genUserFriendlySig.py

letterToPrim = {
  'Z': 'boolean',
  'B': 'byte',
  'C': 'char',
  'S': 'short',
  'I': 'int',
  'J': 'long',
  'F': 'float',
  'D': 'double',
}


# s: type signature of a class or interface type, e.g. Lcom/foo/Bar;
def getSimpleType(s):
  assert len(s) >= 3
  assert s[0] == 'L' and s[-1] == ';'
  pos = s.rfind('/')
  if pos < 0: pos = 0
  s = s[pos + 1:-1]    
  return s


# s: string of appended internal type signatures, e.g. IJ[B[[DLjava/lang/String;[LFoo;
def parseTypes(s, allowVoid=False):
  types = []
  i = 0
  dimcnt = 0
  while i < len(s):
    ch = s[i]
    if ch == '[':
      dimcnt += 1
      i += 1
      continue

    if ch == 'L':
      pos = s.find(';', i)
      t = s[i:pos+1]
      t = getSimpleType(t)
      i = pos + 1
    elif ch == 'V':
      if not allowVoid: raise Exception()
      t = 'void'
      i += 1
    else:
      t = letterToPrim.get(ch)
      if not t: raise Exception()
      i += 1

    if dimcnt != 0:
      t += ('[]' * dimcnt)
      dimcnt = 0

    types.append(t)

  return types


# s: full method internal signature, e.g. LA/B/C;->func1(IJ[B[[DLjava/lang/String;[LFoo;)V
# will return a user-friendly string consisting of the method name and arguments and return types
def generateUserFriendlyMethodSignature(s):
  pos = s.find('->')
  p0, p1 = s[:pos], s[pos+2:]

  pos = p1.find('(')
  mname = p1[:pos]

  pos2 = p1.find(')', pos)
  _argtypes = p1[pos+1:pos2]
  _rettype = p1[pos2+1:]

  argtypes = parseTypes(_argtypes, False)
  rettype = parseTypes(_rettype, True)[0]

  r = '%s %s(%s)' % (rettype, mname, ', '.join(argtypes))
  return r


# simple test case
if __name__ == '__main__':
  s = 'LA/B/C;->func1(IJ[B[[DLjava/lang/String;[LFoo;)V'
  print('%s => %s' % (s, generateUserFriendlyMethodSignature(s)))