fix: use tokenizer-specific pre-tokenization rules (#1975)

src/tokenizers/bpe_tokenizer.cpp

@@ -2,6 +2,7 @@
 
 #include <algorithm>
 #include <sstream>
+#include <stdexcept>
 
 #include "core/util.h"
 #include "tokenize_util.h"
@@ -31,8 +32,37 @@ std::vector<std::pair<int, std::u32string>> BPETokenizer::bytes_to_unicode() {
     return byte_unicode_pairs;
 }
 
-std::vector<std::string> BPETokenizer::token_split(const std::string& text) const {
-    return ::token_split(text);
+BPETokenizer::BPETokenizer(const std::string& pattern) {
+    if (!pattern.empty()) {
+        split_regex_ = std::make_unique<sd::Regex>();
+        std::string error;
+        if (!split_regex_->compile(pattern, &error)) {
+            throw std::runtime_error("invalid tokenizer regex: " + error);
+        }
+    }
+}
+
+bool BPETokenizer::token_split(const std::string& text, std::vector<std::string>& tokens, std::string* error) const {
+    tokens.clear();
+    if (error) {
+        error->clear();
+    }
+    if (!split_regex_) {
+        if (!text.empty()) {
+            tokens.push_back(text);
+        }
+        return true;
+    }
+    std::vector<sd::Regex::Match> matches;
+    if (!split_regex_->find_matches(text, matches, error)) {
+        return false;
+    }
+    for (const auto& match : matches) {
+        if (match.first != match.second) {
+            tokens.push_back(text.substr(match.first, match.second - match.first));
+        }
+    }
+    return true;
 }
 
 std::vector<std::u32string> BPETokenizer::split_utf32(const std::string& text, char32_t delimiter) {
@@ -154,7 +184,10 @@ bool BPETokenizer::encode(const std::string& text, std::vector<int>& result, on_
             token_strs.push_back(splited_text);
             continue;
         }
-        auto tokens = token_split(splited_text);
+        std::vector<std::string> tokens;
+        if (!token_split(splited_text, tokens, error)) {
+            return false;
+        }
         for (auto& token : tokens) {
             if (on_new_token_cb != nullptr) {
                 bool skip = on_new_token_cb(token, bpe_tokens);

src/tokenizers/bpe_tokenizer.h

@@ -5,15 +5,19 @@
 #include <cstdint>
 #include <functional>
 #include <map>
-#include <regex>
+#include <memory>
 #include <set>
 #include <string>
 #include <utility>
 #include <vector>
 
+#include "core/regex.h"
 #include "tokenizer.h"
 
 class BPETokenizer : public Tokenizer {
+private:
+    std::unique_ptr<sd::Regex> split_regex_;
+
 protected:
     std::map<int, std::u32string> byte_encoder;
     std::map<std::u32string, int> byte_decoder;
@@ -28,12 +32,12 @@ protected:
 protected:
     static std::vector<std::pair<int, std::u32string>> bytes_to_unicode();
     static std::vector<std::u32string> split_utf32(const std::string& text, char32_t delimiter = U'\n');
-    virtual std::vector<std::string> token_split(const std::string& text) const;
+    bool token_split(const std::string& text, std::vector<std::string>& tokens, std::string* error = nullptr) const;
     std::vector<std::u32string> bpe(const std::u32string& token) const;
     std::string decode_token(int token_id) const override;
 
 public:
-    BPETokenizer()          = default;
+    explicit BPETokenizer(const std::string& pattern);
     virtual ~BPETokenizer() = default;
 
     bool encode(const std::string& text, std::vector<int>& tokens, on_new_token_cb_t on_new_token_cb = nullptr, std::string* error = nullptr) override;

src/tokenizers/clip_tokenizer.cpp

@@ -8,10 +8,10 @@
 
 #include "core/util.h"
 #include "ggml.h"
-#include "tokenize_util.h"
 #include "vocab/vocab.h"
 
