refactor: introduce shared tokenizer abstraction and split implementations (#1423)

src/tokenizers/mistral_tokenizer.cpp

@@ -0,0 +1,89 @@
+#include "mistral_tokenizer.h"
+
+#include "ggml.h"
+#include "json.hpp"
+#include "util.h"
+#include "vocab/vocab.h"
+
+void MistralTokenizer::load_from_merges(const std::string& merges_utf8_str, const std::string& vocab_utf8_str) {
+    nlohmann::json vocab;
+
+    try {
+        vocab = nlohmann::json::parse(vocab_utf8_str);
+    } catch (const nlohmann::json::parse_error&) {
+        GGML_ABORT("invalid vocab json str");
+    }
+    for (const auto& [key, value] : vocab.items()) {
+        std::u32string token = utf8_to_utf32(key);
+        int i                = value;
+        encoder[token]       = i;
+        decoder[i]           = token;
+    }
+    encoder_len = static_cast<int>(vocab.size());
+    LOG_DEBUG("vocab size: %d", encoder_len);
+
+    auto byte_unicode_pairs = bytes_to_unicode();
+    byte_encoder            = std::map<int, std::u32string>(byte_unicode_pairs.begin(), byte_unicode_pairs.end());
+    for (auto& pair : byte_unicode_pairs) {
+        byte_decoder[pair.second] = pair.first;
+    }
+    std::vector<std::u32string> merges = split_utf32(merges_utf8_str);
+    LOG_DEBUG("merges size %llu", merges.size());
+    std::vector<std::pair<std::u32string, std::u32string>> merge_pairs;
+    for (const auto& merge : merges) {
+        size_t space_pos = merge.find(' ');
+        merge_pairs.emplace_back(merge.substr(0, space_pos), merge.substr(space_pos + 1));
+    }
+
+    int rank = 0;
+    for (const auto& merge : merge_pairs) {
+        bpe_ranks[merge] = rank++;
+    }
+    bpe_len = rank;
+}
+
+MistralTokenizer::MistralTokenizer(const std::string& merges_utf8_str, const std::string& vocab_utf8_str) {
+    add_bos_token = true;
+
+    UNK_TOKEN = "<unk>";
+    BOS_TOKEN = "<s>";
+    EOS_TOKEN = "</s>";
+    PAD_TOKEN = "<pad>";
+
+    UNK_TOKEN_ID = 0;
+    BOS_TOKEN_ID = 1;
+    EOS_TOKEN_ID = 2;
+    PAD_TOKEN_ID = 11;
+
+    special_tokens = {
+        "<unk>",
+        "<s>",
+        "</s>",
+        "[INST]",
+        "[/INST]",
+        "[AVAILABLE_TOOLS]",
+        "[/AVAILABLE_TOOLS]",
+        "[TOOL_RESULTS]",
+        "[/TOOL_RESULTS]",
+        "[TOOL_CALLS]",
+        "[IMG]",
+        "<pad>",
+        "[IMG_BREAK]",
+        "[IMG_END]",
+        "[PREFIX]",
+        "[MIDDLE]",
+        "[SUFFIX]",
+        "[SYSTEM_PROMPT]",
+        "[/SYSTEM_PROMPT]",
+        "[TOOL_CONTENT]",
+    };
+    for (int i = 20; i < 1000; i++) {
+        special_tokens.push_back("<SPECIAL_" + std::to_string(i) + ">");
+    }
+
+    if (merges_utf8_str.size() > 0 && vocab_utf8_str.size() > 0) {
+        load_from_merges(merges_utf8_str, vocab_utf8_str);
+    } else {
+        load_from_merges(load_mistral_merges(), load_mistral_vocab_json());
+    }
+}