import { Buffer } from 'buffer';
import { BSONTypeError } from './error';
import { Long } from './long';
import { isUint8Array } from './parser/utils';
const PARSE_STRING_REGEXP = /^(\+|-)?(\d+|(\d*\.\d*))?(E|e)?([-+])?(\d+)?$/;
const PARSE_INF_REGEXP = /^(\+|-)?(Infinity|inf)$/i;
const PARSE_NAN_REGEXP = /^(\+|-)?NaN$/i;
const EXPONENT_MAX = 6111;
const EXPONENT_MIN = -6176;
const EXPONENT_BIAS = 6176;
const MAX_DIGITS = 34;
// Nan value bits as 32 bit values (due to lack of longs)
const NAN_BUFFER = [
0x7c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
].reverse();
// Infinity value bits 32 bit values (due to lack of longs)
const INF_NEGATIVE_BUFFER = [
0xf8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
].reverse();
const INF_POSITIVE_BUFFER = [
0x78, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
].reverse();
const EXPONENT_REGEX = /^([-+])?(\d+)?$/;
// Extract least significant 5 bits
const COMBINATION_MASK = 0x1f;
// Extract least significant 14 bits
const EXPONENT_MASK = 0x3fff;
// Value of combination field for Inf
const COMBINATION_INFINITY = 30;
// Value of combination field for NaN
const COMBINATION_NAN = 31;
// Detect if the value is a digit
function isDigit(value: string): boolean {
return !isNaN(parseInt(value, 10));
}
// Divide two uint128 values
function divideu128(value: { parts: [number, number, number, number] }) {
const DIVISOR = Long.fromNumber(1000 * 1000 * 1000);
let _rem = Long.fromNumber(0);
if (!value.parts[0] && !value.parts[1] && !value.parts[2] && !value.parts[3]) {
return { quotient: value, rem: _rem };
}
for (let i = 0; i <= 3; i++) {
// Adjust remainder to match value of next dividend
_rem = _rem.shiftLeft(32);
// Add the divided to _rem
_rem = _rem.add(new Long(value.parts[i], 0));
value.parts[i] = _rem.div(DIVISOR).low;
_rem = _rem.modulo(DIVISOR);
}
return { quotient: value, rem: _rem };
}
// Multiply two Long values and return the 128 bit value
function multiply64x2(left: Long, right: Long): { high: Long; low: Long } {
if (!left && !right) {
return { high: Long.fromNumber(0), low: Long.fromNumber(0) };
}
const leftHigh = left.shiftRightUnsigned(32);
const leftLow = new Long(left.getLowBits(), 0);
const rightHigh = right.shiftRightUnsigned(32);
const rightLow = new Long(right.getLowBits(), 0);
let productHigh = leftHigh.multiply(rightHigh);
let productMid = leftHigh.multiply(rightLow);
const productMid2 = leftLow.multiply(rightHigh);
let productLow = leftLow.multiply(rightLow);
productHigh = productHigh.add(productMid.shiftRightUnsigned(32));
productMid = new Long(productMid.getLowBits(), 0)
.add(productMid2)
.add(productLow.shiftRightUnsigned(32));
productHigh = productHigh.add(productMid.shiftRightUnsigned(32));
productLow = productMid.shiftLeft(32).add(new Long(productLow.getLowBits(), 0));
// Return the 128 bit result
return { high: productHigh, low: productLow };
}
function lessThan(left: Long, right: Long): boolean {
// Make values unsigned
const uhleft = left.high >>> 0;
const uhright = right.high >>> 0;
// Compare high bits first
if (uhleft < uhright) {
return true;
} else if (uhleft === uhright) {
const ulleft = left.low >>> 0;
const ulright = right.low >>> 0;
if (ulleft < ulright) return true;
}
return false;
}
function invalidErr(string: string, message: string) {
throw new BSONTypeError(`"${string}" is not a valid Decimal128 string - ${message}`);
}
/** @public */
export interface Decimal128Extended {
$numberDecimal: string;
}
/**
* A class representation of the BSON Decimal128 type.
