lattigo/utils/structs/matrix.go

package structs

import (
	"bufio"
	"fmt"
	"io"

	"github.com/tuneinsight/lattigo/v4/utils/buffer"
)

// Matrix is a struct storing a vector of Vector.
type Matrix[T any] [][]T

func (m Matrix[T]) CopyNew() *Matrix[T] {

	if c, isCopiable := any(new(T)).(CopyNewer[T]); !isCopiable {
		panic(fmt.Errorf("matrix component of type %T does not comply to %T", new(T), c))
	}

	mcpy := Matrix[T](make([][]T, len(m)))

	for i := range m {

		mcpy[i] = make([]T, len(m[i]))

		for j := range m[i] {
			mcpy[i][j] = *any(&m[i][j]).(CopyNewer[T]).CopyNew()
		}
	}

	return &mcpy
}

// BinarySize returns the serialized size of the object in bytes.
func (m Matrix[T]) BinarySize() (size int) {

	if _, isSizable := any(new(T)).(BinarySizer); !isSizable {
		panic(fmt.Errorf("matrix component of type %T does not comply to %T", new(T), new(BinarySizer)))
	}

	size += 8

	for _, v := range m {
		/* #nosec G601 -- Implicit memory aliasing in for loop acknowledged */
		size += (*Vector[T])(&v).BinarySize()
	}
	return
}

// WriteTo writes the object on an io.Writer. It implements the io.WriterTo
// interface, and will write exactly object.BinarySize() bytes on w.
//
// Unless w implements the buffer.Writer interface (see lattigo/utils/buffer/writer.go),
// it will be wrapped into a bufio.Writer. Since this requires allocations, it
// is preferable to pass a buffer.Writer directly:
//
//   - When writing multiple times to a io.Writer, it is preferable to first wrap the
//     io.Writer in a pre-allocated bufio.Writer.
//   - When writing to a pre-allocated var b []byte, it is preferable to pass
//     buffer.NewBuffer(b) as w (see lattigo/utils/buffer/buffer.go).
func (m Matrix[T]) WriteTo(w io.Writer) (n int64, err error) {

	if _, isWritable := any(new(T)).(io.WriterTo); !isWritable {
		return 0, fmt.Errorf("vector component of type %T does not comply to %T", new(T), new(io.WriterTo))
	}

	switch w := w.(type) {
	case buffer.Writer:

		var inc int64
		if inc, err = buffer.WriteAsUint64[int](w, len(m)); err != nil {
			return inc, err
		}
		n += inc

		for _, v := range m {
			vec := Vector[T](v)
			if inc, err = vec.WriteTo(w); err != nil {
				return n + inc, err
			}
			n += inc
		}

		return n, w.Flush()

	default:
		return m.WriteTo(bufio.NewWriter(w))
	}
}

// ReadFrom reads on the object from an io.Writer. It implements the
// io.ReaderFrom interface.
//
// Unless r implements the buffer.Reader interface (see see lattigo/utils/buffer/reader.go),
// it will be wrapped into a bufio.Reader. Since this requires allocation, it
// is preferable to pass a buffer.Reader directly:
//
//   - When reading multiple values from a io.Reader, it is preferable to first
//     first wrap io.Reader in a pre-allocated bufio.Reader.
//   - When reading from a var b []byte, it is preferable to pass a buffer.NewBuffer(b)
//     as w (see lattigo/utils/buffer/buffer.go).
func (m *Matrix[T]) ReadFrom(r io.Reader) (n int64, err error) {

	if _, isReadable := any(new(T)).(io.ReaderFrom); !isReadable {
		return 0, fmt.Errorf("vector component of type %T does not comply to %T", new(T), new(io.ReaderFrom))
	}

	switch r := r.(type) {
	case buffer.Reader:

		var size int
		var inc int64

		if n, err = buffer.ReadAsUint64[int](r, &size); err != nil {
			return int64(n), fmt.Errorf("cannot read matrix size: %w", err)
		}

		if cap(*m) < size {
			*m = make([][]T, size)
		}

		*m = (*m)[:size]

		for i := range *m {
			if inc, err = (*Vector[T])(&(*m)[i]).ReadFrom(r); err != nil {
				return n + inc, err
			}
			n += inc
		}

		return n, nil

	default:
		return m.ReadFrom(bufio.NewReader(r))
	}
}

// MarshalBinary encodes the object into a binary form on a newly allocated slice of bytes.
func (m Matrix[T]) MarshalBinary() (p []byte, err error) {
	buf := buffer.NewBufferSize(m.BinarySize())
	_, err = m.WriteTo(buf)
	return buf.Bytes(), err
}

// UnmarshalBinary decodes a slice of bytes generated by
// MarshalBinary or WriteTo on the object.
func (m *Matrix[T]) UnmarshalBinary(p []byte) (err error) {
	_, err = m.ReadFrom(buffer.NewBuffer(p))
	return
}

func (m Matrix[T]) Equal(other Matrix[T]) bool {

	if _, isEquatable := any(new(T)).(Equatable[T]); !isEquatable {
		panic(fmt.Errorf("matrix component of type %T does not comply to %T", new(T), new(Equatable[T])))
	}

	isEqual := true
	for i := range m {
		for j := range m[i] {
			isEqual = isEqual && any(&m[i][j]).(Equatable[T]).Equal(&other[i][j])
		}
	}

	return isEqual
}