// Copyright 2017 The go-interpreter 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 wasm

import (
	"encoding/binary"
	"io"
)

func readBytes(r io.Reader, n int) ([]byte, error) {
	bytes := make([]byte, n)
	_, err := io.ReadFull(r, bytes)
	if err != nil {
		return bytes, err
	}

	return bytes, nil
}

func readString(r io.Reader, n int) (string, error) {
	bytes, err := readBytes(r, n)
	if err != nil {
		return "", err
	}
	return string(bytes), nil
}

func readU32(r io.Reader) (uint32, error) {
	var buf [4]byte
	_, err := io.ReadFull(r, buf[:])
	if err != nil {
		return 0, err
	}
	return binary.LittleEndian.Uint32(buf[:]), nil
}

func readU64(r io.Reader) (uint64, error) {
	var buf [8]byte
	_, err := io.ReadFull(r, buf[:])
	if err != nil {
		return 0, err
	}
	return binary.LittleEndian.Uint64(buf[:]), nil
}