MRO_CLOCK_NAIF_ID
	The ID used by NAIF for specifying the MRO clock to CSPICE routines. More...

static const char *const	INVALID_UTC_TIME = DEFAULT_INVALID_UTC_TIME

Static Public Attributes inherited from Instrument
static const char *const	ID

static const unsigned int	CCDS

static const unsigned int	CCD_UNKNOWN

static const char *const	CCD_NAMES []

static const char *const	CCD_FILTER_NAMES []

static const unsigned int	CCD_BY_CPMM []

static const unsigned int	CPMM_BY_CCD []

static const char *const	WAVELENGTH_UNITS

static const unsigned int	CCD_CENTER_WAVELENGTHS []

static const unsigned int	CCD_BANDWIDTHS []

static const double	CCD_FOCAL_PLANE_X_OFFSETS_MM []

static const double	CCD_FOCAL_PLANE_Y_OFFSETS_MM []

static const double	CCD_PIXEL_SIZE_MM

static const unsigned int	CCD_CHANNELS

static const unsigned int	CCD_CHANNEL_UNKNOWN

static const unsigned int	CCD_IMAGE_SENSORS

static const unsigned int	MAX_BYTES_PER_PIXEL

static const unsigned int	MAX_PIXEL_VALUES []

static const unsigned int	MAX_IMAGE_LINES

static const unsigned int	TOTAL_TDI_STAGES

static const unsigned int	TDI_STAGES []

static const unsigned int	TOTAL_BINNING_FACTORS

static const unsigned int	BINNING_FACTORS []

static const unsigned int	CCD_BINNED_PIXELS []

static const unsigned int	STORED_LUTS

static const unsigned int	STIMULATOR_LEDS

static const char *const	STIMULATOR_LED_NAMES []

static const double	EXPOSURE_SETUP_MICROS

static const unsigned int	DELTA_LINE_TIME_MAX

static const double	DELTA_LINE_TIME_TICK_NANOS

static const double	LINE_TIME_PRE_OFFSET

static const unsigned int	TRIM_ADDITION_LINES

static const unsigned int	REVERSE_READOUT_LINES

static const unsigned int	MASKED_LINES

static const unsigned int	DLL_LOCKED

static const unsigned int	DLL_NOT_LOCKED

static const unsigned int	SPACECRAFT_EPOCH

static const double	MRO_CLOCK_SUBTICK_MICROS

static const double	HIRISE_CLOCK_SUBTICK_MICROS

static const int	SPACECRAFT_NAIF_ID

static const unsigned int	SSR_BYTE_BOUNDARY

static const int	UNKNOWN_NUMBER

static const int	NOT_APPLICABLE_NUMBER

static const char *const	UNKNOWN_STRING

static const char *const	NOT_APPLICABLE_STRING

Static Public Attributes inherited from Data_Block
static const char *const	ID

static const Index	NO_INDEX

Additional Inherited Members
Public Types inherited from Data_Block
enum	Data_Order

enum	Array_Index_Counts

enum	Array_Offset_Counts

typedef unsigned int	Index

typedef std::vector< Index >	Value_List

typedef void(*	Copier) (unsigned char destination, int destination_amount, const unsigned char source, int source_amount)

Static Public Member Functions inherited from Instrument
static unsigned int	calibration_lines_minimum (unsigned int TDI, unsigned int binning)

static int	focal_plane_x_offset (unsigned int CPMM, unsigned int binning=1)

Static Public Member Functions inherited from Data_Block
static Data_Order	native_order ()

static Value_List &	sizes_to_offsets (Value_List &sizes)

static Index *	sizes_to_offsets (Index *sizes, Index total_elements=NO_INDEX)

static Value_List &	offsets_to_sizes (Value_List &offsets)

static Index *	offsets_to_sizes (Index *offsets, Index total_elements=NO_INDEX)

Public Attributes inherited from Data_Block
	MSB

	LSB

	ELEMENT_INDEX

	INDEX_COUNT

	ELEMENT_OFFSET

	OFFSET_COUNT

Copier	Get

Copier	Put

Protected Member Functions inherited from Data_Block
void	limits_checker (const Index element, const Index index, bool getter, bool array) const

Static Protected Member Functions inherited from Data_Block
static void	get_forwards (unsigned char host, int host_amount, const unsigned char data, int data_amount)

static void	get_backwards (unsigned char host, int host_amount, const unsigned char data, int data_amount)

static void	put_forwards (unsigned char data, int data_amount, const unsigned char host, int host_amount)

static void	put_backwards (unsigned char data, int data_amount, const unsigned char host, int host_amount)

Detailed Description

A Data_Component provides a common, virtual interface for all HiRISE Observation data blocks.

