src/nmutil/util.py

   1 from collections.abc import Iterable
   2
   3 # XXX this already exists in nmigen._utils
   4 # see https://bugs.libre-soc.org/show_bug.cgi?id=297
   5 def flatten(v):
   6     if isinstance(v, Iterable):
   7         for i in v:
   8             yield from flatten(i)
   9     else:
  10         yield v
  11
  12 # tree reduction function.  operates recursively.
  13 def treereduce(tree, op, fn):
  14     """treereduce: apply a map-reduce to a list.
  15     examples: OR-reduction of one member of a list of Records down to a
  16               single data point:
  17               treereduce(tree, operator.or_, lambda x: getattr(x, "data_o"))
  18     """
  19     #print ("treereduce", tree)
  20     if not isinstance(tree, list):
  21         return tree
  22     if len(tree) == 1:
  23         return fn(tree[0])
  24     if len(tree) == 2:
  25         return op(fn(tree[0]), fn(tree[1]))
  26     s = len(tree) // 2 # splitpoint
  27     return treereduce(op(tree[:s], op, fn), treereduce(tree[s:], op, fn))