Delete a node WITHOUT using the HEAD pointer.

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*/ #ifndef CONFIG_DEBUG_LIST static inline void __list_add (struct list_head *new, struct list_head *prev, struct list_head *next) { next->prev = new; new->next = next; new->prev = prev; prev->next = new; } #else extern void __list_add (struct list_head *new, struct list_head *prev, struct list_head *next); #endif /** * list_add - add a new entry * @new: new entry to be added * @head: list head to add it after * * Insert a new entry after the specified head. * This is good for implementing stacks. */ static inline void list_add (struct list_head *new, struct list_head *head) { __list_add (new, head, head->next); } /** * list_add_tail - add a new entry * @new: new entry to be added * @head: list head to add it before * * Insert a new entry before the specified head. * This is useful for implementing queues. */ static inline void list_add_tail (struct list_head *new, struct list_head *head) { __list_add (new, head->prev, head); } /* * Delete a list entry by making the prev/next entries * point to each other. * * This is only for internal list manipulation where we know * the prev/next entries already! */ static inline void __list_del (struct list_head *prev, struct list_head *next) { next->prev = prev; prev->next = next; } /** * list_del - deletes entry from list. * @entry: the element to delete from the list. * Note: list_empty() on entry does not return true after this, the entry is * in an undefined state. */ #ifndef CONFIG_DEBUG_LIST static inline void list_del (struct list_head *entry) { __list_del (entry->prev, entry->next); entry->next = LIST_POISON1; entry->prev = LIST_POISON2; } #else extern void list_del (struct list_head *entry); #endif /** * list_replace - replace old entry by new one * @old : the element to be replaced * @new : the new element to insert * * If @old was empty, it will be overwritten. */ static inline void list_replace (struct list_head *old, struct list_head *new) { new->next = old->next; new->next->prev = new; new->prev = old->prev; new->prev->next = new; } static inline void list_replace_init (struct list_head *old, struct list_head *new) { list_replace (old, new); INIT_LIST_HEAD (old); } /** * list_del_init - deletes entry from list and reinitialize it. * @entry: the element to delete from the list. */ static inline void list_del_init (struct list_head *entry) { __list_del (entry->prev, entry->next); INIT_LIST_HEAD (entry); } /** * list_move - delete from one list and add as another's head * @list: the entry to move * @head: the head that will precede our entry */ static inline void list_move (struct list_head *list, struct list_head *head) { __list_del (list->prev, list->next); list_add (list, head); } /** * list_move_tail - delete from one list and add as another's tail * @list: the entry to move * @head: the head that will follow our entry */ static inline void list_move_tail (struct list_head *list, struct list_head *head) { __list_del (list->prev, list->next); list_add_tail (list, head); } /** * list_is_last - tests whether @list is the last entry in list @head * @list: the entry to test * @head: the head of the list */ static inline int list_is_last (const struct list_head *list, const struct list_head *head) { return list->next == head; } /** * list_empty - tests whether a list is empty * @head: the list to test. */ static inline int list_empty (const struct list_head *head) { return head->next == head; } /** * list_empty_careful - tests whether a list is empty and not being modified * @head: the list to test * * Description: * tests whether a list is empty _and_ checks that no other CPU might be * in the process of modifying either member (next or prev) * * NOTE: using list_empty_careful() without synchronization * can only be safe if the only activity that can happen * to the list entry is list_del_init(). Eg. it cannot be used * if another CPU could re-list_add() it. */ static inline int list_empty_careful (const struct list_head *head) { struct list_head *next = head->next; return (next == head) && (next == head->prev); } /** * list_is_singular - tests whether a list has just one entry. * @head: the list to test. */ static inline int list_is_singular (const struct list_head *head) { return !list_empty (head) && (head->next == head->prev); } static inline void __list_cut_position (struct list_head *list, struct list_head *head, struct list_head *entry) { struct list_head *new_first = entry->next; list->next = head->next; list->next->prev = list; list->prev = entry; entry->next = list; head->next = new_first; new_first->prev = head; } /** * list_cut_position - cut a list into two * @list: a new list to add all removed entries * @head: a list with entries * @entry: an entry within head, could be the head itself * and if so we won't cut the list * * This helper moves the initial part of @head, up to and * including @entry, from @head to @list. You should * pass on @entry an element you know is on @head. @list * should be an empty list or a list you do not care about * losing its data. * */ static inline void list_cut_position (struct list_head *list, struct list_head *head, struct list_head *entry) { if (list_empty (head)) return; if (list_is_singular (head) && (head->next != entry && head != entry)) return; if (entry == head) INIT_LIST_HEAD (list); else __list_cut_position (list, head, entry); } static inline void __list_splice (const struct list_head *list, struct list_head *prev, struct list_head *next) { struct list_head *first = list->next; struct list_head *last = list->prev; first->prev = prev; prev->next = first; last->next = next; next->prev = last; } /** * list_splice - join two lists, this is designed for stacks * @list: the new list to add. * @head: the place to add it in the first list. */ static inline void list_splice (const struct list_head *list, struct list_head *head) { if (!list_empty (list)) __list_splice (list, head, head->next); } /** * list_splice_tail - join two lists, each list being a queue * @list: the new list to add. * @head: the place to add it in the first list. */ static inline void list_splice_tail (struct list_head *list, struct list_head *head) { if (!list_empty (list)) __list_splice (list, head->prev, head); } /** * list_splice_init - join two lists and reinitialise the emptied list. * @list: the new list to add. * @head: the place to add it in the first list. * * The list at @list is reinitialised */ static inline void list_splice_init (struct list_head *list, struct list_head *head) { if (!list_empty (list)) { __list_splice (list, head, head->next); INIT_LIST_HEAD (list); } } /** * list_splice_tail_init - join two lists and reinitialise the emptied list * @list: the new list to add. * @head: the place to add it in the first list. * * Each of the lists is a queue. * The list at @list is reinitialised */ static inline void list_splice_tail_init (struct list_head *list, struct list_head *head) { if (!list_empty (list)) { __list_splice (list, head->prev, head); INIT_LIST_HEAD (list); } } /** * list_entry - get the struct for this entry * @ptr: the &struct list_head pointer. * @type: the type of the struct this is embedded in. * @member: the name of the list_struct within the struct. */ #define list_entry(ptr, type, member) container_of (ptr, type, member) /** * list_first_entry - get the first element from a list * @ptr: the list head to take the element from. * @type: the type of the struct this is embedded in. * @member: the name of the list_struct within the struct. * * Note, that list is expected to be not empty. */ #define list_first_entry(ptr, type, member) \ list_entry ((ptr)->next, type, member) /** * list_for_each - iterate over a list * @pos: the &struct list_head to use as a loop cursor. * @head: the head for your list. */ #define list_for_each(pos, head) \ for (pos = (head)->next; prefetch (pos->next), pos != (head); \ pos = pos->next) /** * __list_for_each - iterate over a list * @pos: the &struct list_head to use as a loop cursor. * @head: the head for your list. * * This variant differs from list_for_each() in that it's the * simplest possible list iteration code, no prefetching is done. * Use this for code that knows the list to be very short (empty * or 1 entry) most of the time. */ #define __list_for_each(pos, head) \ for (pos = (head)->next; pos != (head); pos = pos->next) /** * list_for_each_prev - iterate over a list backwards * @pos: the &struct list_head to use as a loop cursor. * @head: the head for your list. */ #define list_for_each_prev(pos, head) \ for (pos = (head)->prev; prefetch (pos->prev), pos != (head); \ pos = pos->prev) /** * list_for_each_safe - iterate over a list safe against removal of list entry * @pos: the &struct list_head to use as a loop cursor. * @n: another &struct list_head to use as temporary storage * @head: the head for your list. */ #define list_for_each_safe(pos, n, head) \ for (pos = (head)->next, n = pos->next; pos != (head); \ pos = n, n = pos->next) /** * list_for_each_prev_safe - iterate over a list backwards safe against removal * of list entry * @pos: the &struct list_head to use as a loop cursor. * @n: another &struct list_head to use as temporary storage * @head: the head for your list. */ #define list_for_each_prev_safe(pos, n, head) \ for (pos = (head)->prev, n = pos->prev; \ prefetch (pos->prev), pos != (head); pos = n, n = pos->prev) /** * list_for_each_entry - iterate over list of given type * @pos: the type * to use as a loop cursor. * @head: the head for your list. * @member: the name of the list_struct within the struct. */ #define list_for_each_entry(pos, head, member) \ for (pos = list_entry ((head)->next, typeof(*pos), member); \ prefetch (pos->member.next), &pos->member != (head); \ pos = list_entry (pos->member.next, typeof(*pos), member)) /** * list_for_each_entry_reverse - iterate backwards over list of given type. * @pos: the type * to use as a loop cursor. * @head: the head for your list. * @member: the name of the list_struct within the struct. */ #define list_for_each_entry_reverse(pos, head, member) \ for (pos = list_entry ((head)->prev, typeof(*pos), member); \ prefetch (pos->member.prev), &pos->member != (head); \ pos = list_entry (pos->member.prev, typeof(*pos), member)) /** * list_prepare_entry - prepare a pos entry for use in * list_for_each_entry_continue() * @pos: the type * to use as a start point * @head: the head of the list * @member: the name of the list_struct within the struct. * * Prepares a pos entry for use as a start point in * list_for_each_entry_continue(). */ #define list_prepare_entry(pos, head, member) \ ((pos) ?: list_entry (head, typeof(*pos), member)) /** * list_for_each_entry_continue - continue iteration over list of given type * @pos: the type * to use as a loop cursor. * @head: the head for your list. * @member: the name of the list_struct within the struct. * * Continue to iterate over list of given type, continuing after * the current position. */ #define list_for_each_entry_continue(pos, head, member) \ for (pos = list_entry (pos->member.next, typeof(*pos), member); \ prefetch (pos->member.next), &pos->member != (head); \ pos = list_entry (pos->member.next, typeof(*pos), member)) /** * list_for_each_entry_continue_reverse - iterate backwards from the given * point * @pos: the type * to use as a loop cursor. * @head: the head for your list. * @member: the name of the list_struct within the struct. * * Start to iterate over list of given type backwards, continuing after * the current position. */ #define list_for_each_entry_continue_reverse(pos, head, member) \ for (pos = list_entry (pos->member.prev, typeof(*pos), member); \ prefetch (pos->member.prev), &pos->member != (head); \ pos = list_entry (pos->member.prev, typeof(*pos), member)) /** * list_for_each_entry_from - iterate over list of given type from the current * point * @pos: the type * to use as a loop cursor. * @head: the head for your list. * @member: the name of the list_struct within the struct. * * Iterate over list of given type, continuing from current position. */ #define list_for_each_entry_from(pos, head, member) \ for (; prefetch (pos->member.next), &pos->member != (head); \ pos = list_entry (pos->member.next, typeof(*pos), member)) /** * list_for_each_entry_safe - iterate over list of given type safe against * removal of list entry * @pos: the type * to use as a loop cursor. * @n: another type * to use as temporary storage * @head: the head for your list. * @member: the name of the list_struct within the struct. */ #define list_for_each_entry_safe(pos, n, head, member) \ for (pos = list_entry ((head)->next, typeof(*pos), member), \ n = list_entry (pos->member.next, typeof(*pos), member); \ &pos->member != (head); \ pos = n, n = list_entry (n->member.next, typeof(*n), member)) /** * list_for_each_entry_safe_continue * @pos: the type * to use as a loop cursor. * @n: another type * to use as temporary storage * @head: the head for your list. * @member: the name of the list_struct within the struct. * * Iterate over list of given type, continuing after current point, * safe against removal of list entry. */ #define list_for_each_entry_safe_continue(pos, n, head, member) \ for (pos = list_entry (pos->member.next, typeof(*pos), member), \ n = list_entry (pos->member.next, typeof(*pos), member); \ &pos->member != (head); \ pos = n, n = list_entry (n->member.next, typeof(*n), member)) /** * list_for_each_entry_safe_from * @pos: the type * to use as a loop cursor. * @n: another type * to use as temporary storage * @head: the head for your list. * @member: the name of the list_struct within the struct. * * Iterate over list of given type from current point, safe against * removal of list entry. */ #define list_for_each_entry_safe_from(pos, n, head, member) \ for (n = list_entry (pos->member.next, typeof(*pos), member); \ &pos->member != (head); \ pos = n, n = list_entry (n->member.next, typeof(*n), member)) /** * list_for_each_entry_safe_reverse * @pos: the type * to use as a loop cursor. * @n: another type * to use as temporary storage * @head: the head for your list. * @member: the name of the list_struct within the struct. * * Iterate backwards over list of given type, safe against removal * of list entry. */ #define list_for_each_entry_safe_reverse(pos, n, head, member) \ for (pos = list_entry ((head)->prev, typeof(*pos), member), \ n = list_entry (pos->member.prev, typeof(*pos), member); \ &pos->member != (head); \ pos = n, n = list_entry (n->member.prev, typeof(*n), member)) /* * Double linked lists with a single pointer list head. * Mostly useful for hash tables where the two pointer list head is * too wasteful. * You lose the ability to access the tail in O(1). */ struct hlist_head { struct hlist_node *first; }; struct hlist_node { struct hlist_node *next, **pprev; }; #define HLIST_HEAD_INIT \ { \ .first = NULL \ } #define HLIST_HEAD(name) struct hlist_head name = { .first = NULL } #define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL) static inline void INIT_HLIST_NODE (struct hlist_node *h) { h->next = NULL; h->pprev = NULL; } static inline int hlist_unhashed (const struct hlist_node *h) { return !h->pprev; } static inline int hlist_empty (const struct hlist_head *h) { return !h->first; } static inline void __hlist_del (struct hlist_node *n) { struct hlist_node *next = n->next; struct hlist_node **pprev = n->pprev; *pprev = next; if (next) next->pprev = pprev; } static inline void hlist_del (struct hlist_node *n) { __hlist_del (n); n->next = LIST_POISON1; n->pprev = LIST_POISON2; } static inline void hlist_del_init (struct hlist_node *n) { if (!hlist_unhashed (n)) { __hlist_del (n); INIT_HLIST_NODE (n); } } static inline void hlist_add_head (struct hlist_node *n, struct hlist_head *h) { struct hlist_node *first = h->first; n->next = first; if (first) first->pprev = &n->next; h->first = n; n->pprev = &h->first; } /* next must be != NULL */ static inline void hlist_add_before (struct hlist_node *n, struct hlist_node *next) { n->pprev = next->pprev; n->next = next; next->pprev = &n->next; *(n->pprev) = n; } static inline void hlist_add_after (struct hlist_node *n, struct hlist_node *next) { next->next = n->next; n->next = next; next->pprev = &n->next; if (next->next) next->next->pprev = &next->next; } /* * Move a list from one list head to another. Fixup the pprev * reference of the first entry if it exists. */ static inline void hlist_move_list (struct hlist_head *old, struct hlist_head *new) { new->first = old->first; if (new->first) new->first->pprev = &new->first; old->first = NULL; } #define hlist_entry(ptr, type, member) container_of (ptr, type, member) #define hlist_for_each(pos, head) \ for (pos = (head)->first; pos && ({ \ prefetch (pos->next); \ 1; \ }); \ pos = pos->next) #define hlist_for_each_safe(pos, n, head) \ for (pos = (head)->first; pos && ({ \ n = pos->next; \ 1; \ }); \ pos = n) /** * hlist_for_each_entry - iterate over list of given type * @tpos: the type * to use as a loop cursor. * @pos: the &struct hlist_node to use as a loop cursor. * @head: the head for your list. * @member: the name of the hlist_node within the struct. */ #define hlist_for_each_entry(tpos, pos, head, member) \ for (pos = (head)->first; \ pos && ({ \ prefetch (pos->next); \ 1; \ }) \ && ({ \ tpos = hlist_entry (pos, typeof(*tpos), member); \ 1; \ }); \ pos = pos->next) /** * hlist_for_each_entry_continue - iterate over a hlist continuing after * current point * @tpos: the type * to use as a loop cursor. * @pos: the &struct hlist_node to use as a loop cursor. * @member: the name of the hlist_node within the struct. */ #define hlist_for_each_entry_continue(tpos, pos, member) \ for (pos = (pos)->next; \ pos && ({ \ prefetch (pos->next); \ 1; \ }) \ && ({ \ tpos = hlist_entry (pos, typeof(*tpos), member); \ 1; \ }); \ pos = pos->next) /** * hlist_for_each_entry_from - iterate over a hlist continuing from current * point * @tpos: the type * to use as a loop cursor. * @pos: the &struct hlist_node to use as a loop cursor. * @member: the name of the hlist_node within the struct. */ #define hlist_for_each_entry_from(tpos, pos, member) \ for (; pos && ({ \ prefetch (pos->next); \ 1; \ }) \ && ({ \ tpos = hlist_entry (pos, typeof(*tpos), member); \ 1; \ }); \ pos = pos->next) /** * hlist_for_each_entry_safe - iterate over list of given type safe against * removal of list entry * @tpos: the type * to use as a loop cursor. * @pos: the &struct hlist_node to use as a loop cursor. * @n: another &struct hlist_node to use as temporary storage * @head: the head for your list. * @member: the name of the hlist_node within the struct. */ #define hlist_for_each_entry_safe(tpos, pos, n, head, member) \ for (pos = (head)->first; \ pos && ({ \ n = pos->next; \ 1; \ }) \ && ({ \ tpos = hlist_entry (pos, typeof(*tpos), member); \ 1; \ }); \ pos = n) #endif 错误信息为In file included from main.c:4:0: main.c: In function ‘find_per’: list.h:417:8: warning: implicit declaration of function ‘prefetch’; did you mean ‘rpmatch’? [-Wimplicit-function-declaration] prefetch (pos->member.next), &pos->member != (head); \ ^ main.c:63:5: note: in expansion of macro ‘list_for_each_entry’ list_for_each_entry(tmp, head, node) ^~~~~~~~~~~~~~~~~~~ /tmp/cce8BVSj.o: In function `find_per': main.c:(.text+0x297): undefined reference to `prefetch' collect2: error: ld returned 1 exit status,该如何修改
08-24
struct list_head my_list; INIT_LIST_HEAD(&my_list); // 链表操作代码... return 0; } module_init(my_init); ``` ### 相关问题 1. **如何安全地在用户空间程序中使用 Linux 内核数据结构？** [需考虑内存...
