static int cJSONUtils_Compare(cJSON *a, cJSON *b)
{
if (a->type != b->type)
{
/* mismatched type. */
return -1;
}
switch (a->type)
{
case cJSON_Number:
/* numeric mismatch. */
return ((a->valueint != b->valueint) || (a->valuedouble != b->valuedouble)) ? -2 : 0;
case cJSON_String:
/* string mismatch. */
return (strcmp(a->valuestring, b->valuestring) != 0) ? -3 : 0;
case cJSON_Array:
for (a = a->child, b = b->child; a && b; a = a->next, b = b->next)
{
int err = cJSONUtils_Compare(a, b);
if (err)
{
return err;
}
}
/* array size mismatch? (one of both children is not NULL) */
return (a || b) ? -4 : 0;
case cJSON_Object:
cJSONUtils_SortObject(a);
cJSONUtils_SortObject(b);
a = a->child;
b = b->child;
while (a && b)
{
int err;
/* compare object keys */
if (cJSONUtils_strcasecmp(a->string, b->string))
{
/* missing member */
return -6;
}
err = cJSONUtils_Compare(a, b);
if (err)
{
return err;
}
a = a->next;
b = b->next;
}
/* object length mismatch (one of both children is not null) */
return (a || b) ? -5 : 0;
default:
break;
}
/* null, true or false */
return 0;
}
/* sort lists using mergesort */
static cJSON *cJSONUtils_SortList(cJSON *list)
{
cJSON *first = list;
cJSON *second = list;
cJSON *ptr = list;
if (!list || !list->next)
{
/* One entry is sorted already. */
return list;
}
while (ptr && ptr->next && (cJSONUtils_strcasecmp(ptr->string, ptr->next->string) < 0))
{
/* Test for list sorted. */
ptr = ptr->next;
}
if (!ptr || !ptr->next)
{
/* Leave sorted lists unmodified. */
return list;
}
/* reset ptr to the beginning */
ptr = list;
while (ptr)
{
/* Walk two pointers to find the middle. */
second = second->next;
ptr = ptr->next;
/* advances ptr two steps at a time */
if (ptr)
{
ptr = ptr->next;
}
}
if (second && second->prev)
{
/* Split the lists */
second->prev->next = 0;
}
/* Recursively sort the sub-lists. */
first = cJSONUtils_SortList(first);
second = cJSONUtils_SortList(second);
list = ptr = 0;
while (first && second) /* Merge the sub-lists */
{
if (cJSONUtils_strcasecmp(first->string, 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;
}
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)
{
/* Append rest of first list. */
if (!list)
{
return first;
}
ptr->next = first;
first->prev = ptr;
}
if (second)
{
/* Append rest of second list */
if (!list)
{
return second;
}
ptr->next = second;
second->prev = ptr;
}
return list;
}
static void cJSONUtils_CompareToPatch(cJSON *patches, const char *path, cJSON *from, cJSON *to)
{
if (from->type != to->type)
{
cJSONUtils_GeneratePatch(patches, "replace", path, 0, to);
return;
}
switch (from->type)
{
case cJSON_Number:
if ((from->valueint != to->valueint) || (from->valuedouble != to->valuedouble))
{
cJSONUtils_GeneratePatch(patches, "replace", path, 0, to);
}
return;
case cJSON_String:
if (strcmp(from->valuestring, to->valuestring) != 0)
{
cJSONUtils_GeneratePatch(patches, "replace", path, 0, to);
}
return;
case cJSON_Array:
{
int c;
char *newpath = (char*)malloc(strlen(path) + 23); /* Allow space for 64bit int. */
/* generate patches for all array elements that exist in "from" and "to" */
for (c = 0, from = from->child, to = to->child; from && to; from = from->next, to = to->next, c++)
{
sprintf(newpath, "%s/%d", path, c); /* path of the current array element */
cJSONUtils_CompareToPatch(patches, newpath, from, to);
}
/* remove leftover elements from 'from' that are not in 'to' */
for (; from; from = from->next, c++)
{
sprintf(newpath, "%d", c);
cJSONUtils_GeneratePatch(patches, "remove", path, newpath, 0);
}
/* add new elements in 'to' that were not in 'from' */
for (; to; to = to->next, c++)
{
cJSONUtils_GeneratePatch(patches, "add", path, "-", to);
}
free(newpath);
return;
}
case cJSON_Object:
{
cJSON *a;
cJSON *b;
cJSONUtils_SortObject(from);
cJSONUtils_SortObject(to);
a = from->child;
b = to->child;
/* for all object values in the object with more of them */
while (a || b)
{
int diff = (!a) ? 1 : ((!b) ? -1 : cJSONUtils_strcasecmp(a->string, b->string));
