35 lines
1.0 KiB
JavaScript
35 lines
1.0 KiB
JavaScript
'use strict'
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// Attribute types must start with an ASCII alphanum character.
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// https://www.rfc-editor.org/rfc/rfc4514#section-3
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// https://www.rfc-editor.org/rfc/rfc4512#section-1.4
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const isLeadChar = (c) => /[a-zA-Z0-9]/.test(c) === true
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/**
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* Find the starting position of an attribute type (name). Leading spaces and
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* commas are ignored. If an invalid leading character is encountered, an
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* invalid position will be returned.
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*
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* @param {Buffer} searchBuffer
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* @param {number} startPos
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*
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* @returns {number} The position in the buffer where the name starts, or `-1`
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* if an invalid name starting character is encountered.
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*/
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module.exports = function findNameStart ({ searchBuffer, startPos }) {
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let pos = startPos
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while (pos < searchBuffer.byteLength) {
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if (searchBuffer[pos] === 0x20 || searchBuffer[pos] === 0x2c) {
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// Skip leading space and comma.
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pos += 1
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continue
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}
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const char = String.fromCharCode(searchBuffer[pos])
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if (isLeadChar(char) === true) {
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return pos
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}
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break
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}
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return -1
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}
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