opat Namespace Reference

Namespaces
namespace	lattice
	Namespace for table lattice interpolation of OPAT files.

Classes
struct	Bounds
	Structure to hold the minimum and maximum values for a dimension. More...
struct	CardCatalog
	Structure to hold the catalog of tables in a DataCard. More...
struct	CardCatalogEntry
	Structure to hold the index information of a table in an OPAT file. More...
struct	CardHeader
	Structure to hold the header information of a DataCard in an OPAT file. More...
struct	DataCard
	Structure to hold a DataCard, which contains multiple tables. More...
struct	Header
	Structure to hold the header information of an OPAT file. More...
struct	OPAT
	Structure to hold the entire OPAT file. More...
struct	OPATTable
	Structure to hold the data of an OPAT table. More...
struct	Slice
	Structure to represent a slice of data. More...
struct	TableIndex
	Structure to hold the index of tables within a DataCard. More...
struct	TableIndexEntry
	Structure to hold the index information of a table within a DataCard. More...

Functions
bool	is_big_endian ()
	Determines if the system is big-endian.
bool	hasMagic (const std::string &filename)
	Checks if a file has the correct magic number for an OPAT file.
OPAT	readOPAT (const std::string &filename)
	Reads an OPAT file and returns its contents as an OPAT structure.
Header	readHeader (std::ifstream &file)
	Reads the header of an OPAT file.
CardCatalogEntry	readCardCatalogEntry (std::ifstream &file, uint64_t offset, uint16_t numIndex, uint8_t hashPrecision)
	Reads a CardCatalogEntry from the file.
CardCatalog	readCardCatalog (std::ifstream &file, const Header &header)
	Reads the CardCatalog from the file.
std::unordered_map< FloatIndexVector, DataCard >	readDataCards (std::ifstream &file, const Header &header, const CardCatalog &cardCatalog)
	Reads all DataCards from the file.
DataCard	readDataCard (std::ifstream &file, const CardCatalogEntry &entry)
	Reads a single DataCard from the file.
CardHeader	readDataCardHeader (std::ifstream &file, const CardCatalogEntry &entry)
	Reads the header of a DataCard from the file.
TableIndex	readTableIndex (std::ifstream &file, const CardCatalogEntry &entry, const CardHeader &header)
	Reads the TableIndex from a DataCard.
OPATTable	readOPATTable (std::ifstream &file, const CardCatalogEntry &cardEntry, const TableIndexEntry &tableEntry)
	Reads an OPATTable from the file.
std::ostream &	operator<< (std::ostream &os, const Header &header)
std::ostream &	operator<< (std::ostream &os, const CardHeader &header)
std::ostream &	operator<< (std::ostream &os, const CardCatalogEntry &entry)
std::ostream &	operator<< (std::ostream &os, const CardCatalog &catalog)
std::ostream &	operator<< (std::ostream &os, const TableIndexEntry &entry)
std::ostream &	operator<< (std::ostream &os, const TableIndex &index)
std::ostream &	operator<< (std::ostream &os, const OPATTable &table)
std::ostream &	operator<< (std::ostream &os, const DataCard &card)
std::ostream &	operator<< (std::ostream &os, const OPAT &opat)
std::ostream &	operator<< (std::ostream &os, const Slice &slice)
std::ostream &	operator<< (std::ostream &os, const Bounds &bounds)
template<typename T>
T	swap_bytes (T value)
	Swaps the byte order of a value.

Function Documentation

hasMagic()

bool opat::hasMagic

(

const std::string &

filename

)

Checks if a file has the correct magic number for an OPAT file.

This function reads the first four bytes of the file and compares them to the expected "OPAT" magic number.

Parameters

filename

Path to the file.

Returns

True if the file has the correct magic number, false otherwise.

Example:

bool isValid = opat::hasMagic("example.opat");
if (isValid) {
    std::cout << "Valid OPAT file!" << std::endl;
}

is_big_endian()

bool opat::is_big_endian

(

)

Determines if the system is big-endian.

This utility function checks the system's endianness by examining the byte order of a test value.

Returns

True if the system is big-endian, false otherwise.

Example:

if (opat::is_big_endian()) {
    std::cout << "System is big-endian." << std::endl;
}

operator<<() [1/11]

std::ostream & opat::operator<<	(	std::ostream &	os,
		const Bounds &	bounds )

Parameters

os	Output stream.
bounds	Bounds to print.

