--- /dev/null
+// Int64.js
+//
+// Copyright (c) 2012 Robert Kieffer
+// MIT License - http://opensource.org/licenses/mit-license.php
+
+/**
+ * Support for handling 64-bit int numbers in Javascript (node.js)
+ *
+ * JS Numbers are IEEE-754 binary double-precision floats, which limits the
+ * range of values that can be represented with integer precision to:
+ *
+ * 2^^53 <= N <= 2^53
+ *
+ * Int64 objects wrap a node Buffer that holds the 8-bytes of int64 data. These
+ * objects operate directly on the buffer which means that if they are created
+ * using an existing buffer then setting the value will modify the Buffer, and
+ * vice-versa.
+ *
+ * Internal Representation
+ *
+ * The internal buffer format is Big Endian. I.e. the most-significant byte is
+ * at buffer[0], the least-significant at buffer[7]. For the purposes of
+ * converting to/from JS native numbers, the value is assumed to be a signed
+ * integer stored in 2's complement form.
+ *
+ * For details about IEEE-754 see:
+ * http://en.wikipedia.org/wiki/Double_precision_floating-point_format
+ */
+
+// Useful masks and values for bit twiddling
+var MASK31 = 0x7fffffff, VAL31 = 0x80000000;
+var MASK32 = 0xffffffff, VAL32 = 0x100000000;
+
+// Map for converting hex octets to strings
+var _HEX = [];
+for (var i = 0; i < 256; i++) {
+ _HEX[i] = (i > 0xF ? '' : '0') + i.toString(16);
+}
+
+//
+// Int64
+//
+
+/**
+ * Constructor accepts any of the following argument types:
+ *
+ * new Int64(buffer[, offset=0]) - Existing Buffer with byte offset
+ * new Int64(Uint8Array[, offset=0]) - Existing Uint8Array with a byte offset
+ * new Int64(string) - Hex string (throws if n is outside int64 range)
+ * new Int64(number) - Number (throws if n is outside int64 range)
+ * new Int64(hi, lo) - Raw bits as two 32-bit values
+ */
+var Int64 = module.exports = function(a1, a2) {
+ if (a1 instanceof Buffer) {
+ this.buffer = a1;
+ this.offset = a2 || 0;
+ } else if (Object.prototype.toString.call(a1) == '[object Uint8Array]') {
+ // Under Browserify, Buffers can extend Uint8Arrays rather than an
+ // instance of Buffer. We could assume the passed in Uint8Array is actually
+ // a buffer but that won't handle the case where a raw Uint8Array is passed
+ // in. We construct a new Buffer just in case.
+ this.buffer = new Buffer(a1);
+ this.offset = a2 || 0;
+ } else {
+ this.buffer = this.buffer || new Buffer(8);
+ this.offset = 0;
+ this.setValue.apply(this, arguments);
+ }
+};
+
+
+// Max integer value that JS can accurately represent
+Int64.MAX_INT = Math.pow(2, 53);
+
+// Min integer value that JS can accurately represent
+Int64.MIN_INT = -Math.pow(2, 53);
+
+Int64.prototype = {
+
+ constructor: Int64,
+
+ /**
+ * Do in-place 2's compliment. See
+ * http://en.wikipedia.org/wiki/Two's_complement
+ */
+ _2scomp: function() {
+ var b = this.buffer, o = this.offset, carry = 1;
+ for (var i = o + 7; i >= o; i--) {
+ var v = (b[i] ^ 0xff) + carry;
+ b[i] = v & 0xff;
+ carry = v >> 8;
+ }
+ },
+
+ /**
+ * Set the value. Takes any of the following arguments:
+ *
+ * setValue(string) - A hexidecimal string
+ * setValue(number) - Number (throws if n is outside int64 range)
+ * setValue(hi, lo) - Raw bits as two 32-bit values
+ */
+ setValue: function(hi, lo) {
+ var negate = false;
+ if (arguments.length == 1) {
+ if (typeof(hi) == 'number') {
+ // Simplify bitfield retrieval by using abs() value. We restore sign
+ // later
+ negate = hi < 0;
+ hi = Math.abs(hi);
+ lo = hi % VAL32;
+ hi = hi / VAL32;
+ if (hi > VAL32) throw new RangeError(hi + ' is outside Int64 range');
+ hi = hi | 0;
+ } else if (typeof(hi) == 'string') {
+ hi = (hi + '').replace(/^0x/, '');
+ lo = hi.substr(-8);
+ hi = hi.length > 8 ? hi.substr(0, hi.length - 8) : '';
+ hi = parseInt(hi, 16);
+ lo = parseInt(lo, 16);
+ } else {
+ throw new Error(hi + ' must be a Number or String');
+ }
+ }
+
+ // Technically we should throw if hi or lo is outside int32 range here, but
+ // it's not worth the effort. Anything past the 32'nd bit is ignored.
