[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Trova bug sottili e spiega quali invarianti dell'inferenza possono rompersi.

File: ds4.c

```c
fore emits
                 * "   " then " int", not "    " then "int".
                 */
                pos = p - 1;
            } else {
                pos = p;
            }
        } else {
            pos = next_utf8_char(text, len, pos);
        }

        if (pos == start) pos = next_utf8_char(text, len, pos);
        bpe_emit_piece(vocab, (ds4_str){ text + start, pos - start }, out);
    }
}

static int vocab_lookup(const ds4_vocab *vocab, const char *text) {
    int token = -1;
    if (!table_get(&vocab->token_to_id, text, strlen(text), &token)) {
        fprintf(stderr, "ds4: required tokenizer token is missing: %s\n", text);
        exit(1);
    }
    return token;
}

/* Load token strings, special token ids, and merge ranks from GGUF metadata. */
static void vocab_load(ds4_vocab *vocab, const ds4_model *model) {
    memset(vocab, 0, sizeof(*vocab));

    ds4_array_ref tokens;
    ds4_array_ref merges;
    if (!model_get_array(model, "tokenizer.ggml.tokens", &tokens) ||
        tokens.type != GGUF_VALUE_STRING ||
        tokens.len > INT32_MAX) {
        ds4_die("GGUF tokenizer token table is missing or invalid");
    }
    if (!model_get_array(model, "tokenizer.ggml.merges", &merges) ||
        merges.type != GGUF_VALUE_STRING) {
        ds4_die("GGUF tokenizer merge table is missing or invalid");
    }

    vocab->n_vocab = (int)tokens.len;
    vocab->token = xcalloc((size_t)vocab->n_vocab, sizeof(vocab->token[0]));
    table_init(&vocab->token_to_id, tokens.len);

    ds4_cursor c = cursor_at(model, tokens.data_pos);
    for (int i = 0; i < vocab->n_vocab; i++) {
        if (!cursor_string(&c, &vocab->token[i])) ds4_die(c.error);
        table_put(&vocab->token_to_id, vocab->token[i], i);
    }

    table_init(&vocab->merge_rank, merges.len);
    c = cursor_at(model, merges.data_pos);
    for (uint64_t i = 0; i < merges.len; i++) {
        ds4_str merge;
        if (!cursor_string(&c, &merge)) ds4_die(c.error);
        table_put(&vocab->merge_rank, merge, (int)i);
    }

    vocab->bos_id       = vocab_lookup(vocab, "<｜begin▁of▁sentence｜>");
    vocab->eos_id       = vocab_lookup(vocab, "<｜end▁of▁sentence｜>");
    vocab->user_id      = vocab_lookup(vocab, "<｜User｜>");
    vocab->assistant_id = vocab_lookup(vocab, "<｜Assistant｜>");
    vocab->think_start_id = vocab_lookup(vocab, "<think>");
    vocab->think_end_id = vocab_lookup(vocab, "</think>");
    vocab->dsml_id = vocab_lookup(vocab, "｜DSML｜");
}

static void vocab_free(ds4_vocab *vocab) {
    free(vocab->token);
    table_free(&vocab->token_to_id);
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Trova bug sottili e spiega quali invarianti dell'inferenza possono rompersi.

File: ds4.c

```c
fore emits
                 * "   " then " int", not "    " then "int".
                 */
                pos = p - 1;
            } else {
                pos = p;
            }
        } else {
            pos = next_utf8_char(text, len, pos);
        }

        if (pos == start) pos = next_utf8_char(text, len, pos);
        bpe_emit_piece(vocab, (ds4_str){ text + start, pos - start }, out);
    }
}

static int vocab_lookup(const ds4_vocab *vocab, const char *text) {
    int token = -1;
    if (!table_get(&vocab->token_to_id, text, strlen(text), &token)) {
        fprintf(stderr, "ds4: required tokenizer token is missing: %s\n", text);
        exit(1);
    }
    return token;
}

/* Load token strings, special token ids, and merge ranks from GGUF metadata. */
static void vocab_load(ds4_vocab *vocab, const ds4_model *model) {
    memset(vocab, 0, sizeof(*vocab));

    ds4_array_ref tokens;
    ds4_array_ref merges;
    if (!model_get_array(model, "tokenizer.ggml.tokens", &tokens) ||
        tokens.type != GGUF_VALUE_STRING ||
        tokens.len > INT32_MAX) {
        ds4_die("GGUF tokenizer token table is missing or invalid");
    }
    if (!model_get_array(model, "tokenizer.ggml.merges", &merges) ||
        merges.type != GGUF_VALUE_STRING) {
        ds4_die("GGUF tokenizer merge table is missing or invalid");
    }

    vocab->n_vocab = (int)tokens.len;
    vocab->token = xcalloc((size_t)vocab->n_vocab, sizeof(vocab->token[0]));
    table_init(&vocab->token_to_id, tokens.len);

    ds4_cursor c = cursor_at(model, tokens.data_pos);
    for (int i = 0; i < vocab->n_vocab; i++) {
        if (!cursor_string(&c, &vocab->token[i])) ds4_die(c.error);
        table_put(&vocab->token_to_id, vocab->token[i], i);
    }

    table_init(&vocab->merge_rank, merges.len);
    c = cursor_at(model, merges.data_pos);
    for (uint64_t i = 0; i < merges.len; i++) {
        ds4_str merge;
        if (!cursor_string(&c, &merge)) ds4_die(c.error);
        table_put(&vocab->merge_rank, merge, (int)i);
    }

    vocab->bos_id       = vocab_lookup(vocab, "<｜begin▁of▁sentence｜>");
    vocab->eos_id       = vocab_lookup(vocab, "<｜end▁of▁sentence｜>");
    vocab->user_id      = vocab_lookup(vocab, "<｜User｜>");
    vocab->assistant_id = vocab_lookup(vocab, "<｜Assistant｜>");
    vocab->think_start_id = vocab_lookup(vocab, "<think>");
    vocab->think_end_id = vocab_lookup(vocab, "</think>");
    vocab->dsml_id = vocab_lookup(vocab, "｜DSML｜");
}

static void vocab_free(ds4_vocab *vocab) {
    free(vocab->token);
    table_free(&vocab->token_to_id);
```<｜Assistant｜></think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Trova bug sottili e spiega quali invarianti dell'inferenza possono rompersi.

File: ds4.c

```c
fore emits
                 * "   " then " int", not "    " then "int".
                 */
                pos = p - 1;
            } else {
                pos = p;
            }
        } else {
            pos = next_utf8_char(text, len, pos);
        }

        if (pos == start) pos = next_utf8_char(text, len, pos);
        bpe_emit_piece(vocab, (ds4_str){ text + start, pos - start }, out);
    }
}

static int vocab_lookup(const ds4_vocab *vocab, const char *text) {
    int token = -1;
    if (!table_get(&vocab->token_to_id, text, strlen(text), &token)) {
        fprintf(stderr, "ds4: required tokenizer token is missing: %s\n", text);
        exit(1);
    }
    return token;
}

/* Load token strings, special token ids, and merge ranks from GGUF metadata. */
static void vocab_load(ds4_vocab *vocab, const ds4_model *model) {
    memset(vocab, 0, sizeof(*vocab));

    ds4_array_ref tokens;
    ds4_array_ref merges;
    if (!model_get_array(model, "tokenizer.ggml.tokens", &tokens) ||
        tokens.type != GGUF_VALUE_STRING ||
        tokens.len > INT32_MAX) {
        ds4_die("GGUF tokenizer token table is missing or invalid");
    }
    if (!model_get_array(model, "tokenizer.ggml.merges", &merges) ||
        merges.type != GGUF_VALUE_STRING) {
        ds4_die("GGUF tokenizer merge table is missing or invalid");
    }

    vocab->n_vocab = (int)tokens.len;
    vocab->token = xcalloc((size_t)vocab->n_vocab, sizeof(vocab->token[0]));
    table_init(&vocab->token_to_id, tokens.len);

    ds4_cursor c = cursor_at(model, tokens.data_pos);
    for (int i = 0; i < vocab->n_vocab; i++) {
        if (!cursor_string(&c, &vocab->token[i])) ds4_die(c.error);
        table_put(&vocab->token_to_id, vocab->token[i], i);
    }

    table_init(&vocab->merge_rank, merges.len);
    c = cursor_at(model, merges.data_pos);
    for (uint64_t i = 0; i < merges.len; i++) {
        ds4_str merge;
        if (!cursor_string(&c, &merge)) ds4_die(c.error);
        table_put(&vocab->merge_rank, merge, (int)i);
    }

    vocab->bos_id       = vocab_lookup(vocab, "<｜begin▁of▁sentence｜>");
    vocab->eos_id       = vocab_lookup(vocab, "<｜end▁of▁sentence｜>");
    vocab->user_id      = vocab_lookup(vocab, "<｜User｜>");
    vocab->assistant_id = vocab_lookup(vocab, "<｜Assistant｜>");
    vocab->think_start_id = vocab_lookup(vocab, "<think>");
    vocab->think_end_id = vocab_lookup(vocab, "</think>");
    vocab->dsml_id = vocab_lookup(vocab, "｜DSML｜");
}

static void vocab_free(ds4_vocab *vocab) {
    free(vocab->token);
    table_free(&vocab->token_to_id);
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Trova bug sottili e spiega quali invarianti dell'inferenza possono rompersi.

File: ds4.c

```c
fore emits
                 * "   " then " int", not "    " then "int".
                 */
                pos = p - 1;
            } else {
                pos = p;
            }
        } else {
            pos = next_utf8_char(text, len, pos);
        }

        if (pos == start) pos = next_utf8_char(text, len, pos);
        bpe_emit_piece(vocab, (ds4_str){ text + start, pos - start }, out);
    }
}

static int vocab_lookup(const ds4_vocab *vocab, const char *text) {
    int token = -1;
    if (!table_get(&vocab->token_to_id, text, strlen(text), &token)) {
        fprintf(stderr, "ds4: required tokenizer token is missing: %s\n", text);
        exit(1);
    }
    return token;
}

/* Load token strings, special token ids, and merge ranks from GGUF metadata. */
static void vocab_load(ds4_vocab *vocab, const ds4_model *model) {
    memset(vocab, 0, sizeof(*vocab));

    ds4_array_ref tokens;
    ds4_array_ref merges;
    if (!model_get_array(model, "tokenizer.ggml.tokens", &tokens) ||
        tokens.type != GGUF_VALUE_STRING ||
        tokens.len > INT32_MAX) {
        ds4_die("GGUF tokenizer token table is missing or invalid");
    }
    if (!model_get_array(model, "tokenizer.ggml.merges", &merges) ||
        merges.type != GGUF_VALUE_STRING) {
        ds4_die("GGUF tokenizer merge table is missing or invalid");
    }

    vocab->n_vocab = (int)tokens.len;
    vocab->token = xcalloc((size_t)vocab->n_vocab, sizeof(vocab->token[0]));
    table_init(&vocab->token_to_id, tokens.len);

    ds4_cursor c = cursor_at(model, tokens.data_pos);
    for (int i = 0; i < vocab->n_vocab; i++) {
        if (!cursor_string(&c, &vocab->token[i])) ds4_die(c.error);
        table_put(&vocab->token_to_id, vocab->token[i], i);
    }

    table_init(&vocab->merge_rank, merges.len);
    c = cursor_at(model, merges.data_pos);
    for (uint64_t i = 0; i < merges.len; i++) {
        ds4_str merge;
        if (!cursor_string(&c, &merge)) ds4_die(c.error);
        table_put(&vocab->merge_rank, merge, (int)i);
    }

    vocab->bos_id       = vocab_lookup(vocab, "<｜begin▁of▁sentence｜>");
    vocab->eos_id       = vocab_lookup(vocab, "<｜end▁of▁sentence｜>");
    vocab->user_id      = vocab_lookup(vocab, "<｜User｜>");
    vocab->assistant_id = vocab_lookup(vocab, "<｜Assistant｜>");
    vocab->think_start_id = vocab_lookup(vocab, "<think>");
    vocab->think_end_id = vocab_lookup(vocab, "</think>");
    vocab->dsml_id = vocab_lookup(vocab, "｜DSML｜");
}

static void vocab_free(ds4_vocab *vocab) {
    free(vocab->token);
    table_free(&vocab->token_to_id);
```<｜Assistant｜><think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Review this excerpt for correctness risks, memory lifetime issues, and performance bottlenecks.

