stack.c

#include "stack.h"
#include <stdio.h>
#include <stdlib.h>

node_t *init_node() {
  node_t *node;
  node = malloc(sizeof(node_t));
  if (node == NULL) {
    fprintf(stderr, "init_node error: failed to allocate memory\n");
    return NULL;
  }
  // node->data = alloc_data_of(type);
  // node->val = malloc(sizeof(node_val_t));
  node->next = NULL;
  return node;
}

node_t *dup_node(const node_t *n) {
  node_t *new = init_node();
  *new = *n;
  new->next = NULL;
  return new;
}

int push_node(sstack_t *stack, node_t *to_push) {
  if (to_push == NULL || stack == NULL)
    return 0;
  // printf("%s\n", to_push->str);
  to_push->next = stack->node;
  stack->node = to_push;
  return 1;
}

node_t *pop_node(sstack_t *stack) {
  node_t *to_pop = stack->node;
  if (stack->node == NULL)
    return NULL;
  stack->node = stack->node->next;
  to_pop->next = NULL;
  return to_pop;
}

node_t *get_last_node(sstack_t *stack) {
  if (stack->node == NULL) {
    // fprintf(stderr, "get_last_node error: stack is empty\n");
    return stack->node;
  }

  node_t *n = stack->node;
  while (n->next != NULL) {
    n = n->next;
    // printf("gotting last node xd\n");
    // printf("nn: %s\n", n->str);
  }
  // printf("got last node xd\n");
  return n;
}

int append_node(sstack_t *top, node_t *nnew) {
  node_t *last = get_last_node(top);
  if (last == NULL) {
    push_node(top, nnew);
    return 1;
  }

  last->next = nnew;
  return 1;
}

sstack_t *init_stack() {
  sstack_t *stack = malloc(sizeof(sstack_t));
  if (stack == NULL) {
    fprintf(stderr, "init_stack error: could not allocate memory\n");
    return NULL;
  }
  stack->node = NULL;
  return stack;
}

int join_stacks(sstack_t *s1, sstack_t *s2, int debug) {
  // printf("entered join stacks\n");
  // printf("s1: %u\n", s1);
  // printf("s2: %u\n", s2);
  // printf("s2->node: %u\n", s2->node);
  if (s1 == NULL || s2 == NULL || s2->node == NULL) {
    // printf("Error from stack.c: join_stacks was given null argument(s)\n");
    return 0;
  }
  if (debug)
    printf("stuff is non null\n");
  node_t *last = get_last_node(s1);
  if (debug)
    printf("got last node\n");
  if (debug)
    printf("s1->n: %u last->n: %u, s2->n: %u\n", s1->node, last, s2->node);
  if (last == NULL) {
    s1->node = s2->node;
  } else {

    last->next = s2->node;
  }
  free(s2);
  return 1;
}