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
97                .selected
98                .and_then(|selected_index| selected_index.try_into().ok())
99                .unwrap_or(-1),
100            sorted: self.sorted,
101        };
102
103        let result = modify(&mut c_llama_token_data_array);
104
105        assert!(c_llama_token_data_array.size <= self.data.capacity());
106        // SAFETY: caller guarantees the returned data and size are valid.
107        unsafe {
108            if !ptr::eq(c_llama_token_data_array.data, data) {
109                ptr::copy(
110                    c_llama_token_data_array.data,
111                    data,
112                    c_llama_token_data_array.size,
113                );
114            }
115            self.data.set_len(c_llama_token_data_array.size);
116        }
117
118        self.sorted = c_llama_token_data_array.sorted;
119        self.selected = c_llama_token_data_array
120            .selected
121            .try_into()
122            .ok()
123            .filter(|&s| s < self.data.len());
124
125        result
126    }
127
128    /// Modifies the data array by applying a sampler to it
129    pub fn apply_sampler(&mut self, sampler: &LlamaSampler) {
130        unsafe {
131            self.modify_as_c_llama_token_data_array(|c_llama_token_data_array| {
132                llama_cpp_bindings_sys::llama_sampler_apply(
133                    sampler.sampler,
134                    c_llama_token_data_array,
135                );
136            });
137        }
138    }
139
140    /// Modifies the data array by applying a sampler to it
141    #[must_use]
142    pub fn with_sampler(mut self, sampler: &mut LlamaSampler) -> Self {
143        self.apply_sampler(sampler);
144        self
145    }
146
147    /// Randomly selects a token from the candidates based on their probabilities.
148    ///
149    /// # Errors
150    /// Returns [`TokenSamplingError::NoTokenSelected`] if the sampler fails to select a token.
151    pub fn sample_token(&mut self, seed: u32) -> Result<LlamaToken, TokenSamplingError> {
152        self.apply_sampler(&LlamaSampler::dist(seed));
153        self.selected_token()
154            .ok_or(TokenSamplingError::NoTokenSelected)
155    }
156
157    /// Selects the token with the highest probability.
158    ///
159    /// # Errors
160    /// Returns [`TokenSamplingError::NoTokenSelected`] if the sampler fails to select a token.
161    pub fn sample_token_greedy(&mut self) -> Result<LlamaToken, TokenSamplingError> {
162        self.apply_sampler(&LlamaSampler::greedy());
163        self.selected_token()
164            .ok_or(TokenSamplingError::NoTokenSelected)
165    }
166}
167
168#[cfg(test)]
169mod tests {
170    use crate::token::LlamaToken;
171    use crate::token::data::LlamaTokenData;
172
173    use super::LlamaTokenDataArray;
174
175    #[test]
176    fn apply_greedy_sampler_selects_highest_logit() {
177        use crate::sampling::LlamaSampler;
178
179        let mut array = LlamaTokenDataArray::new(
180            vec![
181                LlamaTokenData::new(LlamaToken::new(0), 1.0, 0.0),
182                LlamaTokenData::new(LlamaToken::new(1), 5.0, 0.0),
183                LlamaTokenData::new(LlamaToken::new(2), 3.0, 0.0),
184            ],
185            false,
186        );
187
188        array.apply_sampler(&LlamaSampler::greedy());
189
190        assert_eq!(array.selected_token(), Some(LlamaToken::new(1)));
191    }
192
193    #[test]
194    fn with_sampler_builder_pattern() {
195        use crate::sampling::LlamaSampler;
196
197        let array = LlamaTokenDataArray::new(
198            vec![
199                LlamaTokenData::new(LlamaToken::new(0), 1.0, 0.0),
200                LlamaTokenData::new(LlamaToken::new(1), 5.0, 0.0),
201            ],
202            false,
203        )
204        .with_sampler(&mut LlamaSampler::greedy());
205
206        assert_eq!(array.selected_token(), Some(LlamaToken::new(1)));
207    }
208
209    #[test]
210    fn sample_token_greedy_returns_highest() {
211        let mut array = LlamaTokenDataArray::new(
