Huffman-Encoding/stack.c at master · zacktraczyk/Huffman-Encoding · GitHub

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#include"stack.h"

#include"node.h"

#include<stdio.h>
#include<stdlib.h>// malloc

//
// Structure for defining Stack data structure
//
structStack {
uint32_ttop;
uint32_tcapacity;
Node**items;
};

//
// Creates a stack
//
// capacity: max size of the stack
//
Stack*stack_create(uint32_tcapacity) {
Stack*s= (Stack*) malloc(sizeof(Stack));
if (s) { // if allocation successful
s->top=0;
s->capacity=capacity;
s->items= (Node**) calloc(capacity, sizeof(Node*));
if (!s->items) { // if no room in memory
free(s);
s=NULL; // Ensure pointer is not pointing to memory no longer used
 }
 }
returns;
}

//
// Deletes a stack
//
// s: a stack to delete
//
voidstack_delete(Stack**s) {
if (*s&& (*s)->items) { // if stack exists and has items
free((*s)->items);
free(*s);
*s=NULL; // ensure pointer is not pointing to memory no longer used
 }
return;
}

//
// Returns if stack is empty or not
//
// s: a stack to check
//
boolstack_empty(Stack*s) {
returns->top==0;
}

//
// Returns if stack is full or not
//
// s: stack to check
//
boolstack_full(Stack*s) {
returns->top==s->capacity;
}

//
// Returns size of the stack
//
// s: the stack to return the size of
//
uint32_tstack_size(Stack*s) {
return (s&&s->items) ? s->top : 0; //if stack exists and has items
}

//
// Adds the given item to the top of the stack and returns if successful
//
// s: stack to push item to
// n: Node to add to stack
//
boolstack_push(Stack*s, Node*n) {
if (stack_full(s)) { // can not add to a full stack
return false;
 }
s->items[s->top] =n; // top item = x
s->top+=1;
return true;
}

//
// Removes last item on the stack and stores returns the
//
// s: the stack to pop from
// x: the address to store the popped Node
//
boolstack_pop(Stack*s, Node**n) {
if (stack_empty(s)) { // can not pop from an empty stack
return false;
 }
s->top-=1;
*n=s->items[s->top]; // store top item at given address
return true;
}

voidstack_print(Stack*s) {
for (uint32_ti=0; i<s->top; i+=1) { // iterate through item indices
printf("%d is:\n", i);
node_print(s->items[i]);
if (i+1!=s->top) { // do not print newline for last case
printf("\n");
 }
 }
}