Returns

Reference to the output stream.

operator<<() [2/11]

std::ostream & opat::operator<<	(	std::ostream &	os,
		const CardCatalog &	catalog )

Parameters

os	Output stream.
catalog	CardCatalog to print.

Returns

Reference to the output stream.

operator<<() [3/11]

std::ostream & opat::operator<<	(	std::ostream &	os,
		const CardCatalogEntry &	entry )

Parameters

os	Output stream.
entry	CardCatalogEntry to print.

Returns

Reference to the output stream.

operator<<() [4/11]

std::ostream & opat::operator<<	(	std::ostream &	os,
		const CardHeader &	header )

Parameters

os	Output stream.
header	CardHeader to print.

Returns

Reference to the output stream.

operator<<() [5/11]

std::ostream & opat::operator<<	(	std::ostream &	os,
		const DataCard &	card )

Parameters

os	Output stream.
card	DataCard to print.

Returns

Reference to the output stream.

operator<<() [6/11]

std::ostream & opat::operator<<	(	std::ostream &	os,
		const Header &	header )

Parameters

os	Output stream.
header	Header to print.

Returns

Reference to the output stream.

operator<<() [7/11]

std::ostream & opat::operator<<	(	std::ostream &	os,
		const OPAT &	opat )

Parameters

os	Output stream.
opat	OPAT structure to print.

Returns

Reference to the output stream.

operator<<() [8/11]

std::ostream & opat::operator<<	(	std::ostream &	os,
		const OPATTable &	table )

operator<<() [9/11]

std::ostream & opat::operator<<	(	std::ostream &	os,
		const Slice &	slice )

Parameters

os	Output stream.
slice	Slice to print.

Returns

Reference to the output stream.

operator<<() [10/11]

std::ostream & opat::operator<<	(	std::ostream &	os,
		const TableIndex &	index )

Parameters

os	Output stream.
index	TableIndex to print.

Returns

Reference to the output stream.

operator<<() [11/11]

std::ostream & opat::operator<<	(	std::ostream &	os,
		const TableIndexEntry &	entry )

Parameters

os	Output stream.
entry	TableIndexEntry to print.

Returns

Reference to the output stream.

readCardCatalog()

CardCatalog opat::readCardCatalog	(	std::ifstream &	file,
		const Header &	header )

Reads the CardCatalog from the file.

This function reads all entries in the card catalog, using the header information to determine the number of entries and their locations.

Parameters

file	Input file stream.
header	The header of the OPAT file.

Returns

A CardCatalog structure.

Exceptions

std::runtime_error

if the card catalog cannot be read or is incomplete.

Example:

std::ifstream file("example.opat", std::ios::binary);
opat::Header header = opat::readHeader(file);
opat::CardCatalog catalog = opat::readCardCatalog(file, header);
std::cout << catalog << std::endl;

readCardCatalogEntry()

CardCatalogEntry opat::readCardCatalogEntry	(	std::ifstream &	file,
		uint64_t	offset,
		uint16_t	numIndex,
		uint8_t	hashPrecision )

Reads a CardCatalogEntry from the file.

This function reads a single entry from the card catalog, including its index, byte range, and SHA-256 hash. It also performs byte-swapping for compatibility with big-endian systems.

Parameters

file	Input file stream.
offset	Offset to the entry in the file.
numIndex	Number of indices in the entry.
hashPrecision	Precision of the hash used for validation.

Returns

A CardCatalogEntry structure.

Exceptions

std::runtime_error

if the entry cannot be read or is incomplete.

Example:

std::ifstream file("example.opat", std::ios::binary);
opat::CardCatalogEntry entry = opat::readCardCatalogEntry(file, 128, 3, 8);
std::cout << entry << std::endl;

readDataCard()

DataCard opat::readDataCard	(	std::ifstream &	file,
		const CardCatalogEntry &	entry )

Reads a single DataCard from the file.

This function reads the header, table index, and table data for a single DataCard.

Parameters

file	Input file stream.
entry	The CardCatalogEntry for the DataCard.

Returns

A DataCard structure.

Exceptions

std::runtime_error

if the DataCard cannot be read or is incomplete.

Example:

std::ifstream file("example.opat", std::ios::binary);
opat::CardCatalogEntry entry = ...; // Retrieved from the catalog
opat::DataCard card = opat::readDataCard(file, entry);

readDataCardHeader()

CardHeader opat::readDataCardHeader	(	std::ifstream &	file,
		const CardCatalogEntry &	entry )

Reads the header of a DataCard from the file.

