JSC Class Reference

Static compressor/lookup helper for JS8Call. More...

#include <JSC.h>

Collaboration diagram for JSC:

Static Public Member Functions
static Codeword	codeword (quint32 index, bool separate, quint32 bytesize, quint32 s, quint32 c)
	Build a codeword for the given parameters.
static QList< CodewordPair >	compress (QString text)
	Compress text into a sequence of codewords.
static QString	decompress (Codeword const &bits)
	Decompress a codeword bit-vector into a QString.
static bool	exists (QString w, quint32 *pIndex)
	Test whether a word exists in the dictionary.
static quint32	lookup (QString w, bool *ok)
	Lookup a word and return its dictionary index.
static quint32	lookup (char const *b, bool *ok)
	Lookup a C-string and return its dictionary index.

Static Public Attributes
static const quint32	size = 262144
static const Tuple	map [262144]
static const Tuple	list [262144]
static const quint32	prefixSize = 103
static const Tuple	prefix [103]

Detailed Description

Static compressor/lookup helper for JS8Call.

This class provides compression and decompression helpers and static lookup tables. Most methods are static and operate on QStrings or plain C strings to locate indexes in the compressed dictionary.

Member Function Documentation

codeword()

Codeword JSC::codeword ( quint32 index, bool separate, quint32 bytesize, quint32 s, quint32 c )

static

Build a codeword for the given parameters.

Generates a codeword for the given index and parameters.

Parameters

index	Index into the dictionary.
separate	Whether the codeword is separated by a delimiter.
bytesize	Byte-size of the codeword container.
s	Additional parameter used by the encoding.
c	Additional parameter used by the encoding.

Returns

A Codeword bit vector representing the encoded entry.

Parameters

index
separate
bytesize
s
c

Returns

Codeword

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compress()

QList< CodewordPair > JSC::compress ( QString text )

static

Compress text into a sequence of codewords.

Compresses the given text into a list of codeword pairs.

Parameters

text	Input text to compress.

Returns

A list of CodewordPair entries representing the compressed data.

Parameters

text

Returns

QList<CodewordPair>

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decompress()

QString JSC::decompress ( Codeword const & bitvec )

static

Decompress a codeword bit-vector into a QString.

Decompresses the given bit vector into a string.

Parameters

bits	Bit vector representing compressed data.

Returns

The decompressed string.

Parameters

bitvec

Returns

QString

exists()

bool JSC::exists ( QString w, quint32 * pIndex )

static

Test whether a word exists in the dictionary.

Checks if the given word exists in the compression map.

Parameters

w	Word to test.
pIndex	Optional out-parameter receiving the dictionary index.

Returns

true if the word exists.

Parameters

w
pIndex

Returns

true

false

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lookup() [1/2]

quint32 JSC::lookup ( char const * b, bool * ok )

static

Lookup a C-string and return its dictionary index.

Looks up the index of the given C-style string in the compression map.

Parameters

b	Null-terminated C string to lookup.
ok	Optional out-parameter set to true on success.

Returns

The dictionary index for the string.

Parameters

b
ok

Returns

quint32

lookup() [2/2]

quint32 JSC::lookup ( QString w, bool * ok )

static

Lookup a word and return its dictionary index.

Looks up the index of the given word in the compression map.

Parameters

w	Word to lookup.
ok	Optional out-parameter set to true on success.

Returns

The dictionary index for the word.

Parameters

w
ok

Returns

quint32

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Member Data Documentation

list

const Tuple JSC::list

static

Secondary mapping table.

map

const Tuple JSC::map

static

Primary mapping table.

prefix

const Tuple JSC::prefix

static

Prefix lookup table.

prefixSize

const quint32 JSC::prefixSize = 103

static

Number of prefix entries.

size

const quint32 JSC::size = 262144

static

Size of static lookup arrays.

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

• JS8_JSC/JSC.h
• JS8_JSC/JSC.cpp
• JS8_JSC/JSC_list.cpp
• JS8_JSC/JSC_map.cpp