llama_cpp_bindings/token/
data_array.rs

1//! an rusty equivalent of `llama_token_data_array`.
2use std::ptr;
3
4use crate::error::TokenSamplingError;
5use crate::sampling::LlamaSampler;
6use crate::token::data::LlamaTokenData;
7
8use super::LlamaToken;
9
10/// a safe wrapper around `llama_token_data_array`.
11#[derive(Debug, Clone, PartialEq)]
12pub struct LlamaTokenDataArray {
13    /// the underlying data
14    pub data: Vec<LlamaTokenData>,
15    /// the index of the selected token in ``data``
16    pub selected: Option<usize>,
17    /// is the data sorted?
18    pub sorted: bool,
19}
20
21impl LlamaTokenDataArray {
22    /// Create a new `LlamaTokenDataArray` from a vector and whether or not the data is sorted.
23    ///
24    /// ```
25    /// # use llama_cpp_bindings::token::data::LlamaTokenData;
26    /// # use llama_cpp_bindings::token::data_array::LlamaTokenDataArray;
27    /// # use llama_cpp_bindings::token::LlamaToken;
28    /// let array = LlamaTokenDataArray::new(vec![
29    ///         LlamaTokenData::new(LlamaToken(0), 0.0, 0.0),
30    ///         LlamaTokenData::new(LlamaToken(1), 0.1, 0.1)
31    ///    ], false);
32    /// assert_eq!(array.data.len(), 2);
33    /// assert_eq!(array.sorted, false);
34    /// ```
35    #[must_use]
36    pub const fn new(data: Vec<LlamaTokenData>, sorted: bool) -> Self {
37        Self {
38            data,
39            selected: None,
40            sorted,
41        }
42    }
43
44    /// Create a new `LlamaTokenDataArray` from an iterator and whether or not the data is sorted.
45    /// ```
46    /// # use llama_cpp_bindings::token::data::LlamaTokenData;
47    /// # use llama_cpp_bindings::token::data_array::LlamaTokenDataArray;
48    /// # use llama_cpp_bindings::token::LlamaToken;
49    /// let array = LlamaTokenDataArray::from_iter([
50    ///     LlamaTokenData::new(LlamaToken(0), 0.0, 0.0),
51    ///     LlamaTokenData::new(LlamaToken(1), 0.1, 0.1)
52    /// ], false);
53    /// assert_eq!(array.data.len(), 2);
54    /// assert_eq!(array.sorted, false);
55    pub fn from_iter<TIterator>(data: TIterator, sorted: bool) -> Self
56    where
57        TIterator: IntoIterator<Item = LlamaTokenData>,
58    {
59        Self::new(data.into_iter().collect(), sorted)
60    }
61
62    /// Returns the current selected token, if one exists.
63    #[must_use]
64    pub fn selected_token(&self) -> Option<LlamaToken> {
65        self.data.get(self.selected?).map(LlamaTokenData::id)
66    }
67}
68
69impl LlamaTokenDataArray {
70    /// Modify the underlying data as a `llama_token_data_array`. and reconstruct the `LlamaTokenDataArray`.
71    ///
72    /// # Panics
73    ///
74    /// Panics if some of the safety conditions are not met. (we cannot check all of them at
75    /// runtime so breaking them is UB)
76    ///
77    /// # Safety
78    ///
79    /// The returned array formed by the data pointer and the length must entirely consist of
80    /// initialized token data and the length must be less than the capacity of this array's data
81    /// buffer.
82    /// If the data is not sorted, sorted must be false.
83    pub unsafe fn modify_as_c_llama_token_data_array<TResult>(
84        &mut self,
85        modify: impl FnOnce(&mut llama_cpp_bindings_sys::llama_token_data_array) -> TResult,
86    ) -> TResult {
87        let size = self.data.len();
88        let data = self
89            .data
90            .as_mut_ptr()
91            .cast::<llama_cpp_bindings_sys::llama_token_data>();
92
93        let mut c_llama_token_data_array = llama_cpp_bindings_sys::llama_token_data_array {
94            data,
95            size,
96            selected: self.selected.and_then(|s| s.try_into().ok()).unwrap_or(-1),
97            sorted: self.sorted,
98        };
99
100        let result = modify(&mut c_llama_token_data_array);
101
102        assert!(c_llama_token_data_array.size <= self.data.capacity());
103        // SAFETY: caller guarantees the returned data and size are valid.
