Build a first-fit range allocator

typedef struct {
  int unsigned lo;
  int unsigned hi;
} range_t;

class RangeAllocator;
  range_t free_ranges[$];
  int unsigned managed_base;
  int unsigned managed_limit;

  function new(int unsigned base, int unsigned size);
    if (size == 0) $fatal(1, "allocator size must be positive");
    if (base > 32'hffff_ffff - (size - 1))
      $fatal(1, "managed range wraps the address space");
    managed_base = base;
    managed_limit = base + size - 1;
    free_ranges.push_back('{lo: managed_base, hi: managed_limit});
  endfunction

  function bit alloc(int unsigned size, output int unsigned addr);
    // Implement here: alloc.
  endfunction

  function void dealloc(int unsigned addr, int unsigned size);
    // Implement here: dealloc.
  endfunction

  function void coalesce();
    range_t merged[$];
    range_t current;
    // Implement here: coalesce.
  endfunction
endclass