package vm

import "fmt"

type memory struct {
	entries []uint64
}

func newMemory(size uint64) *memory {
	return &memory{
		entries: make([]uint64, size),
	}
}

func (mem *memory) readUnsigned(index uint64) (uint64, error) {
	if index >= uint64(len(mem.entries)) {
		return 0, fmt.Errorf("Invalid memory index: %016x", index)
	}

	return mem.entries[index], nil
}

func (mem *memory) mustReadUnsigned(index uint64) uint64 {
	value, err := mem.readUnsigned(index)
	if err != nil {
		panic(err)
	}
	return value
}

func (mem *memory) writeUnsigned(index uint64, value uint64) error {
	if index >= uint64(len(mem.entries)) {
		return fmt.Errorf("Invalid memory index: %016x", index)
	}

	mem.entries[index] = value

	return nil
}