Compression codexes for integer sequences. More...

#include <compress_integer.h>

Inheritance diagram for JASS::compress_integer:

Public Types
typedef uint32_t	integer
	This class and descendants will work on integers of this size. Do not change without also changing JASS_COMPRESS_INTEGER_BITS_PER_INTEGER.

Public Member Functions
	compress_integer ()
	Constructor.

virtual	~compress_integer ()
	Destructor.

virtual size_t	encode (void encoded, size_t encoded_buffer_length, const integer source, size_t source_integers)=0
	Encode a sequence of integers returning the number of bytes used for the encoding, or 0 if the encoded sequence doesn't fit in the buffer. More...

virtual void	decode (integer decoded, size_t integers_to_decode, const void source, size_t source_length)=0
	Decode a sequence of integers encoded with this codex. More...

Static Public Member Functions
static size_t	d1_encode (integer encoded, const integer source, size_t source_integers)
	Convert an array of integers into an array of D1 (delta, d-gap) encoded integers. More...

static size_t	d1_decode (integer decoded, const integer source, size_t source_integers)
	Convert a D1 encoded array of integers into an array of integers. More...

static size_t	dn_encode (integer encoded, const integer source, size_t source_integers, size_t n=1)
	Convert an array of integers into an array of Dn (delta, d-gap) encoded integers with a gap of n. More...

static size_t	dn_decode (integer decoded, const integer source, size_t source_integers, size_t n=1)
	Convert a Dn encoded array of integers into an array of integers. More...

static void	unittest_one (compress_integer &encoder, const std::vector< uint32_t > &sequence)
	Test one sequence to make sure it encodes and decodes to the same thing. Assert if not. More...

static void	unittest (compress_integer &compressor, uint32_t staring_from=0)
	Unit test this class, assert on failure. More...

Static Private Attributes
static constexpr int	MAX_D_GAP = 64
	this is the maximum D-ness that this code supports, it can be changes to anything that won't reuslt in stack overflow. It is unlikely to exceed 16 for years (from 2019).

Detailed Description

Compression codexes for integer sequences.

To implement a codex you need to subclass this virtual base class and implement two methods, encode() and decode(). As those methods are virtual, an object of the given subclass is needed in order to encode or decode integer sequences.

Member Function Documentation

◆ d1_decode()

static size_t JASS::compress_integer::d1_decode	(	integer *	decoded,
		const integer *	source,
		size_t	source_integers
	)

inlinestatic

Convert a D1 encoded array of integers into an array of integers.

Parameters

decoded	[out] The decoded integers (can be the same buffer as source). source [in] The D1 encoded integers.
source_integers	[in] The number of integers in the list.

Returns: The number of integers encoded.

◆ d1_encode()

static size_t JASS::compress_integer::d1_encode	(	integer *	encoded,
		const integer *	source,
		size_t	source_integers
	)

inlinestatic

Convert an array of integers into an array of D1 (delta, d-gap) encoded integers.

Parameters

encoded	[out] The d1-encoded result (can be the same buffer as source). source [in] The integers to be D1 encoded.
source_integers	[in] The number of integers in the list.

Returns: The number of integers encoded.

◆ decode()

virtual void JASS::compress_integer::decode	(	integer *	decoded,
		size_t	integers_to_decode,
		const void *	source,
		size_t	source_length
	)

pure virtual

Decode a sequence of integers encoded with this codex.

Parameters

decoded	[out] The sequence of decoded integers.
integers_to_decode	[in] The minimum number of integers to decode (it may decode more).
source	[in] The encoded integers.
source_length	[in] The length (in bytes) of the source buffer.

◆ dn_decode()

static size_t JASS::compress_integer::dn_decode	(	integer *	decoded,
		const integer *	source,
		size_t	source_integers,
		size_t	n = `1`
	)

inlinestatic

Convert a Dn encoded array of integers into an array of integers.

Parameters

decoded	[out] The decoded integers (can be the same buffer as source). source [in] The Dn encoded integers.
source_integers	[in] The number of integers in the list.
n	[in] The encoding distance (normally 1, but can be any inteter up-to source_integers).

Returns: The number of integers encoded.

◆ dn_encode()

static size_t JASS::compress_integer::dn_encode	(	integer *	encoded,
		const integer *	source,
		size_t	source_integers,
		size_t	n = `1`
	)

inlinestatic

Convert an array of integers into an array of Dn (delta, d-gap) encoded integers with a gap of n.

Parameters

encoded	[out] The Dn-encoded result (can be the same buffer as source). source [in] The integers to be Dn encoded.
source_integers	[in] The number of integers in the list.
n	[in] The encoding distance (normally 1, but can be any inteter up-to MAX_D_GAP).

Returns: The number of integers encoded.

◆ encode()

virtual size_t JASS::compress_integer::encode	(	void *	encoded,
		size_t	encoded_buffer_length,
		const integer *	source,
		size_t	source_integers
	)

pure virtual

Encode a sequence of integers returning the number of bytes used for the encoding, or 0 if the encoded sequence doesn't fit in the buffer.

Parameters

encoded	[out] The sequence of bytes that is the encoded sequence.
encoded_buffer_length	[in] The length (in bytes) of the output buffer, encoded.
source	[in] The sequence of integers to encode.
source_integers	[in] The length (in integers) of the source buffer.

Returns: The number of bytes used to encode the integer sequence, or 0 on error (i.e. overflow).

◆ unittest()

void JASS::compress_integer::unittest	(	compress_integer &	compressor,
		uint32_t	staring_from = `0`
	)

static

Unit test this class, assert on failure.

Parameters

compressor	[in] a compressor
staring_from	[in] normally 0. The bitness to start testing from (some schemes cannot encode a 0 (e.g. Elias gama) so use 1 in those cases).

◆ unittest_one()

void JASS::compress_integer::unittest_one	(	compress_integer &	encoder,
		const std::vector< uint32_t > &	sequence
	)

static

Test one sequence to make sure it encodes and decodes to the same thing. Assert if not.

Parameters

encoder	[in] The integer encoded being tested.
sequence	[in] the sequernce to encode.

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

source/compress_integer.h
source/compress_integer.cpp

Public Types

Public Member Functions

Static Public Member Functions

Static Private Attributes

Detailed Description

Member Function Documentation

◆ d1_decode()

◆ d1_encode()

◆ decode()

◆ dn_decode()

◆ dn_encode()

◆ encode()

◆ unittest()

◆ unittest_one()