58 lines
1.4 KiB
Go
58 lines
1.4 KiB
Go
// Copyright 2023-2025 The NATS Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package stree
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// For subject matching.
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const (
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pwc = '*'
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fwc = '>'
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tsep = '.'
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)
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// Determine index of common prefix. No match at all is 0, etc.
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func commonPrefixLen(s1, s2 []byte) int {
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limit := min(len(s1), len(s2))
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var i int
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for ; i < limit; i++ {
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if s1[i] != s2[i] {
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break
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}
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}
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return i
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}
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// Helper to copy bytes.
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func copyBytes(src []byte) []byte {
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if len(src) == 0 {
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return nil
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}
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dst := make([]byte, len(src))
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copy(dst, src)
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return dst
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}
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type position interface{ int | uint16 }
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// No pivot available.
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const noPivot = byte(127)
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// Can return 127 (DEL) if we have all the subject as prefixes.
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// We used to use 0, but when that was in the subject would cause infinite recursion in some situations.
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func pivot[N position](subject []byte, pos N) byte {
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if int(pos) >= len(subject) {
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return noPivot
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}
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return subject[pos]
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}
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