if (!diff)
{
/* both object keys are the same */
char *newpath = (char*)malloc(strlen(path) + cJSONUtils_PointerEncodedstrlen(a->string) + 2);
cJSONUtils_PointerEncodedstrcpy(newpath + sprintf(newpath, "%s/", path), a->string);
/* create a patch for the element */
cJSONUtils_CompareToPatch(patches, newpath, a, b);
free(newpath);
a = a->next;
b = b->next;
}
else if (diff < 0)
{
/* object element doesn't exist in 'to' --> remove it */
cJSONUtils_GeneratePatch(patches, "remove", path, a->string, 0);
a = a->next;
}
else
{
/* object element doesn't exist in 'from' --> add it */
cJSONUtils_GeneratePatch(patches, "add", path, b->string, b);
b = b->next;
}
}
return;
}
default:
break;
}
}
static void cJSONUtils_CompareToPatch(cJSON *patches, const unsigned char *path, cJSON *from, cJSON *to)
{
if ((from == NULL) || (to == NULL))
{
return;
}
if ((from->type & 0xFF) != (to->type & 0xFF))
{
cJSONUtils_GeneratePatch(patches, (const unsigned char*)"replace", path, 0, to);
return;
}
switch ((from->type & 0xFF))
{
case cJSON_Number:
if ((from->valueint != to->valueint) || (from->valuedouble != to->valuedouble))
{
cJSONUtils_GeneratePatch(patches, (const unsigned char*)"replace", path, 0, to);
}
return;
case cJSON_String:
if (strcmp(from->valuestring, to->valuestring) != 0)
{
cJSONUtils_GeneratePatch(patches, (const unsigned char*)"replace", path, 0, to);
}
return;
case cJSON_Array:
{
size_t c = 0;
unsigned char *newpath = (unsigned char*)malloc(strlen((const char*)path) + 23); /* Allow space for 64bit int. */
/* generate patches for all array elements that exist in "from" and "to" */
for ((void)(c = 0), (void)(from = from->child), to = to->child; from && to; (void)(from = from->next), (void)(to = to->next), c++)
{
/* check if conversion to unsigned long is valid
* This should be eliminated at compile time by dead code elimination
* if size_t is an alias of unsigned long, or if it is bigger */
if (c > ULONG_MAX)
{
free(newpath);
return;
}
sprintf((char*)newpath, "%s/%lu", path, (unsigned long)c); /* path of the current array element */
cJSONUtils_CompareToPatch(patches, newpath, from, to);
}
/* remove leftover elements from 'from' that are not in 'to' */
for (; from; (void)(from = from->next), c++)
{
/* check if conversion to unsigned long is valid
* This should be eliminated at compile time by dead code elimination
* if size_t is an alias of unsigned long, or if it is bigger */
if (c > ULONG_MAX)
{
free(newpath);
return;
}
sprintf((char*)newpath, "%lu", (unsigned long)c);
cJSONUtils_GeneratePatch(patches, (const unsigned char*)"remove", path, newpath, 0);
}
/* add new elements in 'to' that were not in 'from' */
for (; to; (void)(to = to->next), c++)
{
cJSONUtils_GeneratePatch(patches, (const unsigned char*)"add", path, (const unsigned char*)"-", to);
}
free(newpath);
return;
}
case cJSON_Object:
{
cJSON *a = NULL;
cJSON *b = NULL;
cJSONUtils_SortObject(from);
cJSONUtils_SortObject(to);
a = from->child;
b = to->child;
/* for all object values in the object with more of them */
while (a || b)
{
int diff = (!a) ? 1 : ((!b) ? -1 : cJSONUtils_strcasecmp((unsigned char*)a->string, (unsigned char*)b->string));
if (!diff)
{
/* both object keys are the same */
unsigned char *newpath = (unsigned char*)malloc(strlen((const char*)path) + cJSONUtils_PointerEncodedstrlen((unsigned char*)a->string) + 2);
cJSONUtils_PointerEncodedstrcpy(newpath + sprintf((char*)newpath, "%s/", path), (unsigned char*)a->string);
/* create a patch for the element */
cJSONUtils_CompareToPatch(patches, newpath, a, b);
free(newpath);
a = a->next;
b = b->next;
}
else if (diff < 0)
{
/* object element doesn't exist in 'to' --> remove it */
cJSONUtils_GeneratePatch(patches, (const unsigned char*)"remove", path, (unsigned char*)a->string, 0);
a = a->next;
}
else
{
/* object element doesn't exist in 'from' --> add it */
cJSONUtils_GeneratePatch(patches, (const unsigned char*)"add", path, (unsigned char*)b->string, b);
b = b->next;
}
}
return;
}
default:
break;
}
}