#!/bin/bash
set -euo pipefail

os_file_size_bytes() {
  local f="$1"
  if stat -f%z "$f" >/dev/null 2>&1; then
    stat -f%z "$f"
  else
    wc -c <"$f" | tr -d ' '
  fi
}

sha256_file() {
  local f="$1"
  if command -v shasum >/dev/null 2>&1; then
    shasum -a 256 "$f" | awk '{print $1}'
  else
    # macOS has 'shasum' by default; fallback:
    openssl dgst -sha256 "$f" | awk '{print $2}'
  fi
}