This function reads the header structure of a DataCard and performs byte-swapping for compatibility with big-endian systems.

Parameters

file	Input file stream.
entry	The CardCatalogEntry for the DataCard.

Returns

A CardHeader structure.

Exceptions

std::runtime_error

if the DataCard header cannot be read or is incomplete.

Example:

std::ifstream file("example.opat", std::ios::binary);
opat::CardCatalogEntry entry = ...; // Retrieved from the catalog
opat::CardHeader header = opat::readDataCardHeader(file, entry);

readDataCards()

std::unordered_map< FloatIndexVector, DataCard > opat::readDataCards	(	std::ifstream &	file,
		const Header &	header,
		const CardCatalog &	cardCatalog )

Reads all DataCards from the file.

This function reads all DataCards in the OPAT file, using the card catalog to locate each card and its associated data.

Parameters

file	Input file stream.
header	The header of the OPAT file.
cardCatalog	The CardCatalog of the OPAT file.

Returns

A map of index vectors to DataCards.

Exceptions

std::runtime_error

if any DataCard cannot be read or is incomplete.

Example:

std::ifstream file("example.opat", std::ios::binary);
opat::Header header = opat::readHeader(file);
opat::CardCatalog catalog = opat::readCardCatalog(file, header);
auto cards = opat::readDataCards(file, header, catalog);

readHeader()

Header opat::readHeader

(

std::ifstream &

file

)

Reads the header of an OPAT file.

This function reads the header structure from the file and performs byte-swapping if the system is big-endian.

Parameters

file	Input file stream positioned at the start of the header.

Returns

A Header structure containing the file's metadata.

Exceptions

std::runtime_error

if the header cannot be read or is incomplete.

Example:

std::ifstream file("example.opat", std::ios::binary);
opat::Header header = opat::readHeader(file);
header.print();

readOPAT()

OPAT opat::readOPAT

(

const std::string &

filename

)

Reads an OPAT file and returns its contents as an OPAT structure.

This function validates the file's magic number, reads the header, card catalog, and all data cards, and constructs an OPAT object representing the file's contents.

Parameters

filename

Path to the OPAT file.

Returns

An OPAT structure containing the file's data.

Exceptions

std::runtime_error

if the file cannot be opened, is invalid, or has an incorrect magic number.

Example:

OPAT file = opat::readOPAT("example.opat");
std::cout << file.header << std::endl;

readOPATTable()

OPATTable opat::readOPATTable	(	std::ifstream &	file,
		const CardCatalogEntry &	cardEntry,
		const TableIndexEntry &	tableEntry )

Reads an OPATTable from the file.

This function reads the row values, column values, and data for a single table within a DataCard.

Parameters

file	Input file stream.
cardEntry	The CardCatalogEntry for the DataCard.
tableEntry	The TableIndexEntry for the table.

Returns

An OPATTable structure.

Exceptions

std::runtime_error

if the table cannot be read or is incomplete.

Example:

std::ifstream file("example.opat", std::ios::binary);
opat::CardCatalogEntry cardEntry = ...; // Retrieved from the catalog
opat::TableIndexEntry tableEntry = ...; // Retrieved from the table index
opat::OPATTable table = opat::readOPATTable(file, cardEntry, tableEntry);

readTableIndex()

TableIndex opat::readTableIndex	(	std::ifstream &	file,
		const CardCatalogEntry &	entry,
		const CardHeader &	header )

Reads the TableIndex from a DataCard.

This function reads the table index of a DataCard, which maps table tags to their metadata and locations within the card.

Parameters

file	Input file stream.
entry	The CardCatalogEntry for the DataCard.
header	The CardHeader of the DataCard.

Returns

A TableIndex structure.

Exceptions

std::runtime_error

if the TableIndex cannot be read or is incomplete.

Example:

std::ifstream file("example.opat", std::ios::binary);
opat::CardCatalogEntry entry = ...; // Retrieved from the catalog
opat::CardHeader header = opat::readDataCardHeader(file, entry);
opat::TableIndex index = opat::readTableIndex(file, entry, header);

swap_bytes()

template<typename T>

T opat::swap_bytes

(

T

value

)

Swaps the byte order of a value.

This function is useful for handling endianness when reading binary files. It ensures compatibility across systems with different byte orders.

Template Parameters

T	The type of the value (must be trivially copyable).

Parameters

value

The value to swap.

Returns

The value with its byte order reversed.

Example:

uint16_t value = 0x1234;
uint16_t swapped = opat::swap_bytes(value);