Stacks
[Data Structures]

Files
file	stack.c
	Stacks implementation.
file	stack.h
	Stacks header.
Functions
void	stack_init (stack *_s)
	Initialize a stack.
stack *	stack_create ()
	Create and initialize a stack.
int	stack_push (stack *_s, void *_elem)
	Pushes a new element onto the stack.
void *	stack_pop (stack *_s)
	Removes the top element from the stack.
size_t	stack_size (stack *_s)
	Compute the size of a stack.
int	stack_is_empty (stack *_s)
	Checks if the stack is empty.
void	stack_delete (stack *_s)
	Deletes a stack, not including its data items.
void	stack_reset (stack *_s)
	Reset a stack as if it has just been created.
void	stack_destroy (stack *_s)
	Destroys a stack, including its data items.
node_l *	stack_data (stack *_s)
	Get a pointer to the internal stack data.

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Function Documentation

void stack_init

(

stack *

_s

)

Initialize a stack.

This function initializes a stack, setting all values to 0 or NULL respectively. This function is here for portability, because not all systems handle NULL as a series of binary zeros.

Parameters:

_s

a stack

Returns:

nothing

Definition at line 50 of file stack.c.

References stack::data, and stack::size.

Referenced by stack_create(), and stack_reset().

stack* stack_create

(

)

Create and initialize a stack.

Returns:

a pointer to a newly allocated stack on success, NULL on failure

Definition at line 64 of file stack.c.

References stack_init().

int stack_push	(	stack *	_s,
		void *	_elem
	)

Pushes a new element onto the stack.

This function puts a new element pointed to by _elem on top of the stack.

Parameters:

	_s	a stack
	_elem	an element

Returns:

-1 on failure (out of memory), 0 on success

Definition at line 84 of file stack.c.

References stack::data, list_push(), and stack::size.

void* stack_pop

(

stack *

_s

)

Removes the top element from the stack.

This function removes the top element from the stack and returns its location. If the stack is empty, stack_pop() returns NULL. Note that NULL is also a valid stack element, so if you previously pushed a NULL pointer onto the stack, you should use stack_size() to determine whether the stack is now empty or the popped stack element was a NULL pointer.

Parameters:

_s

a stack

Returns:

top-most stack element on success, NULL on failure (empty stack)

Definition at line 106 of file stack.c.

References stack::data, list_pop(), and stack::size.

size_t stack_size

(

stack *

_s

)

Compute the size of a stack.

This function returns the size of the stack. Because the stack_*() familiy of functions keeps track of the current stack size, this is a constant time operation.

Parameters:

_s

a stack

Returns:

its size

Definition at line 125 of file stack.c.

References stack::size.

int stack_is_empty

(

stack *

_s

)

Checks if the stack is empty.

Parameters:

_s

a stack

Returns:

0 if the stack is not empty, non-zero otherwise

Definition at line 137 of file stack.c.

References stack::size.

void stack_delete

(

stack *

_s

)

Deletes a stack, not including its data items.

This function deletes a stack, not including its data items. This will result in memory leaks if you don't have a copy of the stack, because all references to the data items are lost.

Parameters:

_s

a stack

Returns:

nothing

Definition at line 152 of file stack.c.

References stack::data, and list_delete().

void stack_reset

(

stack *

_s

)

Reset a stack as if it has just been created.

array_reset() sets the stack size to 0. This will result in memory leaks if you don't have a copy of the stack, because all references to the data items are lost.

Use stack_destroy() first to free the data items.

Parameters:

_s

a stack

Returns:

nothing

Definition at line 171 of file stack.c.

References stack::data, list_delete(), and stack_init().

void stack_destroy

(

stack *

_s

)

Destroys a stack, including its data items.

This function deletes a stack, including its data items. After a call to stack_destroy(), the stack and its data items will be lost. If you have a copy of the stack, it will be invalid (use stack_delete() on it).

Parameters:

_s

a stack

Returns:

nothing

Definition at line 191 of file stack.c.

References stack::data, and list_destroy().

node_l* stack_data

(

stack *

_s

)

Get a pointer to the internal stack data.

Internally, stacks are represented as lists. This function returns a pointer to the stack's internal list. Use with care.

Parameters:

_s

a stack

Returns:

a pointer to the stack's internal list representation

Definition at line 208 of file stack.c.

References stack::data.

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