// Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. // // Copyright 2009 Google Inc. All Rights Reserved /** * This type is for INTERNAL use in MongoDB only and should not be used in applications. * The appropriate corresponding type is the JavaScript Date type. * * Defines a Timestamp class for representing a 64-bit two's-complement * integer value, which faithfully simulates the behavior of a Java "Timestamp". This * implementation is derived from TimestampLib in GWT. * * Constructs a 64-bit two's-complement integer, given its low and high 32-bit * values as *signed* integers. See the from* functions below for more * convenient ways of constructing Timestamps. * * The internal representation of a Timestamp is the two given signed, 32-bit values. * We use 32-bit pieces because these are the size of integers on which * Javascript performs bit-operations. For operations like addition and * multiplication, we split each number into 16-bit pieces, which can easily be * multiplied within Javascript's floating-point representation without overflow * or change in sign. * * In the algorithms below, we frequently reduce the negative case to the * positive case by negating the input(s) and then post-processing the result. * Note that we must ALWAYS check specially whether those values are MIN_VALUE * (-2^63) because -MIN_VALUE == MIN_VALUE (since 2^63 cannot be represented as * a positive number, it overflows back into a negative). Not handling this * case would often result in infinite recursion. * * @class * @param {number} low the low (signed) 32 bits of the Timestamp. * @param {number} high the high (signed) 32 bits of the Timestamp. */ function Timestamp(low, high) { if (!(this instanceof Timestamp)) return new Timestamp(low, high); this._bsontype = 'Timestamp'; /** * @type {number} * @ignore */ this.low_ = low | 0; // force into 32 signed bits. /** * @type {number} * @ignore */ this.high_ = high | 0; // force into 32 signed bits. } /** * Return the int value. * * @return {number} the value, assuming it is a 32-bit integer. */ Timestamp.prototype.toInt = function() { return this.low_; }; /** * Return the Number value. * * @method * @return {number} the closest floating-point representation to this value. */ Timestamp.prototype.toNumber = function() { return this.high_ * Timestamp.TWO_PWR_32_DBL_ + this.getLowBitsUnsigned(); }; /** * Return the JSON value. * * @method * @return {string} the JSON representation. */ Timestamp.prototype.toJSON = function() { return this.toString(); }; /** * Return the String value. * * @method * @param {number} [opt_radix] the radix in which the text should be written. * @return {string} the textual representation of this value. */ Timestamp.prototype.toString = function(opt_radix) { var radix = opt_radix || 10; if (radix < 2 || 36 < radix) { throw Error('radix out of range: ' + radix); } if (this.isZero()) { return '0'; } if (this.isNegative()) { if (this.equals(Timestamp.MIN_VALUE)) { // We need to change the Timestamp value before it can be negated, so we remove // the bottom-most digit in this base and then recurse to do the rest. var radixTimestamp = Timestamp.fromNumber(radix); var div = this.div(radixTimestamp); var rem = div.multiply(radixTimestamp).subtract(this); return div.toString(radix) + rem.toInt().toString(radix); } else { return '-' + this.negate().toString(radix); } } // Do several (6) digits each time through the loop, so as to // minimize the calls to the very expensive emulated div. var radixToPower = Timestamp.fromNumber(Math.pow(radix, 6)); rem = this; var result = ''; while (!rem.isZero()) { var remDiv = rem.div(radixToPower); var intval = rem.subtract(remDiv.multiply(radixToPower)).toInt(); var digits = intval.toString(radix); rem = remDiv; if (rem.isZero()) { return digits + result; } else { while (digits.length < 6) { digits = '0' + digits; } result = '' + digits + result; } } }; /** * Return the high 32-bits value. * * @method * @return {number} the high 32-bits as a signed value. */ Timestamp.prototype.getHighBits = function() { return this.high_; }; /** * Return the low 32-bits value. * * @method * @return {number} the low 32-bits as a signed value. */ Timestamp.prototype.getLowBits = function() { return this.low_; }; /** * Return the low unsigned 32-bits value. * * @method * @return {number} the low 32-bits as an unsigned value. */ Timestamp.prototype.getLowBitsUnsigned = function() { return this.low_ >= 0 ? this.low_ : Timestamp.TWO_PWR_32_DBL_ + this.low_; }; /** * Returns the number of bits needed to represent the absolute value of this Timestamp. * * @method * @return {number} Returns the number of bits needed to represent the absolute value of this Timestamp. */ Timestamp.prototype.getNumBitsAbs = function() { if (this.isNegative()) { if (this.equals(Timestamp.MIN_VALUE)) { return 64; } else { return this.negate().getNumBitsAbs(); } } else { var val = this.high_ !== 0 ? this.high_ : this.low_; for (var bit = 31; bit > 0; bit--) { if ((val & (1 << bit)) !== 0) { break; } } return this.high_ !== 0 ? bit + 33 : bit + 1; } }; /** * Return whether this value is zero. * * @method * @return {boolean} whether this value is zero. */ Timestamp.prototype.isZero = function() { return this.high_ === 0 && this.low_ === 0; }; /** * Return whether this value is negative. * * @method * @return {boolean} whether this value is negative. */ Timestamp.prototype.isNegative = function() { return this.high_ < 0; }; /** * Return whether this value is odd. * * @method * @return {boolean} whether this value is odd. */ Timestamp.prototype.isOdd = function() { return (this.low_ & 1) === 1; }; /** * Return whether this Timestamp equals the other * * @method * @param {Timestamp} other Timestamp to compare against. * @return {boolean} whether this Timestamp equals the other */ Timestamp.prototype.equals = function(other) { return this.high_ === other.high_ && this.low_ === other.low_; }; /** * Return whether this Timestamp does not equal the other. * * @method * @param {Timestamp} other Timestamp to compare against. * @return {boolean} whether this Timestamp does not equal the other. */ Timestamp.prototype.notEquals = function(other) { return this.high_ !== other.high_ || this.low_ !== other.low_; }; /** * Return whether this Timestamp is less than the other. * * @method * @param {Timestamp} other Timestamp to compare against. * @return {boolean} whether this Timestamp is less than the other. */ Timestamp.prototype.lessThan = function(other) { return this.compare(other) < 0; }; /** * Return whether this Timestamp is less than or equal to the other. * * @method * @param {Timestamp} other Timestamp to compare against. * @return {boolean} whether this Timestamp is less than or equal to the other. */ Timestamp.prototype.lessThanOrEqual = function(other) { return this.compare(other) <= 0; }; /** * Return whether this Timestamp is greater than the other. * * @method * @param {Timestamp} other Timestamp to compare against. * @return {boolean} whether this Timestamp is greater than the other. */ Timestamp.prototype.greaterThan = function(other) { return this.compare(other) > 0; }; /** * Return whether this Timestamp is greater than or equal to the other. * * @method * @param {Timestamp} other Timestamp to compare against. * @return {boolean} whether this Timestamp is greater than or equal to the