@opentelemetry/otlp-transformer
Version:
Transform OpenTelemetry SDK data into OTLP
78 lines • 2.08 kB
JavaScript
/*
* Copyright The OpenTelemetry Authors
* SPDX-License-Identifier: Apache-2.0
*/
import { estimateVarintSize } from './utils';
/**
* Calculate UTF-8 byte length without encoding
* @param str valid UTF-16 string
*/
function utf8ByteLength(str) {
// No quick path for ASCII, since we need to loop though all chars anyway.
const len = str.length;
let byteLen = 0;
for (let i = 0; i < len; i++) {
const code = str.charCodeAt(i);
if (code < 0x80) {
byteLen += 1;
}
else if (code < 0x800) {
byteLen += 2;
}
else if (code < 0xd800 || code >= 0xe000) {
byteLen += 3;
}
else {
// Surrogate pair
i++; // Skip the next character
byteLen += 4;
}
}
return byteLen;
}
/**
* Size estimator for protobuf messages.
* Implements the same interface as ProtobufWriter but only counts bytes without allocating a buffer.
* @internal
*/
export class ProtobufSizeEstimator {
pos = 0;
startLengthDelimited() {
return this.pos;
}
finishLengthDelimited(_, length) {
this.pos += estimateVarintSize(length);
}
writeVarint(value) {
this.pos += estimateVarintSize(value);
}
writeSint32(value) {
// Zigzag encode: (n << 1) ^ (n >> 31)
this.pos += estimateVarintSize(((value << 1) ^ (value >> 31)) >>> 0);
}
writeSfixed64(_value) {
this.pos += 8;
}
writeFixed32(_value) {
this.pos += 4;
}
writeFixed64(_low, _high) {
this.pos += 8;
}
writeBytes(bytes) {
this.pos += estimateVarintSize(bytes.length);
this.pos += bytes.length;
}
writeTag(fieldNumber, wireType) {
this.writeVarint((fieldNumber << 3) | wireType);
}
writeDouble(_value) {
this.pos += 8;
}
writeString(str) {
const byteLen = utf8ByteLength(str);
this.pos += estimateVarintSize(byteLen);
this.pos += byteLen;
}
}
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