Revert back to C++11, avoid std::string_view in the tokenizer

CMakeLists.txt

@@ -221,14 +221,14 @@ add_library(utils OBJECT
             utils.h)
 
 target_include_directories(utils PUBLIC .)
-target_compile_features(utils PUBLIC cxx_std_11)
+target_compile_features(utils PUBLIC cxx_std_11) # don't bump
 
 add_library(ggml OBJECT
             ggml.c
             ggml.h)
 
 target_include_directories(ggml PUBLIC .)
-target_compile_features(ggml PUBLIC c_std_17)
+target_compile_features(ggml PUBLIC c_std_11) # don't bump
 
 #
 # Linking

Makefile

@@ -30,8 +30,9 @@ endif
 # Compile flags
 #
 
+# keep standard at C11 and C++11
 CFLAGS   = -I.              -O3 -DNDEBUG -std=c11   -fPIC
-CXXFLAGS = -I. -I./examples -O3 -DNDEBUG -std=c++17 -fPIC
+CXXFLAGS = -I. -I./examples -O3 -DNDEBUG -std=c++11 -fPIC
 LDFLAGS  =
 
 # OS specific

utils.cpp

@@ -250,7 +250,8 @@ struct llama_sp_symbol {
     using index = int;
     index prev;
     index next;
-    std::string_view text;
+    const char * text;
+    size_t n;
 };
 
 struct llama_sp_bigram {
@@ -267,19 +268,23 @@ struct llama_sp_bigram {
     size_t size;
 };
 
+// original implementation:
+// https://github.com/ggerganov/llama.cpp/commit/074bea2eb1f1349a0118239c4152914aecaa1be4
 struct llama_tokenizer {
     llama_tokenizer(const llama_vocab & vocab): vocab_(vocab) {}
 
-    void tokenize(std::string_view text, std::vector<llama_vocab::id> & output) {
+    void tokenize(const std::string & text, std::vector<llama_vocab::id> & output) {
         // split string into utf8 chars
         int index = 0;
-        while (!text.empty()) {
+        size_t offs = 0;
+        while (offs < text.size()) {
             llama_sp_symbol sym;
-            size_t char_len = std::min(text.size(), utf8_len(text.data()[0]));
-            sym.text = std::string_view(text.data(), char_len);
+            size_t char_len = std::min(text.size() - offs, utf8_len(text[offs]));
+            sym.text = text.c_str() + offs;
+            sym.n = char_len;
+            offs += char_len;
             sym.prev = index - 1;
-            text.remove_prefix(char_len);
-            sym.next = text.empty() ? -1 : index + 1;
+            sym.next = offs == text.size() ? -1 : index + 1;
             index++;
             symbols_.emplace_back(std::move(sym));
         }
@@ -298,14 +303,16 @@ struct llama_tokenizer {
             auto & right_sym = symbols_[bigram.right];
 
             // if one of the symbols already got merged, skip it.
-            if (left_sym.text.empty() || right_sym.text.empty() ||
-                left_sym.text.size() + right_sym.text.size() != bigram.size) {
+            if (left_sym.n == 0 || right_sym.n == 0 ||
+                left_sym.n + right_sym.n != bigram.size) {
                 continue;
             }
 
             // merge the right sym into the left one
-            left_sym.text = std::string_view(left_sym.text.data(), left_sym.text.size() + right_sym.text.size());
-            right_sym.text = std::string_view("");
+            left_sym.n += right_sym.n;
+            right_sym.n = 0;
+
+            //printf("left = '%*s' size = %zu\n", (int) left_sym.n, left_sym.text, bigram.size);
 
             // remove the right sym from the chain
             left_sym.next = right_sym.next;
@@ -319,12 +326,12 @@ struct llama_tokenizer {
         }
 
         for (int i = 0; i != -1; i = symbols_[i].next) {
-            auto& symbol = symbols_[i];
-            auto token = vocab_.token_to_id.find(std::string(symbol.text));
+            auto & symbol = symbols_[i];
+            auto token = vocab_.token_to_id.find(std::string(symbol.text, symbol.n));
 
             if (token == vocab_.token_to_id.end()) {
                 // output any symbols that did not form tokens as bytes.
-                for (int j = 0; j < symbol.text.size(); ++j) {
+                for (int j = 0; j < (int) symbol.n; ++j) {
                     llama_vocab::id token_id = static_cast<uint8_t>(symbol.text[j]) + 3;
                     output.push_back(token_id);
                 }
@@ -340,8 +347,8 @@ struct llama_tokenizer {
             return;
         }
 
-        std::string_view text(symbols_[left].text.data(), symbols_[left].text.size() + symbols_[right].text.size());
-        auto token = vocab_.token_to_id.find(std::string(text));
+        const std::string text = std::string(symbols_[left].text, symbols_[left].n + symbols_[right].n);
+        auto token = vocab_.token_to_id.find(text);
 
         if (token == vocab_.token_to_id.end()) {
             return;
@@ -399,16 +406,12 @@ bool llama_vocab_load(const std::string & fname, llama_vocab & vocab) {
         vocab.token_to_id[word] = i;
         vocab.id_to_token[i] = word;
         vocab.score[i] = score;
-
-        //if (i < 30000) {
-        //    fprintf(stderr, "%s: vocab[%d] = '%s'\n", __func__, i, word.c_str());
-        //}
     }
 
     return true;
 }
 
-std::vector<llama_vocab::id> llama_tokenize(const llama_vocab & vocab, std::string_view text, bool bos) {
+std::vector<llama_vocab::id> llama_tokenize(const llama_vocab & vocab, const std::string & text, bool bos) {
     llama_tokenizer tokenizer(vocab);
     std::vector<llama_vocab::id> output;
 

utils.h

@@ -79,7 +79,7 @@ bool llama_vocab_load(const std::string & fname, llama_vocab & vocab);
 
 // TODO: this is probably wrong, but I cannot figure out how this tokenizer works ..
 // ref: https://github.com/google/sentencepiece
-std::vector<llama_vocab::id> llama_tokenize(const llama_vocab & vocab, std::string_view text, bool bos);
+std::vector<llama_vocab::id> llama_tokenize(const llama_vocab & vocab, const std::string & text, bool bos);
 
 // sample next token given probabilities for each embedding
 //