Tape Class Reference

Simulates the bilateral infinite tape layout of a Turing Machine. More...

#include <tape.hpp>

Collaboration diagram for Tape:

Public Member Functions
void	move (Direction dir) noexcept
	Shifts the tape head one cell to the left, right or make it stay.
void	print (std::ostream &os=std::cout) const noexcept
	Renders the active layout of the tape and the head tracking to an output stream.
Symbol	read () const noexcept
	Reads the symbol currently located under the tape head.
	Tape () noexcept
	Default constructor.
	Tape (String str) noexcept(false)
	Constructs a Tape populated with an initial formal String.
void	write (Symbol symbol) noexcept(false)
	Writes a symbol into the cell currently under the tape head.

Private Attributes
std::map< int, Symbol >	cells_
	Memory cells mapping coordinates to written Symbols.
int	head_pos_
	Current mathematical index coordinate of the head.

Friends
std::ostream &	operator<< (std::ostream &os, const Tape &tape) noexcept
	Overloaded stream insertion operator to allow direct streaming of Tape instances.

Detailed Description

Simulates the bilateral infinite tape layout of a Turing Machine.

Uses a dynamic std::map indexed by signed integers to support infinite expansion toward both negative and positive coordinates with logarithmic lookup overhead.

Definition at line 29 of file tape.hpp.

Constructor & Destructor Documentation

Tape() [1/2]

Tape::Tape ( )

inlinenoexcept

Default constructor.

Initializes an empty tape with the head at position 0.

Definition at line 35 of file tape.hpp.

Tape() [2/2]

Tape::Tape ( String  str )

explicit

Constructs a Tape populated with an initial formal String.

Custom constructor to load a formal Word into the machine's memory.

Places the string's symbols sequentially starting at index 0 and sets the head to 0.

Parameters

str	The formal String sequence to load onto the tape.

Exceptions

std::out_of_range

If the input string length exceeds the maximum signed integer capacity of the tape.

Uses C++20 views::enumerate to extract both the structural index and the Symbol object, populating the map from coordinate 0 onward.

Parameters

str	The formal String sequence to load onto the tape.

Exceptions

std::out_of_range

If the input string length exceeds the maximum signed integer capacity of the tape.

Definition at line 27 of file tape.cpp.

Member Function Documentation

move()

void Tape::move ( Direction  dir )

inlinenoexcept

Shifts the tape head one cell to the left, right or make it stay.

Passed by value since Direction is an enum class.

Parameters

dir	The movement direction (LEFT, RIGHT or STAY).

Definition at line 74 of file tape.hpp.

References head_pos_, LEFT, RIGHT, and STAY.

print()

void Tape::print ( std::ostream &  os = std::cout ) const

noexcept

Renders the active layout of the tape and the head tracking to an output stream.

Renders a structural blueprint of the active tape cells to any std::ostream.

Parameters

os	The target output stream (defaults to std::cout).

Automatically wraps current track margins based on the dynamic map bounds and the current hardware head displacement coordinates.

Definition at line 63 of file tape.cpp.

References kBlank.

read()

Symbol Tape::read ( ) const

noexcept

Reads the symbol currently located under the tape head.

Scans the active cell under the simulation head.

If the current coordinate has not been modified yet, it assumes the cell belongs to the infinite blank space and safely returns a kBlank symbol.

Returns

Symbol The symbol scanned at the current head position.

Safeguards the infinite tape constraint by looking up coordinates via std::map::find. If the element is missing, it dynamically rolls a virtual kBlank context.

Definition at line 48 of file tape.cpp.

References cells_, head_pos_, and kBlank.

write()

void Tape::write ( Symbol  symbol )

inline

Writes a symbol into the cell currently under the tape head.

Passed by value since Symbol is a lightweight, trivially-copyable type.

Parameters

symbol

The Symbol instance to write.

Exceptions

std::bad_alloc

If the internal map fails to allocate memory for a new coordinate node.

Definition at line 65 of file tape.hpp.

References cells_, and head_pos_.

Friends And Related Symbol Documentation

operator<<

std::ostream & operator<< ( std::ostream &  os, const Tape &  tape  )

friend

Overloaded stream insertion operator to allow direct streaming of Tape instances.

Parameters

os	The target output stream.
tape	The Tape instance to render.

Returns

std::ostream& A reference to the modified output stream.

Seamlessly pipes the custom Tape print layout directly into standard I/O pipelines.

Definition at line 111 of file tape.cpp.

Member Data Documentation

cells_

std::map<int, Symbol> Tape::cells_

private

Memory cells mapping coordinates to written Symbols.

Definition at line 106 of file tape.hpp.

Referenced by read(), and write().

head_pos_

int Tape::head_pos_

private

Current mathematical index coordinate of the head.

Definition at line 105 of file tape.hpp.

Referenced by move(), read(), and write().

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The documentation for this class was generated from the following files:

• src/core/tape.hpp
• src/core/tape.cpp