56 lines
1.8 KiB
JavaScript
56 lines
1.8 KiB
JavaScript
/**
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* @fileoverview Utilities to index a binary proto by fieldnumbers without
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* relying on strutural proto information.
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*/
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goog.module('protobuf.binary.indexer');
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const BinaryStorage = goog.require('protobuf.runtime.BinaryStorage');
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const BufferDecoder = goog.require('protobuf.binary.BufferDecoder');
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const WireType = goog.require('protobuf.binary.WireType');
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const {Field} = goog.require('protobuf.binary.field');
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const {checkCriticalState} = goog.require('protobuf.internal.checks');
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const {skipField, tagToFieldNumber, tagToWireType} = goog.require('protobuf.binary.tag');
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/**
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* Appends a new entry in the index array for the given field number.
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* @param {!BinaryStorage<!Field>} storage
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* @param {number} fieldNumber
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* @param {!WireType} wireType
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* @param {number} startIndex
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*/
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function addIndexEntry(storage, fieldNumber, wireType, startIndex) {
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const field = storage.get(fieldNumber);
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if (field !== undefined) {
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field.addIndexEntry(wireType, startIndex);
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} else {
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storage.set(fieldNumber, Field.fromFirstIndexEntry(wireType, startIndex));
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}
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}
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/**
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* Creates an index of field locations in a given binary protobuf.
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* @param {!BufferDecoder} bufferDecoder
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* @param {number|undefined} pivot
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* @return {!BinaryStorage<!Field>}
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* @package
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*/
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function buildIndex(bufferDecoder, pivot) {
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bufferDecoder.setCursor(bufferDecoder.startIndex());
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const storage = new BinaryStorage(pivot);
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while (bufferDecoder.hasNext()) {
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const tag = bufferDecoder.getUnsignedVarint32();
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const wireType = tagToWireType(tag);
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const fieldNumber = tagToFieldNumber(tag);
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checkCriticalState(fieldNumber > 0, `Invalid field number ${fieldNumber}`);
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addIndexEntry(storage, fieldNumber, wireType, bufferDecoder.cursor());
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skipField(bufferDecoder, wireType, fieldNumber);
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}
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return storage;
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}
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exports = {
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buildIndex,
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tagToWireType,
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};
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