It also subclasses the Instrument class which contains the HiRISE instrument constants, and the PIRL::Data_Block for host data order independence of the component's data store.

There will be an implmentation of this interface for each specific type of Data_Component that occurs in an Observation or data product.

Author: Bradford Castalia, UA/PIRL

1.38

See also: UA::HiRISE::Instrument; PIRL::Data_Block; Observation

Constructor & Destructor Documentation

◆ Data_Component() [1/2]

Data_Component	(	const char **	names = `NULL`,
		unsigned int	size = `0`,
		const Index *	offsets = `NULL`,
		const Index	indexed_arrays[][2] = `NULL`,
		Data_Order	order = `Data_Block::MSB`
	)

Constructs a Data_Component using component specifications.

Memory is allocated (size bytes) for the component's Data_Block, and initialized to 0. However, if size is 0 no memory is allocated; the Data_Block has NULL data. The memory is deleted when the component is destroyed or the data block is substituted by an external data block.

Parameters

names	The list of Element names in Element order. The names are expected to remain constant, so they are not copied. This list MUST be NULL terminated.
size	The size (bytes) of the component's data block.
offsets	The list of Element offsets in the data block in Element order.
indexed_arrays	The list of array Element entry counts using Element index references. Components with no array Elements will not provide this.
order	The order of data in data block. All HiRISE components are expected to be MSB ordered.

See also: Data_Block

References Data_Component::data(), and Data_Block::size().

◆ Data_Component() [2/2]

Data_Component	(	const Data_Component &	component,
		bool	data_duplicate = `true`
	)

Copy constructor.

This component is a Data_Block copy which results in taking on all of the structural characteristics of the copied component.

The data content is copied only if data_duplicate is true. If data_duplicate is true, then memory for a copy of the source component data block is allocated, and the contents of the source data block is copied into this new data block. If data_duplicate is false, then the new data block will share the data storage memory of the source data block; the source data block retains ownership of the data storage.

Parameters

component	The component to be copied.
data_duplicate	true if the data content of the component is to be duplicated in the copy; false if the source component data is to be shared by this component.

References Data_Component::attach(), Data_Component::data(), and Data_Block::size().

◆ ~Data_Component()

~Data_Component ( )

virtual

Destructor.

If the data block memory for the component has not been substituted by an external data block, it is deleted.

See also: data(void* const)

Member Function Documentation

◆ operator=()

Data_Component & operator= ( const Data_Component & component )

Assignment operator.

Memory is allocated for a duplicate of the assigned data block storage. However, if the current data block is being locally managed (it has its own data storage) and at least as large as the assigned data block the current block is simply reused rather than replaced.

Also, a Data_Block assignment of the assigned compoent is applied to this component so it takes on all of the structural characteristics of assigned component.

Parameters

component The component being assigned.

References Data_Component::data(), and Data_Block::size().

Referenced by Engineering_Header::operator=(), Gap_Map::operator=(), Image_Line::operator=(), LUT::operator=(), MROSP_Header::operator=(), and Science_Channel_Header::operator=().

◆ id()

string id ( ) const

virtual

Gets the identification of this component.

The identification is the Data_Component class ID, the Instrument class ID and the Data_Block class ID each separated by a new-line. Each subclass of Data_Component is excpected to provided their own id method which provides their own class ID line preceeding this identification.

Returns: An identification string for the component.

Reimplemented in Science_Channel_Header, MROSP_Header, LUT, Image_Line, Gap_Map, and Engineering_Header.

