@gmod/bgzf-filehandle/esm/unzip.js

read from a compressed bgzip file (with .gzi) as if it were uncompressed

import { ungzip } from 'pako-esm2';
import { decompressAll, decompressChunkSlice, } from './wasm/bgzf-wasm-inlined.js';
function hasGzipHeader(data) {
    return data[0] === 0x1f && data[1] === 0x8b;
}
function errorMessage(error) {
    return error instanceof Error ? error.message : `${error}`;
}
async function decompressGzip(inputData) {
    if (typeof DecompressionStream !== 'undefined') {
        const stream = new Blob([inputData])
            .stream()
            .pipeThrough(new DecompressionStream('gzip'));
        return new Uint8Array(await new Response(stream).arrayBuffer());
    }
    else {
        return ungzip(inputData, undefined);
    }
}
function wrapGzipHeaderError(error) {
    if (errorMessage(error).includes('invalid gzip header')) {
        return new Error('problem decompressing block: incorrect gzip header check', { cause: error });
    }
    return error;
}
export async function unzip(inputData) {
    try {
        return await decompressAll(inputData);
    }
    catch (error) {
        const message = errorMessage(error);
        if (message.includes('invalid bgzf header')) {
            if (hasGzipHeader(inputData)) {
                return decompressGzip(inputData);
            }
            throw new Error('problem decompressing block: not a valid bgzf or gzip block', { cause: error });
        }
        throw wrapGzipHeaderError(error);
    }
}
export async function unzipChunkSlice(inputData, chunk) {
    const { minv, maxv } = chunk;
    try {
        const result = await decompressChunkSlice(inputData, minv.blockPosition, minv.dataPosition, maxv.blockPosition, maxv.dataPosition);
        return {
            buffer: result.buffer,
            cpositions: result.cpositions,
            dpositions: result.dpositions,
        };
    }
    catch (error) {
        throw wrapGzipHeaderError(error);
    }
}
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