tiktoken 3.1.4

A high-performance pure-Rust implementation of OpenAI's tiktoken BPE tokenizer
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150

// property-based tests: verify invariants hold for 100k random inputs

use proptest::prelude::*;

// strategy: mix of ascii, unicode, whitespace, emoji, CJK, control chars
fn text_strategy() -> impl Strategy<Value = String> {
    prop_oneof![
        // pure ascii
        "[a-zA-Z0-9 .,!?'\\-]{0,500}",
        // unicode mix: latin, CJK, emoji, whitespace
        "[ -~\u{00A0}-\u{00FF}\u{4E00}-\u{9FFF}\u{3000}-\u{303F}\u{1F600}-\u{1F64F}\n\r\t]{0,300}",
        // arbitrary valid utf-8
        "\\PC{0,200}",
        // whitespace-heavy
        "[ \t\n\r\u{3000}]{0,100}",
        // code-like
        "(fn |def |class |import |const |let |var )[a-z_]{1,20}\\([a-z, ]{0,30}\\)\\s*\\{?\\s*\n",
    ]
}

const ENCODINGS: &[&str] = &[
    "cl100k_base",
    "o200k_base",
    "p50k_base",
    "p50k_edit",
    "r50k_base",
    "llama3",
    "deepseek_v3",
    "qwen2",
    "mistral_v3",
];

proptest! {
    #![proptest_config(ProptestConfig::with_cases(25000))]

    #[test]
    fn roundtrip_cl100k(text in text_strategy()) {
        let enc = tiktoken::get_encoding("cl100k_base").unwrap();
        let tokens = enc.encode(&text);
        let decoded = enc.decode(&tokens);
        prop_assert_eq!(&decoded[..], text.as_bytes(), "roundtrip failed");
    }

    #[test]
    fn roundtrip_o200k(text in text_strategy()) {
        let enc = tiktoken::get_encoding("o200k_base").unwrap();
        let tokens = enc.encode(&text);
        let decoded = enc.decode(&tokens);
        prop_assert_eq!(&decoded[..], text.as_bytes(), "roundtrip failed");
    }

    #[test]
    fn roundtrip_p50k(text in text_strategy()) {
        let enc = tiktoken::get_encoding("p50k_base").unwrap();
        let tokens = enc.encode(&text);
        let decoded = enc.decode(&tokens);
        prop_assert_eq!(&decoded[..], text.as_bytes(), "roundtrip failed");
    }

    #[test]
    fn roundtrip_p50k_edit(text in text_strategy()) {
        let enc = tiktoken::get_encoding("p50k_edit").unwrap();
        let tokens = enc.encode(&text);
        let decoded = enc.decode(&tokens);
        prop_assert_eq!(&decoded[..], text.as_bytes(), "roundtrip failed");
    }

    #[test]
    fn roundtrip_r50k(text in text_strategy()) {
        let enc = tiktoken::get_encoding("r50k_base").unwrap();
        let tokens = enc.encode(&text);
        let decoded = enc.decode(&tokens);
        prop_assert_eq!(&decoded[..], text.as_bytes(), "roundtrip failed");
    }

    #[test]
    fn count_equals_encode_len(text in text_strategy()) {
        for &name in ENCODINGS {
            let enc = tiktoken::get_encoding(name).unwrap();
            let tokens = enc.encode(&text);
            let count = enc.count(&text);
            prop_assert_eq!(count, tokens.len(), "count mismatch for {}", name);
        }
    }

    #[test]
    fn roundtrip_llama3(text in text_strategy()) {
        let enc = tiktoken::get_encoding("llama3").unwrap();
        let tokens = enc.encode(&text);
        let decoded = enc.decode(&tokens);
        prop_assert_eq!(&decoded[..], text.as_bytes(), "roundtrip failed");
    }

    #[test]
    fn roundtrip_deepseek_v3(text in text_strategy()) {
        let enc = tiktoken::get_encoding("deepseek_v3").unwrap();
        let tokens = enc.encode(&text);
        let decoded = enc.decode(&tokens);
        prop_assert_eq!(&decoded[..], text.as_bytes(), "roundtrip failed");
    }

    #[test]
    fn roundtrip_qwen2(text in text_strategy()) {
        let enc = tiktoken::get_encoding("qwen2").unwrap();
        let tokens = enc.encode(&text);
        let decoded = enc.decode(&tokens);
        prop_assert_eq!(&decoded[..], text.as_bytes(), "roundtrip failed");
    }

    #[test]
    fn roundtrip_mistral_v3(text in text_strategy()) {
        let enc = tiktoken::get_encoding("mistral_v3").unwrap();
        let tokens = enc.encode(&text);
        let decoded = enc.decode(&tokens);
        prop_assert_eq!(&decoded[..], text.as_bytes(), "roundtrip failed");
    }

    #[test]
    fn encode_with_special_tokens_roundtrip(text in text_strategy()) {
        // encode_with_special_tokens should also roundtrip correctly
        // (special token literals rarely appear in random text, but the
        // code path through special_regex must still be exercised)
        for &name in ENCODINGS {
            let enc = tiktoken::get_encoding(name).unwrap();
            let tokens = enc.encode_with_special_tokens(&text);
            let decoded = enc.decode(&tokens);
            prop_assert_eq!(
                &decoded[..],
                text.as_bytes(),
                "encode_with_special_tokens roundtrip failed for {}",
                name
            );
        }
    }

    #[test]
    fn count_with_special_tokens_equals_encode_with_special_tokens_len(text in text_strategy()) {
        for &name in ENCODINGS {
            let enc = tiktoken::get_encoding(name).unwrap();
            let tokens = enc.encode_with_special_tokens(&text);
            let count = enc.count_with_special_tokens(&text);
            prop_assert_eq!(
                count,
                tokens.len(),
                "count_with_special_tokens mismatch for {}",
                name
            );
        }
    }
}