File: ds4.c

```c
p(vocab, "</think>");
    vocab->dsml_id = vocab_lookup(vocab, "｜DSML｜");
}

static void vocab_free(ds4_vocab *vocab) {
    free(vocab->token);
    table_free(&vocab->token_to_id);
    table_free(&vocab->merge_rank);
    memset(vocab, 0, sizeof(*vocab));
}

/* Build the DS4 chat prompt: BOS, optional system text, user prompt, assistant
 * marker, and either <think> or </think> depending on the requested mode.  Max
 * thinking is only a prompt prefix: the model still enters through <think>. */
static void encode_chat_prompt(
        const ds4_vocab *vocab,
        const char      *system,
        const char      *prompt,
        ds4_think_mode   think_mode,
        token_vec       *out) {
    token_vec_push(out, vocab->bos_id);
    if (think_mode == DS4_THINK_MAX) {
        bpe_tokenize_text(vocab, DS4_REASONING_EFFORT_MAX_PREFIX, out);
    }
    if (system && system[0]) {
        bpe_tokenize_text(vocab, system, out);
    }
    token_vec_push(out, vocab->user_id);
    bpe_tokenize_text(vocab, prompt, out);
    token_vec_push(out, vocab->assistant_id);
    if (ds4_think_mode_enabled(think_mode)) {
        token_vec_push(out, vocab->think_start_id);
    } else {
        token_vec_push(out, vocab->think_end_id);
    }
}

void ds4_tokenize_text(ds4_engine *e, const char *text, ds4_tokens *out) {
    bpe_tokenize_text(&e->vocab, text ? text : "", out);
}

static bool special_token_at(const ds4_vocab *vocab, const char *p, int *token, size_t *len) {
    struct special {
        const char *text;
        int token;
    } specials[] = {
        {"<｜begin▁of▁sentence｜>", vocab->bos_id},
        {"<｜end▁of▁sentence｜>",   vocab->eos_id},
        {"<｜User｜>",              vocab->user_id},
        {"<｜Assistant｜>",         vocab->assistant_id},
        {"<think>",                vocab->think_start_id},
        {"</think>",               vocab->think_end_id},
        {"｜DSML｜",                vocab->dsml_id},
    };

    for (size_t i = 0; i < sizeof(specials) / sizeof(specials[0]); i++) {
        size_t n = strlen(specials[i].text);
        if (!strncmp(p, specials[i].text, n)) {
            *token = specials[i].token;
            *len = n;
            return true;
        }
    }
    return false;
}

static void tokenize_span(const ds4_vocab *vocab, const char *p, size_t n, token_vec *out) {
    if (!n) return;
    char *tmp = xmalloc(n + 1);
    memcpy(tmp, p, n);
    tmp[n] = '\0';
    bpe_tokenize_text(vocab, tmp, out);
    free(tmp);
}

static void tokenize_rendered_chat_vocab(const ds4_vocab *vocab, const char *text,
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Review this excerpt for correctness risks, memory lifetime issues, and performance bottlenecks.

File: ds4.c

```c
p(vocab, "</think>");
    vocab->dsml_id = vocab_lookup(vocab, "｜DSML｜");
}

static void vocab_free(ds4_vocab *vocab) {
    free(vocab->token);
    table_free(&vocab->token_to_id);
    table_free(&vocab->merge_rank);
    memset(vocab, 0, sizeof(*vocab));
}

/* Build the DS4 chat prompt: BOS, optional system text, user prompt, assistant
 * marker, and either <think> or </think> depending on the requested mode.  Max
 * thinking is only a prompt prefix: the model still enters through <think>. */
static void encode_chat_prompt(
        const ds4_vocab *vocab,
        const char      *system,
        const char      *prompt,
        ds4_think_mode   think_mode,
        token_vec       *out) {
    token_vec_push(out, vocab->bos_id);
    if (think_mode == DS4_THINK_MAX) {
        bpe_tokenize_text(vocab, DS4_REASONING_EFFORT_MAX_PREFIX, out);
    }
    if (system && system[0]) {
        bpe_tokenize_text(vocab, system, out);
    }
    token_vec_push(out, vocab->user_id);
    bpe_tokenize_text(vocab, prompt, out);
    token_vec_push(out, vocab->assistant_id);
    if (ds4_think_mode_enabled(think_mode)) {
        token_vec_push(out, vocab->think_start_id);
    } else {
        token_vec_push(out, vocab->think_end_id);
    }
}

void ds4_tokenize_text(ds4_engine *e, const char *text, ds4_tokens *out) {
    bpe_tokenize_text(&e->vocab, text ? text : "", out);
}

static bool special_token_at(const ds4_vocab *vocab, const char *p, int *token, size_t *len) {
    struct special {
        const char *text;
        int token;
    } specials[] = {
        {"<｜begin▁of▁sentence｜>", vocab->bos_id},
        {"<｜end▁of▁sentence｜>",   vocab->eos_id},
        {"<｜User｜>",              vocab->user_id},
        {"<｜Assistant｜>",         vocab->assistant_id},
        {"<think>",                vocab->think_start_id},
        {"</think>",               vocab->think_end_id},
        {"｜DSML｜",                vocab->dsml_id},
    };

    for (size_t i = 0; i < sizeof(specials) / sizeof(specials[0]); i++) {
        size_t n = strlen(specials[i].text);
        if (!strncmp(p, specials[i].text, n)) {
            *token = specials[i].token;
            *len = n;
            return true;
        }
    }
    return false;
}

static void tokenize_span(const ds4_vocab *vocab, const char *p, size_t n, token_vec *out) {
    if (!n) return;
    char *tmp = xmalloc(n + 1);
    memcpy(tmp, p, n);
    tmp[n] = '\0';
    bpe_tokenize_text(vocab, tmp, out);
    free(tmp);
}

static void tokenize_rendered_chat_vocab(const ds4_vocab *vocab, const char *text,
```<｜Assistant｜></think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Review this excerpt for correctness risks, memory lifetime issues, and performance bottlenecks.

File: ds4.c

```c
p(vocab, "</think>");
    vocab->dsml_id = vocab_lookup(vocab, "｜DSML｜");
}

static void vocab_free(ds4_vocab *vocab) {
    free(vocab->token);
    table_free(&vocab->token_to_id);
    table_free(&vocab->merge_rank);
    memset(vocab, 0, sizeof(*vocab));
}

/* Build the DS4 chat prompt: BOS, optional system text, user prompt, assistant
 * marker, and either <think> or </think> depending on the requested mode.  Max
 * thinking is only a prompt prefix: the model still enters through <think>. */
static void encode_chat_prompt(
        const ds4_vocab *vocab,
        const char      *system,
        const char      *prompt,
        ds4_think_mode   think_mode,
        token_vec       *out) {
    token_vec_push(out, vocab->bos_id);
    if (think_mode == DS4_THINK_MAX) {
        bpe_tokenize_text(vocab, DS4_REASONING_EFFORT_MAX_PREFIX, out);
    }
    if (system && system[0]) {
        bpe_tokenize_text(vocab, system, out);
    }
    token_vec_push(out, vocab->user_id);
    bpe_tokenize_text(vocab, prompt, out);
    token_vec_push(out, vocab->assistant_id);
    if (ds4_think_mode_enabled(think_mode)) {
        token_vec_push(out, vocab->think_start_id);
    } else {
        token_vec_push(out, vocab->think_end_id);
    }
}

void ds4_tokenize_text(ds4_engine *e, const char *text, ds4_tokens *out) {
    bpe_tokenize_text(&e->vocab, text ? text : "", out);
}

static bool special_token_at(const ds4_vocab *vocab, const char *p, int *token, size_t *len) {
    struct special {
        const char *text;
        int token;
    } specials[] = {
        {"<｜begin▁of▁sentence｜>", vocab->bos_id},
        {"<｜end▁of▁sentence｜>",   vocab->eos_id},
        {"<｜User｜>",              vocab->user_id},
        {"<｜Assistant｜>",         vocab->assistant_id},
        {"<think>",                vocab->think_start_id},
        {"</think>",               vocab->think_end_id},
        {"｜DSML｜",                vocab->dsml_id},
    };

    for (size_t i = 0; i < sizeof(specials) / sizeof(specials[0]); i++) {
        size_t n = strlen(specials[i].text);
        if (!strncmp(p, specials[i].text, n)) {
            *token = specials[i].token;
            *len = n;
            return true;
        }
    }
    return false;
}

static void tokenize_span(const ds4_vocab *vocab, const char *p, size_t n, token_vec *out) {
    if (!n) return;
    char *tmp = xmalloc(n + 1);
    memcpy(tmp, p, n);
    tmp[n] = '\0';
    bpe_tokenize_text(vocab, tmp, out);
    free(tmp);
}

static void tokenize_rendered_chat_vocab(const ds4_vocab *vocab, const char *text,
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Review this excerpt for correctness risks, memory lifetime issues, and performance bottlenecks.

File: ds4.c

```c
p(vocab, "</think>");
    vocab->dsml_id = vocab_lookup(vocab, "｜DSML｜");
}

static void vocab_free(ds4_vocab *vocab) {
    free(vocab->token);
    table_free(&vocab->token_to_id);
    table_free(&vocab->merge_rank);
    memset(vocab, 0, sizeof(*vocab));
}

/* Build the DS4 chat prompt: BOS, optional system text, user prompt, assistant
 * marker, and either <think> or </think> depending on the requested mode.  Max
 * thinking is only a prompt prefix: the model still enters through <think>. */
static void encode_chat_prompt(
        const ds4_vocab *vocab,
        const char      *system,
        const char      *prompt,
        ds4_think_mode   think_mode,
        token_vec       *out) {
    token_vec_push(out, vocab->bos_id);
    if (think_mode == DS4_THINK_MAX) {
        bpe_tokenize_text(vocab, DS4_REASONING_EFFORT_MAX_PREFIX, out);
    }
    if (system && system[0]) {
        bpe_tokenize_text(vocab, system, out);
    }
    token_vec_push(out, vocab->user_id);
    bpe_tokenize_text(vocab, prompt, out);
    token_vec_push(out, vocab->assistant_id);
    if (ds4_think_mode_enabled(think_mode)) {
        token_vec_push(out, vocab->think_start_id);
    } else {
        token_vec_push(out, vocab->think_end_id);
    }
}

void ds4_tokenize_text(ds4_engine *e, const char *text, ds4_tokens *out) {
    bpe_tokenize_text(&e->vocab, text ? text : "", out);
}

static bool special_token_at(const ds4_vocab *vocab, const char *p, int *token, size_t *len) {
    struct special {
        const char *text;
        int token;
    } specials[] = {
        {"<｜begin▁of▁sentence｜>", vocab->bos_id},
        {"<｜end▁of▁sentence｜>",   vocab->eos_id},
        {"<｜User｜>",              vocab->user_id},
        {"<｜Assistant｜>",         vocab->assistant_id},
        {"<think>",                vocab->think_start_id},
        {"</think>",               vocab->think_end_id},
        {"｜DSML｜",                vocab->dsml_id},
    };

    for (size_t i = 0; i < sizeof(specials) / sizeof(specials[0]); i++) {
        size_t n = strlen(specials[i].text);
        if (!strncmp(p, specials[i].text, n)) {
            *token = specials[i].token;
            *len = n;
            return true;
        }
    }
    return false;
}

static void tokenize_span(const ds4_vocab *vocab, const char *p, size_t n, token_vec *out) {
    if (!n) return;
    char *tmp = xmalloc(n + 1);
    memcpy(tmp, p, n);
    tmp[n] = '\0';
    bpe_tokenize_text(vocab, tmp, out);
    free(tmp);
}

static void tokenize_rendered_chat_vocab(const ds4_vocab *vocab, const char *text,
```<｜Assistant｜><think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Explain what this code does and identify the inference stage it belongs to.