/* Copyright (c) 2009 Dave Gamble Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ #ifndef cJSON__h #define cJSON__h #include <stddef.h> #ifdef __cplusplus extern "C" { #endif /* cJSON Types: */ #define cJSON_False 0 #define cJSON_True 1 #define cJSON_NULL 2 #define cJSON_Number 3 #define cJSON_String 4 #define cJSON_Array 5 #define cJSON_Object 6 #define cJSON_IsReference 256 #define cJSON_StringIsConst 512 /* The cJSON structure: */ typedef struct cJSON { struct cJSON *next,*prev; /* next/prev allow you to walk array/object chains. Alternatively, use GetArraySize/GetArrayItem/GetObjectItem */ struct cJSON *child; /* An array or object item will have a child pointer pointing to a chain of the items in the array/object. */ int type; /* The type of the item, as above. */ char *valuestring; /* The item's string, if type==cJSON_String */ int valueint; /* The item's number, if type==cJSON_Number */ double valuedouble; /* The item's number, if type==cJSON_Number */ char *string; /* The item's name string, if this item is the child of, or is in the list of subitems of an object. */ } cJSON; typedef struct cJSON_Hooks { void *(*malloc_fn)(size_t sz); void (*free_fn)(void *ptr); } cJSON_Hooks; /* Supply malloc, realloc and free functions to cJSON */ extern void cJSON_InitHooks(cJSON_Hooks* hooks); /* Supply a block of JSON, and this returns a cJSON object you can interrogate. Call cJSON_Delete when finished. */ extern cJSON *cJSON_Parse(const char *value); /* Render a cJSON entity to text for transfer/storage. Free the char* when finished. */ extern char *cJSON_Print(cJSON *item); /* Render a cJSON entity to text for transfer/storage without any formatting. Free the char* when finished. */ extern char *cJSON_PrintUnformatted(cJSON *item); /* Render a cJSON entity to text using a buffered strategy. prebuffer is a guess at the final size. guessing well reduces reallocation. fmt=0 gives unformatted, =1 gives formatted */ extern char *cJSON_PrintBuffered(cJSON *item,int prebuffer,int fmt); /* Delete a cJSON entity and all subentities. */ extern void cJSON_Delete(cJSON *c); /* Returns the number of items in an array (or object). */ extern int cJSON_GetArraySize(cJSON *array); /* Retrieve item number "item" from array "array". Returns NULL if unsuccessful. */ extern cJSON *cJSON_GetArrayItem(cJSON *array,int item); /* Get item "string" from object. Case insensitive. */ extern cJSON *cJSON_GetObjectItem(cJSON *object,const char *string); extern int cJSON_HasObjectItem(cJSON *object,const char *string); /* For analysing failed parses. This returns a pointer to the parse error. You'll probably need to look a few chars back to make sense of it. Defined when cJSON_Parse() returns 0. 0 when cJSON_Parse() succeeds. */ extern const char *cJSON_GetErrorPtr(void); /* These calls create a cJSON item of the appropriate type. */ extern cJSON *cJSON_CreateNull(void); extern cJSON *cJSON_CreateTrue(void); extern cJSON *cJSON_CreateFalse(void); extern cJSON *cJSON_CreateBool(int b); extern cJSON *cJSON_CreateNumber(double num); extern cJSON *cJSON_CreateString(const char *string); extern cJSON *cJSON_CreateArray(void); extern cJSON *cJSON_CreateObject(void); /* These utilities create an Array of count items. */ extern cJSON *cJSON_CreateIntArray(const int *numbers,int count); extern cJSON *cJSON_CreateFloatArray(const float *numbers,int count); extern cJSON *cJSON_CreateDoubleArray(const double *numbers,int count); extern cJSON *cJSON_CreateStringArray(const char **strings,int count); /* Append item to the specified array/object. */ extern void cJSON_AddItemToArray(cJSON *array, cJSON *item); extern void cJSON_AddItemToObject(cJSON *object,const char *string,cJSON *item); extern void cJSON_AddItemToObjectCS(cJSON *object,const char *string,cJSON *item); /* Use this when string is definitely const (i.e. a literal, or as good as), and will definitely survive the cJSON object */ /* Append reference to item to the specified array/object. Use this when you want to add an existing cJSON to a new cJSON, but don't want to corrupt your existing cJSON. */ extern void cJSON_AddItemReferenceToArray(cJSON *array, cJSON *item); extern void cJSON_AddItemReferenceToObject(cJSON *object,const char *string,cJSON *item); /* Remove/Detatch items from Arrays/Objects. */ extern cJSON *cJSON_DetachItemFromArray(cJSON *array,int which); extern void cJSON_DeleteItemFromArray(cJSON *array,int which); extern cJSON *cJSON_DetachItemFromObject(cJSON *object,const char *string); extern void cJSON_DeleteItemFromObject(cJSON *object,const char *string); /* Update array items. */ extern void cJSON_InsertItemInArray(cJSON *array,int which,cJSON *newitem); /* Shifts pre-existing items to the right. */ extern void cJSON_ReplaceItemInArray(cJSON *array,int which,cJSON *newitem); extern void cJSON_ReplaceItemInObject(cJSON *object,const char *string,cJSON *newitem); /* Duplicate a cJSON item */ extern cJSON *cJSON_Duplicate(cJSON *item,int recurse); /* Duplicate will create a new, identical cJSON item to the one you pass, in new memory that will need to be released. With recurse!=0, it will duplicate any children connected to the item. The item->next and ->prev pointers are always zero on return from Duplicate. */ /* ParseWithOpts allows you to require (and check) that the JSON is null terminated, and to retrieve the pointer to the final byte parsed. */ extern cJSON *cJSON_ParseWithOpts(const char *value,const char **return_parse_end,int require_null_terminated); extern void cJSON_Minify(char *json); /* Macros for creating things quickly. */ #define cJSON_AddNullToObject(object,name) cJSON_AddItemToObject(object, name, cJSON_CreateNull()) #define cJSON_AddTrueToObject(object,name) cJSON_AddItemToObject(object, name, cJSON_CreateTrue()) #define cJSON_AddFalseToObject(object,name) cJSON_AddItemToObject(object, name, cJSON_CreateFalse()) #define cJSON_AddBoolToObject(object,name,b) cJSON_AddItemToObject(object, name, cJSON_CreateBool(b)) #define cJSON_AddNumberToObject(object,name,n) cJSON_AddItemToObject(object, name, cJSON_CreateNumber(n)) #define cJSON_AddStringToObject(object,name,s) cJSON_AddItemToObject(object, name, cJSON_CreateString(s)) /* When assigning an integer value, it needs to be propagated to valuedouble too. */ #define cJSON_SetIntValue(object,val) ((object)?(object)->valueint=(object)->valuedouble=(val):(val)) #define cJSON_SetNumberValue(object,val) ((object)?