Carryover-12 integer compression. More...
#include <compress_integer_carryover_12.h>
Inheritance diagram for JASS::compress_integer_carryover_12:
Collaboration diagram for JASS::compress_integer_carryover_12:
Classes | |
| class | selector |
| Details of the 23 selectors used in Carryover-12. More... | |
Public Member Functions | |
| compress_integer_carryover_12 () | |
| Constructor. | |
| virtual | ~compress_integer_carryover_12 () |
| 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 (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... | |
Static Private Attributes | |
| static const compress_integer_carryover_12::selector | transition_table [] |
| The selector table for Carryover-12. 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
Carryover-12 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. This means that sometimes its possible to use 30-bits in the integer and sometimes 32-bits (if the selector is in the previous word).
See: V. Anh, A. Moffat (2005), Inverted Index Compression Using Word-Aligned Binary Codes, Information Retrieval, 8(1):151-166
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.
Member Data Documentation
◆ transition_table
|
staticprivate |
Initial value:
=
{
{"a30", 1, 30, false, {0, 1, 2, 11}},
{"b30", 2, 15, false, {0, 1, 2, 11}},
{"c30", 3, 10, false, {1, 2, 3, 11}},
{"d30", 4, 7, true, {14, 15, 16, 23}},
{"e30", 5, 6, false, {3, 4, 5, 11}},
{"f30", 6, 5, false, {4, 5, 6, 11}},
{"g30", 7, 4, true, {17, 18, 19, 23}},
{"h30", 9, 3, true, {18, 19, 20, 23}},
{"i30", 10, 3, false, {7, 8, 9, 11}},
{"j30", 14, 2, true, {20, 21, 22, 23}},
{"k30", 15, 2, false, {8, 9, 10, 11}},
{"l30", 28, 1, true, {17, 20, 22, 23}},
{"a32", 1, 32, false, {0, 1, 2, 11}},
{"b32", 2, 16, false, {0, 1, 2, 11}},
{"c32", 3, 10, true, {13, 14, 15, 23}},
{"d32", 4, 8, false, {2, 3, 4, 11}},
{"e32", 5, 6, true, {15, 16, 17, 23}},
{"f32", 6, 5, true, {16, 17, 18, 23}},
{"g32", 7, 4, true, {17, 18, 19, 23}},
{"h32", 8, 4, false, {6, 7, 8, 11}},
{"i32", 10, 3, true, {19, 20, 21, 23}},
{"j32", 15, 2, true, {20, 21, 22, 23}},
{"k32", 16, 2, false, {8, 9, 10, 11}},
{"l32", 30, 1, true, {17, 20, 22, 23}},
}
The selector table for Carryover-12.
The documentation for this class was generated from the following files:
- source/compress_integer_carryover_12.h
- source/compress_integer_carryover_12.cpp
