mirror of https://github.com/periph/devices
updates and testing of implementations
imle
5 years ago
parent
050bc7a20a
commit
7b71c747f2
@ -1,216 +0,0 @@
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package firmatareg
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import (
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"errors"
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"strconv"
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"strings"
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"sync"
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"periph.io/x/devices/v3/firmata"
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)
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// Opener opens a handle to a firmata device.
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//
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// It is provided by the actual device driver.
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type Opener func() (firmata.ClientI, error)
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// Ref references a Firmata device.
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//
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// It is returned by All() to enumerate all registered devices.
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type Ref struct {
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// Name of the device.
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//
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// It must be unique across the host.
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Name string
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// Aliases are the alternative names that can be used to reference this bus.
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Aliases []string
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// Open is the factory to open a handle to this Firmata device.
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Open Opener
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}
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// Open opens a firmata device by its name, an alias or its file path and returns
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// a handle to it.
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//
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// Specify the empty string "" to get the first available device. This is the
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// recommended default value unless an application knows the exact device to use.
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//
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// Each device can register multiple aliases, each leading to the same device handle.
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//
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// "file path" is a generic concept that is highly dependent on the platform
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// and OS. Depending on the OS, a serial port can be `/dev/tty*` or `COM*`.
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func Open(name string) (firmata.ClientI, error) {
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var r *Ref
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var err error
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func() {
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mu.Lock()
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defer mu.Unlock()
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if len(byName) == 0 {
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err = errors.New("firmatareg: no device found; did you forget to call Init()")
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return
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}
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if len(name) == 0 {
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r = getDefault()
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return
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}
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// Try by name, by alias, by number.
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if r = byName[name]; r == nil {
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r = byAlias[name]
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}
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}()
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if err != nil {
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return nil, err
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}
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if r == nil {
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return nil, errors.New("firmatareg: can't open unknown device: " + strconv.Quote(name))
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}
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return r.Open()
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}
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// All returns a copy of all the registered references to all know firmata devices
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// available on this host.
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//
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// The list is sorted by the bus name.
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func All() []*Ref {
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mu.Lock()
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defer mu.Unlock()
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out := make([]*Ref, 0, len(byName))
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for _, v := range byName {
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r := &Ref{Name: v.Name, Aliases: make([]string, len(v.Aliases)), Open: v.Open}
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copy(r.Aliases, v.Aliases)
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out = insertRef(out, r)
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}
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return out
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}
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// Register registers a firmata device.
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//
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// Registering the same device name twice is an error, e.g. o.Name().
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func Register(name string, aliases []string, o Opener) error {
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if len(name) == 0 {
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return errors.New("firmatareg: can't register a bus with no name")
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}
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if o == nil {
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return errors.New("firmatareg: can't register bus " + strconv.Quote(name) + " with nil Opener")
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}
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if _, err := strconv.Atoi(name); err == nil {
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return errors.New("firmatareg: can't register bus " + strconv.Quote(name) + " with name being only a number")
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}
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if strings.Contains(name, ":") {
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return errors.New("firmatareg: can't register bus " + strconv.Quote(name) + " with name containing ':'")
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}
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for _, alias := range aliases {
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if len(alias) == 0 {
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return errors.New("firmatareg: can't register bus " + strconv.Quote(name) + " with an empty alias")
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}
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if name == alias {
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return errors.New("firmatareg: can't register bus " + strconv.Quote(name) + " with an alias the same as the bus name")
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}
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if _, err := strconv.Atoi(alias); err == nil {
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return errors.New("firmatareg: can't register bus " + strconv.Quote(name) + " with an alias that is a number: " + strconv.Quote(alias))
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}
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if strings.Contains(alias, ":") {
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return errors.New("firmatareg: can't register bus " + strconv.Quote(name) + " with an alias containing ':': " + strconv.Quote(alias))
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}
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}
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mu.Lock()
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defer mu.Unlock()
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if _, ok := byName[name]; ok {
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return errors.New("firmatareg: can't register bus " + strconv.Quote(name) + " twice")
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}
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if _, ok := byAlias[name]; ok {
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return errors.New("firmatareg: can't register bus " + strconv.Quote(name) + " twice; it is already an alias")
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}
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for _, alias := range aliases {
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if _, ok := byName[alias]; ok {
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return errors.New("firmatareg: can't register bus " + strconv.Quote(name) + " twice; alias " + strconv.Quote(alias) + " is already a bus")
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}
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if _, ok := byAlias[alias]; ok {
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return errors.New("firmatareg: can't register bus " + strconv.Quote(name) + " twice; alias " + strconv.Quote(alias) + " is already an alias")
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}
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}
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r := &Ref{Name: name, Aliases: make([]string, len(aliases)), Open: o}
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copy(r.Aliases, aliases)
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byName[name] = r
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for _, alias := range aliases {
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byAlias[alias] = r
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}
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return nil
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}
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// Unregister removes a previously registered firmata device.
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//
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// This can happen when a firmata device is exposed via a USB device and the device
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// is unplugged.
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func Unregister(name string) error {
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mu.Lock()
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defer mu.Unlock()
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r := byName[name]
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if r == nil {
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return errors.New("firmatareg: can't unregister unknown bus name " + strconv.Quote(name))
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}
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delete(byName, name)
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for _, alias := range r.Aliases {
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delete(byAlias, alias)
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}
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return nil
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}
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//
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var (
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mu sync.Mutex
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byName = map[string]*Ref{}
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// Caches
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byNumber = map[int]*Ref{}
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byAlias = map[string]*Ref{}
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)
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// getDefault returns the Ref that should be used as the default bus.
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func getDefault() *Ref {
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var o *Ref
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if len(byNumber) == 0 {
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// Fallback to use byName using a lexical sort.
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name := ""
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for n, o2 := range byName {
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if len(name) == 0 || n < name {
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o = o2
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name = n
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}
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}
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return o
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}
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number := int((^uint(0)) >> 1)
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for n, o2 := range byNumber {
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if number > n {
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number = n
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o = o2
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}
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}
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return o
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}
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func insertRef(l []*Ref, r *Ref) []*Ref {
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n := r.Name
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i := search(len(l), func(i int) bool { return l[i].Name > n })
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l = append(l, nil)
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copy(l[i+1:], l[i:])
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l[i] = r
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return l
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}
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// search implements the same algorithm as sort.Search().
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//
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// It was extracted to not depend on sort, which depends on reflect.
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func search(n int, f func(int) bool) int {
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lo := 0
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for hi := n; lo < hi; {
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if i := int(uint(lo+hi) >> 1); !f(i) {
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lo = i + 1
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} else {
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hi = i
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}
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}
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return lo
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}
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