File: ds4.c

```c
memcpy(tmp, p, n);
    tmp[n] = '\0';
    bpe_tokenize_text(vocab, tmp, out);
    free(tmp);
}

static void tokenize_rendered_chat_vocab(const ds4_vocab *vocab, const char *text,
                                         token_vec *out) {
    if (!text) text = "";

    const char *span = text;
    const char *p = text;
    while (*p) {
        int token = -1;
        size_t len = 0;
        if (special_token_at(vocab, p, &token, &len)) {
            tokenize_span(vocab, span, (size_t)(p - span), out);
            token_vec_push(out, token);
            p += len;
            span = p;
            continue;
        }
        p++;
    }
    tokenize_span(vocab, span, (size_t)(p - span), out);
}

void ds4_tokenize_rendered_chat(ds4_engine *e, const char *text, ds4_tokens *out) {
    tokenize_rendered_chat_vocab(&e->vocab, text, out);
}

void ds4_chat_begin(ds4_engine *e, ds4_tokens *tokens) {
    token_vec_push(tokens, e->vocab.bos_id);
}

void ds4_encode_chat_prompt(
        ds4_engine *e,
        const char *system,
        const char *prompt,
        ds4_think_mode think_mode,
        ds4_tokens *out) {
    encode_chat_prompt(&e->vocab, system, prompt ? prompt : "", think_mode, out);
}

void ds4_chat_append_max_effort_prefix(ds4_engine *e, ds4_tokens *tokens) {
    bpe_tokenize_text(&e->vocab, DS4_REASONING_EFFORT_MAX_PREFIX, tokens);
}

void ds4_chat_append_message(ds4_engine *e, ds4_tokens *tokens, const char *role, const char *content) {
    ds4_vocab *vocab = &e->vocab;
    if (!role) role = "user";
    if (!content) content = "";

    if (!strcmp(role, "system") || !strcmp(role, "developer")) {
        bpe_tokenize_text(vocab, content, tokens);
    } else if (!strcmp(role, "assistant")) {
        token_vec_push(tokens, vocab->assistant_id);
        if (strncmp(content, "<think>", 7) != 0 && strncmp(content, "</think>", 8) != 0) {
            token_vec_push(tokens, vocab->think_end_id);
        }
        bpe_tokenize_text(vocab, content, tokens);
    } else {
        token_vec_push(tokens, vocab->user_id);
        if (!strcmp(role, "tool") || !strcmp(role, "function")) {
            bpe_tokenize_text(vocab, "Tool: ", tokens);
        }
        bpe_tokenize_text(vocab, content, tokens);
    }
}

void ds4_chat_append_assistant_prefix(ds4_engine *e, ds4_tokens *tokens, ds4_think_mode think_mode) {
    token_vec_push(tokens, e->vocab.assistant_id);
    token_vec_push(tokens, ds4_think_mode_enabled(think_mode) ?
                   e->vocab.think_start_id : e->vocab.think_end_id);
}
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Explain what this code does and identify the inference stage it belongs to.

File: ds4.c

```c
memcpy(tmp, p, n);
    tmp[n] = '\0';
    bpe_tokenize_text(vocab, tmp, out);
    free(tmp);
}

static void tokenize_rendered_chat_vocab(const ds4_vocab *vocab, const char *text,
                                         token_vec *out) {
    if (!text) text = "";

    const char *span = text;
    const char *p = text;
    while (*p) {
        int token = -1;
        size_t len = 0;
        if (special_token_at(vocab, p, &token, &len)) {
            tokenize_span(vocab, span, (size_t)(p - span), out);
            token_vec_push(out, token);
            p += len;
            span = p;
            continue;
        }
        p++;
    }
    tokenize_span(vocab, span, (size_t)(p - span), out);
}

void ds4_tokenize_rendered_chat(ds4_engine *e, const char *text, ds4_tokens *out) {
    tokenize_rendered_chat_vocab(&e->vocab, text, out);
}

void ds4_chat_begin(ds4_engine *e, ds4_tokens *tokens) {
    token_vec_push(tokens, e->vocab.bos_id);
}

void ds4_encode_chat_prompt(
        ds4_engine *e,
        const char *system,
        const char *prompt,
        ds4_think_mode think_mode,
        ds4_tokens *out) {
    encode_chat_prompt(&e->vocab, system, prompt ? prompt : "", think_mode, out);
}

void ds4_chat_append_max_effort_prefix(ds4_engine *e, ds4_tokens *tokens) {
    bpe_tokenize_text(&e->vocab, DS4_REASONING_EFFORT_MAX_PREFIX, tokens);
}

void ds4_chat_append_message(ds4_engine *e, ds4_tokens *tokens, const char *role, const char *content) {
    ds4_vocab *vocab = &e->vocab;
    if (!role) role = "user";
    if (!content) content = "";

    if (!strcmp(role, "system") || !strcmp(role, "developer")) {
        bpe_tokenize_text(vocab, content, tokens);
    } else if (!strcmp(role, "assistant")) {
        token_vec_push(tokens, vocab->assistant_id);
        if (strncmp(content, "<think>", 7) != 0 && strncmp(content, "</think>", 8) != 0) {
            token_vec_push(tokens, vocab->think_end_id);
        }
        bpe_tokenize_text(vocab, content, tokens);
    } else {
        token_vec_push(tokens, vocab->user_id);
        if (!strcmp(role, "tool") || !strcmp(role, "function")) {
            bpe_tokenize_text(vocab, "Tool: ", tokens);
        }
        bpe_tokenize_text(vocab, content, tokens);
    }
}

void ds4_chat_append_assistant_prefix(ds4_engine *e, ds4_tokens *tokens, ds4_think_mode think_mode) {
    token_vec_push(tokens, e->vocab.assistant_id);
    token_vec_push(tokens, ds4_think_mode_enabled(think_mode) ?
                   e->vocab.think_start_id : e->vocab.think_end_id);
}
```<｜Assistant｜></think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Explain what this code does and identify the inference stage it belongs to.

File: ds4.c

```c
memcpy(tmp, p, n);
    tmp[n] = '\0';
    bpe_tokenize_text(vocab, tmp, out);
    free(tmp);
}

static void tokenize_rendered_chat_vocab(const ds4_vocab *vocab, const char *text,
                                         token_vec *out) {
    if (!text) text = "";

    const char *span = text;
    const char *p = text;
    while (*p) {
        int token = -1;
        size_t len = 0;
        if (special_token_at(vocab, p, &token, &len)) {
            tokenize_span(vocab, span, (size_t)(p - span), out);
            token_vec_push(out, token);
            p += len;
            span = p;
            continue;
        }
        p++;
    }
    tokenize_span(vocab, span, (size_t)(p - span), out);
}

void ds4_tokenize_rendered_chat(ds4_engine *e, const char *text, ds4_tokens *out) {
    tokenize_rendered_chat_vocab(&e->vocab, text, out);
}

void ds4_chat_begin(ds4_engine *e, ds4_tokens *tokens) {
    token_vec_push(tokens, e->vocab.bos_id);
}

void ds4_encode_chat_prompt(
        ds4_engine *e,
        const char *system,
        const char *prompt,
        ds4_think_mode think_mode,
        ds4_tokens *out) {
    encode_chat_prompt(&e->vocab, system, prompt ? prompt : "", think_mode, out);
}

void ds4_chat_append_max_effort_prefix(ds4_engine *e, ds4_tokens *tokens) {
    bpe_tokenize_text(&e->vocab, DS4_REASONING_EFFORT_MAX_PREFIX, tokens);
}

void ds4_chat_append_message(ds4_engine *e, ds4_tokens *tokens, const char *role, const char *content) {
    ds4_vocab *vocab = &e->vocab;
    if (!role) role = "user";
    if (!content) content = "";

    if (!strcmp(role, "system") || !strcmp(role, "developer")) {
        bpe_tokenize_text(vocab, content, tokens);
    } else if (!strcmp(role, "assistant")) {
        token_vec_push(tokens, vocab->assistant_id);
        if (strncmp(content, "<think>", 7) != 0 && strncmp(content, "</think>", 8) != 0) {
            token_vec_push(tokens, vocab->think_end_id);
        }
        bpe_tokenize_text(vocab, content, tokens);
    } else {
        token_vec_push(tokens, vocab->user_id);
        if (!strcmp(role, "tool") || !strcmp(role, "function")) {
            bpe_tokenize_text(vocab, "Tool: ", tokens);
        }
        bpe_tokenize_text(vocab, content, tokens);
    }
}

void ds4_chat_append_assistant_prefix(ds4_engine *e, ds4_tokens *tokens, ds4_think_mode think_mode) {
    token_vec_push(tokens, e->vocab.assistant_id);
    token_vec_push(tokens, ds4_think_mode_enabled(think_mode) ?
                   e->vocab.think_start_id : e->vocab.think_end_id);
}
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Explain what this code does and identify the inference stage it belongs to.

File: ds4.c

```c
memcpy(tmp, p, n);
    tmp[n] = '\0';
    bpe_tokenize_text(vocab, tmp, out);
    free(tmp);
}

static void tokenize_rendered_chat_vocab(const ds4_vocab *vocab, const char *text,
                                         token_vec *out) {
    if (!text) text = "";

    const char *span = text;
    const char *p = text;
    while (*p) {
        int token = -1;
        size_t len = 0;
        if (special_token_at(vocab, p, &token, &len)) {
            tokenize_span(vocab, span, (size_t)(p - span), out);
            token_vec_push(out, token);
            p += len;
            span = p;
            continue;
        }
        p++;
    }
    tokenize_span(vocab, span, (size_t)(p - span), out);
}

void ds4_tokenize_rendered_chat(ds4_engine *e, const char *text, ds4_tokens *out) {
    tokenize_rendered_chat_vocab(&e->vocab, text, out);
}

void ds4_chat_begin(ds4_engine *e, ds4_tokens *tokens) {
    token_vec_push(tokens, e->vocab.bos_id);
}

void ds4_encode_chat_prompt(
        ds4_engine *e,
        const char *system,
        const char *prompt,
        ds4_think_mode think_mode,
        ds4_tokens *out) {
    encode_chat_prompt(&e->vocab, system, prompt ? prompt : "", think_mode, out);
}

void ds4_chat_append_max_effort_prefix(ds4_engine *e, ds4_tokens *tokens) {
    bpe_tokenize_text(&e->vocab, DS4_REASONING_EFFORT_MAX_PREFIX, tokens);
}

void ds4_chat_append_message(ds4_engine *e, ds4_tokens *tokens, const char *role, const char *content) {
    ds4_vocab *vocab = &e->vocab;
    if (!role) role = "user";
    if (!content) content = "";

    if (!strcmp(role, "system") || !strcmp(role, "developer")) {
        bpe_tokenize_text(vocab, content, tokens);
    } else if (!strcmp(role, "assistant")) {
        token_vec_push(tokens, vocab->assistant_id);
        if (strncmp(content, "<think>", 7) != 0 && strncmp(content, "</think>", 8) != 0) {
            token_vec_push(tokens, vocab->think_end_id);
        }
        bpe_tokenize_text(vocab, content, tokens);
    } else {
        token_vec_push(tokens, vocab->user_id);
        if (!strcmp(role, "tool") || !strcmp(role, "function")) {
            bpe_tokenize_text(vocab, "Tool: ", tokens);
        }
        bpe_tokenize_text(vocab, content, tokens);
    }
}

void ds4_chat_append_assistant_prefix(ds4_engine *e, ds4_tokens *tokens, ds4_think_mode think_mode) {
    token_vec_push(tokens, e->vocab.assistant_id);
    token_vec_push(tokens, ds4_think_mode_enabled(think_mode) ?
                   e->vocab.think_start_id : e->vocab.think_end_id);
}
```<｜Assistant｜><think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Suggest a minimal correctness-preserving optimization for this excerpt.

File: ds4.c

```c
ken_vec_push(tokens, e->vocab.assistant_id);
    token_vec_push(tokens, ds4_think_mode_enabled(think_mode) ?
                   e->vocab.think_start_id : e->vocab.think_end_id);
}

static void dump_tokens_fp(FILE *fp, const ds4_vocab *vocab, const token_vec *tokens) {
    fprintf(fp, "[");
    for (int i = 0; i < tokens->len; i++) {
        if (i) fprintf(fp, ", ");
        fprintf(fp, "%d", tokens->v[i]);
    }
    fprintf(fp, "]\n");

    for (int i = 0; i < tokens->len; i++) {
        int id = tokens->v[i];
        if (id >= 0 && id < vocab->n_vocab) {
            fprintf(fp, "%6d  %.*s\n", id, (int)vocab->token[id].len, vocab->token[id].ptr);
        }
    }
}

static void dump_tokens(const ds4_vocab *vocab, const token_vec *tokens) {
    dump_tokens_fp(stdout, vocab, tokens);
}

static uint32_t utf8_decode_one(const char *s, uint64_t len, uint64_t *pos) {
    const uint8_t c = (uint8_t)s[*pos];
    if (c < 0x80 || *pos + 1 >= len) {
        (*pos)++;
        return c;
    }
    if ((c & 0xe0) == 0xc0 && *pos + 1 < len) {
        uint32_t cp = ((uint32_t)(c & 0x1f) << 6) | ((uint8_t)s[*pos + 1] & 0x3f);
        *pos += 2;
        return cp;
    }
    if ((c & 0xf0) == 0xe0 && *pos + 2 < len) {
        uint32_t cp = ((uint32_t)(c & 0x0f) << 12) |
                      ((uint32_t)((uint8_t)s[*pos + 1] & 0x3f) << 6) |
                      ((uint8_t)s[*pos + 2] & 0x3f);
        *pos += 3;
        return cp;
    }
    if ((c & 0xf8) == 0xf0 && *pos + 3 < len) {
        uint32_t cp = ((uint32_t)(c & 0x07) << 18) |
                      ((uint32_t)((uint8_t)s[*pos + 1] & 0x3f) << 12) |
                      ((uint32_t)((uint8_t)s[*pos + 2] & 0x3f) << 6) |
                      ((uint8_t)s[*pos + 3] & 0x3f);
        *pos += 4;
        return cp;
    }
    (*pos)++;
    return c;
}

static int gpt2_codepoint_to_byte(uint32_t cp) {
    if ((cp >= 33 && cp <= 126) || (cp >= 161 && cp <= 172) || (cp >= 174 && cp <= 255)) {
        return (int)cp;
    }

    uint32_t n = 0;
    for (uint32_t b = 0; b < 256; b++) {
        if ((b >= 33 && b <= 126) || (b >= 161 && b <= 172) || (b >= 174)) {
            continue;
        }
        if (cp == 256 + n) return (int)b;
        n++;
    }
    return -1;
}

static bool vocab_token_is_literal_special(ds4_str s) {
    const unsigned char bar[] = {0xef, 0xbd, 0x9c}; /* U+FF5C fullwidth vertical bar. */
    if (s.len < sizeof(bar)) return false;
    for (uint64_t i = 0; i + sizeof(bar) <= s.len; i++) {
        if (!memcmp(s.ptr + i, bar, sizeof(bar))) return true;
    }
    return false;
}
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Suggest a minimal correctness-preserving optimization for this excerpt.

File: ds4.c

