snapshot of https://github.com/blevesearch/bleve.git (master, 2026-09-15; blobs > 131072B omitted)

analysis/lang/cjk/cjk_width.go

@@ -0,0 +1,104 @@
+//  Copyright (c) 2016 Couchbase, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 		http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cjk
+
+import (
+	"bytes"
+	"unicode/utf8"
+
+	"github.com/blevesearch/bleve/v2/analysis"
+	"github.com/blevesearch/bleve/v2/registry"
+)
+
+const WidthName = "cjk_width"
+
+type CJKWidthFilter struct{}
+
+func NewCJKWidthFilter() *CJKWidthFilter {
+	return &CJKWidthFilter{}
+}
+
+func (s *CJKWidthFilter) Filter(input analysis.TokenStream) analysis.TokenStream {
+	for _, token := range input {
+		runeCount := utf8.RuneCount(token.Term)
+		runes := bytes.Runes(token.Term)
+		for i := 0; i < runeCount; i++ {
+			ch := runes[i]
+			if ch >= 0xFF01 && ch <= 0xFF5E {
+				// fullwidth ASCII variants
+				runes[i] -= 0xFEE0
+			} else if ch >= 0xFF65 && ch <= 0xFF9F {
+				// halfwidth Katakana variants
+				if (ch == 0xFF9E || ch == 0xFF9F) && i > 0 && combine(runes, i, ch) {
+					runes = analysis.DeleteRune(runes, i)
+					i--
+					runeCount = len(runes)
+				} else {
+					runes[i] = kanaNorm[ch-0xFF65]
+				}
+			}
+		}
+		token.Term = analysis.BuildTermFromRunes(runes)
+	}
+
+	return input
+}
+
+var kanaNorm = []rune{
+	0x30fb, 0x30f2, 0x30a1, 0x30a3, 0x30a5, 0x30a7, 0x30a9, 0x30e3, 0x30e5,
+	0x30e7, 0x30c3, 0x30fc, 0x30a2, 0x30a4, 0x30a6, 0x30a8, 0x30aa, 0x30ab,
+	0x30ad, 0x30af, 0x30b1, 0x30b3, 0x30b5, 0x30b7, 0x30b9, 0x30bb, 0x30bd,
+	0x30bf, 0x30c1, 0x30c4, 0x30c6, 0x30c8, 0x30ca, 0x30cb, 0x30cc, 0x30cd,
+	0x30ce, 0x30cf, 0x30d2, 0x30d5, 0x30d8, 0x30db, 0x30de, 0x30df, 0x30e0,
+	0x30e1, 0x30e2, 0x30e4, 0x30e6, 0x30e8, 0x30e9, 0x30ea, 0x30eb, 0x30ec,
+	0x30ed, 0x30ef, 0x30f3, 0x3099, 0x309A,
+}
+
+var kanaCombineVoiced = []rune{
+	78, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1,
+	0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1,
+	0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+	0, 8, 8, 8, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,
+}
+var kanaCombineHalfVoiced = []rune{
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 2, 0, 0, 2,
+	0, 0, 2, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+}
+
+func combine(text []rune, pos int, r rune) bool {
+	prev := text[pos-1]
+	if prev >= 0x30A6 && prev <= 0x30FD {
+		if r == 0xFF9F {
+			text[pos-1] += kanaCombineHalfVoiced[prev-0x30A6]
+		} else {
+			text[pos-1] += kanaCombineVoiced[prev-0x30A6]
+		}
+		return text[pos-1] != prev
+	}
+	return false
+}
+
+func CJKWidthFilterConstructor(config map[string]interface{}, cache *registry.Cache) (analysis.TokenFilter, error) {
+	return NewCJKWidthFilter(), nil
+}
+
+func init() {
+	err := registry.RegisterTokenFilter(WidthName, CJKWidthFilterConstructor)
+	if err != nil {
+		panic(err)
+	}
+}