(object)->valueint=(object)->valuedouble=(val):(val)) /* Macro for iterating over an array */ #define cJSON_ArrayForEach(pos, head) for(pos = (head)->child; pos != NULL; pos = pos->next) #ifdef __cplusplus } #endif #endif /* Copyright (c) 2009 Dave Gamble Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ /* cJSON */ /* JSON parser in C. */ #include <string.h> #include <stdio.h> #include <math.h> #include <stdlib.h> #include <float.h> #include <limits.h> #include <ctype.h> #include "cJSON.h" static const char *ep; const char *cJSON_GetErrorPtr(void) {return ep;} static int cJSON_strcasecmp(const char *s1,const char *s2) { if (!s1) return (s1==s2)?0:1;if (!s2) return 1; for(; tolower(*s1) == tolower(*s2); ++s1, ++s2) if(*s1 == 0) return 0; return tolower(*(const unsigned char *)s1) - tolower(*(const unsigned char *)s2); } static void *(*cJSON_malloc)(size_t sz) = malloc; static void (*cJSON_free)(void *ptr) = free; static char* cJSON_strdup(const char* str) { size_t len; char* copy; len = strlen(str) + 1; if (!(copy = (char*)cJSON_malloc(len))) return 0; memcpy(copy,str,len); return copy; } void cJSON_InitHooks(cJSON_Hooks* hooks) { if (!hooks) { /* Reset hooks */ cJSON_malloc = malloc; cJSON_free = free; return; } cJSON_malloc = (hooks->malloc_fn)?hooks->malloc_fn:malloc; cJSON_free = (hooks->free_fn)?hooks->free_fn:free; } /* Internal constructor. */ static cJSON *cJSON_New_Item(void) { cJSON* node = (cJSON*)cJSON_malloc(sizeof(cJSON)); if (node) memset(node,0,sizeof(cJSON)); return node; } /* Delete a cJSON structure. */ void cJSON_Delete(cJSON *c) { cJSON *next; while (c) { next=c->next; if (!(c->type&cJSON_IsReference) && c->child) cJSON_Delete(c->child); if (!(c->type&cJSON_IsReference) && c->valuestring) cJSON_free(c->valuestring); if (!(c->type&cJSON_StringIsConst) && c->string) cJSON_free(c->string); cJSON_free(c); c=next; } } /* Parse the input text to generate a number, and populate the result into item. */ static const char *parse_number(cJSON *item,const char *num) { double n=0,sign=1,scale=0;int subscale=0,signsubscale=1; if (*num=='-') sign=-1,num++; /* Has sign? */ if (*num=='0') num++; /* is zero */ if (*num>='1' && *num<='9') do n=(n*10.0)+(*num++ -'0'); while (*num>='0' && *num<='9'); /* Number? */ if (*num=='.' && num[1]>='0' && num[1]<='9') {num++; do n=(n*10.0)+(*num++ -'0'),scale--; while (*num>='0' && *num<='9');} /* Fractional part? */ if (*num=='e' || *num=='E') /* Exponent? */ { num++;if (*num=='+') num++; else if (*num=='-') signsubscale=-1,num++; /* With sign? */ while (*num>='0' && *num<='9') subscale=(subscale*10)+(*num++ - '0'); /* Number? */ } n=sign*n*pow(10.0,(scale+subscale*signsubscale)); /* number = +/- number.fraction * 10^+/- exponent */ item->valuedouble=n; item->valueint=(int)n; item->type=cJSON_Number; return num; } static int pow2gt (int x) { --x; x|=x>>1; x|=x>>2; x|=x>>4; x|=x>>8; x|=x>>16; return x+1; } typedef struct {char *buffer; int length; int offset; } printbuffer; static char* ensure(printbuffer *p,int needed) { char *newbuffer;int newsize; if (!p || !p->buffer) return 0; needed+=p->offset; if (needed<=p->length) return p->buffer+p->offset; newsize=pow2gt(needed); newbuffer=(char*)cJSON_malloc(newsize); if (!newbuffer) {cJSON_free(p->buffer);p->length=0,p->buffer=0;return 0;} if (newbuffer) memcpy(newbuffer,p->buffer,p->length); cJSON_free(p->buffer); p->length=newsize; p->buffer=newbuffer; return newbuffer+p->offset; } static int update(printbuffer *p) { char *str; if (!p || !p->buffer) return 0; str=p->buffer+p->offset; return p->offset+strlen(str); } /* Render the number nicely from the given item into a string. */ static char *print_number(cJSON *item,printbuffer *p) { char *str=0; double d=item->valuedouble; if (d==0) { if (p) str=ensure(p,2); else str=(char*)cJSON_malloc(2); /* special case for 0. */ if (str) strcpy(str,"0"); } else if (fabs(((double)item->valueint)-d)<=DBL_EPSILON && d<=INT_MAX && d>=INT_MIN) { if (p) str=ensure(p,21); else str=(char*)cJSON_malloc(21); /* 2^64+1 can be represented in 21 chars. */ if (str) sprintf(str,"%d",item->valueint); } else { if (p) str=ensure(p,64); else str=(char*)cJSON_malloc(64); /* This is a nice tradeoff. */ if (str) { if (fpclassify(d) != FP_ZERO && !isnormal(d)) sprintf(str,"null"); else if (fabs(floor(d)-d)<=DBL_EPSILON && fabs(d)<1.0e60) sprintf(str,"%.0f",d); else if (fabs(d)<1.0e-6 || fabs(d)>1.0e9) sprintf(str,"%e",d); else sprintf(str,"%f",d); } } return str; } static unsigned parse_hex4(const char *str) { unsigned h=0; if (*str>='0' && *str<='9') h+=(*str)-'0'; else if (*str>='A' && *str<='F') h+=10+(*str)-'A'; else if (*str>='a' && *str<='f') h+=10+(*str)-'a'; else return 0; h=h<<4;str++; if (*str>='0' && *str<='9') h+=(*str)-'0'; else if (*str>='A' && *str<='F') h+=10+(*str)-'A'; else if (*str>='a' && *str<='f') h+=10+(*str)-'a'; else return 0; h=h<<4;str++; if (*str>='0' && *str<='9') h+=(*str)-'0'; else if (*str>='A' && *str<='F') h+=10+(*str)-'A'; else if (*str>='a' && *str<='f') h+=10+(*str)-'a'; else return 0; h=h<<4;str++; if (*str>='0' && *str<='9') h+=(*str)-'0'; else if (*str>='A' && *str<='F') h+=10+(*str)-'A'; else if (*str>='a' && *str<='f') h+=10+(*str)-'a'; else return 0; return h; } /* Parse the input text into an unescaped cstring, and populate item. */ static const unsigned char firstByteMark[7] = { 0x00, 0x00, 0xC0, 0xE0, 0xF0, 0xF8, 0xFC }; static const char *parse_string(cJSON *item,const char *str) { const char *ptr=str+1;char *ptr2;char *out;int len=0;unsigned uc,uc2; if (*str!='\"') {ep=str;return 0;} /* not a string! */ while (*ptr!='\"' && *ptr && ++len) if (*ptr++ == '\\') ptr++; /* Skip escaped quotes. */ out=(char*)cJSON_malloc(len+1); /* This is how long we need for the string, roughly. */ if (!out) return 0; ptr=str+1;ptr2=out; while (*ptr!='\"' && *ptr) { if (*ptr!='\\') *ptr2++=*ptr++; else { ptr++; switch (*ptr) { case 'b': *ptr2++='\b'; break; case 'f': *ptr2++='\f'; break; case 'n': *ptr2++='\n'; break; case 'r': *ptr2++='\r'; break; case 't': *ptr2++='\t'; break; case 'u': /* transcode utf16 to utf8. */ uc=parse_hex4(ptr+1);ptr+=4; /* get the unicode char. */ if ((uc>=0xDC00 && uc<=0xDFFF) || uc==0) break; /* check for invalid. */ if (uc>=0xD800 && uc<=0xDBFF) /* UTF16 surrogate pairs. */ { if (ptr[1]!='\\' || ptr[2]!