chatRedux/backend/node_modules/bson/lib/validate_utf8.js

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