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Commit d5895a3c authored by Andre Eisenbach's avatar Andre Eisenbach
Browse files

Make list_foreach() more useful 

- Changed |callback| return type to bool to be able to interrupt
  iteration (to find specific elements for example).
- Added new |extra| parameter for |callback| so a pointer can be passed
  in to receive output values or to pass in criteria etc.
- Also added unit tests.

Change-Id: Id1ddcbabf55292f701d0277f2a1e9ec261b9fbde
parent ecc2dbae

system/osi/include/list.h

+11 −3
Original line number Diff line number Diff line
@@ -10,7 +10,12 @@ struct list_t; 
typedef struct list_t list_t;



typedef void (*list_free_cb)(void *data);

typedef bool (*list_iter_cb)(void *data);



// Iterator callback prototype used for |list_foreach|.

// |data| represents the list item currently being iterated, |context| is a

// user defined value passed into |list_foreach|.

// Callback must return true to continue iterating or false to stop iterating.

typedef bool (*list_iter_cb)(void *data, void *context);



// Returns a new, empty list. Returns NULL if not enough memory could be allocated

// for the list structure. The returned list must be freed with |list_free|. The
@@ -73,12 +78,15 @@ bool list_remove(list_t *list, void *data); 
// same state it was in after |list_new|. |list| may not be NULL.

void list_clear(list_t *list);



// Iterates through the entire |list| and calls |callback| for each data element.

// Iterates through the |list| and calls |callback| for each data element. Iteration

// continues until |callback| returns false. The function returns the result of the

// last executed |callback| or true if the list is empty. |context| is passed to

// |callback| on each iteration.

// If the list is empty, |callback| will never be called. It is safe to mutate the

// list inside the callback. If an element is added before the node being visited,

// there will be no callback for the newly-inserted node. Neither |list| nor

// |callback| may be NULL.

void list_foreach(const list_t *list, list_iter_cb callback);

bool list_foreach(const list_t *list, list_iter_cb callback, void *context);



// Returns an iterator to the first element in |list|. |list| may not be NULL.

// The returned iterator is valid as long as it does not equal the value returned

system/osi/src/list.c

+4 −2
Original line number Diff line number Diff line
@@ -168,15 +168,17 @@ void list_clear(list_t *list) { 
  list->length = 0;

}



void list_foreach(const list_t *list, list_iter_cb callback) {

bool list_foreach(const list_t *list, list_iter_cb callback, void *context) {

  assert(list != NULL);

  assert(callback != NULL);



  for (list_node_t *node = list->head; node; ) {

    list_node_t *next = node->next;

    callback(node->data);

    if (!callback(node->data, context))

      return false;

    node = next;

  }

  return true;

}



list_node_t *list_begin(const list_t *list) {

system/osi/test/list_test.cpp

+62 −0
Original line number Diff line number Diff line
@@ -146,3 +146,65 @@ TEST_F(ListTest, test_list_next) { 
  EXPECT_EQ(list_next(list_begin(list)), list_end(list));

  list_free(list);

}



static bool list_callback_sum(void *data, void *context) {

  assert(data);

  assert(context);

  int *sum = (int *)context;

  int *value = (int *)data;

  *sum += *value;

  return true;

}



static bool list_callback_find_int(void *data, void *context) {

  assert(data);

  assert(context);

  return (*(int *)data != *(int *)context);

}



TEST_F(ListTest, test_list_foreach_full) {

  list_t *list = list_new(NULL);



  // Fill in test data

  int x[] = { 1, 2, 3, 4, 5 };

  for (size_t i = 0; i < ARRAY_SIZE(x); ++i)

    list_append(list, &x[i]);

  EXPECT_EQ(list_length(list), 5);



  // Test complete iteration

  int sum = 0;

  bool rc = list_foreach(list, list_callback_sum, &sum);

  EXPECT_EQ(sum, 15);

  EXPECT_TRUE(rc);



  list_free(list);

}



TEST_F(ListTest, test_list_foreach_partial) {

  list_t *list = list_new(NULL);



  // Fill in test data

  int x[] = { 1, 2, 3, 4, 5 };

  for (size_t i = 0; i < ARRAY_SIZE(x); ++i)

    list_append(list, &x[i]);

  EXPECT_EQ(list_length(list), 5);



  // Test partial iteration

  int find = 4;

  bool rc = list_foreach(list, list_callback_find_int, &find);

  EXPECT_FALSE(rc);



  find = 1;

  rc = list_foreach(list, list_callback_find_int, &find);

  EXPECT_FALSE(rc);



  find = 5;

  rc = list_foreach(list, list_callback_find_int, &find);

  EXPECT_FALSE(rc);



  find = 0;

  rc = list_foreach(list, list_callback_find_int, &find);

  EXPECT_TRUE(rc);



  list_free(list);

}