References Instrument::ID, Data_Component::ID, and ID.

Referenced by Engineering_Header::id(), Gap_Map::id(), Image_Line::id(), LUT::id(), MROSP_Header::id(), and Science_Channel_Header::id().

◆ name() [1/2]

virtual const char* name ( ) const

pure virtual

Gets the name of the component.

Each subclass must provide their name method.

Returns: A constant C-string (char*) that is the name of the implementing class.

Implemented in Science_Channel_Header, MROSP_Header, LUT, Image_Line, Gap_Map, and Engineering_Header.

Referenced by Data_Component::print_element_location().

◆ name() [2/2]

const char * name ( Index element ) const

Gets the name of a component Element.

Parameters

element	An Element Index of the component.
element	The Element Index.

Returns: A constant C-string (char*) that is the name of the Element.

◆ get()

u_int_32 get	(	Index	element,
		Index	index = `0`
	)		const

virtual

Gets a value from a data Element or array entry of the component.

Regardless of the precision (number of bits) of the component Element the value will always be cast up to a 32-bit integer.

Parameters

element	An Element Index of the component.
index	An array Elmenent entry index.

Returns: An unsigned integer value for the Element data.

◆ put()

Data_Component & put	(	const u_int_32	value,
		Index	element,
		Index	index = `0`
	)

virtual

Puts a value into a data Element or array entry of the component.

Regardless of the precision (number of bits) of the component Element the 32-bit integer value will always be cast appropriately.

Parameters

value	An unsigned integer value for the Element data.
element	An Element Index of the component.
index	An array Elmenent entry index.

Returns: This Data_Component.

◆ PVL()

virtual idaeim::PVL::Aggregate* PVL ( ) const

pure virtual

Produces an exhausitive PVL (Parameter Value Language) rendition of the component contents.

Each Element has a parameter with its element name. All the paramters are contained in an Aggregate with the name of component.

Returns: A pointer to a PVL::Aggregate.

Implemented in Science_Channel_Header, MROSP_Header, LUT, Image_Line, Gap_Map, and Engineering_Header.

◆ print()

virtual std::ostream& print	(	std::ostream &	stream = `std::cout`,
		bool	verbose = `false`
	)		const

pure virtual

Prints a detailed description of the component structure and contents.

The listing is expected to start with a line containing the component's name preceeded by a ">>> " marker. In verbose mode this should be immediately followed by a line containing the component's class ID.

After a blank line, each Element of the component should be listed in Element order. Typically the print_element method is used to provide a single line description of an Element. For complex Elements (e.g. packed bit fields) additional lines describing each part of the element should be provided.

When not in verbose mode, inconsequential component Elements - typically padding - will not be included in the Element listings.

Parameters

stream	The ostream where the listing will be written.
verbose	true if the listing is to be verbose, otherwise some structural details will be omitted for easier human consumption.

Returns: The stream that was written.

See also: print_element

Implemented in Science_Channel_Header, MROSP_Header, LUT, Image_Line, Gap_Map, and Engineering_Header.

◆ print_element() [1/2]

ostream & print_element	(	const Index	element,
		int	format = `DECIMAL`,
		std::ostream &	stream = `std::cout`,
		int	width = `0`
	)		const

Prints an Element description.

The description begins with its location listing. Then each Element value is listed, space separated, in the specified format (an array Element has more than one value).

Parameters

element	An Index of an Element in the component.
format	The selected format of the output.
stream	The ostream for output.
width	The width of the representation, as applicable.

Returns: The stream that was written.

See also: print_element_location; print_value

References Data_Block::count_of(), Data_Component::get(), Data_Component::HEX, Data_Component::print_element_location(), UA::HiRISE::print_value(), and Data_Block::value_size_of().

Referenced by Engineering_Header::print(), MROSP_Header::print(), Science_Channel_Header::print(), and Data_Component::print_element().

◆ print_element() [2/2]

std::ostream& print_element	(	const Index	element,
		std::ostream &	stream
	)		const

inline

Prints an Element description.

The Element is printed in DECIMAL format with 0 width.

Parameters

element	An Index of an Element in the component.
stream	The ostream for output.