other. */ Timestamp.prototype.greaterThanOrEqual = function(other) { return this.compare(other) >= 0; }; /** * Compares this Timestamp with the given one. * * @method * @param {Timestamp} other Timestamp to compare against. * @return {boolean} 0 if they are the same, 1 if the this is greater, and -1 if the given one is greater. */ Timestamp.prototype.compare = function(other) { if (this.equals(other)) { return 0; } var thisNeg = this.isNegative(); var otherNeg = other.isNegative(); if (thisNeg && !otherNeg) { return -1; } if (!thisNeg && otherNeg) { return 1; } // at this point, the signs are the same, so subtraction will not overflow if (this.subtract(other).isNegative()) { return -1; } else { return 1; } }; /** * The negation of this value. * * @method * @return {Timestamp} the negation of this value. */ Timestamp.prototype.negate = function() { if (this.equals(Timestamp.MIN_VALUE)) { return Timestamp.MIN_VALUE; } else { return this.not().add(Timestamp.ONE); } }; /** * Returns the sum of this and the given Timestamp. * * @method * @param {Timestamp} other Timestamp to add to this one. * @return {Timestamp} the sum of this and the given Timestamp. */ Timestamp.prototype.add = function(other) { // Divide each number into 4 chunks of 16 bits, and then sum the chunks. var a48 = this.high_ >>> 16; var a32 = this.high_ & 0xffff; var a16 = this.low_ >>> 16; var a00 = this.low_ & 0xffff; var b48 = other.high_ >>> 16; var b32 = other.high_ & 0xffff; var b16 = other.low_ >>> 16; var b00 = other.low_ & 0xffff; var c48 = 0, c32 = 0, c16 = 0, c00 = 0; c00 += a00 + b00; c16 += c00 >>> 16; c00 &= 0xffff; c16 += a16 + b16; c32 += c16 >>> 16; c16 &= 0xffff; c32 += a32 + b32; c48 += c32 >>> 16; c32 &= 0xffff; c48 += a48 + b48; c48 &= 0xffff; return Timestamp.fromBits((c16 << 16) | c00, (c48 << 16) | c32); }; /** * Returns the difference of this and the given Timestamp. * * @method * @param {Timestamp} other Timestamp to subtract from this. * @return {Timestamp} the difference of this and the given Timestamp. */ Timestamp.prototype.subtract = function(other) { return this.add(other.negate()); }; /** * Returns the product of this and the given Timestamp. * * @method * @param {Timestamp} other Timestamp to multiply with this. * @return {Timestamp} the product of this and the other. */ Timestamp.prototype.multiply = function(other) { if (this.isZero()) { return Timestamp.ZERO; } else if (other.isZero()) { return Timestamp.ZERO; } if (this.equals(Timestamp.MIN_VALUE)) { return other.isOdd() ? Timestamp.MIN_VALUE : Timestamp.ZERO; } else if (other.equals(Timestamp.MIN_VALUE)) { return this.isOdd() ? Timestamp.MIN_VALUE : Timestamp.ZERO; } if (this.isNegative()) { if (other.isNegative()) { return this.negate().multiply(other.negate()); } else { return this.negate() .multiply(other) .negate(); } } else if (other.isNegative()) { return this.multiply(other.negate()).negate(); } // If both Timestamps are small, use float multiplication if (this.lessThan(Timestamp.TWO_PWR_24_) && other.lessThan(Timestamp.TWO_PWR_24_)) { return Timestamp.fromNumber(this.toNumber() * other.toNumber()); } // Divide each Timestamp into 4 chunks of 16 bits, and then add up 4x4 products. // We can skip products that would overflow. var a48 = this.high_ >>> 16; var a32 = this.high_ & 0xffff; var a16 = this.low_ >>> 16; var a00 = this.low_ & 0xffff; var b48 = other.high_ >>> 16; var b32 = other.high_ & 0xffff; var b16 = other.low_ >>> 16; var b00 = other.low_ & 0xffff; var c48 = 0, c32 = 0, c16 = 0, c00 = 0; c00 += a00 * b00; c16 += c00 >>> 16; c00 &= 0xffff; c16 += a16 * b00; c32 += c16 >>> 16; c16 &= 0xffff; c16 += a00 * b16; c32 += c16 >>> 16; c16 &= 0xffff; c32 += a32 * b00; c48 += c32 >>> 16; c32 &= 0xffff; c32 += a16 * b16; c48 += c32 >>> 16; c32 &= 0xffff; c32 += a00 * b32; c48 += c32 >>> 16; c32 &= 0xffff; c48 += a48 * b00 + a32 * b16 + a16 * b32 + a00 * b48; c48 &= 0xffff; return Timestamp.fromBits((c16 << 16) | c00, (c48 << 16) | c32); }; /** * Returns this Timestamp divided by the given one. * * @method * @param {Timestamp} other Timestamp by which to divide. * @return {Timestamp} this Timestamp divided by the given one. */ Timestamp.prototype.div = function(other) { if (other.isZero()) { throw Error('division by zero'); } else if (this.isZero()) { return Timestamp.ZERO; } if (this.equals(Timestamp.MIN_VALUE)) { if (other.equals(Timestamp.ONE) || other.equals(Timestamp.NEG_ONE)) { return Timestamp.MIN_VALUE; // recall that -MIN_VALUE == MIN_VALUE } else if (other.equals(Timestamp.MIN_VALUE)) { return Timestamp.ONE; } else { // At this point, we have |other| >= 2, so |this/other| < |MIN_VALUE|. var halfThis = this.shiftRight(1); var approx = halfThis.div(other).shiftLeft(1); if (approx.equals(Timestamp.ZERO)) { return other.isNegative() ? Timestamp.ONE : Timestamp.NEG_ONE; } else { var rem = this.subtract(other.multiply(approx)); var result = approx.add(rem.div(other)); return result; } } } else if (other.equals(Timestamp.MIN_VALUE)) { return Timestamp.ZERO; } if (this.isNegative()) { if (other.isNegative()) { return this.negate().div(other.negate()); } else { return this.negate() .div(other) .negate(); } } else if (other.isNegative()) { return this.div(other.negate()).negate(); } // Repeat the following until the remainder is less than other: find a // floating-point that approximates remainder / other *from below*, add this // into the result, and subtract it from the remainder. It is critical that // the approximate value is less than or equal to the real value so that the // remainder never becomes negative. var res = Timestamp.ZERO; rem = this; while (rem.greaterThanOrEqual(other)) { // Approximate the result of division. This may be a little greater or // smaller than the actual value. approx = Math.max(1, Math.floor(rem.toNumber() / other.toNumber())); // We will tweak the approximate result by changing it in the 48-th digit or // the smallest non-fractional digit, whichever is larger. var log2 = Math.ceil(Math.log(approx) / Math.LN2); var delta = log2 <= 48 ? 1 : Math.pow(2, log2 - 48); // Decrease the approximation until it is smaller than the remainder. Note // that if it is too large, the product overflows and is negative. var approxRes = Timestamp.fromNumber(approx); var approxRem = approxRes.multiply(other); while (approxRem.isNegative() || approxRem.greaterThan(rem)) { approx -= delta; approxRes = Timestamp.fromNumber(approx); approxRem = approxRes.multiply(other); } // We know the answer can't be zero... and actually, zero would cause // infinite recursion since we would make no progress. if (approxRes.isZero()) { approxRes = Timestamp.ONE; } res = res.add(approxRes); rem = rem.subtract(approxRem); } return res; }; /** * Returns this Timestamp modulo the given one. * * @method * @param {Timestamp} other Timestamp by which to mod. * @return {Timestamp} this Timestamp modulo the given one. */ Timestamp.prototype.modulo = function(other) { return this.subtract(this.div(other).multiply(other)); }; /** * The bitwise-NOT of this value. * * @method * @return {Timestamp} the bitwise-NOT of this value. */ Timestamp.prototype.not = function() { return Timestamp.fromBits(~this.low_, ~this.high_); }; /** * Returns the bitwise-AND of this Timestamp and the given one. * * @method * @param {Timestamp} other the Timestamp with which to AND. * @return {Timestamp} the