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# Taken from llama code and lightly modified | |
# Copyright (c) Meta Platforms, Inc. and affiliates. | |
# This software may be used and distributed according to the terms of the Llama 2 Community License Agreement. | |
import os | |
import struct | |
import argparse | |
from typing import List | |
from sentencepiece import SentencePieceProcessor | |
TOKENIZER_MODEL = "tokenizer.model" # the llama sentencepiece tokenizer model | |
class Tokenizer: | |
def __init__(self, tokenizer_model=None): | |
model_path = tokenizer_model if tokenizer_model else TOKENIZER_MODEL | |
assert os.path.isfile(model_path), model_path | |
self.sp_model = SentencePieceProcessor(model_file=model_path) | |
self.model_path = model_path | |
# BOS / EOS token IDs | |
self.n_words: int = self.sp_model.vocab_size() | |
self.bos_id: int = self.sp_model.bos_id() | |
self.eos_id: int = self.sp_model.eos_id() | |
self.pad_id: int = self.sp_model.pad_id() | |
#print(f"#words: {self.n_words} - BOS ID: {self.bos_id} - EOS ID: {self.eos_id}") | |
assert self.sp_model.vocab_size() == self.sp_model.get_piece_size() | |
def encode(self, s: str, bos: bool, eos: bool) -> List[int]: | |
assert type(s) is str | |
t = self.sp_model.encode(s) | |
if bos: | |
t = [self.bos_id] + t | |
if eos: | |
t = t + [self.eos_id] | |
return t | |
def decode(self, t: List[int]) -> str: | |
return self.sp_model.decode(t) | |
def export(self): | |
# get all the tokens (postprocessed) and their scores as floats | |
tokens, scores = [], [] | |
for i in range(self.n_words): | |
# decode the token and light postprocessing | |
t = self.sp_model.id_to_piece(i) | |
s = self.sp_model.get_score(i) | |
if i == self.bos_id: | |
t = '\n<s>\n' | |
elif i == self.eos_id: | |
t = '\n</s>\n' | |
t = t.replace('▁', ' ') # sentencepiece uses this character as whitespace | |
b = t.encode('utf-8') # bytes of this token, utf-8 encoded | |
tokens.append(b) | |
scores.append(s) | |
# record the max token length | |
max_token_length = max(len(t) for t in tokens) | |
# write to a binary file | |
# the tokenizer.bin file is the same as .model file, but .bin | |
tokenizer_bin = self.model_path.replace('.model', '.bin') | |
with open(tokenizer_bin, 'wb') as f: | |
f.write(struct.pack("I", max_token_length)) | |
for bytes, score in zip(tokens, scores): | |
f.write(struct.pack("fI", score, len(bytes))) | |
f.write(bytes) | |
if __name__ == "__main__": | |
parser = argparse.ArgumentParser() | |
parser.add_argument("-t", "--tokenizer-model", type=str, help="optional path to custom tokenizer ") | |
args = parser.parse_args() | |
t = Tokenizer(args.tokenizer_model) | |
t.export() | |