Function gguf_parse_meta

tests/gguf-model-data.cpp:225–371

Follows the same header -> KV -> tensor parsing sequence as gguf() huggingface/gguf

// Follows the same header -> KV -> tensor parsing sequence as gguf() huggingface/gguf
static std::optional<gguf_remote_model> gguf_parse_meta(const std::vector<char> & buf) {
    gguf_buf_reader r(buf);

    // Header: magic(4) + version(4) + tensor_count(8) + kv_count(8) = 24 bytes minimum
    uint32_t magic_raw;
    if (!r.read_val(magic_raw)) {
        return std::nullopt;
    }
    if (memcmp(&magic_raw, "GGUF", 4) != 0) {
        fprintf(stderr, "gguf_parse_meta: invalid magic\n");
        return std::nullopt;
    }

    uint32_t version;
    if (!r.read_val(version)) {
        return std::nullopt;
    }
    if (version < 2 || version > 3) {
        fprintf(stderr, "gguf_parse_meta: unsupported version %u\n", version);
        return std::nullopt;
    }

    int64_t tensor_count_raw;
    int64_t kv_count_raw;
    if (!r.read_val(tensor_count_raw)) {
        return std::nullopt;
    }
    if (!r.read_val(kv_count_raw)) {
        return std::nullopt;
    }

    uint64_t tensor_count = (uint64_t)tensor_count_raw;
    uint64_t kv_count     = (uint64_t)kv_count_raw;

    gguf_remote_model model;

    std::string arch_prefix;

    // Parse KV pairs
    for (uint64_t i = 0; i < kv_count; i++) {
        std::string key;
        if (!r.read_str(key)) {
            return std::nullopt;
        }

        int32_t vtype;
        if (!r.read_val(vtype)) {
            return std::nullopt;
        }

        if (key == "general.architecture" && vtype == GGUF_TYPE_STRING) {
            if (!r.read_str(model.architecture)) {
                return std::nullopt;
            }
            arch_prefix = model.architecture + ".";
            continue;
        }