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|
package sockaddr
import (
"bytes"
"sort"
)
// SockAddrs is a slice of SockAddrs
type SockAddrs []SockAddr
func (s SockAddrs) Len() int { return len(s) }
func (s SockAddrs) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
// CmpAddrFunc is the function signature that must be met to be used in the
// OrderedAddrBy multiAddrSorter
type CmpAddrFunc func(p1, p2 *SockAddr) int
// multiAddrSorter implements the Sort interface, sorting the SockAddrs within.
type multiAddrSorter struct {
addrs SockAddrs
cmp []CmpAddrFunc
}
// Sort sorts the argument slice according to the Cmp functions passed to
// OrderedAddrBy.
func (ms *multiAddrSorter) Sort(sockAddrs SockAddrs) {
ms.addrs = sockAddrs
sort.Sort(ms)
}
// OrderedAddrBy sorts SockAddr by the list of sort function pointers.
func OrderedAddrBy(cmpFuncs ...CmpAddrFunc) *multiAddrSorter {
return &multiAddrSorter{
cmp: cmpFuncs,
}
}
// Len is part of sort.Interface.
func (ms *multiAddrSorter) Len() int {
return len(ms.addrs)
}
// Less is part of sort.Interface. It is implemented by looping along the
// Cmp() functions until it finds a comparison that is either less than,
// equal to, or greater than.
func (ms *multiAddrSorter) Less(i, j int) bool {
p, q := &ms.addrs[i], &ms.addrs[j]
// Try all but the last comparison.
var k int
for k = 0; k < len(ms.cmp)-1; k++ {
cmp := ms.cmp[k]
x := cmp(p, q)
switch x {
case -1:
// p < q, so we have a decision.
return true
case 1:
// p > q, so we have a decision.
return false
}
// p == q; try the next comparison.
}
// All comparisons to here said "equal", so just return whatever the
// final comparison reports.
switch ms.cmp[k](p, q) {
case -1:
return true
case 1:
return false
default:
// Still a tie! Now what?
return false
}
}
// Swap is part of sort.Interface.
func (ms *multiAddrSorter) Swap(i, j int) {
ms.addrs[i], ms.addrs[j] = ms.addrs[j], ms.addrs[i]
}
const (
// NOTE (sean@): These constants are here for code readability only and
// are sprucing up the code for readability purposes. Some of the
// Cmp*() variants have confusing logic (especially when dealing with
// mixed-type comparisons) and this, I think, has made it easier to grok
// the code faster.
sortReceiverBeforeArg = -1
sortDeferDecision = 0
sortArgBeforeReceiver = 1
)
// AscAddress is a sorting function to sort SockAddrs by their respective
// address type. Non-equal types are deferred in the sort.
func AscAddress(p1Ptr, p2Ptr *SockAddr) int {
p1 := *p1Ptr
p2 := *p2Ptr
switch v := p1.(type) {
case IPv4Addr:
return v.CmpAddress(p2)
case IPv6Addr:
return v.CmpAddress(p2)
case UnixSock:
return v.CmpAddress(p2)
default:
return sortDeferDecision
}
}
// AscPort is a sorting function to sort SockAddrs by their respective address
// type. Non-equal types are deferred in the sort.
func AscPort(p1Ptr, p2Ptr *SockAddr) int {
p1 := *p1Ptr
p2 := *p2Ptr
switch v := p1.(type) {
case IPv4Addr:
return v.CmpPort(p2)
case IPv6Addr:
return v.CmpPort(p2)
default:
return sortDeferDecision
}
}
// AscPrivate is a sorting function to sort "more secure" private values before
// "more public" values. Both IPv4 and IPv6 are compared against RFC6890
// (RFC6890 includes, and is not limited to, RFC1918 and RFC6598 for IPv4, and
// IPv6 includes RFC4193).
func AscPrivate(p1Ptr, p2Ptr *SockAddr) int {
p1 := *p1Ptr
p2 := *p2Ptr
switch v := p1.(type) {
case IPv4Addr, IPv6Addr:
return v.CmpRFC(6890, p2)
default:
return sortDeferDecision
}
}
// AscNetworkSize is a sorting function to sort SockAddrs based on their network
// size. Non-equal types are deferred in the sort.
func AscNetworkSize(p1Ptr, p2Ptr *SockAddr) int {
p1 := *p1Ptr
p2 := *p2Ptr
p1Type := p1.Type()
p2Type := p2.Type()
// Network size operations on non-IP types make no sense
if p1Type != p2Type && p1Type != TypeIP {
return sortDeferDecision
}
ipA := p1.(IPAddr)
ipB := p2.(IPAddr)
return bytes.Compare([]byte(*ipA.NetIPMask()), []byte(*ipB.NetIPMask()))
}
// AscType is a sorting function to sort "more secure" types before
// "less-secure" types.
func AscType(p1Ptr, p2Ptr *SockAddr) int {
p1 := *p1Ptr
p2 := *p2Ptr
p1Type := p1.Type()
p2Type := p2.Type()
switch {
case p1Type < p2Type:
return sortReceiverBeforeArg
case p1Type == p2Type:
return sortDeferDecision
case p1Type > p2Type:
return sortArgBeforeReceiver
default:
return sortDeferDecision
}
}
// FilterByType returns two lists: a list of matched and unmatched SockAddrs
func (sas SockAddrs) FilterByType(type_ SockAddrType) (matched, excluded SockAddrs) {
matched = make(SockAddrs, 0, len(sas))
excluded = make(SockAddrs, 0, len(sas))
for _, sa := range sas {
if sa.Type()&type_ != 0 {
matched = append(matched, sa)
} else {
excluded = append(excluded, sa)
}
}
return matched, excluded
}
|
