ethers.js/utils/utf8.js

'use strict';
Object.defineProperty(exports, "__esModule", { value: true });
var bytes_1 = require("./bytes");
var UnicodeNormalizationForm;
(function (UnicodeNormalizationForm) {
    UnicodeNormalizationForm["current"] = "";
    UnicodeNormalizationForm["NFC"] = "NFC";
    UnicodeNormalizationForm["NFD"] = "NFD";
    UnicodeNormalizationForm["NFKC"] = "NFKC";
    UnicodeNormalizationForm["NFKD"] = "NFKD";
})(UnicodeNormalizationForm = exports.UnicodeNormalizationForm || (exports.UnicodeNormalizationForm = {}));
;
// http://stackoverflow.com/questions/18729405/how-to-convert-utf8-string-to-byte-array
function toUtf8Bytes(str, form) {
    if (form === void 0) { form = UnicodeNormalizationForm.current; }
    if (form != UnicodeNormalizationForm.current) {
        str = str.normalize(form);
    }
    var result = [];
    var offset = 0;
    for (var i = 0; i < str.length; i++) {
        var c = str.charCodeAt(i);
        if (c < 128) {
            result[offset++] = c;
        }
        else if (c < 2048) {
            result[offset++] = (c >> 6) | 192;
            result[offset++] = (c & 63) | 128;
        }
        else if (((c & 0xFC00) == 0xD800) && (i + 1) < str.length && ((str.charCodeAt(i + 1) & 0xFC00) == 0xDC00)) {
            // Surrogate Pair
            c = 0x10000 + ((c & 0x03FF) << 10) + (str.charCodeAt(++i) & 0x03FF);
            result[offset++] = (c >> 18) | 240;
            result[offset++] = ((c >> 12) & 63) | 128;
            result[offset++] = ((c >> 6) & 63) | 128;
            result[offset++] = (c & 63) | 128;
        }
        else {
            result[offset++] = (c >> 12) | 224;
            result[offset++] = ((c >> 6) & 63) | 128;
            result[offset++] = (c & 63) | 128;
        }
    }
    return bytes_1.arrayify(result);
}
exports.toUtf8Bytes = toUtf8Bytes;
;
// http://stackoverflow.com/questions/13356493/decode-utf-8-with-javascript#13691499
function toUtf8String(bytes) {
    bytes = bytes_1.arrayify(bytes);
    var result = '';
    var i = 0;
    // Invalid bytes are ignored
    while (i < bytes.length) {
        var c = bytes[i++];
        if (c >> 7 == 0) {
            // 0xxx xxxx
            result += String.fromCharCode(c);
            continue;
        }
        // Invalid starting byte
        if (c >> 6 == 0x02) {
            continue;
        }
        // Multibyte; how many bytes left for thus character?
        var extraLength = null;
        if (c >> 5 == 0x06) {
            extraLength = 1;
        }
        else if (c >> 4 == 0x0e) {
            extraLength = 2;
        }
        else if (c >> 3 == 0x1e) {
            extraLength = 3;
        }
        else if (c >> 2 == 0x3e) {
            extraLength = 4;
        }
        else if (c >> 1 == 0x7e) {
            extraLength = 5;
        }
        else {
            continue;
        }
        // Do we have enough bytes in our data?
        if (i + extraLength > bytes.length) {
            // If there is an invalid unprocessed byte, try to continue
            for (; i < bytes.length; i++) {
                if (bytes[i] >> 6 != 0x02) {
                    break;
                }
            }
            if (i != bytes.length)
                continue;
            // All leftover bytes are valid.
            return result;
        }
        // Remove the UTF-8 prefix from the char (res)
        var res = c & ((1 << (8 - extraLength - 1)) - 1);
        var count;
        for (count = 0; count < extraLength; count++) {
            var nextChar = bytes[i++];
            // Is the char valid multibyte part?
            if (nextChar >> 6 != 0x02) {
                break;
            }
            ;
            res = (res << 6) | (nextChar & 0x3f);
        }
        if (count != extraLength) {
            i--;
            continue;
        }
        if (res <= 0xffff) {
            result += String.fromCharCode(res);
            continue;
        }
        res -= 0x10000;
        result += String.fromCharCode(((res >> 10) & 0x3ff) + 0xd800, (res & 0x3ff) + 0xdc00);
    }
    return result;
}
exports.toUtf8String = toUtf8String;