Carry-8b integer compression. More...
#include <compress_integer_carry_8b.h>
Inheritance diagram for JASS::compress_integer_carry_8b:
Collaboration diagram for JASS::compress_integer_carry_8b:
Classes | |
| class | selector |
| Details of the selectors used in Carry-8b. More... | |
Public Member Functions | |
| compress_integer_carry_8b () | |
| Constructor. | |
| virtual | ~compress_integer_carry_8b () |
| Destructor. | |
| virtual size_t | encode (void *encoded, size_t encoded_buffer_length, const integer *source, size_t source_integers) |
| 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) |
| Decode a sequence of integers encoded with this codex. More... | |
 Public Member Functions inherited from JASS::compress_integer_simple_9 | |
| compress_integer_simple_9 () | |
| Consructor. | |
| virtual | ~compress_integer_simple_9 () |
| Destructor. | |
| Public Member Functions inherited from JASS::compress_integer | |
| compress_integer () | |
| Constructor. | |
| virtual | ~compress_integer () |
| Destructor. | |
Static Public Member Functions | |
| static void | unittest_this (std::vector< integer > every_case) |
| Unit test one sequence of integers - assert on failure. More... | |
| static void | unittest (void) |
| Unit test this class. | |
| Static Public Member Functions inherited from JASS::compress_integer_simple_9 | |
| static void | unittest (void) |
| Unit test this class. | |
| Static Public Member Functions inherited from JASS::compress_integer | |
| 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... | |
Private Member Functions | |
| size_t | pack_one_word (size_t base, size_t highest, uint64_t *destination, const integer *source, size_t source_integers, size_t &next_selector_in_previous_word) |
| encode some number of integers into the given destination using the encoding table. More... | |
Static Private Attributes | |
| static const compress_integer_carry_8b::selector | selector_table [] |
| The selector table for Carry-8b. | |
| static const size_t | base_table [] |
| The starting point in the selector table. More... | |
Additional Inherited Members | |
| Public Types inherited from JASS::compress_integer | |
| 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. | |
| Static Protected Attributes inherited from JASS::compress_integer_simple_9 | |
| static const lookup | simple9_table [] |
| The table mapping bits to slectors and masks. More... | |
| static const uint32_t | bits_to_use [] |
| The number of bits used to store an integer of the given the number of bits in length. More... | |
| static const uint32_t | table_row [] |
| Given the number of bits, which row of simple9_table should be used? More... | |
| static const uint32_t | ints_packed_table [] |
| Number of integers packed into a 32-bit word, given its mask type. More... | |
| static const uint32_t | can_pack_table [] |
| Bitmask map for valid masks at an offset (column) for some num_bits_needed (row). More... | |
| static const uint32_t | row_for_bits_needed [] |
| Translates the 'bits_needed' to the appropriate 'row' offset for use with can_pack table. More... | |
| static const uint32_t | invalid_masks_for_offset [] |
| AND out masks for offsets where we don't know if we can fully pack for that offset. More... | |
| static const uint32_t | simple9_shift_table [] |
| Number of bits to shift when packing - 9 rows for simple-9. More... | |
Detailed Description
Carry-8b integer compression.
Simple-9 compression bin-packs as many integers as possible into a single 28-bit word with a 4-bit selector (to make 32-bits). Relative-10 uses 2-bit selector to encode the current word reltive to the previous word. In Carryover-12 the 2-bit selector is stored in the previous word if there is room. In Carry-8b the selector is 4 bits and carried in the previous word if it fits. Note, however, that there are 22 possible selectors for 60 or 64-bits and which ones are used is carried in the first word - it uses 16 consequitive selectors from the table starting at that base value.
See: V. Anh, A. Moffat (2010), Index compression using 64-bit words, Software Practive & Experience, pp 131-147
Member Function Documentation
◆ decode()
|
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.
Reimplemented from JASS::compress_integer_simple_9.
◆ encode()
|
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).
Reimplemented from JASS::compress_integer_simple_9.
◆ pack_one_word()
|
private |
encode some number of integers into the given destination using the encoding table.
- Parameters
-
base [in] where in the selector_table to start from highest [in] how many selectors to use starting at base destination [in] where to put the encoded codeword source [in] the integer sequence to encode source_integers [in] the maximum number of integers to encode next_selector_in_previous_word [in] Should the compressor pack the selector in the previous word?
- Returns
- the number of integers that were encoded (or 0 on failure to encode)
◆ unittest_this()
|
static |
Unit test one sequence of integers - assert on failure.
- Parameters
-
every_case [in] the sequence to test
Member Data Documentation
◆ base_table
|
staticprivate |
Initial value:
=
{
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
1, 1, 1, 2, 2, 3, 3, 3,
3, 3, 3, 3, 3, 4, 4, 5,
5, 5, 5, 5, 5, 5, 5, 5,
5, 5, 5, 5, 5, 5, 5, 5,
5, 5, 5, 5, 5, 5, 5, 5,
5, 6, 6, 6, 6, 7, 7, 7,
7
}
The starting point in the selector table.
The documentation for this class was generated from the following files:
- source/compress_integer_carry_8b.h
- source/compress_integer_carry_8b.cpp