```c
ken_vec_push(tokens, e->vocab.assistant_id);
    token_vec_push(tokens, ds4_think_mode_enabled(think_mode) ?
                   e->vocab.think_start_id : e->vocab.think_end_id);
}

static void dump_tokens_fp(FILE *fp, const ds4_vocab *vocab, const token_vec *tokens) {
    fprintf(fp, "[");
    for (int i = 0; i < tokens->len; i++) {
        if (i) fprintf(fp, ", ");
        fprintf(fp, "%d", tokens->v[i]);
    }
    fprintf(fp, "]\n");

    for (int i = 0; i < tokens->len; i++) {
        int id = tokens->v[i];
        if (id >= 0 && id < vocab->n_vocab) {
            fprintf(fp, "%6d  %.*s\n", id, (int)vocab->token[id].len, vocab->token[id].ptr);
        }
    }
}

static void dump_tokens(const ds4_vocab *vocab, const token_vec *tokens) {
    dump_tokens_fp(stdout, vocab, tokens);
}

static uint32_t utf8_decode_one(const char *s, uint64_t len, uint64_t *pos) {
    const uint8_t c = (uint8_t)s[*pos];
    if (c < 0x80 || *pos + 1 >= len) {
        (*pos)++;
        return c;
    }
    if ((c & 0xe0) == 0xc0 && *pos + 1 < len) {
        uint32_t cp = ((uint32_t)(c & 0x1f) << 6) | ((uint8_t)s[*pos + 1] & 0x3f);
        *pos += 2;
        return cp;
    }
    if ((c & 0xf0) == 0xe0 && *pos + 2 < len) {
        uint32_t cp = ((uint32_t)(c & 0x0f) << 12) |
                      ((uint32_t)((uint8_t)s[*pos + 1] & 0x3f) << 6) |
                      ((uint8_t)s[*pos + 2] & 0x3f);
        *pos += 3;
        return cp;
    }
    if ((c & 0xf8) == 0xf0 && *pos + 3 < len) {
        uint32_t cp = ((uint32_t)(c & 0x07) << 18) |
                      ((uint32_t)((uint8_t)s[*pos + 1] & 0x3f) << 12) |
                      ((uint32_t)((uint8_t)s[*pos + 2] & 0x3f) << 6) |
                      ((uint8_t)s[*pos + 3] & 0x3f);
        *pos += 4;
        return cp;
    }
    (*pos)++;
    return c;
}

static int gpt2_codepoint_to_byte(uint32_t cp) {
    if ((cp >= 33 && cp <= 126) || (cp >= 161 && cp <= 172) || (cp >= 174 && cp <= 255)) {
        return (int)cp;
    }

    uint32_t n = 0;
    for (uint32_t b = 0; b < 256; b++) {
        if ((b >= 33 && b <= 126) || (b >= 161 && b <= 172) || (b >= 174)) {
            continue;
        }
        if (cp == 256 + n) return (int)b;
        n++;
    }
    return -1;
}

static bool vocab_token_is_literal_special(ds4_str s) {
    const unsigned char bar[] = {0xef, 0xbd, 0x9c}; /* U+FF5C fullwidth vertical bar. */
    if (s.len < sizeof(bar)) return false;
    for (uint64_t i = 0; i + sizeof(bar) <= s.len; i++) {
        if (!memcmp(s.ptr + i, bar, sizeof(bar))) return true;
    }
    return false;
}
```<｜Assistant｜></think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Suggest a minimal correctness-preserving optimization for this excerpt.

File: ds4.c

```c
ken_vec_push(tokens, e->vocab.assistant_id);
    token_vec_push(tokens, ds4_think_mode_enabled(think_mode) ?
                   e->vocab.think_start_id : e->vocab.think_end_id);
}

static void dump_tokens_fp(FILE *fp, const ds4_vocab *vocab, const token_vec *tokens) {
    fprintf(fp, "[");
    for (int i = 0; i < tokens->len; i++) {
        if (i) fprintf(fp, ", ");
        fprintf(fp, "%d", tokens->v[i]);
    }
    fprintf(fp, "]\n");

    for (int i = 0; i < tokens->len; i++) {
        int id = tokens->v[i];
        if (id >= 0 && id < vocab->n_vocab) {
            fprintf(fp, "%6d  %.*s\n", id, (int)vocab->token[id].len, vocab->token[id].ptr);
        }
    }
}

static void dump_tokens(const ds4_vocab *vocab, const token_vec *tokens) {
    dump_tokens_fp(stdout, vocab, tokens);
}

static uint32_t utf8_decode_one(const char *s, uint64_t len, uint64_t *pos) {
    const uint8_t c = (uint8_t)s[*pos];
    if (c < 0x80 || *pos + 1 >= len) {
        (*pos)++;
        return c;
    }
    if ((c & 0xe0) == 0xc0 && *pos + 1 < len) {
        uint32_t cp = ((uint32_t)(c & 0x1f) << 6) | ((uint8_t)s[*pos + 1] & 0x3f);
        *pos += 2;
        return cp;
    }
    if ((c & 0xf0) == 0xe0 && *pos + 2 < len) {
        uint32_t cp = ((uint32_t)(c & 0x0f) << 12) |
                      ((uint32_t)((uint8_t)s[*pos + 1] & 0x3f) << 6) |
                      ((uint8_t)s[*pos + 2] & 0x3f);
        *pos += 3;
        return cp;
    }
    if ((c & 0xf8) == 0xf0 && *pos + 3 < len) {
        uint32_t cp = ((uint32_t)(c & 0x07) << 18) |
                      ((uint32_t)((uint8_t)s[*pos + 1] & 0x3f) << 12) |
                      ((uint32_t)((uint8_t)s[*pos + 2] & 0x3f) << 6) |
                      ((uint8_t)s[*pos + 3] & 0x3f);
        *pos += 4;
        return cp;
    }
    (*pos)++;
    return c;
}

static int gpt2_codepoint_to_byte(uint32_t cp) {
    if ((cp >= 33 && cp <= 126) || (cp >= 161 && cp <= 172) || (cp >= 174 && cp <= 255)) {
        return (int)cp;
    }

    uint32_t n = 0;
    for (uint32_t b = 0; b < 256; b++) {
        if ((b >= 33 && b <= 126) || (b >= 161 && b <= 172) || (b >= 174)) {
            continue;
        }
        if (cp == 256 + n) return (int)b;
        n++;
    }
    return -1;
}

static bool vocab_token_is_literal_special(ds4_str s) {
    const unsigned char bar[] = {0xef, 0xbd, 0x9c}; /* U+FF5C fullwidth vertical bar. */
    if (s.len < sizeof(bar)) return false;
    for (uint64_t i = 0; i + sizeof(bar) <= s.len; i++) {
        if (!memcmp(s.ptr + i, bar, sizeof(bar))) return true;
    }
    return false;
}
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Suggest a minimal correctness-preserving optimization for this excerpt.

File: ds4.c

```c
ken_vec_push(tokens, e->vocab.assistant_id);
    token_vec_push(tokens, ds4_think_mode_enabled(think_mode) ?
                   e->vocab.think_start_id : e->vocab.think_end_id);
}

static void dump_tokens_fp(FILE *fp, const ds4_vocab *vocab, const token_vec *tokens) {
    fprintf(fp, "[");
    for (int i = 0; i < tokens->len; i++) {
        if (i) fprintf(fp, ", ");
        fprintf(fp, "%d", tokens->v[i]);
    }
    fprintf(fp, "]\n");

    for (int i = 0; i < tokens->len; i++) {
        int id = tokens->v[i];
        if (id >= 0 && id < vocab->n_vocab) {
            fprintf(fp, "%6d  %.*s\n", id, (int)vocab->token[id].len, vocab->token[id].ptr);
        }
    }
}

static void dump_tokens(const ds4_vocab *vocab, const token_vec *tokens) {
    dump_tokens_fp(stdout, vocab, tokens);
}

static uint32_t utf8_decode_one(const char *s, uint64_t len, uint64_t *pos) {
    const uint8_t c = (uint8_t)s[*pos];
    if (c < 0x80 || *pos + 1 >= len) {
        (*pos)++;
        return c;
    }
    if ((c & 0xe0) == 0xc0 && *pos + 1 < len) {
        uint32_t cp = ((uint32_t)(c & 0x1f) << 6) | ((uint8_t)s[*pos + 1] & 0x3f);
        *pos += 2;
        return cp;
    }
    if ((c & 0xf0) == 0xe0 && *pos + 2 < len) {
        uint32_t cp = ((uint32_t)(c & 0x0f) << 12) |
                      ((uint32_t)((uint8_t)s[*pos + 1] & 0x3f) << 6) |
                      ((uint8_t)s[*pos + 2] & 0x3f);
        *pos += 3;
        return cp;
    }
    if ((c & 0xf8) == 0xf0 && *pos + 3 < len) {
        uint32_t cp = ((uint32_t)(c & 0x07) << 18) |
                      ((uint32_t)((uint8_t)s[*pos + 1] & 0x3f) << 12) |
                      ((uint32_t)((uint8_t)s[*pos + 2] & 0x3f) << 6) |
                      ((uint8_t)s[*pos + 3] & 0x3f);
        *pos += 4;
        return cp;
    }
    (*pos)++;
    return c;
}

static int gpt2_codepoint_to_byte(uint32_t cp) {
    if ((cp >= 33 && cp <= 126) || (cp >= 161 && cp <= 172) || (cp >= 174 && cp <= 255)) {
        return (int)cp;
    }

    uint32_t n = 0;
    for (uint32_t b = 0; b < 256; b++) {
        if ((b >= 33 && b <= 126) || (b >= 161 && b <= 172) || (b >= 174)) {
            continue;
        }
        if (cp == 256 + n) return (int)b;
        n++;
    }
    return -1;
}

static bool vocab_token_is_literal_special(ds4_str s) {
    const unsigned char bar[] = {0xef, 0xbd, 0x9c}; /* U+FF5C fullwidth vertical bar. */
    if (s.len < sizeof(bar)) return false;
    for (uint64_t i = 0; i + sizeof(bar) <= s.len; i++) {
        if (!memcmp(s.ptr + i, bar, sizeof(bar))) return true;
    }
    return false;
}
```<｜Assistant｜><think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Trova bug sottili e spiega quali invarianti dell'inferenza possono rompersi.