* @public
* @category BSONType
*/
export class Decimal128 {
_bsontype!: 'Decimal128';
readonly bytes!: Buffer;
/**
* @param bytes - a buffer containing the raw Decimal128 bytes in little endian order,
* or a string representation as returned by .toString()
*/
constructor(bytes: Buffer | string) {
if (!(this instanceof Decimal128)) return new Decimal128(bytes);
if (typeof bytes === 'string') {
this.bytes = Decimal128.fromString(bytes).bytes;
} else if (isUint8Array(bytes)) {
if (bytes.byteLength !== 16) {
throw new BSONTypeError('Decimal128 must take a Buffer of 16 bytes');
}
this.bytes = bytes;
} else {
throw new BSONTypeError('Decimal128 must take a Buffer or string');
}
}
/**
* Create a Decimal128 instance from a string representation
*
* @param representation - a numeric string representation.
*/
static fromString(representation: string): Decimal128 {
// Parse state tracking
let isNegative = false;
let sawRadix = false;
let foundNonZero = false;
// Total number of significant digits (no leading or trailing zero)
let significantDigits = 0;
// Total number of significand digits read
let nDigitsRead = 0;
// Total number of digits (no leading zeros)
let nDigits = 0;
// The number of the digits after radix
let radixPosition = 0;
// The index of the first non-zero in *str*
let firstNonZero = 0;
// Digits Array
const digits = [0];
// The number of digits in digits
let nDigitsStored = 0;
// Insertion pointer for digits
let digitsInsert = 0;
// The index of the first non-zero digit
let firstDigit = 0;
// The index of the last digit
let lastDigit = 0;
// Exponent
let exponent = 0;
// loop index over array
let i = 0;
// The high 17 digits of the significand
let significandHigh = new Long(0, 0);
// The low 17 digits of the significand
let significandLow = new Long(0, 0);
// The biased exponent
let biasedExponent = 0;
// Read index
let index = 0;
// Naively prevent against REDOS attacks.
// TODO: implementing a custom parsing for this, or refactoring the regex would yield
// further gains.
if (representation.length >= 7000) {
throw new BSONTypeError('' + representation + ' not a valid Decimal128 string');
}
// Results
const stringMatch = representation.match(PARSE_STRING_REGEXP);
const infMatch = representation.match(PARSE_INF_REGEXP);
const nanMatch = representation.match(PARSE_NAN_REGEXP);
// Validate the string
if ((!stringMatch && !infMatch && !nanMatch) || representation.length === 0) {
throw new BSONTypeError('' + representation + ' not a valid Decimal128 string');
}
if (stringMatch) {
// full_match = stringMatch[0]
// sign = stringMatch[1]
const unsignedNumber = stringMatch[2];
// stringMatch[3] is undefined if a whole number (ex "1", 12")
// but defined if a number w/ decimal in it (ex "1.0, 12.2")
const e = stringMatch[4];
const expSign = stringMatch[5];
const expNumber = stringMatch[6];
// they provided e, but didn't give an exponent number. for ex "1e"
if (e && expNumber === undefined) invalidErr(representation, 'missing exponent power');
// they provided e, but didn't give a number before it. for ex "e1"
if (e && unsignedNumber === undefined) invalidErr(representation, 'missing exponent base');
if (e === undefined && (expSign || expNumber)) {
invalidErr(representation, 'missing e before exponent');
}
}
// Get the negative or positive sign
if (representation[index] === '+' || representation[index] === '-') {
isNegative = representation[index++] === '-';
}
// Check if user passed Infinity or NaN
if (!isDigit(representation[index]) && representation[index] !== '.') {
if (representation[index] === 'i' || representation[index] === 'I') {
