preprocess_utils.py

# Copyright 2021 The TensorFlow Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# coding=utf-8
"""Utilities for pre-processing."""
import unicodedata

import six

SPIECE_UNDERLINE = '▁'


def printable_text(text):
  """Returns text encoded in a way suitable for print or `tf.logging`."""

  # These functions want `str` for both Python2 and Python3, but in one case
  # it's a Unicode string and in the other it's a byte string.
  if six.PY3:
    if isinstance(text, str):
      return text
    elif isinstance(text, bytes):
      return text.decode('utf-8', 'ignore')
    else:
      raise ValueError('Unsupported string type: %s' % (type(text)))
  elif six.PY2:
    if isinstance(text, str):
      return text
    elif isinstance(text, unicode):  # pylint: disable=undefined-variable
      return text.encode('utf-8')
    else:
      raise ValueError('Unsupported string type: %s' % (type(text)))
  else:
    raise ValueError('Not running on Python2 or Python 3?')


def print_(*args):
  new_args = []
  for arg in args:
    if isinstance(arg, list):
      s = [printable_text(i) for i in arg]
      s = ' '.join(s)
      new_args.append(s)
    else:
      new_args.append(printable_text(arg))
  print(*new_args)


def preprocess_text(inputs, lower=False, remove_space=True, keep_accents=False):
  """Preprocesses texts."""
  if remove_space:
    outputs = ' '.join(inputs.strip().split())
  else:
    outputs = inputs

  outputs = outputs.replace('``', '"').replace("''", '"')

  if six.PY2 and isinstance(outputs, str):
    outputs = outputs.decode('utf-8')

  if not keep_accents:
    outputs = unicodedata.normalize('NFKD', outputs)
    outputs = ''.join([c for c in outputs if not unicodedata.combining(c)])
  if lower:
    outputs = outputs.lower()

  return outputs


def encode_pieces(sp_model, text, return_unicode=True, sample=False):
  """Encodes pieces."""
  # return_unicode is used only for py2

  if six.PY2 and isinstance(text, unicode):  # pylint: disable=undefined-variable
    text = text.encode('utf-8')

  if not sample:
    pieces = sp_model.EncodeAsPieces(text)
  else:
    pieces = sp_model.SampleEncodeAsPieces(text, 64, 0.1)
  new_pieces = []
  for piece in pieces:
    if len(piece) > 1 and piece[-1] == ',' and piece[-2].isdigit():
      cur_pieces = sp_model.EncodeAsPieces(piece[:-1].replace(
          SPIECE_UNDERLINE, ''))
      if piece[0] != SPIECE_UNDERLINE and cur_pieces[0][0] == SPIECE_UNDERLINE:
        if len(cur_pieces[0]) == 1:
          cur_pieces = cur_pieces[1:]
        else:
          cur_pieces[0] = cur_pieces[0][1:]
      cur_pieces.append(piece[-1])
      new_pieces.extend(cur_pieces)
    else:
      new_pieces.append(piece)

  # note(zhiliny): convert back to unicode for py2
  if six.PY2 and return_unicode:
    ret_pieces = []
    for piece in new_pieces:
      if isinstance(piece, str):
        piece = piece.decode('utf-8')
      ret_pieces.append(piece)
    new_pieces = ret_pieces

  return new_pieces


def encode_ids(sp_model, text, sample=False):
  pieces = encode_pieces(sp_model, text, return_unicode=False, sample=sample)
  ids = [sp_model.PieceToId(piece) for piece in pieces]
  return ids