parse-zstd-benc-isbn-data.ts

import * as bencode from 'https://deno.land/x/[email protected]/mod.ts'
import { gtin } from 'npm:cdigit'
import ISBN from 'npm:isbn3'

// zstd -d data/aa_isbn13_codes_20241204T185335Z.benc.zst
const data = await Deno.readFile('data/aa_isbn13_codes_20241204T185335Z.benc').then(bencode.decode)

for (const [key, value] of Object.entries(data as Record<string, Uint8Array>)) {
  console.log(key)

  let streak = true
  let position = 0

  const view = new DataView(value.buffer)

  for (let byteOffset = 0; byteOffset < view.byteLength; byteOffset += 4) {
    const value = view.getUint32(byteOffset, true)

    if (streak) {
      for (let i = 0; i < value; i++) {
        const isbn = String(978000000000 + position)
        const checked = gtin.generate(isbn)
        const data = ISBN.parse(checked)
        console.log(data)
        position++
      }
    } else {
      position += value
    }

    streak = !streak
  }
}