// Copyright 2018 Google AI, Google Brain and Carnegie Mellon University Authors and the HuggingFace Inc. team.
// Copyright 2019-2020 Guillaume Becquin
// 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.
use std::path::Path;
use crate::error::TokenizerError;
use crate::tokenizer::base_tokenizer::{TokenIdsWithOffsets, TokenIdsWithSpecialTokens};
use crate::tokenizer::tokenization_utils::strip_accents;
use crate::tokenizer::tokenization_utils::{
clean_text, decompose_nfkc, is_whitespace, lowercase, replace_string, split_on_special_tokens,
};
use crate::tokenizer::{MultiThreadedTokenizer, Tokenizer};
use crate::vocab::{SentencePieceModel, Vocab, XLNetVocab};
use crate::{Mask, Offset, OffsetSize, Token, TokenRef};
/// # XLNet tokenizer
/// XLNet tokenizer performing:
/// - Splitting on special tokens
/// - Text cleaning
/// - NFKC decomposition
/// - (optional) lower casing
/// - (optional) accents stripping
/// - SentencePiece decomposition
#[allow(clippy::upper_case_acronyms)]
pub struct XLNetTokenizer {
model: SentencePieceModel,
vocab: XLNetVocab,
lower_case: bool,
strip_accents: bool,
}
impl XLNetTokenizer {
/// Create a new instance of a `XLNetTokenizer`
/// Expects a SentencePiece protobuf file as an input.
///
/// # Parameters
/// - path (`&str`): path to the SentencePiece model file
/// - lower_case (`bool`): flag indicating if the text should be lower-cased as part of the tokenization
/// - strip_accents (`bool`): flag indicating if accents should be stripped from the text
///
/// # Example
///
/// ```no_run
/// use rust_tokenizers::tokenizer::{Tokenizer, XLNetTokenizer};
/// let lower_case = false;
/// let strip_accents = false;
/// let tokenizer =
/// XLNetTokenizer::from_file("path/to/vocab/file", lower_case, strip_accents).unwrap();
/// ```
pub fn from_file<P: AsRef<Path>>(
path: P,
lower_case: bool,
strip_accents: bool,
) -> Result<XLNetTokenizer, TokenizerError> {
let model = SentencePieceModel::from_file(&path)?;
let vocab = XLNetVocab::from_file(path)?;
Ok(XLNetTokenizer {
model,
vocab,
lower_case,
strip_accents,
})
}
/// Create a new instance of a `XLNetTokenizer`
/// Expects a SentencePiece protobuf file and special token mapping file as inputs.
///
/// # Parameters
/// - path (`&str`): path to the SentencePiece model file
/// - lower_case (`bool`): flag indicating if the text should be lower-cased as part of the tokenization
/// - strip_accents (`bool`): flag indicating if accents should be stripped from the text
/// - special_token_mapping_path (`&str`): path to a special token mapping file to overwrite default special tokens
///
/// # Example
///
/// ```no_run
/// use rust_tokenizers::tokenizer::{Tokenizer, XLNetTokenizer};
/// let lower_case = false;
/// let strip_accents = false;
/// let tokenizer = XLNetTokenizer::from_file_with_special_token_mapping(
/// "path/to/vocab/file",
/// lower_case,
/// strip_accents,
/// "path/to/special/token/mapping/file",
/// )
/// .unwrap();
/// ```
pub fn from_file_with_special_token_mapping<P: AsRef<Path>, S: AsRef<Path>>(
path: P,
lower_case: bool,
strip_accents: bool,
special_token_mapping_path: S,
) -> Result<XLNetTokenizer, TokenizerError> {
let model = SentencePieceModel::from_file(&path)?;
let vocab =
XLNetVocab::from_file_with_special_token_mapping(path, special_token_mapping_path)?;
Ok(XLNetTokenizer {
model,
vocab,
lower_case,
strip_accents,
})
}
/// Create a new instance of a `XLNetTokenizer` from an existing vocabulary and model
///
/// # Parameters
/// - vocab (`XLNetVocab`): vocabulary
/// - model (`SentencePieceModel`): SentencePiece model
/// - lower_case (`bool`): flag indicating if the text should be lower-cased as part of the tokenization
/// - strip_accents (`bool`): flag indicating if accents should be stripped from the text
///
/// # Example
///
/// ```no_run
/// use rust_tokenizers::tokenizer::{Tokenizer, XLNetTokenizer};
/// use rust_tokenizers::vocab::{SentencePieceModel, Vocab, XLNetVocab};
/// let lower_case = false;
/// let strip_accents = false;
/// let vocab = XLNetVocab::from_file("path/to/vocab/file").unwrap();
/// let model = SentencePieceModel::from_file("path/to/model/file").unwrap();
///
/// let tokenizer =
/// XLNetTokenizer::from_existing_vocab_and_model(vocab, model, lower_case, strip_accents);
/// ```
pub fn from_existing_vocab_and_model(
vocab: XLNetVocab,
model: SentencePieceModel,
lower_case: bool,
strip_accents: bool,
) -> XLNetTokenizer {
XLNetTokenizer {
model,
vocab,
lower_case,
strip_accents,
}
}
fn post_process_pieces<'a>(&self, tokens: &'a mut Vec<Token>) -> &'a Vec<Token> {
let mut positions_to_update: Vec<(usize, Vec<Token>)> = vec![];
for (token_idx, token) in tokens.iter().enumerate() {
if token.text.chars().count() > 1 {
let mut token_chars = token.text.chars().rev();
if (token_chars.next().unwrap() == ',')
& token_chars.next().unwrap().is_ascii_digit()
{
let mut new_token = token.clone();
let last_char = new_token.text.pop().unwrap();
let updated_tokens = self.model.decode_forward_token_ref(new_token.as_ref());
let updated_tokens = self.model.decode_backward(&updated_tokens);
let mut updated_tokens = self.model.parse_nodes_to_tokens(updated_tokens);
if !token.text.starts_with('\u{2581}')
& updated_tokens[0].text.starts_with('\u{2581}')
{
if updated_tokens[0].text.chars().count() == 1 {
updated_tokens.remove(0);
} else {
let first_char_length =
updated_tokens[0].text.chars().next().unwrap().len_utf8();
updated_tokens[0].text = (updated_tokens[0].text[first_char_length..])