return new Decimal128(Buffer.from(isNegative ? INF_NEGATIVE_BUFFER : INF_POSITIVE_BUFFER));
} else if (representation[index] === 'N') {
return new Decimal128(Buffer.from(NAN_BUFFER));
}
}
// Read all the digits
while (isDigit(representation[index]) || representation[index] === '.') {
if (representation[index] === '.') {
if (sawRadix) invalidErr(representation, 'contains multiple periods');
sawRadix = true;
index = index + 1;
continue;
}
if (nDigitsStored < 34) {
if (representation[index] !== '0' || foundNonZero) {
if (!foundNonZero) {
firstNonZero = nDigitsRead;
}
foundNonZero = true;
// Only store 34 digits
digits[digitsInsert++] = parseInt(representation[index], 10);
nDigitsStored = nDigitsStored + 1;
}
}
if (foundNonZero) nDigits = nDigits + 1;
if (sawRadix) radixPosition = radixPosition + 1;
nDigitsRead = nDigitsRead + 1;
index = index + 1;
}
if (sawRadix && !nDigitsRead)
throw new BSONTypeError('' + representation + ' not a valid Decimal128 string');
// Read exponent if exists
if (representation[index] === 'e' || representation[index] === 'E') {
// Read exponent digits
const match = representation.substr(++index).match(EXPONENT_REGEX);
// No digits read
if (!match || !match[2]) return new Decimal128(Buffer.from(NAN_BUFFER));
// Get exponent
exponent = parseInt(match[0], 10);
// Adjust the index
index = index + match[0].length;
}
// Return not a number
if (representation[index]) return new Decimal128(Buffer.from(NAN_BUFFER));
// Done reading input
// Find first non-zero digit in digits
firstDigit = 0;
if (!nDigitsStored) {
firstDigit = 0;
lastDigit = 0;
digits[0] = 0;
nDigits = 1;
nDigitsStored = 1;
significantDigits = 0;
} else {
lastDigit = nDigitsStored - 1;
significantDigits = nDigits;
if (significantDigits !== 1) {
while (digits[firstNonZero + significantDigits - 1] === 0) {
significantDigits = significantDigits - 1;
}
}
}
// Normalization of exponent
// Correct exponent based on radix position, and shift significand as needed
// to represent user input
// Overflow prevention
if (exponent <= radixPosition && radixPosition - exponent > 1 << 14) {
exponent = EXPONENT_MIN;
} else {
exponent = exponent - radixPosition;
}
// Attempt to normalize the exponent
while (exponent > EXPONENT_MAX) {
// Shift exponent to significand and decrease
lastDigit = lastDigit + 1;
if (lastDigit - firstDigit > MAX_DIGITS) {
// Check if we have a zero then just hard clamp, otherwise fail
const digitsString = digits.join('');
if (digitsString.match(/^0+$/)) {
exponent = EXPONENT_MAX;
break;
}
invalidErr(representation, 'overflow');
}
exponent = exponent - 1;
}
while (exponent < EXPONENT_MIN || nDigitsStored < nDigits) {
// Shift last digit. can only do this if < significant digits than # stored.
if (lastDigit === 0 && significantDigits < nDigitsStored) {
exponent = EXPONENT_MIN;
significantDigits = 0;
break;
}
if (nDigitsStored < nDigits) {
// adjust to match digits not stored
nDigits = nDigits - 1;
} else {
// adjust to round
lastDigit = lastDigit - 1;
}
if (exponent < EXPONENT_MAX) {
exponent = exponent + 1;
} else {
// Check if we have a zero then just hard clamp, otherwise fail
const digitsString = digits.join('');
if (digitsString.match(/^0+$/)) {
exponent = EXPONENT_MAX;
break;
}
invalidErr(representation, 'overflow');
}
}
// Round
// We've normalized the exponent, but might still need to round.
if (lastDigit - firstDigit + 1 < significantDigits) {
let endOfString = nDigitsRead;
// If we have seen a radix point, 'string' is 1 longer than we have
// documented with ndigits_read, so inc the position of the first nonzero
// digit and the position that digits are read to.
