ollama source for Momentry Core verification

x/tokenizer/tokenizer_decode.go

@@ -0,0 +1,54 @@
+package tokenizer
+
+import (
+	"strconv"
+	"strings"
+)
+
+// Decode converts token IDs back to text
+func (t *Tokenizer) Decode(ids []int32) string {
+	var sb strings.Builder
+
+	for _, id := range ids {
+		if int(id) >= len(t.vocab.Values) {
+			continue
+		}
+
+		token := t.vocab.Values[id]
+
+		switch t.typ {
+		case TokenizerSentencePiece:
+			// SentencePiece style: replace ▁ with space, decode byte tokens
+			token = strings.ReplaceAll(token, "▁", " ")
+			// Handle byte fallback tokens like <0x0D>
+			if len(token) == 6 && token[0] == '<' && token[1] == '0' && token[2] == 'x' && token[5] == '>' {
+				if v, err := strconv.ParseUint(token[3:5], 16, 8); err == nil {
+					sb.WriteByte(byte(v))
+					continue
+				}
+			}
+			sb.WriteString(token)
+		default:
+			// GPT-2 BPE style: decode byte-level encoding
+			for _, r := range token {
+				switch {
+				case r == 0x0100:
+					// Mirror GGML tokenizer behavior for NULL byte.
+					// 0x00 is omitted during decode.
+					continue
+				case r == 0x0143:
+					r = 0x00ad
+				case r > 0x0100 && r <= 0x0120:
+					r = r - 0x0100
+				case r > 0x0120 && r <= 0x0142:
+					r = r - 0x00a2
+				}
+
+				// Write as byte, not UTF-8 encoded rune
+				sb.WriteByte(byte(r))
+			}
+		}
+	}
+
+	return sb.String()
+}