// Copyright 2026 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package spec

// Most of these are top-level functions, not methods, because their first
// argument is not a Vec.

// BroadcastZ returns a vector with the input x assigned to all elements of the
// result.
//
//specgen:name Broadcast{z}
func BroadcastZ[E Elt, W Width](x E) (z Vec[E, W]) {
	z = makeVec[E, W]()
	for i := range z {
		z[i] = x
	}
	return z
}

// LoadZ loads a slice into a vector. If len(s) is less than the number of
// elements in the vector, it panics.
//
//specgen:name Load{z}
func LoadZ[E Elt, W Width](s []E) (z Vec[E, W]) {
	z = makeVec[E, W]()
	_ = s[:z.len()]
	copy(z, s)
	return z
}

// LoadZArray loads an array into a vector.
//
//specgen:name Load{z}Array
func LoadZArray[E Elt, W FixedWidth](x *Array[E, W]) (z Vec[E, W]) {
	z = makeVec[E, W]()
	if len(*x) != z.len() {
		panic("bad array size")
	}
	copy(z, *x)
	return z
}

// LoadZPart loads a slice into a vector and returns the vector and the number
// of elements loaded from s. If len(s) is less than the number of elements in
// the vector, the remaining vector elements will be zero-filled.
//
//specgen:name Load{z}Part
func LoadZPart[E Elt, W Width](s []E) (z Vec[E, W], n int) {
	z = makeVec[E, W]()
	n = copy(z, s)
	return z, n
}

// Store stores the elements of x into a slice. If len(s) is less than x.Len(),
// it panics.
func Store[E Elt, W Width](x Vec[E, W], s []E) {
	_ = s[:x.len()]
	copy(s, x)
}

// StoreArray stores the elements of x to an array.
func StoreArray[E Elt, W FixedWidth](x Vec[E, W], y *Array[E, W]) {
	if x.len() != len(*y) {
		panic("bad array size")
	}
	copy(*y, x)
}

// StoreArrayMasked stores the masked elements of x to an array. It does not
// modify elements of y that are false in the mask.
//
//specgen:require maskN=xN
func StoreArrayMasked[E Elt, W FixedWidth, mE MaskElt](x Vec[E, W], y *Array[E, W], mask Vec[mE, W]) {
	for i, elt := range x {
		if mask[i] != 0 {
			(*y)[i] = elt
		}
	}
}

// StorePart stores at most len(s) elements of x into s and returns the number
// of elements stored.
func StorePart[E Elt, W Width](x Vec[E, W], s []E) int {
	return copy(s, x)
}