if (sawRadix) {
firstNonZero = firstNonZero + 1;
endOfString = endOfString + 1;
}
// if negative, we need to increment again to account for - sign at start.
if (isNegative) {
firstNonZero = firstNonZero + 1;
endOfString = endOfString + 1;
}
const roundDigit = parseInt(representation[firstNonZero + lastDigit + 1], 10);
let roundBit = 0;
if (roundDigit >= 5) {
roundBit = 1;
if (roundDigit === 5) {
roundBit = digits[lastDigit] % 2 === 1 ? 1 : 0;
for (i = firstNonZero + lastDigit + 2; i < endOfString; i++) {
if (parseInt(representation[i], 10)) {
roundBit = 1;
break;
}
}
}
}
if (roundBit) {
let dIdx = lastDigit;
for (; dIdx >= 0; dIdx--) {
if (++digits[dIdx] > 9) {
digits[dIdx] = 0;
// overflowed most significant digit
if (dIdx === 0) {
if (exponent < EXPONENT_MAX) {
exponent = exponent + 1;
digits[dIdx] = 1;
} else {
return new Decimal128(
Buffer.from(isNegative ? INF_NEGATIVE_BUFFER : INF_POSITIVE_BUFFER)
);
}
}
}
}
}
}
// Encode significand
// The high 17 digits of the significand
significandHigh = Long.fromNumber(0);
// The low 17 digits of the significand
significandLow = Long.fromNumber(0);
// read a zero
if (significantDigits === 0) {
significandHigh = Long.fromNumber(0);
significandLow = Long.fromNumber(0);
} else if (lastDigit - firstDigit < 17) {
let dIdx = firstDigit;
significandLow = Long.fromNumber(digits[dIdx++]);
significandHigh = new Long(0, 0);
for (; dIdx <= lastDigit; dIdx++) {
significandLow = significandLow.multiply(Long.fromNumber(10));
significandLow = significandLow.add(Long.fromNumber(digits[dIdx]));
}
} else {
let dIdx = firstDigit;
significandHigh = Long.fromNumber(digits[dIdx++]);
for (; dIdx <= lastDigit - 17; dIdx++) {
significandHigh = significandHigh.multiply(Long.fromNumber(10));
significandHigh = significandHigh.add(Long.fromNumber(digits[dIdx]));
}
significandLow = Long.fromNumber(digits[dIdx++]);
for (; dIdx <= lastDigit; dIdx++) {
significandLow = significandLow.multiply(Long.fromNumber(10));
significandLow = significandLow.add(Long.fromNumber(digits[dIdx]));
}
}
const significand = multiply64x2(significandHigh, Long.fromString('100000000000000000'));
significand.low = significand.low.add(significandLow);
if (lessThan(significand.low, significandLow)) {
significand.high = significand.high.add(Long.fromNumber(1));
}
// Biased exponent
biasedExponent = exponent + EXPONENT_BIAS;
const dec = { low: Long.fromNumber(0), high: Long.fromNumber(0) };
// Encode combination, exponent, and significand.
