From 48047df8d56a1c2e675e1c492a26a5147e6855bd Mon Sep 17 00:00:00 2001
From: Milo <zxz065047@gmail.com>
Date: Sun, 19 Apr 2026 13:50:44 +0800
Subject: [PATCH] feat: implement batch tokenization for TokenizeManager

  - Use tokenizer() for batch encoding plain texts
  - Use apply_chat_template() for batch processing chat templates
  - Remove padding tokens using attention mask
  - Preserve original message order
  - Add comprehensive unit tests for batch tokenization
---
 python/minisgl/tokenizer/tokenize.py | 58 +++++++++++++++++++++-------
 1 file changed, 43 insertions(+), 15 deletions(-)

diff --git a/python/minisgl/tokenizer/tokenize.py b/python/minisgl/tokenizer/tokenize.py
index e4d070b1..d3c72bab 100644
--- a/python/minisgl/tokenizer/tokenize.py
+++ b/python/minisgl/tokenizer/tokenize.py
@@ -7,25 +7,53 @@
 from transformers import PreTrainedTokenizerBase
 
 
-class TokenizeManager:
+class TokenizeManager: 
     def __init__(self, tokenizer: PreTrainedTokenizerBase) -> None:
         self.tokenizer = tokenizer
 
     def tokenize(self, msgs: List[TokenizeMsg]) -> List[torch.Tensor]:
-        results: List[torch.Tensor] = []
-        # TODO: batch tokenization
-        for msg in msgs:
+        if not msgs:
+            return []
+
+        # Separate plain text and chat template messages while preserving order
+        plain_indices: List[int] = []
+        plain_texts: List[str] = []
+        chat_indices: List[int] = []
+        chat_convs: List[List[dict]] = []
+
+        for i, msg in enumerate(msgs):
             if isinstance(msg.text, list):
-                prompt = self.tokenizer.apply_chat_template(
-                    msg.text,
-                    tokenize=False,
-                    add_generation_prompt=True,
-                )
-                assert isinstance(prompt, str)
+                chat_indices.append(i)
+                chat_convs.append(msg.text)
             else:
-                prompt = msg.text
-            input_ids: torch.Tensor = (  # type: ignore
-                self.tokenizer.encode(prompt, return_tensors="pt")
+                plain_indices.append(i)
+                plain_texts.append(msg.text)
+
+        results: List[torch.Tensor | None] = [None] * len(msgs)
+
+        # Batch encode plain texts
+        if plain_texts:
+            encoded = self.tokenizer(plain_texts, return_tensors="pt", padding=True)
+            input_ids = encoded["input_ids"]
+            attention_mask = encoded["attention_mask"]
+            for i, (ids, mask) in enumerate(zip(input_ids, attention_mask)):
+                # Remove padding tokens
+                length = mask.sum().item()
+                results[plain_indices[i]] = ids[:length].to(torch.int32)
+
+        # Batch encode chat templates
+        if chat_convs:
+            prompts = self.tokenizer.apply_chat_template(
+                chat_convs,
+                tokenize=False,
+                add_generation_prompt=True,
             )
-            results.append(input_ids.view(-1).to(torch.int32))
-        return results
+            encoded = self.tokenizer(prompts, return_tensors="pt", padding=True)
+            input_ids = encoded["input_ids"]
+            attention_mask = encoded["attention_mask"]
+            for i, (ids, mask) in enumerate(zip(input_ids, attention_mask)):
+                # Remove padding tokens
+                length = mask.sum().item()
+                results[chat_indices[i]] = ids[:length].to(torch.int32)
+
+        return results  # type: ignore