gitee.com/sy_183/go-common@v1.0.5-0.20231205030221-958cfe129b47/slice/slice.go

package slice

import (
	sliceUnsafe "gitee.com/sy_183/go-common/slice/unsafe"
	"unsafe"
)

func JoinNew[E any](ss ...[]E) []E {
	switch len(ss) {
	case 0:
		return nil
	case 1:
		return append([]E(nil), ss[0]...)
	case 2:
		return append(ss[0], ss[1]...)
	default:
		var n int
		for _, s := range ss {
			n += len(s)
		}
		s := make([]E, n)
		sp := copy(s, ss[0])
		for _, es := range ss[1:] {
			sp += copy(s[sp:], es)
		}
		return s
	}
}

func Assign[E any](s []E, l, c int) []E {
	if cap(s) >= c {
		return s[:l:c]
	}
	n := make([]E, l, c)
	copy(n, s)
	return n
}

//go:linkname growslice reflect.growslice
func growslice(t unsafe.Pointer, old sliceUnsafe.Slice, num int) sliceUnsafe.Slice

type emptyInterface struct {
	typ  unsafe.Pointer
	word unsafe.Pointer
}

func Grow[E any](s []E, n int) []E {
	p := (*sliceUnsafe.Slice)(unsafe.Pointer(&s))
	if p.Len+n > p.Cap {
		a := any(s)
		*p = growslice((*emptyInterface)(unsafe.Pointer(&a)).typ, *p, n)
		return *(*[]E)(unsafe.Pointer(p))
	}
	return s
}

func AssignLen[E any](s []E, l int) []E {
	if cap(s) >= l {
		return s[:l]
	}
	s = Grow(s, l-len(s))
	return s[:l]
}

func Delete[E any](s []E, i int) []E {
	return s[:copy(s[i:], s[i+1:])+i]
}

func Deletes[E any](s []E, delete func(i int) bool) []E {
	var ec int
	i1, i2, i3 := -1, -1, -1
	for i := 0; i < len(s); i++ {
		if delete(i) {
			if i1 < 0 {
				i1, i2 = i, i+1
			} else if i2 == i {
				i2++
			} else {
				copy(s[i1-ec:], s[i2:i3])
				ec += i2 - i1
				i1, i2, i3 = i, i+1, -1
			}
		} else if i2 > 0 {
			if i3 < 0 {
				i3 = i + 1
			} else if i3 == i {
				i3++
			}
		}
	}
	if i2 > 0 {
		if i3 > 0 {
			copy(s[i1-ec:], s[i2:i3])
		}
		ec += i2 - i1
	}
	s = s[:len(s)-ec]
	return s
}

func Reverse[E any](s []E) {
	c := len(s) >> 1
	for i := 0; i < c; i++ {
		s[i], s[len(s)-i-1] = s[len(s)-i-1], s[i]
	}
}

type Entry[E any] struct {
	Index int
	Elem  E
}

func NewEntry[E any](i int, elem E) Entry[E] {
	return Entry[E]{Index: i, Elem: elem}
}

func ForEach[E any](s []E, action func(E)) {
	for i := range s {
		action(s[i])
	}
}

func ForEachP[E any](s []E, action func(*E)) {
	for i := range s {
		action(&s[i])
	}
}

func Map[I, O any](s []I, mapper func(I) O) (mapped []O) {
	mapped = make([]O, len(s))
	for i := range s {
		mapped[i] = mapper(s[i])
	}
	return
}

func MapP[I, O any](s []I, mapper func(*I) O) (mapped []O) {
	mapped = make([]O, len(s))
	for i := range s {
		mapped[i] = mapper(&s[i])
	}
	return
}

func Filter[E any](s []E, filter func(E) bool) (filtered []E) {
	for i := range s {
		if filter(s[i]) {
			filtered = append(filtered, s[i])
		}
	}
	return
}

func FilterP[E any](s []E, filter func(*E) bool) (filtered []E) {
	for i := range s {
		if filter(&s[i]) {
			filtered = append(filtered, s[i])
		}
	}
	return
}

func FilterPP[E any](s []E, filter func(*E) bool) (filtered []*E) {
	for i := range s {
		if filter(&s[i]) {
			filtered = append(filtered, &s[i])
		}
	}
	return
}

func Reduce[E, R any](s []E, reduce func(cur R, elem E) R, init R) R {
	for i := 0; i < len(s); i++ {
		init = reduce(init, s[i])
	}
	return init
}

func ReduceP[E, R any](s []E, reduce func(cur R, elem *E) R, init R) R {
	for i := 0; i < len(s); i++ {
		init = reduce(init, &s[i])
	}
	return init
}