104        unsafe {
105            if !ptr::eq(c_llama_token_data_array.data, data) {
106                ptr::copy(
107                    c_llama_token_data_array.data,
108                    data,
109                    c_llama_token_data_array.size,
110                );
111            }
112            self.data.set_len(c_llama_token_data_array.size);
113        }
114
115        self.sorted = c_llama_token_data_array.sorted;
116        self.selected = c_llama_token_data_array
117            .selected
118            .try_into()
119            .ok()
120            .filter(|&s| s < self.data.len());
121
122        result
123    }
124
125    /// Modifies the data array by applying a sampler to it
126    pub fn apply_sampler(&mut self, sampler: &LlamaSampler) {
127        unsafe {
128            self.modify_as_c_llama_token_data_array(|c_llama_token_data_array| {
129                llama_cpp_bindings_sys::llama_sampler_apply(
130                    sampler.sampler,
131                    c_llama_token_data_array,
132                );
133            });
134        }
135    }
136
137    /// Modifies the data array by applying a sampler to it
138    #[must_use]
139    pub fn with_sampler(mut self, sampler: &mut LlamaSampler) -> Self {
140        self.apply_sampler(sampler);
141        self
142    }
143
144    /// Randomly selects a token from the candidates based on their probabilities.
145    ///
146    /// # Errors
147    /// Returns [`TokenSamplingError::NoTokenSelected`] if the sampler fails to select a token.
148    pub fn sample_token(&mut self, seed: u32) -> Result<LlamaToken, TokenSamplingError> {
149        self.apply_sampler(&LlamaSampler::dist(seed));
150        self.selected_token()
151            .ok_or(TokenSamplingError::NoTokenSelected)
152    }
153
154    /// Selects the token with the highest probability.
155    ///
156    /// # Errors
157    /// Returns [`TokenSamplingError::NoTokenSelected`] if the sampler fails to select a token.
158    pub fn sample_token_greedy(&mut self) -> Result<LlamaToken, TokenSamplingError> {
159        self.apply_sampler(&LlamaSampler::greedy());
160        self.selected_token()
161            .ok_or(TokenSamplingError::NoTokenSelected)
162    }
163}
164
165#[cfg(test)]
166mod tests {
167    use crate::token::LlamaToken;
168    use crate::token::data::LlamaTokenData;
169
170    use super::LlamaTokenDataArray;
171
172    #[test]
173    fn apply_greedy_sampler_selects_highest_logit() {
174        use crate::sampling::LlamaSampler;
175
176        let mut array = LlamaTokenDataArray::new(
177            vec![
178                LlamaTokenData::new(LlamaToken::new(0), 1.0, 0.0),
179                LlamaTokenData::new(LlamaToken::new(1), 5.0, 0.0),
180                LlamaTokenData::new(LlamaToken::new(2), 3.0, 0.0),
181            ],
182            false,
183        );
184
185        array.apply_sampler(&LlamaSampler::greedy());
186
187        assert_eq!(array.selected_token(), Some(LlamaToken::new(1)));
188    }
189
190    #[test]
191    fn with_sampler_builder_pattern() {
192        use crate::sampling::LlamaSampler;
193
194        let array = LlamaTokenDataArray::new(
195            vec![
196                LlamaTokenData::new(LlamaToken::new(0), 1.0, 0.0),
197                LlamaTokenData::new(LlamaToken::new(1), 5.0, 0.0),
198            ],
199            false,
200        )
201        .with_sampler(&mut LlamaSampler::greedy());
202
203        assert_eq!(array.selected_token(), Some(LlamaToken::new(1)));
204    }
205
206    #[test]
207    fn sample_token_greedy_returns_highest() {
208        let mut array = LlamaTokenDataArray::new(
209            vec![
210                LlamaTokenData::new(LlamaToken::new(10), 0.1, 0.0),
211                LlamaTokenData::new(LlamaToken::new(20), 9.9, 0.0),
212            ],
213            false,
214        );