='u') break; /* missing second-half of surrogate. */ uc2=parse_hex4(ptr+3);ptr+=6; if (uc2<0xDC00 || uc2>0xDFFF) break; /* invalid second-half of surrogate. */ uc=0x10000 + (((uc&0x3FF)<<10) | (uc2&0x3FF)); } len=4;if (uc<0x80) len=1;else if (uc<0x800) len=2;else if (uc<0x10000) len=3; ptr2+=len; switch (len) { case 4: *--ptr2 =((uc | 0x80) & 0xBF); uc >>= 6; case 3: *--ptr2 =((uc | 0x80) & 0xBF); uc >>= 6; case 2: *--ptr2 =((uc | 0x80) & 0xBF); uc >>= 6; case 1: *--ptr2 =(uc | firstByteMark[len]); } ptr2+=len; break; default: *ptr2++=*ptr; break; } ptr++; } } *ptr2=0; if (*ptr=='\"') ptr++; item->valuestring=out; item->type=cJSON_String; return ptr; } /* Render the cstring provided to an escaped version that can be printed. */ static char *print_string_ptr(const char *str,printbuffer *p) { const char *ptr;char *ptr2,*out;int len=0,flag=0;unsigned char token; for (ptr=str;*ptr;ptr++) flag|=((*ptr>0 && *ptr<32)||(*ptr=='\"')||(*ptr=='\\'))?1:0; if (!flag) { len=ptr-str; if (p) out=ensure(p,len+3); else out=(char*)cJSON_malloc(len+3); if (!out) return 0; ptr2=out;*ptr2++='\"'; strcpy(ptr2,str); ptr2[len]='\"'; ptr2[len+1]=0; return out; } if (!str) { if (p) out=ensure(p,3); else out=(char*)cJSON_malloc(3); if (!out) return 0; strcpy(out,"\"\""); return out; } ptr=str;while ((token=*ptr) && ++len) {if (strchr("\"\\\b\f\n\r\t",token)) len++; else if (token<32) len+=5;ptr++;} if (p) out=ensure(p,len+3); else out=(char*)cJSON_malloc(len+3); if (!out) return 0; ptr2=out;ptr=str; *ptr2++='\"'; while (*ptr) { if ((unsigned char)*ptr>31 && *ptr!='\"' && *ptr!='\\') *ptr2++=*ptr++; else { *ptr2++='\\'; switch (token=*ptr++) { case '\\': *ptr2++='\\'; break; case '\"': *ptr2++='\"'; break; case '\b': *ptr2++='b'; break; case '\f': *ptr2++='f'; break; case '\n': *ptr2++='n'; break; case '\r': *ptr2++='r'; break; case '\t': *ptr2++='t'; break; default: sprintf(ptr2,"u%04x",token);ptr2+=5; break; /* escape and print */ } } } *ptr2++='\"';*ptr2++=0; return out; } /* Invote print_string_ptr (which is useful) on an item. */ static char *print_string(cJSON *item,printbuffer *p) {return print_string_ptr(item->valuestring,p);} /* Predeclare these prototypes. */ static const char *parse_value(cJSON *item,const char *value); static char *print_value(cJSON *item,int depth,int fmt,printbuffer *p); static const char *parse_array(cJSON *item,const char *value); static char *print_array(cJSON *item,int depth,int fmt,printbuffer *p); static const char *parse_object(cJSON *item,const char *value); static char *print_object(cJSON *item,int depth,int fmt,printbuffer *p); /* Utility to jump whitespace and cr/lf */ static const char *skip(const char *in) {while (in && *in && (unsigned char)*in<=32) in++; return in;} /* Parse an object - create a new root, and populate. */ cJSON *cJSON_ParseWithOpts(const char *value,const char **return_parse_end,int require_null_terminated) { const char *end=0; cJSON *c=cJSON_New_Item(); ep=0; if (!c) return 0; /* memory fail */ end=parse_value(c,skip(value)); if (!end) {cJSON_Delete(c);return 0;} /* parse failure. ep is set. */ /* if we require null-terminated JSON without appended garbage, skip and then check for a null terminator */ if (require_null_terminated) {end=skip(end);if (*end) {cJSON_Delete(c);ep=end;return 0;}} if (return_parse_end) *return_parse_end=end; return c; } /* Default options for cJSON_Parse */ cJSON *cJSON_Parse(const char *value) {return cJSON_ParseWithOpts(value,0,0);} /* Render a cJSON item/entity/structure to text. */ char *cJSON_Print(cJSON *item) {return print_value(item,0,1,0);} char *cJSON_PrintUnformatted(cJSON *item) {return print_value(item,0,0,0);} char *cJSON_PrintBuffered(cJSON *item,int prebuffer,int fmt) { printbuffer p; p.buffer=(char*)cJSON_malloc(prebuffer); p.length=prebuffer; p.offset=0; return print_value(item,0,fmt,&p); return p.buffer; } /* Parser core - when encountering text, process appropriately. */ static const char *parse_value(cJSON *item,const char *value) { if (!value) return 0; /* Fail on null. */ if (!strncmp(value,"null",4)) { item->type=cJSON_NULL; return value+4; } if (!strncmp(value,"false",5)) { item->type=cJSON_False; return value+5; } if (!strncmp(value,"true",4)) { item->type=cJSON_True; item->valueint=1; return value+4; } if (*value=='\"') { return parse_string(item,value); } if (*value=='-' || (*value>='0' && *value<='9')) { return parse_number(item,value); } if (*value=='[') { return parse_array(item,value); } if (*value=='{') { return parse_object(item,value); } ep=value;return 0; /* failure. */ } /* Render a value to text. */ static char *print_value(cJSON *item,int depth,int fmt,printbuffer *p) { char *out=0; if (!item) return 0; if (p) { switch ((item->type)&255) { case cJSON_NULL: {out=ensure(p,5); if (out) strcpy(out,"null"); break;} case cJSON_False: {out=ensure(p,6); if (out) strcpy(out,"false"); break;} case cJSON_True: {out=ensure(p,5); if (out) strcpy(out,"true"); break;} case cJSON_Number: out=print_number(item,p);break; case cJSON_String: out=print_string(item,p);break; case cJSON_Array: out=print_array(item,depth,fmt,p);break; case cJSON_Object: out=print_object(item,depth,fmt,p);break; } } else { switch ((item->type)&255) { case cJSON_NULL: out=cJSON_strdup("null"); break; case cJSON_False: out=cJSON_strdup("false");break; case cJSON_True: out=cJSON_strdup("true"); break; case cJSON_Number: out=print_number(item,0);break; case cJSON_String: out=print_string(item,0);break; case cJSON_Array: out=print_array(item,depth,fmt,0);break; case cJSON_Object: out=print_object(item,depth,fmt,0);break; } } return out; } /* Build an array from input text. */ static const char *parse_array(cJSON *item,const char *value) { cJSON *child; if (*value!='[') {ep=value;return 0;} /* not an array! */ item->type=cJSON_Array; value=skip(value+1); if (*value==']') return value+1; /* empty array. */ item->child=child=cJSON_New_Item(); if (!item->child) return 0; /* memory fail */ value=skip(parse_value(child,skip(value))); /* skip any spacing, get the value. */ if (!value) return 0; while (*value==',') { cJSON *new_item; if (!