File: ds4.c

```c
len < sizeof(bar)) return false;
    for (uint64_t i = 0; i + sizeof(bar) <= s.len; i++) {
        if (!memcmp(s.ptr + i, bar, sizeof(bar))) return true;
    }
    return false;
}

char *ds4_token_text(ds4_engine *e, int token, size_t *len) {
    ds4_vocab *vocab = &e->vocab;
    if (token < 0 || token >= vocab->n_vocab) {
        if (len) *len = 0;
        char *out = xmalloc(1);
        out[0] = '\0';
        return out;
    }

    ds4_str s = vocab->token[token];
    char *out = xmalloc((size_t)s.len + 1);
    if (vocab_token_is_literal_special(s)) {
        memcpy(out, s.ptr, (size_t)s.len);
        out[s.len] = '\0';
        if (len) *len = (size_t)s.len;
        return out;
    }

    size_t n = 0;
    uint64_t pos = 0;
    while (pos < s.len) {
        uint32_t cp = utf8_decode_one(s.ptr, s.len, &pos);
        int b = gpt2_codepoint_to_byte(cp);
        if (b >= 0) out[n++] = (char)b;
    }
    out[n] = '\0';
    if (len) *len = n;
    return out;
}

int ds4_token_eos(ds4_engine *e) {
    return e->vocab.eos_id;
}

int ds4_token_user(ds4_engine *e) {
    return e->vocab.user_id;
}

int ds4_token_assistant(ds4_engine *e) {
    return e->vocab.assistant_id;
}

static int sample_argmax(const float *logits, uint32_t n_vocab) {
    int best = 0;
    float best_v = DS4_NEG_INF;
    for (uint32_t i = 0; i < n_vocab; i++) {
        const float v = logits[i];
        if (v > best_v) {
            best_v = v;
            best = (int)i;
        }
    }
    return best;
}

static DS4_MAYBE_UNUSED void logits_top2(const float *logits, uint32_t n_vocab,
                        int *top0, float *logit0,
                        int *top1, float *logit1) {
    int b0 = -1, b1 = -1;
    float v0 = DS4_NEG_INF, v1 = DS4_NEG_INF;
    for (uint32_t i = 0; i < n_vocab; i++) {
        const float v = logits[i];
        if (v > v0) {
            b1 = b0; v1 = v0;
            b0 = (int)i; v0 = v;
        } else if (v > v1) {
            b1 = (int)i; v1 = v;
        }
    }
    if (top0) *top0 = b0;
    if (logit0) *logit0 = v0;
    if (top1) *top1 = b1;
    if (logit1) *logit1 = v1;
}

static uint64_t sample_rng_next(uint64_t *state) {
    uint64_t x = *state;
    if (x == 0) x = 0x9e3779b97f4a7c15ULL;
    x ^= x >> 12;
    x ^= x << 25;
    x ^= x >> 27;
    *state = x;
    return x * 0x2545f4914f6cdd1dULL;
}

static float sample_rng_f32(uint64_t *state) {
    const uint64_t x = sample_rng_next(state);
    return (float)((x >> 40) & 0xffffffu) / 16777216.0f;
}

typedef struct {
    int id;
    float logit;
    float prob;
} sample_candidate;
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Trova bug sottili e spiega quali invarianti dell'inferenza possono rompersi.

File: ds4.c

```c
len < sizeof(bar)) return false;
    for (uint64_t i = 0; i + sizeof(bar) <= s.len; i++) {
        if (!memcmp(s.ptr + i, bar, sizeof(bar))) return true;
    }
    return false;
}

char *ds4_token_text(ds4_engine *e, int token, size_t *len) {
    ds4_vocab *vocab = &e->vocab;
    if (token < 0 || token >= vocab->n_vocab) {
        if (len) *len = 0;
        char *out = xmalloc(1);
        out[0] = '\0';
        return out;
    }

    ds4_str s = vocab->token[token];
    char *out = xmalloc((size_t)s.len + 1);
    if (vocab_token_is_literal_special(s)) {
        memcpy(out, s.ptr, (size_t)s.len);
        out[s.len] = '\0';
        if (len) *len = (size_t)s.len;
        return out;
    }

    size_t n = 0;
    uint64_t pos = 0;
    while (pos < s.len) {
        uint32_t cp = utf8_decode_one(s.ptr, s.len, &pos);
        int b = gpt2_codepoint_to_byte(cp);
        if (b >= 0) out[n++] = (char)b;
    }
    out[n] = '\0';
    if (len) *len = n;
    return out;
}

int ds4_token_eos(ds4_engine *e) {
    return e->vocab.eos_id;
}

int ds4_token_user(ds4_engine *e) {
    return e->vocab.user_id;
}

int ds4_token_assistant(ds4_engine *e) {
    return e->vocab.assistant_id;
}

static int sample_argmax(const float *logits, uint32_t n_vocab) {
    int best = 0;
    float best_v = DS4_NEG_INF;
    for (uint32_t i = 0; i < n_vocab; i++) {
        const float v = logits[i];
        if (v > best_v) {
            best_v = v;
            best = (int)i;
        }
    }
    return best;
}

static DS4_MAYBE_UNUSED void logits_top2(const float *logits, uint32_t n_vocab,
                        int *top0, float *logit0,
                        int *top1, float *logit1) {
    int b0 = -1, b1 = -1;
    float v0 = DS4_NEG_INF, v1 = DS4_NEG_INF;
    for (uint32_t i = 0; i < n_vocab; i++) {
        const float v = logits[i];
        if (v > v0) {
            b1 = b0; v1 = v0;
            b0 = (int)i; v0 = v;
        } else if (v > v1) {
            b1 = (int)i; v1 = v;
        }
    }
    if (top0) *top0 = b0;
    if (logit0) *logit0 = v0;
    if (top1) *top1 = b1;
    if (logit1) *logit1 = v1;
}

static uint64_t sample_rng_next(uint64_t *state) {
    uint64_t x = *state;
    if (x == 0) x = 0x9e3779b97f4a7c15ULL;
    x ^= x >> 12;
    x ^= x << 25;
    x ^= x >> 27;
    *state = x;
    return x * 0x2545f4914f6cdd1dULL;
}

static float sample_rng_f32(uint64_t *state) {
    const uint64_t x = sample_rng_next(state);
    return (float)((x >> 40) & 0xffffffu) / 16777216.0f;
}

typedef struct {
    int id;
    float logit;
    float prob;
} sample_candidate;
```<｜Assistant｜></think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Trova bug sottili e spiega quali invarianti dell'inferenza possono rompersi.

File: ds4.c

```c
len < sizeof(bar)) return false;
    for (uint64_t i = 0; i + sizeof(bar) <= s.len; i++) {
        if (!memcmp(s.ptr + i, bar, sizeof(bar))) return true;
    }
    return false;
}

char *ds4_token_text(ds4_engine *e, int token, size_t *len) {
    ds4_vocab *vocab = &e->vocab;
    if (token < 0 || token >= vocab->n_vocab) {
        if (len) *len = 0;
        char *out = xmalloc(1);
        out[0] = '\0';
        return out;
    }

    ds4_str s = vocab->token[token];
    char *out = xmalloc((size_t)s.len + 1);
    if (vocab_token_is_literal_special(s)) {
        memcpy(out, s.ptr, (size_t)s.len);
        out[s.len] = '\0';
        if (len) *len = (size_t)s.len;
        return out;
    }

    size_t n = 0;
    uint64_t pos = 0;
    while (pos < s.len) {
        uint32_t cp = utf8_decode_one(s.ptr, s.len, &pos);
        int b = gpt2_codepoint_to_byte(cp);
        if (b >= 0) out[n++] = (char)b;
    }
    out[n] = '\0';
    if (len) *len = n;
    return out;
}

int ds4_token_eos(ds4_engine *e) {
    return e->vocab.eos_id;
}

int ds4_token_user(ds4_engine *e) {
    return e->vocab.user_id;
}

int ds4_token_assistant(ds4_engine *e) {
    return e->vocab.assistant_id;
}

static int sample_argmax(const float *logits, uint32_t n_vocab) {
    int best = 0;
    float best_v = DS4_NEG_INF;
    for (uint32_t i = 0; i < n_vocab; i++) {
        const float v = logits[i];
        if (v > best_v) {
            best_v = v;
            best = (int)i;
        }
    }
    return best;
}

static DS4_MAYBE_UNUSED void logits_top2(const float *logits, uint32_t n_vocab,
                        int *top0, float *logit0,
                        int *top1, float *logit1) {
    int b0 = -1, b1 = -1;
    float v0 = DS4_NEG_INF, v1 = DS4_NEG_INF;
    for (uint32_t i = 0; i < n_vocab; i++) {
        const float v = logits[i];
        if (v > v0) {
            b1 = b0; v1 = v0;
            b0 = (int)i; v0 = v;
        } else if (v > v1) {
            b1 = (int)i; v1 = v;
        }
    }
    if (top0) *top0 = b0;
    if (logit0) *logit0 = v0;
    if (top1) *top1 = b1;
    if (logit1) *logit1 = v1;
}

static uint64_t sample_rng_next(uint64_t *state) {
    uint64_t x = *state;
    if (x == 0) x = 0x9e3779b97f4a7c15ULL;
    x ^= x >> 12;
    x ^= x << 25;
    x ^= x >> 27;
    *state = x;
    return x * 0x2545f4914f6cdd1dULL;
}

static float sample_rng_f32(uint64_t *state) {
    const uint64_t x = sample_rng_next(state);
    return (float)((x >> 40) & 0xffffffu) / 16777216.0f;
}

typedef struct {
    int id;
    float logit;
    float prob;
} sample_candidate;
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Trova bug sottili e spiega quali invarianti dell'inferenza possono rompersi.

File: ds4.c

```c
len < sizeof(bar)) return false;
    for (uint64_t i = 0; i + sizeof(bar) <= s.len; i++) {
        if (!memcmp(s.ptr + i, bar, sizeof(bar))) return true;
    }
    return false;
}

char *ds4_token_text(ds4_engine *e, int token, size_t *len) {
    ds4_vocab *vocab = &e->vocab;
    if (token < 0 || token >= vocab->n_vocab) {
        if (len) *len = 0;
        char *out = xmalloc(1);
        out[0] = '\0';
        return out;
    }

    ds4_str s = vocab->token[token];
    char *out = xmalloc((size_t)s.len + 1);
    if (vocab_token_is_literal_special(s)) {
        memcpy(out, s.ptr, (size_t)s.len);
        out[s.len] = '\0';
        if (len) *len = (size_t)s.len;
        return out;
    }

    size_t n = 0;
    uint64_t pos = 0;
    while (pos < s.len) {
        uint32_t cp = utf8_decode_one(s.ptr, s.len, &pos);
        int b = gpt2_codepoint_to_byte(cp);
        if (b >= 0) out[n++] = (char)b;
    }
    out[n] = '\0';
    if (len) *len = n;
    return out;
}

int ds4_token_eos(ds4_engine *e) {
    return e->vocab.eos_id;
}

int ds4_token_user(ds4_engine *e) {
    return e->vocab.user_id;
}

int ds4_token_assistant(ds4_engine *e) {
    return e->vocab.assistant_id;
}

static int sample_argmax(const float *logits, uint32_t n_vocab) {
    int best = 0;
    float best_v = DS4_NEG_INF;
    for (uint32_t i = 0; i < n_vocab; i++) {
        const float v = logits[i];
        if (v > best_v) {
            best_v = v;
            best = (int)i;
        }
    }
    return best;
}

static DS4_MAYBE_UNUSED void logits_top2(const float *logits, uint32_t n_vocab,
                        int *top0, float *logit0,
                        int *top1, float *logit1) {
    int b0 = -1, b1 = -1;
    float v0 = DS4_NEG_INF, v1 = DS4_NEG_INF;
    for (uint32_t i = 0; i < n_vocab; i++) {
        const float v = logits[i];
        if (v > v0) {
            b1 = b0; v1 = v0;
            b0 = (int)i; v0 = v;
        } else if (v > v1) {
            b1 = (int)i; v1 = v;
        }
    }
    if (top0) *top0 = b0;
    if (logit0) *logit0 = v0;
    if (top1) *top1 = b1;
    if (logit1) *logit1 = v1;
}

static uint64_t sample_rng_next(uint64_t *state) {
    uint64_t x = *state;
    if (x == 0) x = 0x9e3779b97f4a7c15ULL;
    x ^= x >> 12;
    x ^= x << 25;
    x ^= x >> 27;
    *state = x;
    return x * 0x2545f4914f6cdd1dULL;
}

static float sample_rng_f32(uint64_t *state) {
    const uint64_t x = sample_rng_next(state);
    return (float)((x >> 40) & 0xffffffu) / 16777216.0f;
}

typedef struct {
    int id;
    float logit;
    float prob;
} sample_candidate;
```<｜Assistant｜><think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Review this excerpt for correctness risks, memory lifetime issues, and performance bottlenecks.