if (
significand.high.shiftRightUnsigned(49).and(Long.fromNumber(1)).equals(Long.fromNumber(1))
) {
// Encode '11' into bits 1 to 3
dec.high = dec.high.or(Long.fromNumber(0x3).shiftLeft(61));
dec.high = dec.high.or(
Long.fromNumber(biasedExponent).and(Long.fromNumber(0x3fff).shiftLeft(47))
);
dec.high = dec.high.or(significand.high.and(Long.fromNumber(0x7fffffffffff)));
} else {
dec.high = dec.high.or(Long.fromNumber(biasedExponent & 0x3fff).shiftLeft(49));
dec.high = dec.high.or(significand.high.and(Long.fromNumber(0x1ffffffffffff)));
}
dec.low = significand.low;
// Encode sign
if (isNegative) {
dec.high = dec.high.or(Long.fromString('9223372036854775808'));
}
// Encode into a buffer
const buffer = Buffer.alloc(16);
index = 0;
// Encode the low 64 bits of the decimal
// Encode low bits
buffer[index++] = dec.low.low & 0xff;
buffer[index++] = (dec.low.low >> 8) & 0xff;
buffer[index++] = (dec.low.low >> 16) & 0xff;
buffer[index++] = (dec.low.low >> 24) & 0xff;
// Encode high bits
buffer[index++] = dec.low.high & 0xff;
buffer[index++] = (dec.low.high >> 8) & 0xff;
buffer[index++] = (dec.low.high >> 16) & 0xff;
buffer[index++] = (dec.low.high >> 24) & 0xff;
// Encode the high 64 bits of the decimal
// Encode low bits
buffer[index++] = dec.high.low & 0xff;
buffer[index++] = (dec.high.low >> 8) & 0xff;
buffer[index++] = (dec.high.low >> 16) & 0xff;
buffer[index++] = (dec.high.low >> 24) & 0xff;
// Encode high bits
buffer[index++] = dec.high.high & 0xff;
buffer[index++] = (dec.high.high >> 8) & 0xff;
buffer[index++] = (dec.high.high >> 16) & 0xff;
buffer[index++] = (dec.high.high >> 24) & 0xff;
// Return the new Decimal128
return new Decimal128(buffer);
}
/** Create a string representation of the raw Decimal128 value */
toString(): string {
// Note: bits in this routine are referred to starting at 0,
// from the sign bit, towards the coefficient.
// decoded biased exponent (14 bits)
let biased_exponent;
// the number of significand digits
let significand_digits = 0;
// the base-10 digits in the significand
const significand = new Array<number>(36);
for (let i = 0; i < significand.length; i++) significand[i] = 0;
// read pointer into significand
let index = 0;
// true if the number is zero
let is_zero = false;
// the most significant significand bits (50-46)
let significand_msb;
// temporary storage for significand decoding
let significand128: { parts: [number, number, number, number] } = { parts: [0, 0, 0, 0] };
// indexing variables
let j, k;
// Output string
const string: string[] = [];
// Unpack index
index = 0;
// Buffer reference
const buffer = this.bytes;
// Unpack the low 64bits into a long
// bits 96 - 127
const low =
buffer[index++] | (buffer[index++] << 8) | (buffer[index++] << 16) | (buffer[index++] << 24);
// bits 64 - 95
const midl =
buffer[index++] | (buffer[index++] << 8) | (buffer[index++] << 16) | (buffer[index++] << 24);
// Unpack the high 64bits into a long
// bits 32 - 63
const midh =
buffer[index++] | (buffer[index++] << 8) | (buffer[index++] << 16) | (buffer[index++] << 24);
// bits 0 - 31
const high =
buffer[index++] | (buffer[index++] << 8) | (buffer[index++] << 16) | (buffer[index++] << 24);
// Unpack index
index = 0;
// Create the state of the decimal
const dec = {
low: new Long(low, midl),
high: new Long(midh, high)
};
if (dec.high.lessThan(Long.ZERO)) {
string.push('-');
}
// Decode combination field and exponent
// bits 1 - 5
const combination = (high >> 26) & COMBINATION_MASK;
if (combination >> 3 === 3) {
// Check for 'special' values
if (combination === COMBINATION_INFINITY) {
return string.join('') + 'Infinity';
} else if (combination === COMBINATION_NAN) {
return 'NaN';
} else {
biased_exponent = (high >> 15) & EXPONENT_MASK;
significand_msb = 0x08 + ((high >> 14) & 0x01);
}
} else {
significand_msb = (high >> 14) & 0x07;
biased_exponent = (high >> 17) & EXPONENT_MASK;
}
// unbiased exponent
const exponent = biased_exponent - EXPONENT_BIAS;
// Create string of significand digits
// Convert the 114-bit binary number represented by
// (significand_high, significand_low) to at most 34 decimal
// digits through modulo and division.