(new_item=cJSON_New_Item())) return 0; /* memory fail */ child->next=new_item;new_item->prev=child;child=new_item; value=skip(parse_value(child,skip(value+1))); if (!value) return 0; /* memory fail */ } if (*value==']') return value+1; /* end of array */ ep=value;return 0; /* malformed. */ } /* Render an array to text */ static char *print_array(cJSON *item,int depth,int fmt,printbuffer *p) { char **entries; char *out=0,*ptr,*ret;int len=5; cJSON *child=item->child; int numentries=0,i=0,fail=0; size_t tmplen=0; /* How many entries in the array? */ while (child) numentries++,child=child->next; /* Explicitly handle numentries==0 */ if (!numentries) { if (p) out=ensure(p,3); else out=(char*)cJSON_malloc(3); if (out) strcpy(out,"[]"); return out; } if (p) { /* Compose the output array. */ i=p->offset; ptr=ensure(p,1);if (!ptr) return 0; *ptr='['; p->offset++; child=item->child; while (child && !fail) { print_value(child,depth+1,fmt,p); p->offset=update(p); if (child->next) {len=fmt?2:1;ptr=ensure(p,len+1);if (!ptr) return 0;*ptr++=',';if(fmt)*ptr++=' ';*ptr=0;p->offset+=len;} child=child->next; } ptr=ensure(p,2);if (!ptr) return 0; *ptr++=']';*ptr=0; out=(p->buffer)+i; } else { /* Allocate an array to hold the values for each */ entries=(char**)cJSON_malloc(numentries*sizeof(char*)); if (!entries) return 0; memset(entries,0,numentries*sizeof(char*)); /* Retrieve all the results: */ child=item->child; while (child && !fail) { ret=print_value(child,depth+1,fmt,0); entries[i++]=ret; if (ret) len+=strlen(ret)+2+(fmt?1:0); else fail=1; child=child->next; } /* If we didn't fail, try to malloc the output string */ if (!fail) out=(char*)cJSON_malloc(len); /* If that fails, we fail. */ if (!out) fail=1; /* Handle failure. */ if (fail) { for (i=0;i<numentries;i++) if (entries[i]) cJSON_free(entries[i]); cJSON_free(entries); return 0; } /* Compose the output array. */ *out='['; ptr=out+1;*ptr=0; for (i=0;i<numentries;i++) { tmplen=strlen(entries[i]);memcpy(ptr,entries[i],tmplen);ptr+=tmplen; if (i!=numentries-1) {*ptr++=',';if(fmt)*ptr++=' ';*ptr=0;} cJSON_free(entries[i]); } cJSON_free(entries); *ptr++=']';*ptr++=0; } return out; } /* Build an object from the text. */ static const char *parse_object(cJSON *item,const char *value) { cJSON *child; if (*value!='{') {ep=value;return 0;} /* not an object! */ item->type=cJSON_Object; value=skip(value+1); if (*value=='}') return value+1; /* empty array. */ item->child=child=cJSON_New_Item(); if (!item->child) return 0; value=skip(parse_string(child,skip(value))); if (!value) return 0; child->string=child->valuestring;child->valuestring=0; if (*value!=':') {ep=value;return 0;} /* fail! */ value=skip(parse_value(child,skip(value+1))); /* skip any spacing, get the value. */ if (!value) return 0; while (*value==',') { cJSON *new_item; if (!(new_item=cJSON_New_Item())) return 0; /* memory fail */ child->next=new_item;new_item->prev=child;child=new_item; value=skip(parse_string(child,skip(value+1))); if (!value) return 0; child->string=child->valuestring;child->valuestring=0; if (*value!=':') {ep=value;return 0;} /* fail! */ value=skip(parse_value(child,skip(value+1))); /* skip any spacing, get the value. */ if (!value) return 0; } if (*value=='}') return value+1; /* end of array */ ep=value;return 0; /* malformed. */ } /* Render an object to text. */ static char *print_object(cJSON *item,int depth,int fmt,printbuffer *p) { char **entries=0,**names=0; char *out=0,*ptr,*ret,*str;int len=7,i=0,j; cJSON *child=item->child; int numentries=0,fail=0; size_t tmplen=0; /* Count the number of entries. */ while (child) numentries++,child=child->next; /* Explicitly handle empty object case */ if (!numentries) { if (p) out=ensure(p,fmt?depth+4:3); else out=(char*)cJSON_malloc(fmt?depth+4:3); if (!out) return 0; ptr=out;*ptr++='{'; if (fmt) {*ptr++='\n';for (i=0;i<depth-1;i++) *ptr++='\t';} *ptr++='}';*ptr++=0; return out; } if (p) { /* Compose the output: */ i=p->offset; len=fmt?2:1; ptr=ensure(p,len+1); if (!ptr) return 0; *ptr++='{'; if (fmt) *ptr++='\n'; *ptr=0; p->offset+=len; child=item->child;depth++; while (child) { if (fmt) { ptr=ensure(p,depth); if (!ptr) return 0; for (j=0;j<depth;j++) *ptr++='\t'; p->offset+=depth; } print_string_ptr(child->string,p); p->offset=update(p); len=fmt?2:1; ptr=ensure(p,len); if (!ptr) return 0; *ptr++=':';if (fmt) *ptr++='\t'; p->offset+=len; print_value(child,depth,fmt,p); p->offset=update(p); len=(fmt?1:0)+(child->next?1:0); ptr=ensure(p,len+1); if (!ptr) return 0; if (child->next) *ptr++=','; if (fmt) *ptr++='\n';*ptr=0; p->offset+=len; child=child->next; } ptr=ensure(p,fmt?(depth+1):2); if (!ptr) return 0; if (fmt) for (i=0;i<depth-1;i++) *ptr++='\t'; *ptr++='}';*ptr=0; out=(p->buffer)+i; } else { /* Allocate space for the names and the objects */ entries=(char**)cJSON_malloc(numentries*sizeof(char*)); if (!entries) return 0; names=(char**)cJSON_malloc(numentries*sizeof(char*)); if (!names) {cJSON_free(entries);return 0;} memset(entries,0,sizeof(char*)*numentries); memset(names,0,sizeof(char*)*numentries); /* Collect all the results into our arrays: */ child=item->child;depth++;if (fmt) len+=depth; while (child && !fail) { names[i]=str=print_string_ptr(child->string,0); entries[i++]=ret=print_value(child,depth,fmt,0); if (str && ret) len+=strlen(ret)+strlen(str)+2+(fmt?2+depth:0); else fail=1; child=child->next; } /* Try to allocate the output string */ if (!fail) out=(char*)cJSON_malloc(len); if (!out) fail=1; /* Handle failure */ if (fail) { for (i=0;i<numentries;i++) {if (names[i]) cJSON_free(names[i]);if (entries[i]) cJSON_free(entries[i]);} cJSON_free(names);cJSON_free(entries); return 0; } /* Compose the output: */ *out='{';ptr=out+1;if (fmt)*ptr++='\n';*ptr=0; for (i=0;i<numentries;i++) { if (fmt) for (j=0;j<depth;j++) *ptr++='\t'; tmplen=strlen(names[i]);memcpy(ptr,names[i],tmplen);ptr+=tmplen; *ptr++=':';if (fmt) *ptr++='\t'; strcpy(ptr,entries[i]);ptr+=strlen(entries[i]); if (i!=numentries-1) *ptr++=','; if (fmt) *ptr++='\n';*ptr=0; cJSON_free(names[i]);cJSON_free(entries[i]); } cJSON_free(names);cJSON_free(entries); if (fmt) for (i=0;i<depth-1;i++) *ptr++='\t'; *ptr++='}';*ptr++=0; } return out; } /* Get Array size/item / object item. */ int cJSON_GetArraySize(cJSON *array) {cJSON *c=array->child;int i=0;while(c)i++,c=c->next;return i;} cJSON *cJSON_GetArrayItem(cJSON *array,int item) {cJSON *c=array->child; while (c && item>0) item--,c=c->next; return c;} cJSON *cJSON_GetObjectItem(cJSON *object,const char *string) {cJSON *c=object->child; while (c && cJSON_strcasecmp(c->string,string)) c=c->next; return c;} int cJSON_HasObjectItem(cJSON *object,const char *string) { cJSON *c=object->child; while (c ) { if(cJSON_strcasecmp(c->string,string)==0){ return 1; } c=c->next; } return 0; } /* Utility for array list handling. */ static void suffix_object(cJSON *prev,cJSON *item) {prev->next=item;item->prev=prev;} /* Utility for handling references. */ static cJSON *create_reference(cJSON *item) {cJSON *ref=cJSON_New_Item();if (!ref) return 0;memcpy(ref,item,sizeof(cJSON));ref->string=0;ref->type|=cJSON_IsReference;ref->next=ref->prev=0;return ref;} /* Add item to array/object. */ void cJSON_AddItemToArray(cJSON *array, cJSON *item) {cJSON *c=array->child;if (!item) return; if (!c) {array->child=item;} else {while (c && c->next) c=c->next; suffix_object(c,item);}} void cJSON_AddItemToObject(cJSON *object,const char *string,cJSON *item) {if (!item) return; if (item->string) cJSON_free(item->string);item->string=cJSON_strdup(string);cJSON_AddItemToArray(object,item);} void cJSON_AddItemToObjectCS(cJSON *object,const char *string,cJSON *item) {if (!item) return; if (!