File: ds4.c

```c
uint64_t x = sample_rng_next(state);
    return (float)((x >> 40) & 0xffffffu) / 16777216.0f;
}

typedef struct {
    int id;
    float logit;
    float prob;
} sample_candidate;

static int sample_candidate_cmp_desc(const void *a, const void *b) {
    const sample_candidate *ca = a;
    const sample_candidate *cb = b;
    return (cb->logit > ca->logit) - (cb->logit < ca->logit);
}

static int sample_full_vocab(
        const float *logits,
        uint32_t     n_vocab,
        float        temperature,
        float        top_p,
        float        min_p,
        uint64_t    *rng) {
    float max_logit = DS4_NEG_INF;
    int best = 0;
    uint32_t finite = 0;
    for (uint32_t i = 0; i < n_vocab; i++) {
        const float v = logits[i];
        if (!isfinite(v)) continue;
        finite++;
        if (v > max_logit) {
            max_logit = v;
            best = (int)i;
        }
    }
    if (finite == 0) return sample_argmax(logits, n_vocab);

    if (top_p >= 1.0f) {
        float sum = 0.0f;
        const float min_rel = min_p > 0.0f ? min_p : 0.0f;
        for (uint32_t i = 0; i < n_vocab; i++) {
            const float v = logits[i];
            if (!isfinite(v)) continue;
            const float p = expf((v - max_logit) / temperature);
            if (p < min_rel) continue;
            sum += p;
        }
        if (sum <= 0.0f || !isfinite(sum)) return best;
        float r = sample_rng_f32(rng) * sum;
        for (uint32_t i = 0; i < n_vocab; i++) {
            const float v = logits[i];
            if (!isfinite(v)) continue;
            const float p = expf((v - max_logit) / temperature);
            if (p < min_rel) continue;
            r -= p;
            if (r <= 0.0f) return (int)i;
        }
        return best;
    }

    sample_candidate *cand = xmalloc((size_t)finite * sizeof(cand[0]));
    uint32_t n = 0;
    float sum = 0.0f;
    for (uint32_t i = 0; i < n_vocab; i++) {
        const float v = logits[i];
        if (!isfinite(v)) continue;
        const float p = expf((v - max_logit) / temperature);
        cand[n++] = (sample_candidate){.id = (int)i, .logit = v, .prob = p};
        sum += p;
    }
    if (sum <= 0.0f || !isfinite(sum)) {
        free(cand);
        return best;
    }

    qsort(cand, n, sizeof(cand[0]), sample_candidate_cmp_desc);
    const float min_prob = (cand[0].prob / sum) * (min_p > 0.0f ? min_p : 0.0f);
    float filtered_sum = 0.0f;
    uint32_t filtered = 0;
    for (uint32_t i = 0; i < n; i++) {
        const float p = cand[i].prob / sum;
        if (i > 0 && p < min_prob) break;
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Review this excerpt for correctness risks, memory lifetime issues, and performance bottlenecks.

File: ds4.c

```c
uint64_t x = sample_rng_next(state);
    return (float)((x >> 40) & 0xffffffu) / 16777216.0f;
}

typedef struct {
    int id;
    float logit;
    float prob;
} sample_candidate;

static int sample_candidate_cmp_desc(const void *a, const void *b) {
    const sample_candidate *ca = a;
    const sample_candidate *cb = b;
    return (cb->logit > ca->logit) - (cb->logit < ca->logit);
}

static int sample_full_vocab(
        const float *logits,
        uint32_t     n_vocab,
        float        temperature,
        float        top_p,
        float        min_p,
        uint64_t    *rng) {
    float max_logit = DS4_NEG_INF;
    int best = 0;
    uint32_t finite = 0;
    for (uint32_t i = 0; i < n_vocab; i++) {
        const float v = logits[i];
        if (!isfinite(v)) continue;
        finite++;
        if (v > max_logit) {
            max_logit = v;
            best = (int)i;
        }
    }
    if (finite == 0) return sample_argmax(logits, n_vocab);

    if (top_p >= 1.0f) {
        float sum = 0.0f;
        const float min_rel = min_p > 0.0f ? min_p : 0.0f;
        for (uint32_t i = 0; i < n_vocab; i++) {
            const float v = logits[i];
            if (!isfinite(v)) continue;
            const float p = expf((v - max_logit) / temperature);
            if (p < min_rel) continue;
            sum += p;
        }
        if (sum <= 0.0f || !isfinite(sum)) return best;
        float r = sample_rng_f32(rng) * sum;
        for (uint32_t i = 0; i < n_vocab; i++) {
            const float v = logits[i];
            if (!isfinite(v)) continue;
            const float p = expf((v - max_logit) / temperature);
            if (p < min_rel) continue;
            r -= p;
            if (r <= 0.0f) return (int)i;
        }
        return best;
    }

    sample_candidate *cand = xmalloc((size_t)finite * sizeof(cand[0]));
    uint32_t n = 0;
    float sum = 0.0f;
    for (uint32_t i = 0; i < n_vocab; i++) {
        const float v = logits[i];
        if (!isfinite(v)) continue;
        const float p = expf((v - max_logit) / temperature);
        cand[n++] = (sample_candidate){.id = (int)i, .logit = v, .prob = p};
        sum += p;
    }
    if (sum <= 0.0f || !isfinite(sum)) {
        free(cand);
        return best;
    }

    qsort(cand, n, sizeof(cand[0]), sample_candidate_cmp_desc);
    const float min_prob = (cand[0].prob / sum) * (min_p > 0.0f ? min_p : 0.0f);
    float filtered_sum = 0.0f;
    uint32_t filtered = 0;
    for (uint32_t i = 0; i < n; i++) {
        const float p = cand[i].prob / sum;
        if (i > 0 && p < min_prob) break;
```<｜Assistant｜></think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Review this excerpt for correctness risks, memory lifetime issues, and performance bottlenecks.

File: ds4.c

```c
uint64_t x = sample_rng_next(state);
    return (float)((x >> 40) & 0xffffffu) / 16777216.0f;
}

typedef struct {
    int id;
    float logit;
    float prob;
} sample_candidate;

static int sample_candidate_cmp_desc(const void *a, const void *b) {
    const sample_candidate *ca = a;
    const sample_candidate *cb = b;
    return (cb->logit > ca->logit) - (cb->logit < ca->logit);
}

static int sample_full_vocab(
        const float *logits,
        uint32_t     n_vocab,
        float        temperature,
        float        top_p,
        float        min_p,
        uint64_t    *rng) {
    float max_logit = DS4_NEG_INF;
    int best = 0;
    uint32_t finite = 0;
    for (uint32_t i = 0; i < n_vocab; i++) {
        const float v = logits[i];
        if (!isfinite(v)) continue;
        finite++;
        if (v > max_logit) {
            max_logit = v;
            best = (int)i;
        }
    }
    if (finite == 0) return sample_argmax(logits, n_vocab);

    if (top_p >= 1.0f) {
        float sum = 0.0f;
        const float min_rel = min_p > 0.0f ? min_p : 0.0f;
        for (uint32_t i = 0; i < n_vocab; i++) {
            const float v = logits[i];
            if (!isfinite(v)) continue;
            const float p = expf((v - max_logit) / temperature);
            if (p < min_rel) continue;
            sum += p;
        }
        if (sum <= 0.0f || !isfinite(sum)) return best;
        float r = sample_rng_f32(rng) * sum;
        for (uint32_t i = 0; i < n_vocab; i++) {
            const float v = logits[i];
            if (!isfinite(v)) continue;
            const float p = expf((v - max_logit) / temperature);
            if (p < min_rel) continue;
            r -= p;
            if (r <= 0.0f) return (int)i;
        }
        return best;
    }

    sample_candidate *cand = xmalloc((size_t)finite * sizeof(cand[0]));
    uint32_t n = 0;
    float sum = 0.0f;
    for (uint32_t i = 0; i < n_vocab; i++) {
        const float v = logits[i];
        if (!isfinite(v)) continue;
        const float p = expf((v - max_logit) / temperature);
        cand[n++] = (sample_candidate){.id = (int)i, .logit = v, .prob = p};
        sum += p;
    }
    if (sum <= 0.0f || !isfinite(sum)) {
        free(cand);
        return best;
    }

    qsort(cand, n, sizeof(cand[0]), sample_candidate_cmp_desc);
    const float min_prob = (cand[0].prob / sum) * (min_p > 0.0f ? min_p : 0.0f);
    float filtered_sum = 0.0f;
    uint32_t filtered = 0;
    for (uint32_t i = 0; i < n; i++) {
        const float p = cand[i].prob / sum;
        if (i > 0 && p < min_prob) break;
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Review this excerpt for correctness risks, memory lifetime issues, and performance bottlenecks.

File: ds4.c

```c
uint64_t x = sample_rng_next(state);
    return (float)((x >> 40) & 0xffffffu) / 16777216.0f;
}

typedef struct {
    int id;
    float logit;
    float prob;
} sample_candidate;

static int sample_candidate_cmp_desc(const void *a, const void *b) {
    const sample_candidate *ca = a;
    const sample_candidate *cb = b;
    return (cb->logit > ca->logit) - (cb->logit < ca->logit);
}

static int sample_full_vocab(
        const float *logits,
        uint32_t     n_vocab,
        float        temperature,
        float        top_p,
        float        min_p,
        uint64_t    *rng) {
    float max_logit = DS4_NEG_INF;
    int best = 0;
    uint32_t finite = 0;
    for (uint32_t i = 0; i < n_vocab; i++) {
        const float v = logits[i];
        if (!isfinite(v)) continue;
        finite++;
        if (v > max_logit) {
            max_logit = v;
            best = (int)i;
        }
    }
    if (finite == 0) return sample_argmax(logits, n_vocab);

    if (top_p >= 1.0f) {
        float sum = 0.0f;
        const float min_rel = min_p > 0.0f ? min_p : 0.0f;
        for (uint32_t i = 0; i < n_vocab; i++) {
            const float v = logits[i];
            if (!isfinite(v)) continue;
            const float p = expf((v - max_logit) / temperature);
            if (p < min_rel) continue;
            sum += p;
        }
        if (sum <= 0.0f || !isfinite(sum)) return best;
        float r = sample_rng_f32(rng) * sum;
        for (uint32_t i = 0; i < n_vocab; i++) {
            const float v = logits[i];
            if (!isfinite(v)) continue;
            const float p = expf((v - max_logit) / temperature);
            if (p < min_rel) continue;
            r -= p;
            if (r <= 0.0f) return (int)i;
        }
        return best;
    }

    sample_candidate *cand = xmalloc((size_t)finite * sizeof(cand[0]));
    uint32_t n = 0;
    float sum = 0.0f;
    for (uint32_t i = 0; i < n_vocab; i++) {
        const float v = logits[i];
        if (!isfinite(v)) continue;
        const float p = expf((v - max_logit) / temperature);
        cand[n++] = (sample_candidate){.id = (int)i, .logit = v, .prob = p};
        sum += p;
    }
    if (sum <= 0.0f || !isfinite(sum)) {
        free(cand);
        return best;
    }

    qsort(cand, n, sizeof(cand[0]), sample_candidate_cmp_desc);
    const float min_prob = (cand[0].prob / sum) * (min_p > 0.0f ? min_p : 0.0f);
    float filtered_sum = 0.0f;
    uint32_t filtered = 0;
    for (uint32_t i = 0; i < n; i++) {
        const float p = cand[i].prob / sum;
        if (i > 0 && p < min_prob) break;
```<｜Assistant｜><think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Explain what this code does and identify the inference stage it belongs to.

File: ds4.c

```c
bsum += sumi * (int32_t)ls;
        }
        sumf += d * (float)bsum;
    }
    *s = 0.125f * sumf;
#endif
}

static void ds4_vec_dot_iq2_xxs_pair_q8_K(
        int n,
        float *s0,
        float *s1,
        const block_iq2_xxs *x0,
        const block_iq2_xxs *x1,
        const block_q8_K *y) {
#if defined(__ARM_NEON) && defined(__ARM_FEATURE_DOTPROD)
    const int nb = n / QK_K;
    float total0 = 0.0f;
    float total1 = 0.0f;

    for (int i = 0; i < nb; i++) {
        const float d0 = f16_to_f32(x0[i].d) * y[i].d;
        const float d1 = f16_to_f32(x1[i].d) * y[i].d;
        const uint16_t *q20 = x0[i].qs;
        const uint16_t *q21 = x1[i].qs;
        const int8_t *q8 = y[i].qs;
        float sum01 = 0.0f;
        float sum02 = 0.0f;
        float sum11 = 0.0f;
        float sum12 = 0.0f;

        for (int ib32 = 0; ib32 < QK_K / 32; ib32 += 2) {
            const int8x16x4_t q8b = vld1q_s8_x4(q8);
            q8 += 64;

            uint32_t aux0[4];
            uint32_t aux1[4];
            memcpy(aux0, q20, sizeof(aux0));
            memcpy(aux1, q21, sizeof(aux1));
            q20 += 8;
            q21 += 8;
            const uint8_t *a0 = (const uint8_t *)aux0;
            const uint8_t *a1 = (const uint8_t *)aux1;

#define DS4_IQ2_PAIR_DOT(aux, aux8, accum_a, accum_b) do {                                              \
                int8x16_t u0 = vcombine_s8(vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[0])),          \
                                           vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[1])));          \
                int8x16_t u1 = vcombine_s8(vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[2])),          \
                                           vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[3])));          \
                int8x16_t u2 = vcombine_s8(vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[8])),          \
                                           vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[9])));          \
                int8x16_t u3 = vcombine_s8(vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[10])),         \
                                           vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[11])));         \
                const int8x16_t sgn0 = vcombine_s8(vld1_s8(iq2xxs_signs[((aux)[1] >>  0) & 127]),       \
                                                   vld1_s8(iq2xxs_signs[((aux)[1] >>  7) & 127]));      \
                const int8x16_t sgn1 = vcombine_s8(vld1_s8(iq2xxs_signs[((aux)[1] >> 14) & 127]),       \
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Explain what this code does and identify the inference stage it belongs to.

File: ds4.c

