@gmod/bam/esm/indexFile.js

Parser for BAM and BAM index (bai) files

import QuickLRU from '@jbrowse/quick-lru';
import { optimizeChunks } from "./util.js";
// SYNC: ~/src/gmod/tabix-js/src/util.ts memoizeByRefId
// LRU-cache the result of getIndices(refId) so repeated lookups for the same
// reference don't re-walk the index bytes.
export function memoizeByRefId(getIndices, maxSize = 5) {
    const cache = new QuickLRU({ maxSize });
    return (refId) => {
        if (cache.has(refId)) {
            return cache.get(refId);
        }
        const result = getIndices(refId);
        if (result) {
            cache.set(refId, result);
        }
        return result;
    };
}
export default class IndexFile {
    filehandle;
    renameRefSeq;
    setupP;
    constructor({ filehandle, renameRefSeq = (n) => n, }) {
        this.filehandle = filehandle;
        this.renameRefSeq = renameRefSeq;
    }
    async blocksForRange(refId, min, max, opts = {}) {
        if (min < 0) {
            min = 0;
        }
        const indexData = await this.parse(opts);
        const ba = indexData.indices(refId);
        if (!ba) {
            return [];
        }
        const overlappingBins = this.reg2bins(min, max);
        if (overlappingBins.length === 0) {
            return [];
        }
        const chunks = [];
        const { binIndex } = ba;
        for (const [start, end] of overlappingBins) {
            for (let bin = start; bin <= end; bin++) {
                const binChunks = binIndex[bin];
                if (binChunks) {
                    for (let i = 0, l = binChunks.length; i < l; i++) {
                        chunks.push(binChunks[i]);
                    }
                }
            }
        }
        return optimizeChunks(chunks, this.getLowestChunk(ba, min));
    }
    parse(opts = {}) {
        if (!this.setupP) {
            this.setupP = this._parse(opts).catch((e) => {
                this.setupP = undefined;
                throw e;
            });
        }
        return this.setupP;
    }
    async lineCount(refId, opts) {
        const indexData = await this.parse(opts);
        return indexData.indices(refId)?.stats?.lineCount ?? 0;
    }
    async hasRefSeq(seqId, opts) {
        const indexData = await this.parse(opts);
        return !!indexData.indices(seqId);
    }
    async estimatedBytesForRegions(regions, opts) {
        const blockResults = await Promise.all(regions.map(r => this.blocksForRange(r.refId, r.start, r.end, opts)));
        // Deduplicate and merge overlapping blocks across all regions
        const mergedBlocks = optimizeChunks(blockResults.flat());
        let total = 0;
        for (const block of mergedBlocks) {
            total += block.fetchedSize();
        }
        return total;
    }
}
//# sourceMappingURL=indexFile.js.map