view lib/llist.c @ 1101:ccf4193167c3 draft

Make the patch -x option (only enabled with CONFIG_DEBUG) provide more information about why a patch didn't apply. (Offset of first nonmatching character at each line during seek phase.)
author Rob Landley <>
date Thu, 31 Oct 2013 09:36:55 -0500
parents c2663b7eca78
children 114ec0ab161c
line wrap: on
line source

/* llist.c - Linked list functions
 * Linked list structures have a next pointer as their first element.

#include "toys.h"

// Call a function (such as free()) on each element of a linked list.
void llist_traverse(void *list, void (*using)(void *data))
  void *old = list;

  while (list) {
    void *pop = llist_pop(&list);

    // End doubly linked list too.
    if (old == list) break;

// Return the first item from the list, advancing the list (which must be called
// as &list)
void *llist_pop(void *list)
  // I'd use a void ** for the argument, and even accept the typecast in all
  // callers as documentation you need the &, except the stupid compiler
  // would then scream about type-punned pointers.  Screw it.
  void **llist = (void **)list;
  void **next = (void **)*llist;
  *llist = *next;

  return (void *)next;

void *dlist_pop(void *list)
  struct double_list **pdlist = (struct double_list **)list, *dlist = *pdlist;

  if (dlist->next == dlist) *pdlist = 0;
  else {
    dlist->next->prev = dlist->prev;
    dlist->prev->next = *pdlist = dlist->next;

  return dlist;

void dlist_add_nomalloc(struct double_list **list, struct double_list *new)
  if (*list) {
    new->next = *list;
    new->prev = (*list)->prev;
    (*list)->prev->next = new;
    (*list)->prev = new;
  } else *list = new->next = new->prev = new;

// Add an entry to the end of a doubly linked list
struct double_list *dlist_add(struct double_list **list, char *data)
  struct double_list *new = xmalloc(sizeof(struct double_list));

  new->data = data;
  dlist_add_nomalloc(list, new);

  return new;