mirror of
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9fe4437bda
* Use vendored go-swagger * vendor go-swagger * revert un wanteed change * remove un-needed GO111MODULE * Update Makefile Co-Authored-By: techknowlogick <matti@mdranta.net>
453 lines
11 KiB
Go
453 lines
11 KiB
Go
// Package denco provides fast URL router.
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package denco
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import (
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"fmt"
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"sort"
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"strings"
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)
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const (
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// ParamCharacter is a special character for path parameter.
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ParamCharacter = ':'
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// WildcardCharacter is a special character for wildcard path parameter.
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WildcardCharacter = '*'
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// TerminationCharacter is a special character for end of path.
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TerminationCharacter = '#'
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// MaxSize is max size of records and internal slice.
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MaxSize = (1 << 22) - 1
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)
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// Router represents a URL router.
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type Router struct {
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// SizeHint expects the maximum number of path parameters in records to Build.
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// SizeHint will be used to determine the capacity of the memory to allocate.
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// By default, SizeHint will be determined from given records to Build.
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SizeHint int
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static map[string]interface{}
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param *doubleArray
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}
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// New returns a new Router.
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func New() *Router {
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return &Router{
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SizeHint: -1,
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static: make(map[string]interface{}),
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param: newDoubleArray(),
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}
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}
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// Lookup returns data and path parameters that associated with path.
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// params is a slice of the Param that arranged in the order in which parameters appeared.
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// e.g. when built routing path is "/path/to/:id/:name" and given path is "/path/to/1/alice". params order is [{"id": "1"}, {"name": "alice"}], not [{"name": "alice"}, {"id": "1"}].
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func (rt *Router) Lookup(path string) (data interface{}, params Params, found bool) {
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if data, found := rt.static[path]; found {
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return data, nil, true
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}
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if len(rt.param.node) == 1 {
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return nil, nil, false
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}
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nd, params, found := rt.param.lookup(path, make([]Param, 0, rt.SizeHint), 1)
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if !found {
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return nil, nil, false
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}
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for i := 0; i < len(params); i++ {
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params[i].Name = nd.paramNames[i]
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}
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return nd.data, params, true
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}
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// Build builds URL router from records.
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func (rt *Router) Build(records []Record) error {
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statics, params := makeRecords(records)
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if len(params) > MaxSize {
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return fmt.Errorf("denco: too many records")
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}
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if rt.SizeHint < 0 {
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rt.SizeHint = 0
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for _, p := range params {
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size := 0
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for _, k := range p.Key {
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if k == ParamCharacter || k == WildcardCharacter {
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size++
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}
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}
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if size > rt.SizeHint {
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rt.SizeHint = size
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}
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}
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}
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for _, r := range statics {
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rt.static[r.Key] = r.Value
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}
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if err := rt.param.build(params, 1, 0, make(map[int]struct{})); err != nil {
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return err
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}
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return nil
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}
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// Param represents name and value of path parameter.
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type Param struct {
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Name string
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Value string
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}
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// Params represents the name and value of path parameters.
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type Params []Param
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// Get gets the first value associated with the given name.
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// If there are no values associated with the key, Get returns "".
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func (ps Params) Get(name string) string {
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for _, p := range ps {
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if p.Name == name {
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return p.Value
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}
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}
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return ""
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}
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type doubleArray struct {
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bc []baseCheck
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node []*node
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}
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func newDoubleArray() *doubleArray {
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return &doubleArray{
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bc: []baseCheck{0},
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node: []*node{nil}, // A start index is adjusting to 1 because 0 will be used as a mark of non-existent node.
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}
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}
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// baseCheck contains BASE, CHECK and Extra flags.
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// From the top, 22bits of BASE, 2bits of Extra flags and 8bits of CHECK.
