ll_of_str.c

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/* llos defines a linked list of strings type */
#include "nortlib.h"
#include "ll_of_str.h"
char rcsid_ll_of_str_c[] =
  "$Header: /cvsroot/arp-das/nortlib2/src/ll_of_str.c,v 1.2 1998/01/06 18:28:50 nort Doc $";

/*
Functionality:
  void llos_enq(ll_of_str *ll, const char *str);
        duplicates str and places it on the list.
        Dies if memory allocation fails.
        Accepts NULL in either argument. ll==NULL does nothing.
        str == NULL gets mapped into empty string "".
  char *llos_deq(ll_of_str *ll);
        produces the duplicated string at the head of the list
        and deletes it from the list. The string should be
        freed (free_memory()) after it is used, since it was
        dynamically allocated when enqueued.

Possible additional functionality: Iteration.
    init
        next (yielding first after init)
        insert_before
        insert_after
        delete
*/

void llos_enq(ll_of_str *ll, const char *str) {
  char *s;
  struct llosleaf *lf;

  if (ll != 0) {
        { int resp = set_response(3);
          lf = new_memory( sizeof( struct llosleaf ) );
          if (str == 0) s = nl_strdup("");
          else s = nl_strdup(str);
          set_response(resp);
        }
        lf->text = s;
        lf->next = 0;
        if (ll->last == 0)
          ll->first = ll->last = lf;
        else {
          ll->last->next = lf;
          ll->last = lf;
        }
  }
}

char *llos_deq(ll_of_str *ll) {
  char *s;
  struct llosleaf *lf;

  if (ll == 0 || ll->first == 0) return 0;
  lf = ll->first;
  s = lf->text;
  ll->first = lf->next;
  if (ll->first == 0)
        ll->last = 0;
  free_memory(lf);
  return s;
}