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refactor cJSONUtils_SortList

This commit is contained in:
Max Bruckner 2017-04-30 13:16:30 +02:00
parent f030058183
commit 7bf62ff4dc
1 changed files with 54 additions and 50 deletions
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104
cJSON_Utils.c
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@ -1034,39 +1034,41 @@ static cJSON *cJSONUtils_SortList(cJSON *list)
{
cJSON *first = list;
cJSON *second = list;
cJSON *ptr = list;
cJSON *current_item = list;
cJSON *result = list;
cJSON *result_tail = NULL;
if (!list || !list->next)
if ((list == NULL) || (list->next == NULL))
{
/* One entry is sorted already. */
return list;
return result;
}
while (ptr && ptr->next && (cJSONUtils_strcasecmp((unsigned char*)ptr->string, (unsigned char*)ptr->next->string) < 0))
while ((current_item != NULL) && (current_item->next != NULL) && (cJSONUtils_strcasecmp((unsigned char*)current_item->string, (unsigned char*)current_item->next->string) < 0))
{
/* Test for list sorted. */
ptr = ptr->next;
current_item = current_item->next;
}
if (!ptr || !ptr->next)
if ((current_item == NULL) || (current_item->next == NULL))
{
/* Leave sorted lists unmodified. */
return list;
return result;
}
/* reset ptr to the beginning */
ptr = list;
while (ptr)
/* reset pointer to the beginning */
current_item = list;
while (current_item != NULL)
{
/* Walk two pointers to find the middle. */
second = second->next;
ptr = ptr->next;
/* advances ptr two steps at a time */
if (ptr)
current_item = current_item->next;
/* advances current_item two steps at a time */
if (current_item != NULL)
{
ptr = ptr->next;
current_item = current_item->next;
}
}
if (second && second->prev)
if ((second != NULL) && (second->prev != NULL))
{
/* Split the lists */
second->prev->next = NULL;
@ -1075,65 +1077,67 @@ static cJSON *cJSONUtils_SortList(cJSON *list)
/* Recursively sort the sub-lists. */
first = cJSONUtils_SortList(first);
second = cJSONUtils_SortList(second);
list = ptr = NULL;
result = NULL;
while (first && second) /* Merge the sub-lists */
/* Merge the sub-lists */
while ((first != NULL) && (second != NULL))
{
cJSON *smaller = NULL;
if (cJSONUtils_strcasecmp((unsigned char*)first->string, (unsigned char*)second->string) < 0)
{
if (!list)
{
/* start merged list with the first element of the first list */
list = ptr = first;
}
else
{
/* add first element of first list to merged list */
ptr->next = first;
first->prev = ptr;
ptr = first;
}
smaller = first;
}
else
{
smaller = second;
}
if (result == NULL)
{
/* start merged list with the smaller element */
result_tail = smaller;
result = smaller;
}
else
{
/* add smaller element to the list */
result_tail->next = smaller;
smaller->prev = result_tail;
result_tail = smaller;
}
if (first == smaller)
{
first = first->next;
}
else
{
if (!list)
{
/* start merged list with the first element of the second list */
list = ptr = second;
}
else
{
/* add first element of second list to merged list */
ptr->next = second;
second->prev = ptr;
ptr = second;
}
second = second->next;
}
}
if (first)
if (first != NULL)
{
/* Append rest of first list. */
if (!list)
if (result == NULL)
{
return first;
}
ptr->next = first;
first->prev = ptr;
result_tail->next = first;
first->prev = result_tail;
}
if (second)
if (second != NULL)
{
/* Append rest of second list */
if (!list)
if (result == NULL)
{
return second;
}
ptr->next = second;
second->prev = ptr;
result_tail->next = second;
second->prev = result_tail;
}
return list;
return result;
}
CJSON_PUBLIC(void) cJSONUtils_SortObject(cJSON *object)