Returns: The stream that was written.

See also: print_element(const Index, int, std::ostream&, int)

References Data_Component::DECIMAL, and Data_Component::print_element().

◆ print_element_location()

ostream & print_element_location	(	const Index	element,
		std::ostream &	stream = `std::cout`
	)		const

Prints the location of an Element in the component.

The format of the location listing is:

Element@Offset:Count*Size Name:

Element: The Element Index in the component (width 3).
Offset: The byte offset from the begining of the component, at byte 0, where the Element data is located (width 3).
Count: The number of Array entries composing the Element; a non-Array Element has a Count of 1 (width 3).
Size: The size, in bytes, of each Array entry (width 1). Note: there is a single space following this field.
Name: The name of the Element (width name_field_width). Note: there is a colon and space following this field.

All parts of the location listing are right justified in their
space padded fields.

@param  element An Index of an Element in the component.
@param  stream  The ostream where the listing will be written.
@return The stream that was written.

References Data_Block::count_of(), Data_Component::name(), Data_Block::offset_of(), and Data_Block::value_size_of().

Referenced by Data_Component::element_location_print_width(), Image_Line::print(), Science_Channel_Header::print(), and Data_Component::print_element().

◆ element_location_print_width()

unsigned int element_location_print_width ( Index element ) const

Gets the width of the Element location printing fields.

The width of the Element location field should be constant as determined by its fixed format. However, unusually large location data values or a name_field_width specification less than the length of the Element name will result in an actual field width that is longer than expected. This method prints the Element location and name to a string stream to determine its actual listing length.

Parameters

element An Index of an Element in the component.

Returns: The width of the location and name printing fields.

See also: print_element_location

References Data_Component::print_element_location().

Referenced by MROSP_Header::print(), and Science_Channel_Header::print().

◆ name_field_width() [1/2]

unsigned int name_field_width ( ) const

Gets the width of the Element name printing field.

Returns: The character width of the Element name print field.

See also: name_field_width(unsigned int)

◆ name_field_width() [2/2]

Data_Component & name_field_width ( unsigned int width )

Sets the width of the Element name field for printing.

To provide a nicely formatted print listing, a consistent width for the Element name field is maintained as the Name_Field_Width data member of the Data_Component. When the object is constructed the maximum length of all Elements names is determined (and saved as the Max_Name_Length data member) and the Name_Field_Width value is initialzed with the value of Max_Name_Length. When an application is printing multiple Data_Component objects it may reset the Name_Field_Width to some other value; e.g. the maximum of all name_field_width values from each Data_Component.

If the width argument is 0 then the Name_Field_Width will be reset to the Max_Name_Length value.

Parameters

width The character width for the Element name print field. If the value is 0 then the width will be reset to the Max_Name_Length value.

Returns: This Data_Component.

See also: print_element

◆ is_valid()

virtual bool is_valid ( ) const

pure virtual

Tests if the component data is valid.

Returns: true if the component has valid data; false otherwise.

Implemented in Science_Channel_Header, MROSP_Header, LUT, Image_Line, Gap_Map, and Engineering_Header.

◆ data() [1/2]

Data_Block & data ( void *const block )

virtual

Overrides the base Data_Block::data to reset Local_Data.

When a Data_Component is constructed it provides its own local data storage which is managed by the Data_Component. It may be appropriate to substitute an external data storage block that is managed externally.

When a new data block replaces a local block, the local block is deleted and the data storage is marked as being externally managed. If the new data block replaces an external block, the external block is not deleted; the external storage is the responsibility of the external owner.

N.B.: The contents of the previous data block are not copied into the new block.

Warning: It the responsibility of the new data block owner to ensure that it contains sufficient storage to accommodate all Elements of the component, as determined by the Data_Block::size method.

Parameters

block The address of the new Data_Block storage.

Returns: The Data_Block.

See also: Data_Block::data(void* const)

Reimplemented from Data_Block.

References Data_Component::data().

Referenced by Observation::components(), Data_Component::Data_Component(), Observation::line(), Line_Cache::Line_Cache(), Line_Cache::next_line(), and Data_Component::operator=().