212            vec![
213                LlamaTokenData::new(LlamaToken::new(10), 0.1, 0.0),
214                LlamaTokenData::new(LlamaToken::new(20), 9.9, 0.0),
215            ],
216            false,
217        );
218
219        let token = array
220            .sample_token_greedy()
221            .expect("test: greedy sampler should select a token");
222
223        assert_eq!(token, LlamaToken::new(20));
224    }
225
226    #[test]
227    fn from_iter_creates_array_from_iterator() {
228        let array = LlamaTokenDataArray::from_iter(
229            [
230                LlamaTokenData::new(LlamaToken::new(0), 0.0, 0.0),
231                LlamaTokenData::new(LlamaToken::new(1), 1.0, 0.0),
232                LlamaTokenData::new(LlamaToken::new(2), 2.0, 0.0),
233            ],
234            false,
235        );
236
237        assert_eq!(array.data.len(), 3);
238        assert!(!array.sorted);
239        assert!(array.selected.is_none());
240    }
241
242    #[test]
243    fn sample_token_with_seed_selects_a_token() {
244        let mut array = LlamaTokenDataArray::new(
245            vec![
246                LlamaTokenData::new(LlamaToken::new(10), 1.0, 0.0),
247                LlamaTokenData::new(LlamaToken::new(20), 1.0, 0.0),
248            ],
249            false,
250        );
251
252        let token = array
253            .sample_token(42)
254            .expect("test: dist sampler should select a token");
255
256        assert!(token == LlamaToken::new(10) || token == LlamaToken::new(20));
257    }
258
259    #[test]
260    fn selected_token_returns_none_when_no_selection() {
261        let array = LlamaTokenDataArray::new(
262            vec![LlamaTokenData::new(LlamaToken::new(0), 1.0, 0.0)],
263            false,
264        );
265
266        assert!(array.selected_token().is_none());
267    }
268
269    #[test]
270    fn selected_token_returns_none_when_index_out_of_bounds() {
271        let array = LlamaTokenDataArray {
272            data: vec![LlamaTokenData::new(LlamaToken::new(0), 1.0, 0.0)],
273            selected: Some(5),
274            sorted: false,
275        };
276
277        assert!(array.selected_token().is_none());
278    }
279
280    #[test]
281    fn modify_as_c_llama_token_data_array_copies_when_data_pointer_changes() {
282        let mut array = LlamaTokenDataArray::new(
283            vec![
284                LlamaTokenData::new(LlamaToken::new(0), 1.0, 0.0),
285                LlamaTokenData::new(LlamaToken::new(1), 2.0, 0.0),
286                LlamaTokenData::new(LlamaToken::new(2), 3.0, 0.0),
287            ],
288            false,
289        );
290
291        let replacement = [
292            llama_cpp_bindings_sys::llama_token_data {
293                id: 10,
294                logit: 5.0,
295                p: 0.0,
296            },
297            llama_cpp_bindings_sys::llama_token_data {
298                id: 20,
299                logit: 6.0,
300                p: 0.0,
301            },
302        ];
303
304        unsafe {
305            array.modify_as_c_llama_token_data_array(|c_array| {
306                c_array.data = replacement.as_ptr().cast_mut();
307                c_array.size = replacement.len();
308                c_array.selected = 0;
309            });
310        }
311
312        assert_eq!(array.data.len(), 2);
313        assert_eq!(array.data[0].id(), LlamaToken::new(10));
314        assert_eq!(array.data[1].id(), LlamaToken::new(20));
315        assert_eq!(array.selected, Some(0));
316    }
317
318    #[test]
319    fn selected_overflow_uses_negative_one() {
320        let mut array = LlamaTokenDataArray {
321            data: vec![LlamaTokenData::new(LlamaToken::new(0), 1.0, 0.0)],
322            selected: Some(usize::MAX),
323            sorted: false,
324        };
325
326        unsafe {
327            array.modify_as_c_llama_token_data_array(|c_array| {
328                assert_eq!(c_array.selected, -1);
329            });
330        }
331    }
332}
llama_cpp_bindings/token/data_array.rs

llama_cpp_bindings/token/
data_array.rs