bitwise-AND of this and the other. */ Timestamp.prototype.and = function(other) { return Timestamp.fromBits(this.low_ & other.low_, this.high_ & other.high_); }; /** * Returns the bitwise-OR of this Timestamp and the given one. * * @method * @param {Timestamp} other the Timestamp with which to OR. * @return {Timestamp} the bitwise-OR of this and the other. */ Timestamp.prototype.or = function(other) { return Timestamp.fromBits(this.low_ | other.low_, this.high_ | other.high_); }; /** * Returns the bitwise-XOR of this Timestamp and the given one. * * @method * @param {Timestamp} other the Timestamp with which to XOR. * @return {Timestamp} the bitwise-XOR of this and the other. */ Timestamp.prototype.xor = function(other) { return Timestamp.fromBits(this.low_ ^ other.low_, this.high_ ^ other.high_); }; /** * Returns this Timestamp with bits shifted to the left by the given amount. * * @method * @param {number} numBits the number of bits by which to shift. * @return {Timestamp} this shifted to the left by the given amount. */ Timestamp.prototype.shiftLeft = function(numBits) { numBits &= 63; if (numBits === 0) { return this; } else { var low = this.low_; if (numBits < 32) { var high = this.high_; return Timestamp.fromBits(low << numBits, (high << numBits) | (low >>> (32 - numBits))); } else { return Timestamp.fromBits(0, low << (numBits - 32)); } } }; /** * Returns this Timestamp with bits shifted to the right by the given amount. * * @method * @param {number} numBits the number of bits by which to shift. * @return {Timestamp} this shifted to the right by the given amount. */ Timestamp.prototype.shiftRight = function(numBits) { numBits &= 63; if (numBits === 0) { return this; } else { var high = this.high_; if (numBits < 32) { var low = this.low_; return Timestamp.fromBits((low >>> numBits) | (high << (32 - numBits)), high >> numBits); } else { return Timestamp.fromBits(high >> (numBits - 32), high >= 0 ? 0 : -1); } } }; /** * Returns this Timestamp with bits shifted to the right by the given amount, with the new top bits matching the current sign bit. * * @method * @param {number} numBits the number of bits by which to shift. * @return {Timestamp} this shifted to the right by the given amount, with zeros placed into the new leading bits. */ Timestamp.prototype.shiftRightUnsigned = function(numBits) { numBits &= 63; if (numBits === 0) { return this; } else { var high = this.high_; if (numBits < 32) { var low = this.low_; return Timestamp.fromBits((low >>> numBits) | (high << (32 - numBits)), high >>> numBits); } else if (numBits === 32) { return Timestamp.fromBits(high, 0); } else { return Timestamp.fromBits(high >>> (numBits - 32), 0); } } }; /** * Returns a Timestamp representing the given (32-bit) integer value. * * @method * @param {number} value the 32-bit integer in question. * @return {Timestamp} the corresponding Timestamp value. */ Timestamp.fromInt = function(value) { if (-128 <= value && value < 128) { var cachedObj = Timestamp.INT_CACHE_[value]; if (cachedObj) { return cachedObj; } } var obj = new Timestamp(value | 0, value < 0 ? -1 : 0); if (-128 <= value && value < 128) { Timestamp.INT_CACHE_[value] = obj; } return obj; }; /** * Returns a Timestamp representing the given value, provided that it is a finite number. Otherwise, zero is returned. * * @method * @param {number} value the number in question. * @return {Timestamp} the corresponding Timestamp value. */ Timestamp.fromNumber = function(value) { if (isNaN(value) || !isFinite(value)) { return Timestamp.ZERO; } else if (value <= -Timestamp.TWO_PWR_63_DBL_) { return Timestamp.MIN_VALUE; } else if (value + 1 >= Timestamp.TWO_PWR_63_DBL_) { return