ReedSolomonCodec.md

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ReedSolomonCodec

Reed-Solomon codec for 8-bit characters.

Based on libfec by Phil Karn, KA9Q.

• Full name: \BaconQrCode\Common\ReedSolomonCodec
• This class is marked as final and can't be subclassed
• This class is a Final class

Properties

symbolSize

Symbol size in bits.

private int $symbolSize

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blockSize

Block size in symbols.

private int $blockSize

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firstRoot

First root of RS code generator polynomial, index form.

private int $firstRoot

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primitive

Primitive element to generate polynomial roots, index form.

private int $primitive

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iPrimitive

Prim-th root of 1, index form.

private int $iPrimitive

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numRoots

RS code generator polynomial degree (number of roots).

private int $numRoots

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padding

Padding bytes at front of shortened block.

private int $padding

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alphaTo

Log lookup table.

private \SplFixedArray $alphaTo

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indexOf

Anti-Log lookup table.

private \SplFixedArray $indexOf

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generatorPoly

Generator polynomial.

private \SplFixedArray $generatorPoly

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Methods

__construct

public __construct(int $symbolSize, int $gfPoly, int $firstRoot, int $primitive, int $numRoots, int $padding): mixed

Parameters:

Parameter	Type	Description
$symbolSize	int
$gfPoly	int
$firstRoot	int
$primitive	int
$numRoots	int
$padding	int

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encode

Encodes data and writes result back into parity array.

public encode(\SplFixedArray $data, \SplFixedArray $parity): void

Parameters:

Parameter	Type	Description
$data	\SplFixedArray
$parity	\SplFixedArray

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decode

Decodes received data.

public decode(\SplFixedArray $data, \SplFixedArray $erasures = null): ?int

Parameters:

Parameter	Type	Description
$data	\SplFixedArray
$erasures	\SplFixedArray

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modNn

Computes $x % GF_SIZE, where GF_SIZE is 2**GF_BITS - 1, without a slow divide.

private modNn(int $x): int

Parameters:

Parameter	Type	Description
$x	int

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