Files
2026-01-09 15:09:53 +08:00

84 lines
3.5 KiB
Python

from vllm.sampling_params import SamplingParams
from vllm.sequence import VLLM_INVALID_TOKEN_ID
from vllm.transformers_utils.detokenizer import Detokenizer
from vllm.transformers_utils.detokenizer_utils import convert_prompt_ids_to_tokens, detokenize_incrementally
from vllm.zero_overhead.sequence import ZeroOverheadSequence
class ZeroOverheadDetokenizer(Detokenizer):
def __init__(self, tokenizer_group):
super().__init__(tokenizer_group)
def decode_sequence_inplace(self, seq: ZeroOverheadSequence,
prms: SamplingParams) -> int:
"""Decodes the new token for a sequence. In-place operation.
Args:
seq: The sequence to decode.
prms: The sampling parameters used to generate the sequence.
Returns:
The number of characters added to the output text.
"""
eff_length = seq.get_prompt_len() + seq.effective_output_len
all_input_ids = seq.get_token_ids()[ : eff_length]
token_id_generated_this_iteration = all_input_ids[-1]
tokenizer = self.get_tokenizer_for_seq(seq)
# Convert prompt token IDs to tokens if necessary.
# Do it here so that we don't have to repeat this
# computation for each logprob.
if seq.tokens is None:
(seq.tokens, seq.prefix_offset,
seq.read_offset) = convert_prompt_ids_to_tokens(
tokenizer=tokenizer,
prompt_ids=all_input_ids[:-1],
skip_special_tokens=prms.skip_special_tokens,
)
(new_tokens, new_decoded_token_text, prefix_offset,
read_offset) = detokenize_incrementally(
tokenizer=tokenizer,
all_input_ids=all_input_ids,
prev_tokens=seq.tokens,
prefix_offset=seq.prefix_offset,
read_offset=seq.read_offset,
skip_special_tokens=prms.skip_special_tokens,
spaces_between_special_tokens=prms.spaces_between_special_tokens,
)
# Decode logprobs
logprobs = seq.output_logprobs[-1]
if logprobs:
previous_tokens = all_input_ids[:-1]
for token_id, sample_logprob in logprobs.items():
# If the token was generated this iteration,
# use the provided text.
if token_id == token_id_generated_this_iteration:
sample_logprob.decoded_token = new_decoded_token_text
continue
if (sample_logprob.decoded_token is None
and token_id != VLLM_INVALID_TOKEN_ID):
all_input_ids_with_logprob = previous_tokens + [token_id]
(_, new_text, _, _) = detokenize_incrementally(
tokenizer=tokenizer,
all_input_ids=all_input_ids_with_logprob,
prev_tokens=seq.tokens,
prefix_offset=seq.prefix_offset,
read_offset=seq.read_offset,
skip_special_tokens=prms.skip_special_tokens,
spaces_between_special_tokens=prms.
spaces_between_special_tokens,
)
sample_logprob.decoded_token = new_text
seq.tokens.extend(new_tokens)
seq.prefix_offset = prefix_offset
seq.read_offset = read_offset
seq.output_text += new_decoded_token_text
return len(new_decoded_token_text)