@opentelemetry/sdk-metrics
Version:
63 lines • 2.1 kB
JavaScript
;
/*
* Copyright The OpenTelemetry Authors
*
* 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
*
* https://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.
*/
Object.defineProperty(exports, "__esModule", { value: true });
exports.nextGreaterSquare = exports.ldexp = void 0;
/**
* Note: other languages provide this as a built in function. This is
* a naive, but functionally correct implementation. This is used sparingly,
* when creating a new mapping in a running application.
*
* ldexp returns frac × 2**exp. With the following special cases:
* ldexp(±0, exp) = ±0
* ldexp(±Inf, exp) = ±Inf
* ldexp(NaN, exp) = NaN
* @param frac
* @param exp
* @returns {number}
*/
function ldexp(frac, exp) {
if (frac === 0 ||
frac === Number.POSITIVE_INFINITY ||
frac === Number.NEGATIVE_INFINITY ||
Number.isNaN(frac)) {
return frac;
}
return frac * Math.pow(2, exp);
}
exports.ldexp = ldexp;
/**
* Computes the next power of two that is greater than or equal to v.
* This implementation more efficient than, but functionally equivalent
* to Math.pow(2, Math.ceil(Math.log(x)/Math.log(2))).
* @param v
* @returns {number}
*/
function nextGreaterSquare(v) {
// The following expression computes the least power-of-two
// that is >= v. There are a number of tricky ways to
// do this, see https://stackoverflow.com/questions/466204/rounding-up-to-next-power-of-2
v--;
v |= v >> 1;
v |= v >> 2;
v |= v >> 4;
v |= v >> 8;
v |= v >> 16;
v++;
return v;
}
exports.nextGreaterSquare = nextGreaterSquare;
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