Mp3.hdr.layer: def of emerging-ezaudio@0.4.0.0
Import: import emerging-ezaudio@0.4.0.0/src/mp3.bend as Mp3
Lines 18-24 of emerging-ezaudio@0.4.0.0/src/mp3.bend: https://jend.leeeet.dev/read.txt?path=emerging-ezaudio@0.4.0.0/src/mp3.bend&start_line=18&end_line=24

import Base

# 'MPEG-1 Layer III' is layer code 1 in the header
def hdr.layer(xs: List<&2, U32>) -> U32:
  match xs:
    case _b0 <> +b1 <> _b2 <> _b3 <> _rest:
      ((b1 >> 1n : U32) .&. 3 : U32)
    case _:
      0

Uses (4):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.and
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.shrn