node-ejs-renderer/node_modules/qrcode/lib/core/mode.js
2024-06-09 13:55:01 -04:00

168 lines
3.9 KiB
JavaScript

const VersionCheck = require('./version-check')
const Regex = require('./regex')
/**
* Numeric mode encodes data from the decimal digit set (0 - 9)
* (byte values 30HEX to 39HEX).
* Normally, 3 data characters are represented by 10 bits.
*
* @type {Object}
*/
exports.NUMERIC = {
id: 'Numeric',
bit: 1 << 0,
ccBits: [10, 12, 14]
}
/**
* Alphanumeric mode encodes data from a set of 45 characters,
* i.e. 10 numeric digits (0 - 9),
* 26 alphabetic characters (A - Z),
* and 9 symbols (SP, $, %, *, +, -, ., /, :).
* Normally, two input characters are represented by 11 bits.
*
* @type {Object}
*/
exports.ALPHANUMERIC = {
id: 'Alphanumeric',
bit: 1 << 1,
ccBits: [9, 11, 13]
}
/**
* In byte mode, data is encoded at 8 bits per character.
*
* @type {Object}
*/
exports.BYTE = {
id: 'Byte',
bit: 1 << 2,
ccBits: [8, 16, 16]
}
/**
* The Kanji mode efficiently encodes Kanji characters in accordance with
* the Shift JIS system based on JIS X 0208.
* The Shift JIS values are shifted from the JIS X 0208 values.
* JIS X 0208 gives details of the shift coded representation.
* Each two-byte character value is compacted to a 13-bit binary codeword.
*
* @type {Object}
*/
exports.KANJI = {
id: 'Kanji',
bit: 1 << 3,
ccBits: [8, 10, 12]
}
/**
* Mixed mode will contain a sequences of data in a combination of any of
* the modes described above
*
* @type {Object}
*/
exports.MIXED = {
bit: -1
}
/**
* Returns the number of bits needed to store the data length
* according to QR Code specifications.
*
* @param {Mode} mode Data mode
* @param {Number} version QR Code version
* @return {Number} Number of bits
*/
exports.getCharCountIndicator = function getCharCountIndicator (mode, version) {
if (!mode.ccBits) throw new Error('Invalid mode: ' + mode)
if (!VersionCheck.isValid(version)) {
throw new Error('Invalid version: ' + version)
}
if (version >= 1 && version < 10) return mode.ccBits[0]
else if (version < 27) return mode.ccBits[1]
return mode.ccBits[2]
}
/**
* Returns the most efficient mode to store the specified data
*
* @param {String} dataStr Input data string
* @return {Mode} Best mode
*/
exports.getBestModeForData = function getBestModeForData (dataStr) {
if (Regex.testNumeric(dataStr)) return exports.NUMERIC
else if (Regex.testAlphanumeric(dataStr)) return exports.ALPHANUMERIC
else if (Regex.testKanji(dataStr)) return exports.KANJI
else return exports.BYTE
}
/**
* Return mode name as string
*
* @param {Mode} mode Mode object
* @returns {String} Mode name
*/
exports.toString = function toString (mode) {
if (mode && mode.id) return mode.id
throw new Error('Invalid mode')
}
/**
* Check if input param is a valid mode object
*
* @param {Mode} mode Mode object
* @returns {Boolean} True if valid mode, false otherwise
*/
exports.isValid = function isValid (mode) {
return mode && mode.bit && mode.ccBits
}
/**
* Get mode object from its name
*
* @param {String} string Mode name
* @returns {Mode} Mode object
*/
function fromString (string) {
if (typeof string !== 'string') {
throw new Error('Param is not a string')
}
const lcStr = string.toLowerCase()
switch (lcStr) {
case 'numeric':
return exports.NUMERIC
case 'alphanumeric':
return exports.ALPHANUMERIC
case 'kanji':
return exports.KANJI
case 'byte':
return exports.BYTE
default:
throw new Error('Unknown mode: ' + string)
}
}
/**
* Returns mode from a value.
* If value is not a valid mode, returns defaultValue
*
* @param {Mode|String} value Encoding mode
* @param {Mode} defaultValue Fallback value
* @return {Mode} Encoding mode
*/
exports.from = function from (value, defaultValue) {
if (exports.isValid(value)) {
return value
}
try {
return fromString(value)
} catch (e) {
return defaultValue
}
}