215
216        let token = array
217            .sample_token_greedy()
218            .expect("test: greedy sampler should select a token");
219
220        assert_eq!(token, LlamaToken::new(20));
221    }
222
223    #[test]
224    fn from_iter_creates_array_from_iterator() {
225        let array = LlamaTokenDataArray::from_iter(
226            [
227                LlamaTokenData::new(LlamaToken::new(0), 0.0, 0.0),
228                LlamaTokenData::new(LlamaToken::new(1), 1.0, 0.0),
229                LlamaTokenData::new(LlamaToken::new(2), 2.0, 0.0),
230            ],
231            false,
232        );
233
234        assert_eq!(array.data.len(), 3);
235        assert!(!array.sorted);
236        assert!(array.selected.is_none());
237    }
238
239    #[test]
240    fn sample_token_with_seed_selects_a_token() {
241        let mut array = LlamaTokenDataArray::new(
242            vec![
243                LlamaTokenData::new(LlamaToken::new(10), 1.0, 0.0),
244                LlamaTokenData::new(LlamaToken::new(20), 1.0, 0.0),
245            ],
246            false,
247        );
248
249        let token = array
250            .sample_token(42)
251            .expect("test: dist sampler should select a token");
252
253        assert!(token == LlamaToken::new(10) || token == LlamaToken::new(20));
254    }
255
256    #[test]
257    fn selected_token_returns_none_when_no_selection() {
258        let array = LlamaTokenDataArray::new(
259            vec![LlamaTokenData::new(LlamaToken::new(0), 1.0, 0.0)],
260            false,
261        );
262
263        assert!(array.selected_token().is_none());
264    }
265
266    #[test]
267    fn selected_token_returns_none_when_index_out_of_bounds() {
268        let array = LlamaTokenDataArray {
269            data: vec![LlamaTokenData::new(LlamaToken::new(0), 1.0, 0.0)],
270            selected: Some(5),
271            sorted: false,
272        };
273
274        assert!(array.selected_token().is_none());
275    }
276
277    #[test]
278    fn modify_as_c_llama_token_data_array_copies_when_data_pointer_changes() {
279        let mut array = LlamaTokenDataArray::new(
280            vec![
281                LlamaTokenData::new(LlamaToken::new(0), 1.0, 0.0),
282                LlamaTokenData::new(LlamaToken::new(1), 2.0, 0.0),
283                LlamaTokenData::new(LlamaToken::new(2), 3.0, 0.0),
284            ],
285            false,
286        );
287
288        let replacement = [
289            llama_cpp_bindings_sys::llama_token_data {
290                id: 10,
291                logit: 5.0,
292                p: 0.0,
293            },
294            llama_cpp_bindings_sys::llama_token_data {
295                id: 20,
296                logit: 6.0,
297                p: 0.0,
298            },
299        ];
300
301        unsafe {
302            array.modify_as_c_llama_token_data_array(|c_array| {
303                c_array.data = replacement.as_ptr().cast_mut();
304                c_array.size = replacement.len();
305                c_array.selected = 0;
306            });
307        }
308
309        assert_eq!(array.data.len(), 2);
310        assert_eq!(array.data[0].id(), LlamaToken::new(10));
311        assert_eq!(array.data[1].id(), LlamaToken::new(20));
312        assert_eq!(array.selected, Some(0));
313    }
314
315    #[test]
316    fn selected_overflow_uses_negative_one() {
317        let mut array = LlamaTokenDataArray {
318            data: vec![LlamaTokenData::new(LlamaToken::new(0), 1.0, 0.0)],
319            selected: Some(usize::MAX),
320            sorted: false,
321        };
322
323        unsafe {
324            array.modify_as_c_llama_token_data_array(|c_array| {
325                assert_eq!(c_array.selected, -1);
326            });
327        }
328    }
329}
llama_cpp_bindings/token/data_array.rs

llama_cpp_bindings/token/
data_array.rs