Timestamp.MAX_VALUE; } else if (value < 0) { return Timestamp.fromNumber(-value).negate(); } else { return new Timestamp( (value % Timestamp.TWO_PWR_32_DBL_) | 0, (value / Timestamp.TWO_PWR_32_DBL_) | 0 ); } }; /** * Returns a Timestamp representing the 64-bit integer that comes by concatenating the given high and low bits. Each is assumed to use 32 bits. * * @method * @param {number} lowBits the low 32-bits. * @param {number} highBits the high 32-bits. * @return {Timestamp} the corresponding Timestamp value. */ Timestamp.fromBits = function(lowBits, highBits) { return new Timestamp(lowBits, highBits); }; /** * Returns a Timestamp representation of the given string, written using the given radix. * * @method * @param {string} str the textual representation of the Timestamp. * @param {number} opt_radix the radix in which the text is written. * @return {Timestamp} the corresponding Timestamp value. */ Timestamp.fromString = function(str, opt_radix) { if (str.length === 0) { throw Error('number format error: empty string'); } var radix = opt_radix || 10; if (radix < 2 || 36 < radix) { throw Error('radix out of range: ' + radix); } if (str.charAt(0) === '-') { return Timestamp.fromString(str.substring(1), radix).negate(); } else if (str.indexOf('-') >= 0) { throw Error('number format error: interior "-" character: ' + str); } // Do several (8) digits each time through the loop, so as to // minimize the calls to the very expensive emulated div. var radixToPower = Timestamp.fromNumber(Math.pow(radix, 8)); var result = Timestamp.ZERO; for (var i = 0; i < str.length; i += 8) { var size = Math.min(8, str.length - i); var value = parseInt(str.substring(i, i + size), radix); if (size < 8) { var power = Timestamp.fromNumber(Math.pow(radix, size)); result = result.multiply(power).add(Timestamp.fromNumber(value)); } else { result = result.multiply(radixToPower); result = result.add(Timestamp.fromNumber(value)); } } return result; }; // NOTE: Common constant values ZERO, ONE, NEG_ONE, etc. are defined below the // from* methods on which they depend. /** * A cache of the Timestamp representations of small integer values. * @type {Object} * @ignore */ Timestamp.INT_CACHE_ = {}; // NOTE: the compiler should inline these constant values below and then remove // these variables, so there should be no runtime penalty for these. /** * Number used repeated below in calculations. This must appear before the * first call to any from* function below. * @type {number} * @ignore */ Timestamp.TWO_PWR_16_DBL_ = 1 << 16; /** * @type {number} * @ignore */ Timestamp.TWO_PWR_24_DBL_ = 1 << 24; /** * @type {number} * @ignore */ Timestamp.TWO_PWR_32_DBL_ = Timestamp.TWO_PWR_16_DBL_ * Timestamp.TWO_PWR_16_DBL_; /** * @type {number} * @ignore */ Timestamp.TWO_PWR_31_DBL_ = Timestamp.TWO_PWR_32_DBL_ / 2; /** * @type {number} * @ignore */ Timestamp.TWO_PWR_48_DBL_ = Timestamp.TWO_PWR_32_DBL_ * Timestamp.TWO_PWR_16_DBL_; /** * @type {number} * @ignore */ Timestamp.TWO_PWR_64_DBL_ = Timestamp.TWO_PWR_32_DBL_ * Timestamp.TWO_PWR_32_DBL_; /** * @type {number} * @ignore */ Timestamp.TWO_PWR_63_DBL_ = Timestamp.TWO_PWR_64_DBL_ / 2; /** @type {Timestamp} */ Timestamp.ZERO = Timestamp.fromInt(0); /** @type {Timestamp} */ Timestamp.ONE = Timestamp.fromInt(1); /** @type {Timestamp} */ Timestamp.NEG_ONE = Timestamp.fromInt(-1); /** @type {Timestamp} */ Timestamp.MAX_VALUE = Timestamp.fromBits(0xffffffff | 0, 0x7fffffff | 0); /** @type {Timestamp} */ Timestamp.MIN_VALUE = Timestamp.fromBits(0, 0x80000000 | 0); /** * @type {Timestamp} * @ignore */ Timestamp.TWO_PWR_24_ = Timestamp.fromInt(1 << 24); /** * Expose. */ module.exports = Timestamp; module.exports.Timestamp = Timestamp;