bare-operating-system/packages/bare-os-seeder/kernel/bin/cut

/* BARE_OS_BIN_API 1.0.0 — bump when staged /bin script semantics change (see developer guide). */
/** Shared helpers for drive-resident /bin scripts (prepended before each command). */
function bareStdin(ctx) {
  return typeof ctx.shellStdin === 'string' ? ctx.shellStdin : ''
}

/** @param {number} mode @param {'file' | 'directory' | 'symlink'} type */
function bareFormatModeString(mode, type) {
  const typeChar = type === 'directory' ? 'd' : type === 'symlink' ? 'l' : '-'
  const perm = mode & 0o777
  const r = (bit) => (perm & bit ? 'r' : '-')
  const w = (bit) => (perm & bit ? 'w' : '-')
  const x = (bit) => (perm & bit ? 'x' : '-')
  return (
    typeChar +
    r(0o400) +
    w(0o200) +
    x(0o100) +
    r(0o040) +
    w(0o020) +
    x(0o010) +
    r(0o004) +
    w(0o002) +
    x(0o001)
  )
}

/** @param {number} mtimeMs @param {number} [nowMs] */
function bareFormatLsMtime(mtimeMs, nowMs) {
  const now = nowMs != null ? nowMs : Date.now()
  const d = new Date(mtimeMs)
  const months = [
    'Jan',
    'Feb',
    'Mar',
    'Apr',
    'May',
    'Jun',
    'Jul',
    'Aug',
    'Sep',
    'Oct',
    'Nov',
    'Dec'
  ]
  const mon = months[d.getMonth()]
  const day = String(d.getDate()).padStart(2, ' ')
  const sixMo = 180 * 24 * 3600 * 1000
  if (Math.abs(now - mtimeMs) > sixMo) {
    const yr = String(d.getFullYear()).padStart(4, ' ')
    return mon + ' ' + day + '  ' + yr
  }
  const hh = String(d.getHours()).padStart(2, '0')
  const mm = String(d.getMinutes()).padStart(2, '0')
  return mon + ' ' + day + ' ' + hh + ':' + mm
}

/** @param {number} size */
function barePosixBlocks(size) {
  return Math.ceil(Number(size) / 512) || 0
}

/**
 * Raw stdout for NUL/binary when **`process.stdout.write`** is missing.
 * If **`ctx.bareOsBinWrite(Uint8Array|string)`** is set (tests / host), use it.
 * @param {Record<string, unknown>} ctx
 * @param {string | Uint8Array} chunk
 * @returns {boolean}
 */
function bareOsEmitRaw(ctx, chunk) {
  if (typeof ctx.bareOsBinWrite === 'function') {
    const b4 = ctx.b4a
    const u8 =
      typeof chunk === 'string'
        ? b4 && typeof b4.from === 'function'
          ? b4.from(chunk)
          : new TextEncoder().encode(chunk)
        : chunk
    ctx.bareOsBinWrite(u8 instanceof Uint8Array ? u8 : new Uint8Array(u8))
    return true
  }
  const w = globalThis.process?.stdout?.write
  if (typeof w === 'function') {
    w.call(globalThis.process.stdout, chunk)
    return true
  }
  return false
}

async function run(ctx, argv) {
  let delimChar = '\t'
  let fieldsSpec = ''
  let suppressNoDelim = false
  const files = []
  function decodeDelim(raw) {
    if (raw === '\\t') return '\t'
    if (raw === '\\n') return '\n'
    if (raw === '\\0') return '\0'
    return raw
  }
  for (let i = 1; i < argv.length; i++) {
    const a = argv[i]
    if (a === '-d') {
      const raw = argv[++i]
      if (raw == null) {
        ctx.console.error('cut: option -d requires an argument')
        ctx.exitCode = 1
        return
      }
      const parsed = decodeDelim(raw)
      if (parsed.length !== 1) {
        ctx.console.error('cut: delimiter must be a single character')
        ctx.exitCode = 1
        return
      }
      delimChar = parsed
      continue
    }
    if (a.startsWith('-d') && a.length > 2) {
      const parsed = decodeDelim(a.slice(2))
      if (parsed.length !== 1) {
        ctx.console.error('cut: delimiter must be a single character')
        ctx.exitCode = 1
        return
      }
      delimChar = parsed
      continue
    }
    if (a === '-f') {
      fieldsSpec = argv[++i] || ''
      continue
    }
    if (a === '-s' || a === '--only-delimited') {
      suppressNoDelim = true
      continue
    }
    if (a === '--') {
      files.push(...argv.slice(i + 1))
      break
    }
    if (a.startsWith('-')) {
      ctx.console.error('cut: unsupported option ' + a)
      ctx.exitCode = 1
      return
    }
    files.push(a)
  }
  if (!fieldsSpec) {
    ctx.console.error('usage: cut -f LIST [-d DELIM] [-s] [FILE...]')
    ctx.exitCode = 1
    return
  }

  function parseFields(s) {
    /** @type {Set<number>} */
    const set = new Set()
    for (const part of s.split(',')) {
      const m = /^(\d+)(?:-(\d+))?$/.exec(part.trim())
      if (!m) continue
      const a = Number(m[1])
      const b = m[2] != null ? Number(m[2]) : a
      for (let j = a; j <= b; j++) set.add(j)
    }
    return set
  }
  const want = parseFields(fieldsSpec)
  if (!want.size) {
    ctx.console.error('cut: invalid field list')
    ctx.exitCode = 1
    return
  }

  async function cutLines(text) {
    const lines = text.split(/\r?\n/)
    for (const line of lines) {
      if (line === '' && lines.length === 1) continue
      if (suppressNoDelim && !line.includes(delimChar)) {
        continue
      }
      const cols = line.split(delimChar)
      const out = []
      for (const n of [...want].sort((a, b) => a - b)) {
        out.push(cols[n - 1] != null ? cols[n - 1] : '')
      }
      ctx.console.log(out.join(delimChar))
    }
  }

  if (!files.length) {
    await cutLines(bareStdin(ctx))
    return
  }
  for (const f of files) {
    const buf = await ctx.vfs.readFile(f)
    if (!buf) {
      ctx.console.error('cut: ' + f + ': No such file')
      ctx.exitCode = 1
      continue
    }
    await cutLines(ctx.b4a.toString(buf))
  }
}