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gslice.go
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gslice.go
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/*
* Copyright (c) 2022, nwillc@gmail.com
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
package container
import (
"github.com/nwillc/genfuncs"
"golang.org/x/exp/slices"
"math/rand"
"time"
)
var (
_ HasValues[int] = (*GSlice[int])(nil)
_ Sequence[int] = (*GSlice[int])(nil)
_ Iterator[int] = (*sliceIterator[int])(nil)
random = rand.New(rand.NewSource(time.Now().Unix()))
)
// GSlice is a generic type corresponding to a standard Go slice that implements HasValues.
type (
GSlice[T any] []T
sliceIterator[T any] struct {
slice []T
index int
}
)
// Filter returns a slice containing only elements matching the given predicate.
func (s GSlice[T]) Filter(predicate genfuncs.Function[T, bool]) GSlice[T] {
length := len(s)
var results []T
var t T
for i := 0; i < length; i++ {
t = s[i]
if predicate(t) {
results = append(results, t)
}
}
return results
}
// ForEach element of the GSlice invoke given function with the element. Syntactic sugar for a range that intends to
// traverse all the elements, i.e. no exiting midway through.
func (s GSlice[T]) ForEach(action func(i int, t T)) {
length := s.Len()
for i := 0; i < length; i++ {
action(i, s[i])
}
}
// Iterator returns an Iterator that will iterate over the GSlice.
func (s GSlice[T]) Iterator() Iterator[T] {
return NewSliceIterator[T](s)
}
// Len is the number of elements in the GSlice.
func (s GSlice[T]) Len() int {
return len(s)
}
// Random returns a random element of the GSlice.
func (s GSlice[T]) Random() (t T) {
t = s[random.Intn(s.Len())]
return t
}
// SortBy copies a slice, sorts the copy applying the Ordered and returns it. This is not a pure function, the GSlice
// is sorted in place, the returned slice is to allow for fluid calls in chains.
func (s GSlice[T]) SortBy(order genfuncs.BiFunction[T, T, bool]) (sorted GSlice[T]) {
slices.SortStableFunc(s, order)
sorted = s
return sorted
}
// Swap two values in the slice.
func (s GSlice[T]) Swap(i, j int) {
s[i], s[j] = s[j], s[i]
}
// Values is the GSlice itself.
func (s GSlice[T]) Values() (values GSlice[T]) {
values = s
return values
}
func NewSliceIterator[T any](slice []T) Iterator[T] {
return &sliceIterator[T]{slice: slice}
}
func NewValuesIterator[T any](values ...T) Iterator[T] {
return NewSliceIterator(values)
}
func (s *sliceIterator[T]) HasNext() bool {
return s.index < len(s.slice)
}
func (s *sliceIterator[T]) Next() (value T) {
if !s.HasNext() {
panic(genfuncs.NoSuchElement)
}
value = s.slice[s.index]
s.index++
return value
}