a general regex match algorithm to fix all related issues (#874)

* a general regex match algorithm to fix all related issues

* fix all issues and code clean up

* revert the test case

Author: wenbingl

operators/tokenizer/bpe_kernels.cc

@@ -263,6 +263,10 @@ std::vector<int64_t> KernelBpeTokenizer::Tokenize(ustring& input,
   // Parse input
   auto special_token_split_res = bbpe_tokenizer_->SplitByAddedAndSpecial(input);
   bpe::PreTokenizerWithRegEx reg_splitter;
+  // NOTE: the pattern was already validated on loading json file.
+  // safe to ingore the return value here.
+  auto status = reg_splitter.Compile(bbpe_tokenizer_->GetPreTokenizerRegex(ModelName()));
+  assert(status.IsOk());
 
   for (auto& seg_id : special_token_split_res) {
     if (static_cast<int64_t>(res.size()) >= max_length) break;
@@ -287,13 +291,12 @@ std::vector<int64_t> KernelBpeTokenizer::Tokenize(ustring& input,
     }
 
     while (static_cast<int64_t>(res.size()) < max_length) {
-      std::string regex_expr =  bbpe_tokenizer_->GetPreTokenizerRegex(ModelName());
-      auto [b, tok] = reg_splitter.GetNextToken(regex_expr);
-
-      if (!b) break;
+      std::u32string_view tok = reg_splitter.GetNextToken();
+      if (tok.empty()) {
+        break;
+      }
 
       std::string utf8_token = std::string(ustring(tok));
-
       size_t space_dif = 0;
       if (compute_offset_mapping) {
         // Handle special case for offset mapping

operators/tokenizer/bpe_tokenizer_model.hpp

@@ -77,6 +77,12 @@ class BpeModel {
         ORTX_JSON_RETURN_IF_NULL(&node, "pattern", iter_pattern);
         ORTX_JSON_RETURN_IF_NULL(iter_pattern, "Regex", regex_str);
         pre_tokenizer_regex_ = regex_str->get<std::string>();
+        // Validate the regex pattern
+        bpe::PreTokenizerWithRegEx pre_tokenizer;
+        auto status = pre_tokenizer.Compile(pre_tokenizer_regex_);
+        if (!status.IsOk()) {
+          return status;
+        }
       } else {
         if (pre_tokenizer_types_.count(pre_type) == 0) {
           return {kOrtxErrorNotImplemented, "Unsupported pretokenizer type!"};
@@ -146,7 +152,7 @@ class BpeModel {
         } else {
           vocab_map_[line] = id;
         }
-        special_tokens_.Add(std::move(line_32), id);
+        ORTX_RETURN_IF_ERROR(special_tokens_.Add(std::move(line_32), id));
       }
     }