(item->type&cJSON_StringIsConst) && item->string) cJSON_free(item->string);item->string=(char*)string;item->type|=cJSON_StringIsConst;cJSON_AddItemToArray(object,item);} void cJSON_AddItemReferenceToArray(cJSON *array, cJSON *item) {cJSON_AddItemToArray(array,create_reference(item));} void cJSON_AddItemReferenceToObject(cJSON *object,const char *string,cJSON *item) {cJSON_AddItemToObject(object,string,create_reference(item));} cJSON *cJSON_DetachItemFromArray(cJSON *array,int which) {cJSON *c=array->child;while (c && which>0) c=c->next,which--;if (!c) return 0; if (c->prev) c->prev->next=c->next;if (c->next) c->next->prev=c->prev;if (c==array->child) array->child=c->next;c->prev=c->next=0;return c;} void cJSON_DeleteItemFromArray(cJSON *array,int which) {cJSON_Delete(cJSON_DetachItemFromArray(array,which));} cJSON *cJSON_DetachItemFromObject(cJSON *object,const char *string) {int i=0;cJSON *c=object->child;while (c && cJSON_strcasecmp(c->string,string)) i++,c=c->next;if (c) return cJSON_DetachItemFromArray(object,i);return 0;} void cJSON_DeleteItemFromObject(cJSON *object,const char *string) {cJSON_Delete(cJSON_DetachItemFromObject(object,string));} /* Replace array/object items with new ones. */ void cJSON_InsertItemInArray(cJSON *array,int which,cJSON *newitem) {cJSON *c=array->child;while (c && which>0) c=c->next,which--;if (!c) {cJSON_AddItemToArray(array,newitem);return;} newitem->next=c;newitem->prev=c->prev;c->prev=newitem;if (c==array->child) array->child=newitem; else newitem->prev->next=newitem;} void cJSON_ReplaceItemInArray(cJSON *array,int which,cJSON *newitem) {cJSON *c=array->child;while (c && which>0) c=c->next,which--;if (!c) return; newitem->next=c->next;newitem->prev=c->prev;if (newitem->next) newitem->next->prev=newitem; if (c==array->child) array->child=newitem; else newitem->prev->next=newitem;c->next=c->prev=0;cJSON_Delete(c);} void cJSON_ReplaceItemInObject(cJSON *object,const char *string,cJSON *newitem){int i=0;cJSON *c=object->child;while(c && cJSON_strcasecmp(c->string,string))i++,c=c->next;if(c){newitem->string=cJSON_strdup(string);cJSON_ReplaceItemInArray(object,i,newitem);}} /* Create basic types: */ cJSON *cJSON_CreateNull(void) {cJSON *item=cJSON_New_Item();if(item)item->type=cJSON_NULL;return item;} cJSON *cJSON_CreateTrue(void) {cJSON *item=cJSON_New_Item();if(item)item->type=cJSON_True;return item;} cJSON *cJSON_CreateFalse(void) {cJSON *item=cJSON_New_Item();if(item)item->type=cJSON_False;return item;} cJSON *cJSON_CreateBool(int b) {cJSON *item=cJSON_New_Item();if(item)item->type=b?cJSON_True:cJSON_False;return item;} cJSON *cJSON_CreateNumber(double num) {cJSON *item=cJSON_New_Item();if(item){item->type=cJSON_Number;item->valuedouble=num;item->valueint=(int)num;}return item;} cJSON *cJSON_CreateString(const char *string) {cJSON *item=cJSON_New_Item();if(item){item->type=cJSON_String;item->valuestring=cJSON_strdup(string);}return item;} cJSON *cJSON_CreateArray(void) {cJSON *item=cJSON_New_Item();if(item)item->type=cJSON_Array;return item;} cJSON *cJSON_CreateObject(void) {cJSON *item=cJSON_New_Item();if(item)item->type=cJSON_Object;return item;} /* Create Arrays: */ cJSON *cJSON_CreateIntArray(const int *numbers,int count) {int i;cJSON *n=0,*p=0,*a=cJSON_CreateArray();for(i=0;a && i<count;i++){n=cJSON_CreateNumber(numbers[i]);if(!i)a->child=n;else suffix_object(p,n);p=n;}return a;} cJSON *cJSON_CreateFloatArray(const float *numbers,int count) {int i;cJSON *n=0,*p=0,*a=cJSON_CreateArray();for(i=0;a && i<count;i++){n=cJSON_CreateNumber(numbers[i]);if(!i)a->child=n;else suffix_object(p,n);p=n;}return a;} cJSON *cJSON_CreateDoubleArray(const double *numbers,int count) {int i;cJSON *n=0,*p=0,*a=cJSON_CreateArray();for(i=0;a && i<count;i++){n=cJSON_CreateNumber(numbers[i]);if(!i)a->child=n;else suffix_object(p,n);p=n;}return a;} cJSON *cJSON_CreateStringArray(const char **strings,int count) {int i;cJSON *n=0,*p=0,*a=cJSON_CreateArray();for(i=0;a && i<count;i++){n=cJSON_CreateString(strings[i]);if(!i)a->child=n;else suffix_object(p,n);p=n;}return a;} /* Duplication */ cJSON *cJSON_Duplicate(cJSON *item,int recurse) { cJSON *newitem,*cptr,*nptr=0,*newchild; /* Bail on bad ptr */ if (!item) return 0; /* Create new item */ newitem=cJSON_New_Item(); if (!newitem) return 0; /* Copy over all vars */ newitem->type=item->type&(~cJSON_IsReference),newitem->valueint=item->valueint,newitem->valuedouble=item->valuedouble; if (item->valuestring) {newitem->valuestring=cJSON_strdup(item->valuestring); if (!newitem->valuestring) {cJSON_Delete(newitem);return 0;}} if (item->string) {newitem->string=cJSON_strdup(item->string); if (!newitem->string) {cJSON_Delete(newitem);return 0;}} /* If non-recursive, then we're done! */ if (!recurse) return newitem; /* Walk the ->next chain for the child. */ cptr=item->child; while (cptr) { newchild=cJSON_Duplicate(cptr,1); /* Duplicate (with recurse) each item in the ->next chain */ if (!newchild) {cJSON_Delete(newitem);return 0;} if (nptr) {nptr->next=newchild,newchild->prev=nptr;nptr=newchild;} /* If newitem->child already set, then crosswire ->prev and ->next and move on */ else {newitem->child=newchild;nptr=newchild;} /* Set newitem->child and move to it */ cptr=cptr->next; } return newitem; } void cJSON_Minify(char *json) { char *into=json; while (*json) { if (*json==' ') json++; else if (*json=='\t') json++; /* Whitespace characters. */ else if (*json=='\r') json++; else if (*json=='\n') json++; else if (*json=='/' && json[1]=='/') while (*json && *json!='\n') json++; /* double-slash comments, to end of line. */ else if (*json=='/' && json[1]=='*') {while (*json && !(*json=='*' && json[1]=='/')) json++;json+=2;} /* multiline comments. */ else if (*json=='\"'){*into++=*json++;while (*json && *json!