```c
bsum += sumi * (int32_t)ls;
        }
        sumf += d * (float)bsum;
    }
    *s = 0.125f * sumf;
#endif
}

static void ds4_vec_dot_iq2_xxs_pair_q8_K(
        int n,
        float *s0,
        float *s1,
        const block_iq2_xxs *x0,
        const block_iq2_xxs *x1,
        const block_q8_K *y) {
#if defined(__ARM_NEON) && defined(__ARM_FEATURE_DOTPROD)
    const int nb = n / QK_K;
    float total0 = 0.0f;
    float total1 = 0.0f;

    for (int i = 0; i < nb; i++) {
        const float d0 = f16_to_f32(x0[i].d) * y[i].d;
        const float d1 = f16_to_f32(x1[i].d) * y[i].d;
        const uint16_t *q20 = x0[i].qs;
        const uint16_t *q21 = x1[i].qs;
        const int8_t *q8 = y[i].qs;
        float sum01 = 0.0f;
        float sum02 = 0.0f;
        float sum11 = 0.0f;
        float sum12 = 0.0f;

        for (int ib32 = 0; ib32 < QK_K / 32; ib32 += 2) {
            const int8x16x4_t q8b = vld1q_s8_x4(q8);
            q8 += 64;

            uint32_t aux0[4];
            uint32_t aux1[4];
            memcpy(aux0, q20, sizeof(aux0));
            memcpy(aux1, q21, sizeof(aux1));
            q20 += 8;
            q21 += 8;
            const uint8_t *a0 = (const uint8_t *)aux0;
            const uint8_t *a1 = (const uint8_t *)aux1;

#define DS4_IQ2_PAIR_DOT(aux, aux8, accum_a, accum_b) do {                                              \
                int8x16_t u0 = vcombine_s8(vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[0])),          \
                                           vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[1])));          \
                int8x16_t u1 = vcombine_s8(vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[2])),          \
                                           vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[3])));          \
                int8x16_t u2 = vcombine_s8(vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[8])),          \
                                           vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[9])));          \
                int8x16_t u3 = vcombine_s8(vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[10])),         \
                                           vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[11])));         \
                const int8x16_t sgn0 = vcombine_s8(vld1_s8(iq2xxs_signs[((aux)[1] >>  0) & 127]),       \
                                                   vld1_s8(iq2xxs_signs[((aux)[1] >>  7) & 127]));      \
                const int8x16_t sgn1 = vcombine_s8(vld1_s8(iq2xxs_signs[((aux)[1] >> 14) & 127]),       \
```<｜Assistant｜></think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Explain what this code does and identify the inference stage it belongs to.

File: ds4.c

```c
bsum += sumi * (int32_t)ls;
        }
        sumf += d * (float)bsum;
    }
    *s = 0.125f * sumf;
#endif
}

static void ds4_vec_dot_iq2_xxs_pair_q8_K(
        int n,
        float *s0,
        float *s1,
        const block_iq2_xxs *x0,
        const block_iq2_xxs *x1,
        const block_q8_K *y) {
#if defined(__ARM_NEON) && defined(__ARM_FEATURE_DOTPROD)
    const int nb = n / QK_K;
    float total0 = 0.0f;
    float total1 = 0.0f;

    for (int i = 0; i < nb; i++) {
        const float d0 = f16_to_f32(x0[i].d) * y[i].d;
        const float d1 = f16_to_f32(x1[i].d) * y[i].d;
        const uint16_t *q20 = x0[i].qs;
        const uint16_t *q21 = x1[i].qs;
        const int8_t *q8 = y[i].qs;
        float sum01 = 0.0f;
        float sum02 = 0.0f;
        float sum11 = 0.0f;
        float sum12 = 0.0f;

        for (int ib32 = 0; ib32 < QK_K / 32; ib32 += 2) {
            const int8x16x4_t q8b = vld1q_s8_x4(q8);
            q8 += 64;

            uint32_t aux0[4];
            uint32_t aux1[4];
            memcpy(aux0, q20, sizeof(aux0));
            memcpy(aux1, q21, sizeof(aux1));
            q20 += 8;
            q21 += 8;
            const uint8_t *a0 = (const uint8_t *)aux0;
            const uint8_t *a1 = (const uint8_t *)aux1;

#define DS4_IQ2_PAIR_DOT(aux, aux8, accum_a, accum_b) do {                                              \
                int8x16_t u0 = vcombine_s8(vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[0])),          \
                                           vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[1])));          \
                int8x16_t u1 = vcombine_s8(vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[2])),          \
                                           vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[3])));          \
                int8x16_t u2 = vcombine_s8(vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[8])),          \
                                           vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[9])));          \
                int8x16_t u3 = vcombine_s8(vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[10])),         \
                                           vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[11])));         \
                const int8x16_t sgn0 = vcombine_s8(vld1_s8(iq2xxs_signs[((aux)[1] >>  0) & 127]),       \
                                                   vld1_s8(iq2xxs_signs[((aux)[1] >>  7) & 127]));      \
                const int8x16_t sgn1 = vcombine_s8(vld1_s8(iq2xxs_signs[((aux)[1] >> 14) & 127]),       \
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Explain what this code does and identify the inference stage it belongs to.

File: ds4.c

```c
bsum += sumi * (int32_t)ls;
        }
        sumf += d * (float)bsum;
    }
    *s = 0.125f * sumf;
#endif
}

static void ds4_vec_dot_iq2_xxs_pair_q8_K(
        int n,
        float *s0,
        float *s1,
        const block_iq2_xxs *x0,
        const block_iq2_xxs *x1,
        const block_q8_K *y) {
#if defined(__ARM_NEON) && defined(__ARM_FEATURE_DOTPROD)
    const int nb = n / QK_K;
    float total0 = 0.0f;
    float total1 = 0.0f;

    for (int i = 0; i < nb; i++) {
        const float d0 = f16_to_f32(x0[i].d) * y[i].d;
        const float d1 = f16_to_f32(x1[i].d) * y[i].d;
        const uint16_t *q20 = x0[i].qs;
        const uint16_t *q21 = x1[i].qs;
        const int8_t *q8 = y[i].qs;
        float sum01 = 0.0f;
        float sum02 = 0.0f;
        float sum11 = 0.0f;
        float sum12 = 0.0f;

        for (int ib32 = 0; ib32 < QK_K / 32; ib32 += 2) {
            const int8x16x4_t q8b = vld1q_s8_x4(q8);
            q8 += 64;

            uint32_t aux0[4];
            uint32_t aux1[4];
            memcpy(aux0, q20, sizeof(aux0));
            memcpy(aux1, q21, sizeof(aux1));
            q20 += 8;
            q21 += 8;
            const uint8_t *a0 = (const uint8_t *)aux0;
            const uint8_t *a1 = (const uint8_t *)aux1;

#define DS4_IQ2_PAIR_DOT(aux, aux8, accum_a, accum_b) do {                                              \
                int8x16_t u0 = vcombine_s8(vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[0])),          \
                                           vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[1])));          \
                int8x16_t u1 = vcombine_s8(vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[2])),          \
                                           vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[3])));          \
                int8x16_t u2 = vcombine_s8(vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[8])),          \
                                           vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[9])));          \
                int8x16_t u3 = vcombine_s8(vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[10])),         \
                                           vld1_s8((const int8_t *)(iq2xxs_grid + (aux8)[11])));         \
                const int8x16_t sgn0 = vcombine_s8(vld1_s8(iq2xxs_signs[((aux)[1] >>  0) & 127]),       \
                                                   vld1_s8(iq2xxs_signs[((aux)[1] >>  7) & 127]));      \
                const int8x16_t sgn1 = vcombine_s8(vld1_s8(iq2xxs_signs[((aux)[1] >> 14) & 127]),       \
```<｜Assistant｜><think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Explain what this code does and identify the inference stage it belongs to.

File: ds4.c

```c
float filtered_sum = 0.0f;
    uint32_t filtered = 0;
    for (uint32_t i = 0; i < n; i++) {
        const float p = cand[i].prob / sum;
        if (i > 0 && p < min_prob) break;
        filtered_sum += cand[i].prob;
        filtered++;
        if (filtered_sum / sum >= top_p) break;
    }
    if (filtered == 0) {
        free(cand);
        return best;
    }

    float r = sample_rng_f32(rng) * filtered_sum;
    for (uint32_t i = 0; i < filtered; i++) {
        r -= cand[i].prob;
        if (r <= 0.0f) {
            const int id = cand[i].id;
            free(cand);
            return id;
        }
    }
    const int id = cand[filtered - 1].id;
    free(cand);
    return id;
}

static int sample_top_p_min_p(
        const float *logits,
        uint32_t     n_vocab,
        float        temperature,
        int          top_k,
        float        top_p,
        float        min_p,
        uint64_t    *rng) {
    if (temperature <= 0.0f) return sample_argmax(logits, n_vocab);
    if (top_p <= 0.0f || top_p > 1.0f) top_p = 1.0f;
    if (min_p < 0.0f) min_p = 0.0f;
    if (top_k <= 0) return sample_full_vocab(logits, n_vocab, temperature, top_p, min_p, rng);
    if (top_k > 1024) top_k = 1024;
    if ((uint32_t)top_k > n_vocab) top_k = (int)n_vocab;

    int ids[1024];
    float vals[1024];
    int n = 0;
    for (uint32_t i = 0; i < n_vocab; i++) {
        float v = logits[i];
        if (!isfinite(v)) continue;
        if (n == top_k && v <= vals[n - 1]) continue;
        int j = n < top_k ? n++ : n - 1;
        while (j > 0 && vals[j - 1] < v) {
            vals[j] = vals[j - 1];
            ids[j] = ids[j - 1];
            j--;
        }
        vals[j] = v;
        ids[j] = (int)i;
    }
    if (n == 0) return sample_argmax(logits, n_vocab);

    float probs[1024];
    const float max_logit = vals[0];
    float sum = 0.0f;
    for (int i = 0; i < n; i++) {
        probs[i] = expf((vals[i] - max_logit) / temperature);
        sum += probs[i];
    }
    if (sum <= 0.0f || !isfinite(sum)) return ids[0];

    const float min_prob = (probs[0] / sum) * min_p;
    float filtered_sum = 0.0f;
    int filtered = 0;
    for (int i = 0; i < n; i++) {
        float p = probs[i] / sum;
        if (i > 0 && p < min_prob) break;
        filtered_sum += probs[i];
        filtered++;
        if (filtered_sum / sum >= top_p) break;
    }
    if (filtered <= 0) return ids[0];

    float r = sample_rng_f32(rng) * filtered_sum;
    for (int i = 0; i < filtered; i++) {
        r -= probs[i];
        if (r <= 0.0f) return ids[i];
    }
    return ids[filtered - 1];
}
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Explain what this code does and identify the inference stage it belongs to.

File: ds4.c

```c
float filtered_sum = 0.0f;
    uint32_t filtered = 0;
    for (uint32_t i = 0; i < n; i++) {
        const float p = cand[i].prob / sum;
        if (i > 0 && p < min_prob) break;
        filtered_sum += cand[i].prob;
        filtered++;
        if (filtered_sum / sum >= top_p) break;
    }
    if (filtered == 0) {
        free(cand);
        return best;
    }

    float r = sample_rng_f32(rng) * filtered_sum;
    for (uint32_t i = 0; i < filtered; i++) {
        r -= cand[i].prob;
        if (r <= 0.0f) {
            const int id = cand[i].id;
            free(cand);
            return id;
        }
    }
    const int id = cand[filtered - 1].id;
    free(cand);
    return id;
}

static int sample_top_p_min_p(
        const float *logits,
        uint32_t     n_vocab,
        float        temperature,
        int          top_k,
        float        top_p,
        float        min_p,
        uint64_t    *rng) {
    if (temperature <= 0.0f) return sample_argmax(logits, n_vocab);
    if (top_p <= 0.0f || top_p > 1.0f) top_p = 1.0f;
    if (min_p < 0.0f) min_p = 0.0f;
    if (top_k <= 0) return sample_full_vocab(logits, n_vocab, temperature, top_p, min_p, rng);
    if (top_k > 1024) top_k = 1024;
    if ((uint32_t)top_k > n_vocab) top_k = (int)n_vocab;

    int ids[1024];
    float vals[1024];
    int n = 0;
    for (uint32_t i = 0; i < n_vocab; i++) {
        float v = logits[i];
        if (!isfinite(v)) continue;
        if (n == top_k && v <= vals[n - 1]) continue;
        int j = n < top_k ? n++ : n - 1;
        while (j > 0 && vals[j - 1] < v) {
            vals[j] = vals[j - 1];
            ids[j] = ids[j - 1];
            j--;
        }
        vals[j] = v;
        ids[j] = (int)i;
    }
    if (n == 0) return sample_argmax(logits, n_vocab);

    float probs[1024];
    const float max_logit = vals[0];
    float sum = 0.0f;
    for (int i = 0; i < n; i++) {
        probs[i] = expf((vals[i] - max_logit) / temperature);
        sum += probs[i];
    }
    if (sum <= 0.0f || !isfinite(sum)) return ids[0];

    const float min_prob = (probs[0] / sum) * min_p;
    float filtered_sum = 0.0f;
    int filtered = 0;
    for (int i = 0; i < n; i++) {
        float p = probs[i] / sum;
        if (i > 0 && p < min_prob) break;
        filtered_sum += probs[i];
        filtered++;
        if (filtered_sum / sum >= top_p) break;
    }
    if (filtered <= 0) return ids[0];

    float r = sample_rng_f32(rng) * filtered_sum;
    for (int i = 0; i < filtered; i++) {
        r -= probs[i];
        if (r <= 0.0f) return ids[i];
    }
    return ids[filtered - 1];
}
```<｜Assistant｜></think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Explain what this code does and identify the inference stage it belongs to.

File: ds4.c

