47 lines
1.4 KiB
JavaScript
47 lines
1.4 KiB
JavaScript
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"use strict";
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Object.defineProperty(exports, "__esModule", { value: true });
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exports.validateUtf8 = void 0;
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var FIRST_BIT = 0x80;
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var FIRST_TWO_BITS = 0xc0;
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var FIRST_THREE_BITS = 0xe0;
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var FIRST_FOUR_BITS = 0xf0;
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var FIRST_FIVE_BITS = 0xf8;
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var TWO_BIT_CHAR = 0xc0;
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var THREE_BIT_CHAR = 0xe0;
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var FOUR_BIT_CHAR = 0xf0;
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var CONTINUING_CHAR = 0x80;
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/**
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* Determines if the passed in bytes are valid utf8
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* @param bytes - An array of 8-bit bytes. Must be indexable and have length property
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* @param start - The index to start validating
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* @param end - The index to end validating
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*/
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function validateUtf8(bytes, start, end) {
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var continuation = 0;
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for (var i = start; i < end; i += 1) {
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var byte = bytes[i];
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if (continuation) {
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if ((byte & FIRST_TWO_BITS) !== CONTINUING_CHAR) {
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return false;
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}
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continuation -= 1;
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}
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else if (byte & FIRST_BIT) {
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if ((byte & FIRST_THREE_BITS) === TWO_BIT_CHAR) {
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continuation = 1;
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}
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else if ((byte & FIRST_FOUR_BITS) === THREE_BIT_CHAR) {
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continuation = 2;
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}
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else if ((byte & FIRST_FIVE_BITS) === FOUR_BIT_CHAR) {
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continuation = 3;
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}
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else {
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return false;
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}
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}
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}
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return !continuation;
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}
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exports.validateUtf8 = validateUtf8;
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//# sourceMappingURL=validate_utf8.js.map
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