significand128.parts[0] = (high & 0x3fff) + ((significand_msb & 0xf) << 14);
significand128.parts[1] = midh;
significand128.parts[2] = midl;
significand128.parts[3] = low;
if (
significand128.parts[0] === 0 &&
significand128.parts[1] === 0 &&
significand128.parts[2] === 0 &&
significand128.parts[3] === 0
) {
is_zero = true;
} else {
for (k = 3; k >= 0; k--) {
let least_digits = 0;
// Perform the divide
const result = divideu128(significand128);
significand128 = result.quotient;
least_digits = result.rem.low;
// We now have the 9 least significant digits (in base 2).
// Convert and output to string.
if (!least_digits) continue;
for (j = 8; j >= 0; j--) {
// significand[k * 9 + j] = Math.round(least_digits % 10);
significand[k * 9 + j] = least_digits % 10;
// least_digits = Math.round(least_digits / 10);
least_digits = Math.floor(least_digits / 10);
}
}
}
// Output format options:
// Scientific - [-]d.dddE(+/-)dd or [-]dE(+/-)dd
// Regular - ddd.ddd
if (is_zero) {
significand_digits = 1;
significand[index] = 0;
} else {
significand_digits = 36;
while (!significand[index]) {
significand_digits = significand_digits - 1;
index = index + 1;
}
}
// the exponent if scientific notation is used
const scientific_exponent = significand_digits - 1 + exponent;
// The scientific exponent checks are dictated by the string conversion
// specification and are somewhat arbitrary cutoffs.
//
// We must check exponent > 0, because if this is the case, the number
// has trailing zeros. However, we *cannot* output these trailing zeros,
// because doing so would change the precision of the value, and would
// change stored data if the string converted number is round tripped.
if (scientific_exponent >= 34 || scientific_exponent <= -7 || exponent > 0) {
// Scientific format
// if there are too many significant digits, we should just be treating numbers
// as + or - 0 and using the non-scientific exponent (this is for the "invalid
// representation should be treated as 0/-0" spec cases in decimal128-1.json)
if (significand_digits > 34) {
string.push(`${0}`);
if (exponent > 0) string.push(`E+${exponent}`);
else if (exponent < 0) string.push(`E${exponent}`);
return string.join('');
}
string.push(`${significand[index++]}`);
significand_digits = significand_digits - 1;
if (significand_digits) {
string.push('.');
}
for (let i = 0; i < significand_digits; i++) {
string.push(`${significand[index++]}`);
}
// Exponent
string.push('E');
if (scientific_exponent > 0) {
string.push(`+${scientific_exponent}`);
} else {
string.push(`${scientific_exponent}`);
}
} else {
// Regular format with no decimal place
if (exponent >= 0) {
for (let i = 0; i < significand_digits; i++) {
string.push(`${significand[index++]}`);
}
} else {
let radix_position = significand_digits + exponent;
// non-zero digits before radix
if (radix_position > 0) {
for (let i = 0; i < radix_position; i++) {
string.push(`${significand[index++]}`);
}
} else {
string.push('0');
}
string.push('.');
// add leading zeros after radix
while (radix_position++ < 0) {
string.push('0');
}
for (let i = 0; i < significand_digits - Math.max(radix_position - 1, 0); i++) {
string.push(`${significand[index++]}`);
}
}
}
return string.join('');
}
toJSON(): Decimal128Extended {
return { $numberDecimal: this.toString() };
}
/** @internal */
toExtendedJSON(): Decimal128Extended {
return { $numberDecimal: this.toString() };
}
/** @internal */
static fromExtendedJSON(doc: Decimal128Extended): Decimal128 {
return Decimal128.fromString(doc.$numberDecimal);
}
/** @internal */
[Symbol.for('nodejs.util.inspect.custom')](): string {
return this.inspect();
}
inspect(): string {
return `new Decimal128("${this.toString()}")`;
}
}
Object.defineProperty(Decimal128.prototype, '_bsontype', { value: 'Decimal128' });