```c
float filtered_sum = 0.0f;
    uint32_t filtered = 0;
    for (uint32_t i = 0; i < n; i++) {
        const float p = cand[i].prob / sum;
        if (i > 0 && p < min_prob) break;
        filtered_sum += cand[i].prob;
        filtered++;
        if (filtered_sum / sum >= top_p) break;
    }
    if (filtered == 0) {
        free(cand);
        return best;
    }

    float r = sample_rng_f32(rng) * filtered_sum;
    for (uint32_t i = 0; i < filtered; i++) {
        r -= cand[i].prob;
        if (r <= 0.0f) {
            const int id = cand[i].id;
            free(cand);
            return id;
        }
    }
    const int id = cand[filtered - 1].id;
    free(cand);
    return id;
}

static int sample_top_p_min_p(
        const float *logits,
        uint32_t     n_vocab,
        float        temperature,
        int          top_k,
        float        top_p,
        float        min_p,
        uint64_t    *rng) {
    if (temperature <= 0.0f) return sample_argmax(logits, n_vocab);
    if (top_p <= 0.0f || top_p > 1.0f) top_p = 1.0f;
    if (min_p < 0.0f) min_p = 0.0f;
    if (top_k <= 0) return sample_full_vocab(logits, n_vocab, temperature, top_p, min_p, rng);
    if (top_k > 1024) top_k = 1024;
    if ((uint32_t)top_k > n_vocab) top_k = (int)n_vocab;

    int ids[1024];
    float vals[1024];
    int n = 0;
    for (uint32_t i = 0; i < n_vocab; i++) {
        float v = logits[i];
        if (!isfinite(v)) continue;
        if (n == top_k && v <= vals[n - 1]) continue;
        int j = n < top_k ? n++ : n - 1;
        while (j > 0 && vals[j - 1] < v) {
            vals[j] = vals[j - 1];
            ids[j] = ids[j - 1];
            j--;
        }
        vals[j] = v;
        ids[j] = (int)i;
    }
    if (n == 0) return sample_argmax(logits, n_vocab);

    float probs[1024];
    const float max_logit = vals[0];
    float sum = 0.0f;
    for (int i = 0; i < n; i++) {
        probs[i] = expf((vals[i] - max_logit) / temperature);
        sum += probs[i];
    }
    if (sum <= 0.0f || !isfinite(sum)) return ids[0];

    const float min_prob = (probs[0] / sum) * min_p;
    float filtered_sum = 0.0f;
    int filtered = 0;
    for (int i = 0; i < n; i++) {
        float p = probs[i] / sum;
        if (i > 0 && p < min_prob) break;
        filtered_sum += probs[i];
        filtered++;
        if (filtered_sum / sum >= top_p) break;
    }
    if (filtered <= 0) return ids[0];

    float r = sample_rng_f32(rng) * filtered_sum;
    for (int i = 0; i < filtered; i++) {
        r -= probs[i];
        if (r <= 0.0f) return ids[i];
    }
    return ids[filtered - 1];
}
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Explain what this code does and identify the inference stage it belongs to.

File: ds4.c

```c
float filtered_sum = 0.0f;
    uint32_t filtered = 0;
    for (uint32_t i = 0; i < n; i++) {
        const float p = cand[i].prob / sum;
        if (i > 0 && p < min_prob) break;
        filtered_sum += cand[i].prob;
        filtered++;
        if (filtered_sum / sum >= top_p) break;
    }
    if (filtered == 0) {
        free(cand);
        return best;
    }

    float r = sample_rng_f32(rng) * filtered_sum;
    for (uint32_t i = 0; i < filtered; i++) {
        r -= cand[i].prob;
        if (r <= 0.0f) {
            const int id = cand[i].id;
            free(cand);
            return id;
        }
    }
    const int id = cand[filtered - 1].id;
    free(cand);
    return id;
}

static int sample_top_p_min_p(
        const float *logits,
        uint32_t     n_vocab,
        float        temperature,
        int          top_k,
        float        top_p,
        float        min_p,
        uint64_t    *rng) {
    if (temperature <= 0.0f) return sample_argmax(logits, n_vocab);
    if (top_p <= 0.0f || top_p > 1.0f) top_p = 1.0f;
    if (min_p < 0.0f) min_p = 0.0f;
    if (top_k <= 0) return sample_full_vocab(logits, n_vocab, temperature, top_p, min_p, rng);
    if (top_k > 1024) top_k = 1024;
    if ((uint32_t)top_k > n_vocab) top_k = (int)n_vocab;

    int ids[1024];
    float vals[1024];
    int n = 0;
    for (uint32_t i = 0; i < n_vocab; i++) {
        float v = logits[i];
        if (!isfinite(v)) continue;
        if (n == top_k && v <= vals[n - 1]) continue;
        int j = n < top_k ? n++ : n - 1;
        while (j > 0 && vals[j - 1] < v) {
            vals[j] = vals[j - 1];
            ids[j] = ids[j - 1];
            j--;
        }
        vals[j] = v;
        ids[j] = (int)i;
    }
    if (n == 0) return sample_argmax(logits, n_vocab);

    float probs[1024];
    const float max_logit = vals[0];
    float sum = 0.0f;
    for (int i = 0; i < n; i++) {
        probs[i] = expf((vals[i] - max_logit) / temperature);
        sum += probs[i];
    }
    if (sum <= 0.0f || !isfinite(sum)) return ids[0];

    const float min_prob = (probs[0] / sum) * min_p;
    float filtered_sum = 0.0f;
    int filtered = 0;
    for (int i = 0; i < n; i++) {
        float p = probs[i] / sum;
        if (i > 0 && p < min_prob) break;
        filtered_sum += probs[i];
        filtered++;
        if (filtered_sum / sum >= top_p) break;
    }
    if (filtered <= 0) return ids[0];

    float r = sample_rng_f32(rng) * filtered_sum;
    for (int i = 0; i < filtered; i++) {
        r -= probs[i];
        if (r <= 0.0f) return ids[i];
    }
    return ids[filtered - 1];
}
```<｜Assistant｜><think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Suggest a minimal correctness-preserving optimization for this excerpt.

File: ds4.c

```c
r = sample_rng_f32(rng) * filtered_sum;
    for (int i = 0; i < filtered; i++) {
        r -= probs[i];
        if (r <= 0.0f) return ids[i];
    }
    return ids[filtered - 1];
}

static void print_top_logits(
        FILE          * fp,
        const char    * label,
        const ds4_vocab * vocab,
        const float   * logits,
        uint32_t        n_vocab,
        int             k) {
    int best[16];
    if (k > 16) k = 16;
    for (int i = 0; i < k; i++) best[i] = -1;

    for (uint32_t i = 0; i < n_vocab; i++) {
        for (int j = 0; j < k; j++) {
            if (best[j] < 0 || logits[i] > logits[best[j]]) {
                for (int l = k - 1; l > j; l--) best[l] = best[l - 1];
                best[j] = (int)i;
                break;
            }
        }
    }

    fprintf(fp, "ds4: top logits %s:\n", label);
    for (int i = 0; i < k && best[i] >= 0; i++) {
        const int id = best[i];
        fprintf(fp, "  %2d %7d % .9g  ", i, id, logits[id]);
        if (id >= 0 && id < vocab->n_vocab) {
            fprintf(fp, "%.*s", (int)vocab->token[id].len, vocab->token[id].ptr);
        }
        fputc('\n', fp);
    }
}

/* CPU generation entry point.  It runs layer-major prefill once, then decodes
 * one token at a time using the persistent KV cache and scratch arena. */
static int generate_raw_swa_cpu(
        const ds4_model   * model,
        const ds4_vocab   * vocab,
        const ds4_weights * weights,
        const token_vec   * prompt,
        int                 n_predict,
        int                 ctx_size,
        const float       * directional_steering_dirs,
        float               directional_steering_attn,
        float               directional_steering_ffn,
        ds4_token_emit_fn   emit,
        ds4_generation_done_fn done,
        void              * emit_ud,
        ds4_session_progress_fn progress,
        void              * progress_ud) {
    (void)progress;
    (void)progress_ud;
    fprintf(stderr, "ds4: using CPU generation with layer-major prefill\n");

    ds4_kv_cache cache;
    kv_cache_init(&cache, (uint32_t)ctx_size, 0);
    ds4_cpu_decode_scratch decode_scratch;
    cpu_decode_scratch_init(&decode_scratch, (uint32_t)ctx_size);

    float *logits = xmalloc((size_t)DS4_N_VOCAB * sizeof(logits[0]));
    int pos = prompt->len;
    const bool trace_top = getenv("DS4_TRACE_TOP") != NULL;
    const double t_prefill0 = now_sec();

    if (prompt->len <= 0 || prompt->len > ctx_size) {
        fprintf(stderr, "ds4: prompt is empty or exceeds context size\n");
        free(logits);
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Suggest a minimal correctness-preserving optimization for this excerpt.

File: ds4.c

```c
r = sample_rng_f32(rng) * filtered_sum;
    for (int i = 0; i < filtered; i++) {
        r -= probs[i];
        if (r <= 0.0f) return ids[i];
    }
    return ids[filtered - 1];
}

static void print_top_logits(
        FILE          * fp,
        const char    * label,
        const ds4_vocab * vocab,
        const float   * logits,
        uint32_t        n_vocab,
        int             k) {
    int best[16];
    if (k > 16) k = 16;
    for (int i = 0; i < k; i++) best[i] = -1;

    for (uint32_t i = 0; i < n_vocab; i++) {
        for (int j = 0; j < k; j++) {
            if (best[j] < 0 || logits[i] > logits[best[j]]) {
                for (int l = k - 1; l > j; l--) best[l] = best[l - 1];
                best[j] = (int)i;
                break;
            }
        }
    }

    fprintf(fp, "ds4: top logits %s:\n", label);
    for (int i = 0; i < k && best[i] >= 0; i++) {
        const int id = best[i];
        fprintf(fp, "  %2d %7d % .9g  ", i, id, logits[id]);
        if (id >= 0 && id < vocab->n_vocab) {
            fprintf(fp, "%.*s", (int)vocab->token[id].len, vocab->token[id].ptr);
        }
        fputc('\n', fp);
    }
}

/* CPU generation entry point.  It runs layer-major prefill once, then decodes
 * one token at a time using the persistent KV cache and scratch arena. */
static int generate_raw_swa_cpu(
        const ds4_model   * model,
        const ds4_vocab   * vocab,
        const ds4_weights * weights,
        const token_vec   * prompt,
        int                 n_predict,
        int                 ctx_size,
        const float       * directional_steering_dirs,
        float               directional_steering_attn,
        float               directional_steering_ffn,
        ds4_token_emit_fn   emit,
        ds4_generation_done_fn done,
        void              * emit_ud,
        ds4_session_progress_fn progress,
        void              * progress_ud) {
    (void)progress;
    (void)progress_ud;
    fprintf(stderr, "ds4: using CPU generation with layer-major prefill\n");

    ds4_kv_cache cache;
    kv_cache_init(&cache, (uint32_t)ctx_size, 0);
    ds4_cpu_decode_scratch decode_scratch;
    cpu_decode_scratch_init(&decode_scratch, (uint32_t)ctx_size);

    float *logits = xmalloc((size_t)DS4_N_VOCAB * sizeof(logits[0]));
    int pos = prompt->len;
    const bool trace_top = getenv("DS4_TRACE_TOP") != NULL;
    const double t_prefill0 = now_sec();

    if (prompt->len <= 0 || prompt->len > ctx_size) {
        fprintf(stderr, "ds4: prompt is empty or exceeds context size\n");
        free(logits);
```<｜Assistant｜></think>