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https://github.com/coredns/coredns.git
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5301c5af5f
Cleanup the errors and removed deadcode along the way. The leaves some error laying around, mostly about commenting exported identifier. We should look hard if those really are needed.
59 lines
1.3 KiB
Go
59 lines
1.3 KiB
Go
package tree
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import (
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"bytes"
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"github.com/miekg/dns"
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)
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// less returns <0 when a is less than b, 0 when they are equal and
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// >0 when a is larger than b.
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// The function orders names in DNSSEC canonical order: RFC 4034s section-6.1
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//
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// See http://bert-hubert.blogspot.co.uk/2015/10/how-to-do-fast-canonical-ordering-of.html
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// for a blog article on this implementation.
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//
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// The values of a and b are *not* lowercased before the comparison!
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func less(a, b string) int {
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i := 1
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aj := len(a)
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bj := len(b)
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for {
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ai, oka := dns.PrevLabel(a, i)
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bi, okb := dns.PrevLabel(b, i)
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if oka && okb {
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return 0
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}
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// sadly this []byte will allocate... TODO(miek): check if this is needed
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// for a name, otherwise compare the strings.
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ab := []byte(a[ai:aj])
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bb := []byte(b[bi:bj])
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doDDD(ab)
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doDDD(bb)
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res := bytes.Compare(ab, bb)
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if res != 0 {
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return res
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}
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i++
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aj, bj = ai, bi
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}
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}
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func doDDD(b []byte) {
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lb := len(b)
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for i := 0; i < lb; i++ {
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if i+3 < lb && b[i] == '\\' && isDigit(b[i+1]) && isDigit(b[i+2]) && isDigit(b[i+3]) {
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b[i] = dddToByte(b[i:])
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for j := i + 1; j < lb-3; j++ {
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b[j] = b[j+3]
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}
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lb -= 3
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}
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}
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}
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func isDigit(b byte) bool { return b >= '0' && b <= '9' }
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func dddToByte(s []byte) byte { return (s[1]-'0')*100 + (s[2]-'0')*10 + (s[3] - '0') }
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