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//
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// BASE (22bit) | Extra flags (2bit) | CHECK (8bit)
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// |----------------------|--|--------|
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// 32 10 8 0
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type baseCheck uint32
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func (bc baseCheck) Base() int {
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return int(bc >> 10)
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}
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func (bc *baseCheck) SetBase(base int) {
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*bc |= baseCheck(base) << 10
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}
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func (bc baseCheck) Check() byte {
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return byte(bc)
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}
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func (bc *baseCheck) SetCheck(check byte) {
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*bc |= baseCheck(check)
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}
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func (bc baseCheck) IsEmpty() bool {
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return bc&0xfffffcff == 0
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}
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func (bc baseCheck) IsSingleParam() bool {
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return bc¶mTypeSingle == paramTypeSingle
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}
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func (bc baseCheck) IsWildcardParam() bool {
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return bc¶mTypeWildcard == paramTypeWildcard
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}
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func (bc baseCheck) IsAnyParam() bool {
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return bc¶mTypeAny != 0
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}
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func (bc *baseCheck) SetSingleParam() {
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*bc |= (1 << 8)
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}
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func (bc *baseCheck) SetWildcardParam() {
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*bc |= (1 << 9)
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}
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const (
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paramTypeSingle = 0x0100
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paramTypeWildcard = 0x0200
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paramTypeAny = 0x0300
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)
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func (da *doubleArray) lookup(path string, params []Param, idx int) (*node, []Param, bool) {
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indices := make([]uint64, 0, 1)
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for i := 0; i < len(path); i++ {
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if da.bc[idx].IsAnyParam() {
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indices = append(indices, (uint64(i)<<32)|(uint64(idx)&0xffffffff))
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}
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c := path[i]
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if idx = nextIndex(da.bc[idx].Base(), c); idx >= len(da.bc) || da.bc[idx].Check() != c {
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goto BACKTRACKING
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}
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}
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if next := nextIndex(da.bc[idx].Base(), TerminationCharacter); next < len(da.bc) && da.bc[next].Check() == TerminationCharacter {
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return da.node[da.bc[next].Base()], params, true
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}
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BACKTRACKING:
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for j := len(indices) - 1; j >= 0; j-- {
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i, idx := int(indices[j]>>32), int(indices[j]&0xffffffff)
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if da.bc[idx].IsSingleParam() {
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idx := nextIndex(da.bc[idx].Base(), ParamCharacter)
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if idx >= len(da.bc) {
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break
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}
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next := NextSeparator(path, i)
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params := append(params, Param{Value: path[i:next]})
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if nd, params, found := da.lookup(path[next:], params, idx); found {
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return nd, params, true
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}
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}
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if da.bc[idx].IsWildcardParam() {
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idx := nextIndex(da.bc[idx].Base(), WildcardCharacter)
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params := append(params, Param{Value: path[i:]})
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return da.node[da.bc[idx].Base()], params, true
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}
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}
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return nil, nil, false
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}
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// build builds double-array from records.
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func (da *doubleArray) build(srcs []*record, idx, depth int, usedBase map[int]struct{}) error {
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sort.Stable(recordSlice(srcs))
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base, siblings, leaf, err := da.arrange(srcs, idx, depth, usedBase)
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if err != nil {
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return err
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}
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if leaf != nil {
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nd, err := makeNode(leaf)
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if err != nil {
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return err
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}
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da.bc[idx].SetBase(len(da.node))
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da.node = append(da.node, nd)
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}
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for _, sib := range siblings {
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da.setCheck(nextIndex(base, sib.c), sib.c)
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}
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for _, sib := range siblings {
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records := srcs[sib.start:sib.end]
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switch sib.c {
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case ParamCharacter:
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for _, r := range records {
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next := NextSeparator(r.Key, depth+1)
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name := r.Key[depth+1 : next]
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r.paramNames = append(r.paramNames, name)
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r.Key = r.Key[next:]
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}
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da.bc[idx].SetSingleParam()
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if err := da.build(records, nextIndex(base, sib.c), 0, usedBase); err != nil {
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return err
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}
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case WildcardCharacter:
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r := records[0]
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name := r.Key[depth+1 : len(r.Key)-1]
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r.paramNames = append(r.paramNames, name)
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r.Key = ""
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da.bc[idx].SetWildcardParam()
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if err := da.build(records, nextIndex(base, sib.c), 0, usedBase); err != nil {
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return err
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}
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default:
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if err := da.build(records, nextIndex(base, sib.c), depth+1, usedBase); err != nil {
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return err
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}
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}
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}
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return nil
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}
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// setBase sets BASE.
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func (da *doubleArray) setBase(i, base int) {
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da.bc[i].SetBase(base)
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}
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// setCheck sets CHECK.
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func (da *doubleArray) setCheck(i int, check byte) {
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da.bc[i].SetCheck(check)
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}
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// findEmptyIndex returns an index of unused BASE/CHECK node.
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func (da *doubleArray) findEmptyIndex(start int) int {
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i := start
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for ; i < len(da.bc); i++ {
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if da.bc[i].IsEmpty() {
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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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// findBase returns good BASE.
