Function getXzCompressionOptions

src/utils/compression.ts:53–79

(
  cpuCount: number,
  env: Environment = process.env,
)

}

export const getXzCompressionOptions = (
  cpuCount: number,
  env: Environment = process.env,
): { preset: number; threads: number } => {
  const parsedPreset = parseIntegerEnv('NOSTREAM_XZ_PRESET', env)
  const preset = parsedPreset ?? DEFAULT_XZ_PRESET

  if (preset < MIN_XZ_PRESET || preset > MAX_XZ_PRESET) {
    throw new Error(
      `Invalid NOSTREAM_XZ_PRESET: ${preset}. Expected an integer between ${MIN_XZ_PRESET} and ${MAX_XZ_PRESET}.`,
    )
  }

  const parsedThreadCap = parseIntegerEnv('NOSTREAM_XZ_THREADS', env)
  if (parsedThreadCap !== undefined && parsedThreadCap <= 0) {
    throw new Error('Invalid NOSTREAM_XZ_THREADS: expected a positive integer.')
  }

  // Keep one core available by default to reduce contention with the running relay.
  const availableThreads = Math.max(1, Math.max(1, Math.trunc(cpuCount)) - 1)
  const maxThreads = parsedThreadCap ?? DEFAULT_MAX_XZ_THREADS

  return {
    preset,
    threads: Math.max(1, Math.min(availableThreads, maxThreads)),
  }
}

export const parseCompressionFormat = (input: string): CompressionFormat => {
  switch (input.trim().toLowerCase()) {