='\"'){if (*json=='\\') *into++=*json++;*into++=*json++;}*into++=*json++;} /* string literals, which are \" sensitive. */ else *into++=*json++; /* All other characters. */ } *into=0; /* and null-terminate. */ } #include <stdio.h> #include <stdlib.h> #include <string.h> #include <cJSON.h> // 引入 cJSON 头文件 #include "MQTTClient.h" #define ADDRESS "tcp://192.168.12.53:1883" #define CLIENTID "C_Subscriber" #define TOPIC "control/led" // 必须和 Qt 发送的主题一致！ #define QOS 1 #define TIMEOUT 10000L volatile MQTTClient_deliveryToken deliveredtoken; void delivered(void *context, MQTTClient_deliveryToken dt) { printf("Message with token %d confirmed\n", dt); deliveredtoken = dt; } void connlost(void *context, char *cause) { printf("Connection lost: %s\n", cause); } int msgarrvd(void *context, char *topicName, int topicLen, MQTTClient_message *message) { // 提取 payload char* payload = (char*)message->payload; int len = message->payloadlen; printf("【消息到达】\n"); printf(" 主题: %.*s\n", topicLen, topicName); printf(" 内容: %.*s\n", len, payload); // 将 payload 转为以 '\0' 结尾的字符串用于解析 JSON char* jsonStr = (char*)malloc(len + 1); if (!jsonStr) { printf("内存分配失败\n"); goto cleanup; } memcpy(jsonStr, payload, len); jsonStr[len] = '\0'; // 解析 JSON cJSON *root = cJSON_Parse(jsonStr); if (!root) { printf("JSON 解析失败: %s\n", cJSON_GetErrorPtr()); free(jsonStr); goto cleanup; } cJSON *device = cJSON_GetObjectItem(root, "device"); cJSON *status = cJSON_GetObjectItem(root, "status"); if (device && cJSON_IsString(device) && status && cJSON_IsString(status)) { if (strcmp(device->valuestring, "led") == 0) { if (strcmp(status->valuestring, "on") == 0) { printf("✅ 操作执行：LED 已开启\n"); } else if (strcmp(status->valuestring, "off") == 0) { printf("🛑 操作执行：LED 已关闭\n"); } else { printf("⚠️ 未知状态: %s\n", status->valuestring); } } else { printf("💡 设备不支持: %s\n", device->valuestring); } } else { printf("❌ JSON 缺少必要字段 (device/status)\n"); } cJSON_Delete(root); // 释放 cJSON 对象 free(jsonStr); cleanup: MQTTClient_freeMessage(&message); MQTTClient_free(topicName); return 1; } int main(int argc, char* argv[]) { MQTTClient client; MQTTClient_connectOptions conn_opts = MQTTClient_connectOptions_initializer; int rc; int ch; // 创建客户端（注意 persistence 设置为 NULL） MQTTClient_create(&client, ADDRESS, CLIENTID, MQTTCLIENT_PERSISTENCE_NONE, NULL); conn_opts.keepAliveInterval = 20; conn_opts.cleansession = 1; // 注册回调函数 MQTTClient_setCallbacks(client, NULL, connlost, msgarrvd, delivered); // 连接 Broker if ((rc = MQTTClient_connect(client, &conn_opts)) != MQTTCLIENT_SUCCESS) { printf("连接失败，返回码: %d\n", rc); exit(EXIT_FAILURE); } printf("正在订阅主题: %s\n", TOPIC); printf("等待来自 Qt 的 LED 控制指令...\n"); printf("按 Q + Enter 退出程序\n\n"); // 订阅主题 MQTTClient_subscribe(client, TOPIC, QOS); // 等待用户输入 Q 退出 do { ch = getchar(); } while(ch != 'Q' && ch != 'q'); // 清理资源 MQTTClient_unsubscribe(client, TOPIC); MQTTClient_disconnect(client, TIMEOUT); MQTTClient_destroy(&client); return rc; } 这样写对吗
最新发布
11-01
更糟的是：如果 `root == NULL`（解析失败），你还调用了 `cJSON_Delete(root)` —— 其实 cJSON 支持 `NULL` 输入（内部判断了），所以这不算错，但最好统一管理。 ✅ 推荐修改为： ```c cleanup: if (root) ...
链表-有序单链表的合并 时间限制：50MS 内存限制：256MB 分数： 0/100 描述 给定两个有序单链表，带空的头节点，要求合并两个链表为一个新链表，新链表也要带空的头节点。例如： 链表1：1->3->5->7->^ 链表2：2->4->6->8->^ 结果：1->2->3->4->5->6->7->8->^ 两个链表都是有序的，不要移除其中的重复元素。例如： 链表1：1->2->3->^ 链表2：1->2->3->^ 结果：1->1->2->2->3->3->^ 你应该输出新链表，同时保证三个链表都可以被销毁。 输入 入参为两个链表的头节点指针。 输出 输出为结果链表的头节点指针。 输入样例 1 list1: 1->3->5->7->^ list2: 2->4->6->8->^ 输出样例 1 1->2->3->4->5->6->7->8->^ 输入样例 2 list1: 1->2->3->^ list2: 1->2->3->^ 输出样例 2 1->1->2->2->3->3->^ 在以下模板上做修改 //typedef struct __NODE { // int value; // struct __NODE* next; //} NODE; NODE* list_merge(NODE* list1, NODE* list2){ return NULL; }
10-18
- Both input lists have a dummy head node (which means the actual data starts from list->next). - We are to merge them into a new sorted linked list (with a dummy head node as well). - We do not ...
STM32 解析 JSON 之 cJSON
太阳火神的美丽人生
03-03 1557
什么是 JSON ？ 可以参考此网站链接：JSONhttp://www.json.org/json-en.html 此网站首页最下方是各种语言的实现库： cJSON 的 GitHub 地址：DaveGamble/cJSON: Ultralightweight JSON parser in ANSI C (github.com)https://github.com/DaveGamble/cJSON 只下载 cJSON.h 和 cJSON.c 两个文件即可： ...
输出1到100中的偶数，一行5个
weizhongdai的专栏
11-06 3258
 #include using namespace std;int main(){ for (int i=1; i != 101; i++) { if (!(i%2)) cout << i << " "; if (!(i%10)) cout << endl; } system("PAUSE"); return
写一个函数，将其中的/t都转换成4个空格。
weizhongdai的专栏
11-06 2468
 string replaceTab(const string& strSrc){//strSrc 源字符串， 将源字符串中的/t转换为4个空格 string strDes; for (int i=0; i!=strSrc.size(); i++) { if (strSrc[i] == /t) //转换成4个空格 { strDes
有一段文本，统计其中的单词数
weizhongdai的专栏
11-07 1834
 #include #include int main(){ int c; int flag = 0; // flag=0 表示当前位于单词间。 int count = 0; while ((c = getchar()) != EOF) { if (isalpha(c)) { if (flag == 0) // 进入单
输入一个整数, 用a-z表示, 相当于从10进制转换到26进制 比如27->aa, 28->ab.
weizhongdai的专栏
11-06 1708
 #include #include #include using namespace std;int main(int argc, char *argv[]){ string az("zabcdefghijklmnopqrstuvwxy"); string dest; int i; cin >> i; do {
实现对数组的降序排序
weizhongdai的专栏
11-07 1505
 #include #define N 9int array[N] = {45, 56, 76, 234, 1, 34, 23, 2, 3}; //数字任意给出void sort();int main(){ int m; sort(); for (m=0; m<N; m++) printf("%d ", array[m]); system("P
设计函数 int atoi(char *s)。
weizhongdai的专栏
11-07 1200
 /*设计函数 int atoi(char *s)函数说明atoi() 会扫描参数s字符串，跳过前面的空格字符，直到遇上数字或正负符号才开始转换，而再遇到非数字或字符串结束时(/0)才结束转换，并将结果返回。返回值：返回转换后的整型数相关函数 isspace，isdigit 表头文件 #include */int atoi(char *s){ int
For a linked queue without head node,what should we do in dequeue operation.
06-08
In a linked queue without head node, when performing dequeue operation, we need to consider two cases: 1. If the queue is empty, we cannot perform dequeue operation. So we need to check if the queue is empty before dequeueing. 2. If the queue is not empty, we can remove the first element from the queue. We need to update the front pointer of the queue to point to the next element in the queue. We also need to free the memory occupied by the node that was removed from the queue. Here is the sample code for dequeuing an element from a linked queue without head node in C++: ``` int dequeue(Node* &front, Node* &rear) { if (front == NULL) { cout << "Queue is empty"; return -1; } int data = front->data; Node* temp = front; front = front->next; if (front == NULL) { rear = NULL; } delete temp; return data; } ``` In this code, `front` and `rear` are pointers to the first and last nodes of the queue respectively. The `dequeue()` function removes the first node from the front of the queue and returns its data value. If the queue is empty, the function displays a message and returns -1.
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