+
+ // Copy bytes to buffer
+ var b = this.buffer, o = this.offset;
+ for (var i = 7; i >= 0; i--) {
+ b[o+i] = lo & 0xff;
+ lo = i == 4 ? hi : lo >>> 8;
+ }
+
+ // Restore sign of passed argument
+ if (negate) this._2scomp();
+ },
+
+ /**
+ * Convert to a native JS number.
+ *
+ * WARNING: Do not expect this value to be accurate to integer precision for
+ * large (positive or negative) numbers!
+ *
+ * @param allowImprecise If true, no check is performed to verify the
+ * returned value is accurate to integer precision. If false, imprecise
+ * numbers (very large positive or negative numbers) will be forced to +/-
+ * Infinity.
+ */
+ toNumber: function(allowImprecise) {
+ var b = this.buffer, o = this.offset;
+
+ // Running sum of octets, doing a 2's complement
+ var negate = b[o] & 0x80, x = 0, carry = 1;
+ for (var i = 7, m = 1; i >= 0; i--, m *= 256) {
+ var v = b[o+i];
+
+ // 2's complement for negative numbers
+ if (negate) {
+ v = (v ^ 0xff) + carry;
+ carry = v >> 8;
+ v = v & 0xff;
+ }
+
+ x += v * m;
+ }
+
+ // Return Infinity if we've lost integer precision
+ if (!allowImprecise && x >= Int64.MAX_INT) {
+ return negate ? -Infinity : Infinity;
+ }
+
+ return negate ? -x : x;
+ },
+
+ /**
+ * Convert to a JS Number. Returns +/-Infinity for values that can't be
+ * represented to integer precision.
+ */
+ valueOf: function() {
+ return this.toNumber(false);
+ },
+
+ /**
+ * Return string value
+ *
+ * @param radix Just like Number#toString()'s radix
+ */
+ toString: function(radix) {
+ return this.valueOf().toString(radix || 10);
+ },
+
+ /**
+ * Return a string showing the buffer octets, with MSB on the left.
+ *
+ * @param sep separator string. default is '' (empty string)
+ */
+ toOctetString: function(sep) {
+ var out = new Array(8);
+ var b = this.buffer, o = this.offset;
+ for (var i = 0; i < 8; i++) {
+ out[i] = _HEX[b[o+i]];
+ }
+ return out.join(sep || '');
+ },
+
+ /**
+ * Returns the int64's 8 bytes in a buffer.
+ *
+ * @param {bool} [rawBuffer=false] If no offset and this is true, return the internal buffer. Should only be used if
+ * you're discarding the Int64 afterwards, as it breaks encapsulation.
+ */
+ toBuffer: function(rawBuffer) {
+ if (rawBuffer && this.offset === 0) return this.buffer;
+
+ var out = new Buffer(8);
+ this.buffer.copy(out, 0, this.offset, this.offset + 8);
+ return out;
+ },
+
+ /**
+ * Copy 8 bytes of int64 into target buffer at target offset.
+ *
+ * @param {Buffer} targetBuffer Buffer to copy into.
+ * @param {number} [targetOffset=0] Offset into target buffer.
+ */
+ copy: function(targetBuffer, targetOffset) {
+ this.buffer.copy(targetBuffer, targetOffset || 0, this.offset, this.offset + 8);
+ },
+
+ /**
+ * Returns a number indicating whether this comes before or after or is the
+ * same as the other in sort order.
+ *
+ * @param {Int64} other Other Int64 to compare.
+ */
+ compare: function(other) {
+
+ // If sign bits differ ...
+ if ((this.buffer[this.offset] & 0x80) != (other.buffer[other.offset] & 0x80)) {
+ return other.buffer[other.offset] - this.buffer[this.offset];
+ }
+
+ // otherwise, compare bytes lexicographically
+ for (var i = 0; i < 8; i++) {
+ if (this.buffer[this.offset+i] !== other.buffer[other.offset+i]) {
+ return this.buffer[this.offset+i] - other.buffer[other.offset+i];
+ }
+ }
+ return 0;
+ },
+
+ /**
+ * Returns a boolean indicating if this integer is equal to other.
+ *
+ * @param {Int64} other Other Int64 to compare.
+ */
+ equals: function(other) {
+ return this.compare(other) === 0;
+ },
+
+ /**
+ * Pretty output in console.log
+ */
+ inspect: function() {
+ return '[Int64 value:' + this + ' octets:' + this.toOctetString(' ') + ']';
+ }
+};
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