Press n or j to go to the next uncovered block, b, p or k for the previous block.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 | 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 160x 160x 160x 1x 1x 1x 1x 1x 1x 160x 160x 160x 160x 160x 160x 160x 160x 160x 160x 160x 160x 160x 160x 160x 160x 160x 160x 160x 160x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 662x 662x 662x 662x 497x 497x 160x 160x 160x 160x 1x 1x 1x 1x 1x 662x 662x 662x 662x 662x 662x 662x 658x 662x 5x 5x 662x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x | import { EC_BLOCK_TABLE } from './qr-ec-block-table.constants.js'
import { CORRECTION_LEVEL_M, CORRECTION_LEVEL_Q } from './ec-level.js'
/**
* @param {number} totalCount - total codewords capacity
* @param {number} dataCount - data codewords capacity
* @returns {Readonly<ECBlock>} created Error Correction block object
*/
const ECBlock = (totalCount, dataCount) => Object.freeze({ totalCount, dataCount, ecCount: totalCount - dataCount })
/**
* gets how much actual space there is in a QR Code, i.e. codewords that can be used to store data and error correction information in a specific version.
*
* Version 1 has no alignment pattern, so the amount of available modules is:
*
* 21**2 (441, where 21 is the size of the QR Code)
* - 3⋅8⋅8 (192, for 3 finder patterns)
* - 2⋅5 (10, the timing patterns)
* - 1 (the dark module)
* - 2⋅15 (30, the error level and mask information)
*
*
* for a total of 208, i.e. 26 codewords.
*
* For larger versions, we have to compute this (let v the version number and n the number of alignment pattern coordinates):
*
* v2 (total modules)
* - 3⋅8⋅8 (finder patterns)
* - (n2 - 3)⋅5 (alignment patterns)
* - 2⋅(4v + 1) (timing patterns)
* + 2⋅(n - 2)⋅5 (reading the intersection of alignment and timing patterns)
* - 1 (dark module)
* - 2⋅3⋅6 (format data, only if v > 6)
* @param {number} version - qr code version
* @returns {number} total Count
*/
function getAvailableModules (version) {
return version === 1 ? 208 : 16 * (version + 4) ** 2 - (5 * (Math.floor(version / 7) + 2) - 1) ** 2 - (version > 6 ? 172 : 136)
}
/**
* @param {number} version - qr code version
* @param {number} errorCorrectionLevel - numeric value of error Correction Level
* @returns {ECBlocksInfo} block info
*/
function buildECBlocksInfo (version, errorCorrectionLevel) {
const totalCount = getAvailableModules(version) >> 3
const index = ((version - 1) * 4 + errorCorrectionLevel) * 2
const blockAmount = EC_BLOCK_TABLE[index + 1]
const group2Blocks = totalCount % blockAmount
const group1Blocks = blockAmount - group2Blocks
const totalBlockCount = Math.floor(totalCount / blockAmount)
const ecBlockSize = EC_BLOCK_TABLE[index]
const dcBlockSize = totalBlockCount - ecBlockSize
const totalDcCount = dcBlockSize * group1Blocks + (dcBlockSize + 1) * group2Blocks
const totalEcCount = ecBlockSize * blockAmount
const maxDcCount = dcBlockSize + (group2Blocks > 0 ? 1 : 0)
const maxEcCount = ecBlockSize
const blocks = Object.freeze([
...new Array(group1Blocks).fill(ECBlock(totalBlockCount, dcBlockSize)),
...new Array(group2Blocks).fill(ECBlock(totalBlockCount + 1, dcBlockSize + 1)),
])
return Object.freeze({ blocks, totalCount, totalDcCount, totalEcCount, maxDcCount, maxEcCount })
}
/**
* The idea was to pre-calculate everything on the EC block table, but it is better to memoize to reduce JS hydration
*/
const memoEcBlockInfo = /** @type {ECBlocksInfo[]} */([])
/**
* @param {number} typeNumber - qr code version
* @param {number} errorCorrectionLevel - numeric value of error Correction Level
* @returns {ECBlocksInfo} error correction blocks information
*/
export function ECBlocksInfo (typeNumber, errorCorrectionLevel) {
versionEcCheck(typeNumber, errorCorrectionLevel)
const index = (typeNumber - 1) * 4 + errorCorrectionLevel
const memo = memoEcBlockInfo[index]
if (memo) {
return memo
}
const result = buildECBlocksInfo(typeNumber, errorCorrectionLevel)
memoEcBlockInfo[index] = result
return result
}
/**
* @param {number} typeNumber - qr code version
* @param {number} errorCorrectionLevel - numeric value of error Correction Level
*/
function versionEcCheck (typeNumber, errorCorrectionLevel) {
if (
typeof errorCorrectionLevel !== 'number' ||
typeof typeNumber !== 'number' ||
errorCorrectionLevel < CORRECTION_LEVEL_M ||
errorCorrectionLevel > CORRECTION_LEVEL_Q ||
typeNumber < 1 ||
typeNumber > 40
) {
throw Error(`bad rs block @ typeNumber:${typeNumber}', errorCorrectionLevel: ${errorCorrectionLevel}`)
}
}
/**
* @typedef {object} ECBlocksInfoData
* @property {ECBlocks} blocks - total codewords count capacity
* @property {number} totalCount - total codewords count
* @property {number} totalDcCount - total data codewords count
* @property {number} totalEcCount - total error correction codewords count
* @property {number} maxDcCount - max data codewords count capacity
* @property {number} maxEcCount - max error codewords count capacity
*/
/**
* @typedef {Readonly<ECBlocksInfoData>} ECBlocksInfo Error Correction blocks information
*/
/**
* @typedef {object} ECBlockData - Error Correction block
* @property {number} totalCount - total codewords count capacity
* @property {number} dataCount - data codewords count capacity
* @property {number} ecCount - error correction codewords count capacity
*/
/**
* @typedef {Readonly<ECBlockData>} ECBlock Error Correction block
*/
/**
* @typedef {Readonly<ECBlock[]>} ECBlocks Error Correction blocks
*/
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