◆ attach()

Data_Block & attach	(	void *const	block,
		unsigned int	size
	)

Attaches a new block of data to the component.

The new data block is attached to this Data_Component: ownership of the new data block is passed to this Data_Component; the data block will be deleted when this Data_Component is destroyed.

Warning: The new data block must be dynamically allocated.

When a the new data block replaces a local block at a different address, the local block is deleted. N.B.: The contents of the previous data block are not copied into the new block.

Parameters

block	The address of the new Data_Block storage.
size	The size, in bytes, of the new data block.

Returns: The Data_Block.

Exceptions

length_error If the size of the new block is insufficient to accommodate all Elements of the component, as determined by the Data_Block::size() method.

See also: Data_Block::data(void* const)

References Data_Component::data(), Data_Component::ID, and Data_Block::size().

Referenced by Data_Component::Data_Component(), Gap_Map::insert_range(), and Data_Component::resize().

◆ resize()

Data_Component & resize ( unsigned int size )

Resizes the block of local data storage.

If the component has its own local data or has no no data block and the requested new data block size is greater than the currently allocated amount, then local data block is reallocated at the larger size and the contents of the previous data block are copied into the new data block. N.B.: The size of the local data block is never decreased (use attach instead).

Parameters

size	The requested size of the local data block.

Returns: This Data_Component.

See also: local_data()

References Data_Component::attach(), Data_Component::data(), Data_Component::ID, and Data_Block::size().

Referenced by Image_Line::pixel_bytes(), and Image_Line::pixel_count().

◆ data() [2/2]

unsigned char* data ( ) const

inline

Gets a pointer to the current component storage.

Returns: The component storage pointer.

See also: Data_Block::data()

References Data_Block::data().

Referenced by Data_Component::attach(), Data_Component::data(), Data_Component::Data_Component(), Gap_Map::insert_range(), FELICS_Line_Cache::is_sync(), LUT::is_valid(), Line_Cache::Line_Cache(), Image_Line::next_sync(), Image_Line::pukool(), Gap_Map::remove_range(), and Data_Component::resize().

◆ local_data()

unsigned int local_data ( )

inline

Gets the size of the local data storage area.

Returns: The size, in bytes, of the local storage area. If the data storage is being externally managed this will be zero.

See also: data(void* const)

◆ internet_checksum()

u_int_16 internet_checksum ( ) const

Calculates the Internet Checksum as per RFC 1071.

In outline, the Internet Checksum algorithm is very simple:

Adjacent octets to be checksummed are paired to form 16-bit integers, and the 1's complement sum of these 16-bit integers is formed.

To generate a checksum, the checksum field itself is cleared, the 16-bit 1's complement sum is computed over the octets concerned, and the 1's complement of this sum is placed in the checksum field.

To check a checksum, the 1's complement sum is computed over the same set of octets, including the checksum field. If the result is all 1 bits (-0 in 1's complement arithmetic), the check succeeds.

Suppose a checksum is to be computed over the sequence of octets A, B, C, D, ... , Y, Z. Using the notation [a,b] for the 16-bit integer a * 256 + b, where a and b are bytes, then the 16-bit 1's complement sum of these bytes is given by one of the following:

    [A,B] +' [C,D] +' ... +' [Y,Z]
    [A,B] +' [C,D] +' ... +' [Z,0]

where +' indicates 1's complement addition. These cases correspond to an even or odd count of bytes, respectively.

On a 2's complement machine, the 1's complement sum must be computed by means of an "end around carry", i.e., any overflows from the most significant bits are added into the least significant bits.

For details see: http://www.faqs.org/rfcs/rfc1071.html

Returns: The checksum of the this Data_Component. If the component contains a valid checksum Element, the result should be 0.

References Data_Block::Get, and Data_Block::size().

Referenced by Science_Channel_Header::is_valid(), main(), MROSP_Header::print(), and Science_Channel_Header::print().

Member Data Documentation

◆ ID

const char *const ID

static

Initial value:

=

"UA::HiRISE::Data_Component (1.51 2020/05/14 22:48:28)"

Class identification name with source code version and date.

