vlq.es.js 1.68 KB
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var charToInteger = {};
var integerToChar = {};
'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/='
    .split('')
    .forEach(function (char, i) {
    charToInteger[char] = i;
    integerToChar[i] = char;
});
function decode(string) {
    var result = [];
    var shift = 0;
    var value = 0;
    for (var i = 0; i < string.length; i += 1) {
        var integer = charToInteger[string[i]];
        if (integer === undefined) {
            throw new Error('Invalid character (' + string[i] + ')');
        }
        var hasContinuationBit = integer & 32;
        integer &= 31;
        value += integer << shift;
        if (hasContinuationBit) {
            shift += 5;
        }
        else {
            var shouldNegate = value & 1;
            value >>>= 1;
            if (shouldNegate) {
                result.push(value === 0 ? -0x80000000 : -value);
            }
            else {
                result.push(value);
            }
            // reset
            value = shift = 0;
        }
    }
    return result;
}
function encode(value) {
    var result;
    if (typeof value === 'number') {
        result = encodeInteger(value);
    }
    else {
        result = '';
        for (var i = 0; i < value.length; i += 1) {
            result += encodeInteger(value[i]);
        }
    }
    return result;
}
function encodeInteger(num) {
    var result = '';
    if (num < 0) {
        num = (-num << 1) | 1;
    }
    else {
        num <<= 1;
    }
    do {
        var clamped = num & 31;
        num >>>= 5;
        if (num > 0) {
            clamped |= 32;
        }
        result += integerToChar[clamped];
    } while (num > 0);
    return result;
}

export { decode, encode };