-CLIPTokenizer::CLIPTokenizer(int pad_token_id, const std::string& merges_utf8_str) {
+CLIPTokenizer::CLIPTokenizer(int pad_token_id, const std::string& merges_utf8_str)
+    : BPETokenizer(R"((?i:'s|'t|'re|'ve|'m|'ll|'d)|\p{L}+|\p{N}|[^\s\p{L}\p{N}]+)") {
     UNK_TOKEN = "<|endoftext|>";
     BOS_TOKEN = "<|startoftext|>";
     EOS_TOKEN = "<|endoftext|>";
@@ -101,17 +101,3 @@ std::string CLIPTokenizer::normalize(const std::string& text) const {
     std::transform(normalized_text.begin(), normalized_text.end(), normalized_text.begin(), [](unsigned char c) { return static_cast<char>(std::tolower(c)); });
     return normalized_text;
 }
-
-std::vector<std::string> CLIPTokenizer::token_split(const std::string& text) const {
-    std::regex clip_pat(R"('s|'t|'re|'ve|'m|'ll|'d|[[:alpha:]]+|[[:digit:]]|[^[:space:][:alpha:][:digit:]]+)",
-                        std::regex::icase);
-    std::sregex_iterator iter(text.begin(), text.end(), clip_pat);
-    std::sregex_iterator end;
-
-    std::vector<std::string> result;
-    for (; iter != end; ++iter) {
-        result.emplace_back(iter->str());
-    }
-
-    return result;
-}

src/tokenizers/clip_tokenizer.h

@@ -11,7 +11,6 @@ class CLIPTokenizer : public BPETokenizer {
 protected:
     void load_from_merges(const std::string& merges_utf8_str);
     std::string normalize(const std::string& text) const override;
-    std::vector<std::string> token_split(const std::string& text) const override;
 
 public:
     explicit CLIPTokenizer(int pad_token_id = 49407, const std::string& merges_utf8_str = "");

src/tokenizers/gemma_tokenizer.cpp

@@ -46,7 +46,9 @@ void GemmaTokenizer::load_from_merges(const std::string& merges_utf8_str, const
     bpe_len = rank;
 }
 
-GemmaTokenizer::GemmaTokenizer(const std::string& merges_utf8_str, const std::string& vocab_utf8_str) {
+GemmaTokenizer::GemmaTokenizer(const std::string& merges_utf8_str, const std::string& vocab_utf8_str)
+    : BPETokenizer("") {
+    // Gemma replaces spaces with metaspace before its literal-space Split, so no regex boundaries apply.
     byte_level_bpe = false;
     byte_fallback  = true;
     add_bos_token  = true;

src/tokenizers/mistral_tokenizer.cpp

@@ -42,7 +42,8 @@ void MistralTokenizer::load_from_merges(const std::string& merges_utf8_str, cons
     bpe_len = rank;
 }
 
-MistralTokenizer::MistralTokenizer(const std::string& merges_utf8_str, const std::string& vocab_utf8_str) {
+MistralTokenizer::MistralTokenizer(const std::string& merges_utf8_str, const std::string& vocab_utf8_str)
+    : BPETokenizer(R"([^\r\n\p{L}\p{N}]?[\p{Lu}\p{Lt}\p{Lm}\p{Lo}\p{M}]*[\p{Ll}\p{Lm}\p{Lo}\p{M}]+|[^\r\n\p{L}\p{N}]?[\p{Lu}\p{Lt}\p{Lm}\p{Lo}\p{M}]+[\p{Ll}\p{Lm}\p{Lo}\p{M}]*|\p{N}| ?[^\s\p{L}\p{N}]+[\r\n/]*|\s*[\r\n]+|\s+(?!\S)|\s+)") {
     add_bos_token = true;
 
     UNK_TOKEN = "<unk>";

src/tokenizers/qwen2_tokenizer.cpp

@@ -87,7 +87,8 @@ Qwen2Tokenizer::Qwen2Tokenizer(const std::string& merges_utf8_str)
 }
 
 Qwen2Tokenizer::Qwen2Tokenizer(const std::string& merges_utf8_str,
-                               const std::vector<std::string>& special_tokens_override) {
+                               const std::vector<std::string>& special_tokens_override)
+    : BPETokenizer(R"((?i:'s|'t|'re|'ve|'m|'ll|'d)|[^\r\n\p{L}\p{N}]?\p{L}+|\p{N}| ?[^\s\p{L}\p{N}]+[\r\n]*|\s*[\r\n]+|\s+(?!\S)|\s+)") {
     UNK_TOKEN = "<|endoftext|>";
     EOS_TOKEN = "<|endoftext|>";
     PAD_TOKEN = "<|endoftext|>";

src/tokenizers/tokenize_util.h

@@ -4,7 +4,6 @@
 #include <string>
 #include <vector>
 
-std::vector<std::string> token_split(const std::string& text);
 std::vector<std::string> split_with_special_tokens(const std::string& text, const std::vector<std::string>& special_tokens);
 
-#endif  // __SD_TOKENIZERS_BPE_TOKENIZE_UTIL_H__
+#endif  // __SD_TOKENIZERS_BPE_TOKENIZE_UTIL_H__