.parse()
.unwrap();
}
}
updated_tokens.push(Token {
text: last_char.to_string(),
offset: Offset {
begin: token.offset.end,
end: token.offset.end,
},
reference_offsets: vec![*token.reference_offsets.last().unwrap()],
mask: token.mask,
});
positions_to_update.push((token_idx, updated_tokens.clone()));
}
}
}
for (pos, new_tokens) in positions_to_update {
tokens.splice(pos..pos + 1, new_tokens);
}
tokens
}
}
impl Tokenizer<XLNetVocab> for XLNetTokenizer {
fn vocab(&self) -> &XLNetVocab {
&self.vocab
}
fn tokenize_to_tokens(&self, text: TokenRef) -> Vec<Token> {
let mut tokens = split_on_special_tokens(text, &self.vocab)
.into_iter()
.map(|token| token.to_owned())
.collect::<Vec<Token>>();
let mut sub_tokens: Vec<Token> = Vec::new();
for token in tokens.iter_mut() {
if token.mask != Mask::Special && token.mask != Mask::Unknown {
replace_string(token, "``", "\"");
replace_string(token, "\'\'", "\"");
clean_text(token, true);
decompose_nfkc(token);
if self.lower_case {
lowercase(token);
}
if self.strip_accents {
strip_accents(token);
}
token.text = token.text.replace(|c: char| is_whitespace(&c), "\u{2581}");
if !token.text.starts_with('\u{2581}') {
token.text.insert(0, '\u{2581}');
token.reference_offsets.insert(0, 0);
};
let output = self.model.decode_forward_token_ref(token.as_ref());
let decoded = self.model.decode_backward(&output);
let mut output: Vec<Token> = self.model.parse_nodes_to_tokens(decoded);
self.post_process_pieces(&mut output);
sub_tokens.extend(output)
} else {
sub_tokens.push(token.clone());
}
}
sub_tokens
}
fn convert_tokens_to_string(&self, tokens: Vec<String>) -> String {
tokens
.into_iter()
.map(|v| v.replace('\u{2581}', " "))
.collect::<Vec<String>>()
.join("")
}
fn build_input_with_special_tokens(
&self,
tokens_ids_with_offsets_1: TokenIdsWithOffsets,
tokens_ids_with_offsets_2: Option<TokenIdsWithOffsets>,
) -> TokenIdsWithSpecialTokens {
let mut output: Vec<i64> = vec![];
let mut token_segment_ids: Vec<i8> = vec![];
let mut special_tokens_mask: Vec<i8> = vec![];
let mut offsets: Vec<Option<Offset>> = vec![];
let mut original_offsets: Vec<Vec<OffsetSize>> = vec![];
let mut mask: Vec<Mask> = vec![];
// Push the first sequence with a SEP token
special_tokens_mask.extend(vec![0; tokens_ids_with_offsets_1.ids.len()]);
special_tokens_mask.push(1);
token_segment_ids.extend(vec![0; tokens_ids_with_offsets_1.ids.len() + 1]);
output.extend(tokens_ids_with_offsets_1.ids);
output.push(self.vocab.token_to_id(self.vocab.get_sep_value()));
offsets.extend(tokens_ids_with_offsets_1.offsets);
offsets.push(None);
original_offsets.extend(tokens_ids_with_offsets_1.reference_offsets);
original_offsets.push(vec![]);
mask.extend(tokens_ids_with_offsets_1.masks);
mask.push(Mask::Special);
// Push the second sequence with a SEP token if provided
if let Some(tokens_ids_with_offsets_2_value) = tokens_ids_with_offsets_2 {
let length = tokens_ids_with_offsets_2_value.ids.len();
special_tokens_mask.extend(vec![0; length]);
special_tokens_mask.push(1);
token_segment_ids.extend(vec![1; length + 1]);
output.extend(tokens_ids_with_offsets_2_value.ids);
output.push(self.vocab.token_to_id(self.vocab.get_sep_value()));
offsets.extend(tokens_ids_with_offsets_2_value.offsets);
original_offsets.extend(tokens_ids_with_offsets_2_value.reference_offsets);
offsets.push(None);
original_offsets.push(vec![]);
mask.extend(tokens_ids_with_offsets_2_value.masks);
mask.push(Mask::Special);
}
// Push the CLS token at the end of the sequence
output.push(self.vocab.token_to_id(self.vocab.get_cls_value()));
special_tokens_mask.push(1);
offsets.push(None);
original_offsets.push(vec![]);
mask.push(Mask::Special);
TokenIdsWithSpecialTokens {
token_ids: output,
segment_ids: token_segment_ids,
special_tokens_mask,
token_offsets: offsets,
reference_offsets: original_offsets,
mask,
}
}
}
impl MultiThreadedTokenizer<XLNetVocab> for XLNetTokenizer {}