summaryrefslogtreecommitdiff
path: root/llm/tokenbuffer.go
blob: e2d8a91e32d0b0bdd50b43ae49204b860842a275 (plain)
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
package llm

import "iter"

type TokenBuffer struct {
	tokenizer   Tokenizer
	window      int
	stride      int
	buffer      []int64
	document    int
	position    int
	includeTail bool
}

type TokenBufferConfig struct {
	Window int
	Stride int
}

type TokenWindow struct {
	Document int
	Tokens   []int64
	Seen     int
}

func NewTokenBuffer(tokenizer Tokenizer, cfg TokenBufferConfig) *TokenBuffer {
	if cfg.Stride > cfg.Window {
		panic("stride exceeds window")
	}

	return &TokenBuffer{
		tokenizer:   tokenizer,
		window:      cfg.Window,
		stride:      cfg.Stride,
		buffer:      make([]int64, 0, 2*cfg.Window),
		document:    -1,
		position:    0,
		includeTail: true,
	}
}

func (tb *TokenBuffer) IncludeTail() bool {
	return tb.includeTail
}

func (tb *TokenBuffer) SetIncludeTail(includeTail bool) {
	tb.includeTail = includeTail
}

func (tb *TokenBuffer) Position() int {
	return tb.position
}

func (tb *TokenBuffer) Push(document int, text string) iter.Seq[TokenWindow] {
	return func(yield func(window TokenWindow) bool) {
		if tb.document != -1 && document != tb.document {
			w, ok := tb.Tail()

			if ok && !yield(w) {
				return
			}
		}

		tb.document = document

		if text == "" {
			return
		}

		ids := toInt64(tb.tokenizer.Tokenize(text))

		tb.buffer = append(tb.buffer, ids...)

		for len(tb.buffer) >= tb.window {
			w := TokenWindow{
				Document: tb.document,
				Tokens:   make([]int64, tb.window),
				Seen:     min(tb.Position(), tb.window-tb.stride),
			}

			copy(w.Tokens, tb.buffer[:tb.window])

			if !yield(w) {
				return
			}

			tb.position += tb.stride

			tb.buffer = append(tb.buffer[:0], tb.buffer[tb.stride:]...)
		}
	}
}

func (tb *TokenBuffer) Tail() (TokenWindow, bool) {
	seen := min(tb.Position(), min(len(tb.buffer), tb.window-tb.stride))

	w := TokenWindow{
		Document: tb.document,
		Seen:     seen,
	}

	tb.document = -1
	tb.position = 0

	if !tb.includeTail || len(tb.buffer) == 0 {
		tb.buffer = tb.buffer[:0]

		return w, false
	}

	w.Tokens = make([]int64, len(tb.buffer))

	copy(w.Tokens, tb.buffer)

	tb.buffer = tb.buffer[:0]

	return w, true
}

func (tb *TokenBuffer) Stream(docs iter.Seq2[int, string]) iter.Seq[TokenWindow] {
	return func(yield func(window TokenWindow) bool) {
		for n, d := range docs {
			for w := range tb.Push(n, d) {
				if !yield(w) {
					return
				}
			}

			if w, ok := tb.Tail(); ok && !yield(w) {
				return
			}
		}
	}
}