Referenced by Data_Component::attach(), Data_Component::id(), main(), Data_Component::resize(), and UA::HiRISE::seconds().

◆ DECIMAL

const int DECIMAL = 0

static

Format specifier.

See also: print_value

Referenced by Data_Component::print_element(), and UA::HiRISE::print_value().

◆ HEX

const int HEX = -1

static

Referenced by main(), Engineering_Header::print(), Image_Line::print(), MROSP_Header::print(), Science_Channel_Header::print(), Data_Component::print_element(), and UA::HiRISE::print_value().

◆ BOOLEAN

const int BOOLEAN = -2

static

Referenced by Engineering_Header::print(), Science_Channel_Header::print(), and UA::HiRISE::print_value().

◆ PATHNAME_DELIMITER

const char PATHNAME_DELIMITER = FILESYSTEM_PATHNAME_DELIMITER

static

Host filesystem pathname delimiter.

Referenced by UA::HiRISE::filename(), main(), and UA::HiRISE::pathname().

◆ UTC_SECONDS_PRECISION

const int UTC_SECONDS_PRECISION = SECONDS_PRECISION

static

UTC seconds precision (digits after the decimal point).

Referenced by UA::HiRISE::UTC_time().

◆ SUBSECONDS_DELIMITER

const char SUBSECONDS_DELIMITER = ':'

static

Delimits subseconds from seconds in clock count representations.

Referenced by UA::HiRISE::clock_count(), Science_Channel_Header::clock_count(), and UA::HiRISE::seconds().

◆ SPICE_METAKERNEL_VARIABLE

const char *const SPICE_METAKERNEL_VARIABLE

static

Initial value:

=

SPICE_METAKERNEL_VARIABLE_NAME

#define SPICE_METAKERNEL_VARIABLE_NAME

Definition: Data_Component.cc:148

The name of the environment variable for the SPICE metakernel pathname.

A pathname ust be provided to a SPICE metakernel that lists a SCLK kernal for the MRO spacecraft and a leap seconds kernel. The environment variable is tried first before the fallback default.

Referenced by UA::HiRISE::UTC_time().

◆ DEFAULT_SPICE_METAKERNEL

const char *const DEFAULT_SPICE_METAKERNEL

static

Initial value:

=

DEFAULT_SPICE_METAKERNEL_PATHNAME

#define DEFAULT_SPICE_METAKERNEL_PATHNAME

Definition: Data_Component.cc:155

The default SPICE metakernal pathname.

Referenced by UA::HiRISE::UTC_time().

◆ MRO_CLOCK_ID

const int MRO_CLOCK_ID = MRO_CLOCK_NAIF_ID

static

The ID used by NAIF for specifying the MRO clock to CSPICE routines.

Referenced by UA::HiRISE::UTC_time().

◆ INVALID_UTC_TIME

const char *const INVALID_UTC_TIME = DEFAULT_INVALID_UTC_TIME

static

Referenced by UA::HiRISE::UTC_time().

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

Public Member Functions

Static Public Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ Data_Component() [1/2]

◆ Data_Component() [2/2]

◆ ~Data_Component()

Member Function Documentation

◆ operator=()

◆ id()

◆ name() [1/2]

◆ name() [2/2]

◆ get()

◆ put()

◆ PVL()

◆ print()

◆ print_element() [1/2]

◆ print_element() [2/2]

◆ print_element_location()

◆ element_location_print_width()

◆ name_field_width() [1/2]

◆ name_field_width() [2/2]

◆ is_valid()

◆ data() [1/2]

◆ attach()

◆ resize()

◆ data() [2/2]

◆ local_data()

◆ internet_checksum()

Member Data Documentation

◆ ID

◆ DECIMAL

◆ HEX

◆ BOOLEAN

◆ PATHNAME_DELIMITER

◆ UTC_SECONDS_PRECISION

◆ SUBSECONDS_DELIMITER

◆ SPICE_METAKERNEL_VARIABLE

◆ DEFAULT_SPICE_METAKERNEL

◆ MRO_CLOCK_ID

◆ INVALID_UTC_TIME