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func (da *doubleArray) findBase(siblings []sibling, start int, usedBase map[int]struct{}) (base int) {
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for idx, firstChar := start+1, siblings[0].c; ; idx = da.findEmptyIndex(idx + 1) {
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base = nextIndex(idx, firstChar)
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if _, used := usedBase[base]; used {
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continue
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}
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i := 0
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for ; i < len(siblings); i++ {
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next := nextIndex(base, siblings[i].c)
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if len(da.bc) <= next {
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da.bc = append(da.bc, make([]baseCheck, next-len(da.bc)+1)...)
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}
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if !da.bc[next].IsEmpty() {
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break
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}
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}
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if i == len(siblings) {
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break
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}
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}
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usedBase[base] = struct{}{}
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return base
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}
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func (da *doubleArray) arrange(records []*record, idx, depth int, usedBase map[int]struct{}) (base int, siblings []sibling, leaf *record, err error) {
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siblings, leaf, err = makeSiblings(records, depth)
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if err != nil {
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return -1, nil, nil, err
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}
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if len(siblings) < 1 {
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return -1, nil, leaf, nil
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}
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base = da.findBase(siblings, idx, usedBase)
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if base > MaxSize {
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return -1, nil, nil, fmt.Errorf("denco: too many elements of internal slice")
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}
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da.setBase(idx, base)
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return base, siblings, leaf, err
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}
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// node represents a node of Double-Array.
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type node struct {
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data interface{}
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// Names of path parameters.
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paramNames []string
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}
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// makeNode returns a new node from record.
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func makeNode(r *record) (*node, error) {
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dups := make(map[string]bool)
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for _, name := range r.paramNames {
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if dups[name] {
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return nil, fmt.Errorf("denco: path parameter `%v' is duplicated in the key `%v'", name, r.Key)
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}
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dups[name] = true
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}
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return &node{data: r.Value, paramNames: r.paramNames}, nil
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}
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// sibling represents an intermediate data of build for Double-Array.
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type sibling struct {
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// An index of start of duplicated characters.
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start int
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// An index of end of duplicated characters.
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end int
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// A character of sibling.
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c byte
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}
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// nextIndex returns a next index of array of BASE/CHECK.
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func nextIndex(base int, c byte) int {
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return base ^ int(c)
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}
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// makeSiblings returns slice of sibling.
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func makeSiblings(records []*record, depth int) (sib []sibling, leaf *record, err error) {
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var (
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pc byte
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n int
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)
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for i, r := range records {
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if len(r.Key) <= depth {
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leaf = r
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continue
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}
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c := r.Key[depth]
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switch {
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case pc < c:
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sib = append(sib, sibling{start: i, c: c})
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case pc == c:
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continue
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default:
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return nil, nil, fmt.Errorf("denco: BUG: routing table hasn't been sorted")
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}
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if n > 0 {
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sib[n-1].end = i
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}
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pc = c
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n++
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}
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if n == 0 {
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return nil, leaf, nil
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}
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sib[n-1].end = len(records)
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return sib, leaf, nil
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}
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// Record represents a record data for router construction.
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type Record struct {
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// Key for router construction.
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Key string
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// Result value for Key.
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Value interface{}
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}
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// NewRecord returns a new Record.
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func NewRecord(key string, value interface{}) Record {
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return Record{
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Key: key,
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Value: value,
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}
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}
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// record represents a record that use to build the Double-Array.
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type record struct {
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Record
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paramNames []string
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}
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// makeRecords returns the records that use to build Double-Arrays.
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func makeRecords(srcs []Record) (statics, params []*record) {
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spChars := string([]byte{ParamCharacter, WildcardCharacter})
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termChar := string(TerminationCharacter)
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for _, r := range srcs {
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if strings.ContainsAny(r.Key, spChars) {
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r.Key += termChar
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params = append(params, &record{Record: r})
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} else {
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statics = append(statics, &record{Record: r})
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}
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}
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return statics, params
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}
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// recordSlice represents a slice of Record for sort and implements the sort.Interface.
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type recordSlice []*record
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// Len implements the sort.Interface.Len.
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func (rs recordSlice) Len() int {
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return len(rs)
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}
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// Less implements the sort.Interface.Less.
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func (rs recordSlice) Less(i, j int) bool {
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return rs[i].Key < rs[j].Key
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}
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// Swap implements the sort.Interface.Swap.
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func (rs recordSlice) Swap(i, j int) {
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rs[i], rs[j] = rs[j], rs[i]
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}
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