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Clean up documentation and correct sample code

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This commit is contained in:
Keith Derrick
2012-04-23 15:34:44 -07:00
parent 178a4b059c
commit ded667a612
2 changed files with 83 additions and 97 deletions
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32
json_object_iterator.c
View File

@@ -1,17 +1,17 @@
/**
/**
*******************************************************************************
* @file cjson_object_iterator.c
*
* Copyright (c) 2009 Hewlett-Packard Development Company, L.P.
* @file json_object_iterator.c
*
* Copyright (c) 2009-2012 Hewlett-Packard Development Company, L.P.
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the MIT license. See COPYING for details.
*
* @brief cjson forces clients to use its private data
* @brief json-c forces clients to use its private data
* structures for JSON Object iteration. This API
* implementation corrects that by abstracting the
* private cjson details.
*
* private json-c details.
*
*******************************************************************************
*/
@@ -25,30 +25,30 @@
/**
* How It Works
*
* For each JSON Object, cjson maintains a linked list of zero
*
* For each JSON Object, json-c maintains a linked list of zero
* or more lh_entry (link-hash entry) structures inside the
* Object's link-hash table (lh_table).
*
*
* Each lh_entry structure on the JSON Object's linked list
* represents a single name/value pair. The "next" field of the
* last lh_entry in the list is set to NULL, which terminates
* the list.
*
*
* We represent a valid iterator that refers to an actual
* name/value pair via a pointer to the pair's lh_entry
* structure set as the iterator's opaque_ field.
*
* We follow cjson's current pair list representation by
*
* We follow json-c's current pair list representation by
* representing a valid "end" iterator (one that refers past the
* last pair) with a NULL value in the iterator's opaque_ field.
*
*
* A JSON Object without any pairs in it will have the "head"
* field of its lh_table structure set to NULL. For such an
* object, json_object_iter_begin will return an iterator with
* the opaque_ field set to NULL, which is equivalent to the
* "end" iterator.
*
*
* When iterating, we simply update the iterator's opaque_ field
* to point to the next lh_entry structure in the linked list.
* opaque_ will become NULL once we iterate past the last pair
@@ -57,7 +57,7 @@
*/
/// Our current representation of the "end" iterator;
///
///
/// @note May not always be NULL
static const void* kObjectEndIterValue = NULL;

148
json_object_iterator.h
View File

@@ -1,26 +1,21 @@
/**
/**
*******************************************************************************
* @file json_object_iterator.h
*
* Copyright (c) 2009 Hewlett-Packard Development Company, L.P.
*
* Copyright (c) 2009-2012 Hewlett-Packard Development Company, L.P.
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the MIT license. See COPYING for details.
*
* @brief cjson forces clients to use its private data
*
* @brief json-c forces clients to use its private data
* structures for JSON Object iteration. This API
* corrects that by abstracting the private cjson
* corrects that by abstracting the private json-c
* details.
*
* The intention is to add this API (and its
* implementation) to Palm's version of the cjson
* library, at which point it can be removed from the
* Wireless System Framework library implementation.
*
* API attributes:
* * Thread-safe: NO
* * Re-entrant: NO
*
*
* API attributes: <br>
* * Thread-safe: NO<br>
* * Reentrant: NO
*
*******************************************************************************
*/
@@ -31,7 +26,7 @@
#include <stddef.h>
#include <stdbool.h>
#ifdef __cplusplus
#ifdef __cplusplus
extern "C" {
#endif
@@ -42,7 +37,7 @@ struct json_object_iter_info_;
/**
* The opaque iterator that references a name/value pair within
* a JSON Object intance or the "end" iterator value.
* a JSON Object instance or the "end" iterator value.
*/
struct json_object_iterator {
const void* opaque_;
@@ -50,7 +45,7 @@ struct json_object_iterator {
/**
* forward declaration of cjson's JSON value instance structure
* forward declaration of json-c's JSON value instance structure
*/
struct json_object;
@@ -60,33 +55,32 @@ struct json_object;
* is convenient for initializing an iterator variable to a
* default state (e.g., initialization list in a class'
* constructor).
*
* @code
*
* @code
* struct json_object_iterator iter = json_object_iter_init_default();
* MyClass() : iter_(json_object_iter_init_default())
* @endcode
*
*
* @note The initialized value doesn't reference any specific
* pair, is considered an invalid iterator, and MUST NOT
* be passed to any cjson API that expects a valid
* be passed to any json-c API that expects a valid
* iterator.
*
*
* @note User and internal code MUST NOT make any assumptions
* about and dependencies on the value of the "default"
* iterator value.
*
*
* @return json_object_iterator
*/
struct json_object_iterator
json_object_iter_init_default(void);
/** Retrieves an iterator to the first pair of the JSON Object.
*
* @note WARNING: Any modification of the underlying pair
* invalidates all iterators to that pair.
*
* @param obj JSON Object instance (MUST be of type
* json_type_object)
*
* @warning Any modification of the underlying pair invalidates all
* iterators to that pair.
*
* @param obj JSON Object instance (MUST be of type json_object)
*
* @return json_object_iterator If the JSON Object has at
* least one pair, on return, the iterator refers
@@ -94,29 +88,22 @@ json_object_iter_init_default(void);
* have any pairs, the returned iterator is
* equivalent to the "end" iterator for the same
* JSON Object instance.
*
* @code
*
* @code
* struct json_object_iterator it;
* struct json_object_iterator itEnd;
* struct json_object* obj = json_tokener_parse(
* "{'first':'george', 'age':100}");
* json_object_iter_begin(obj, &it);
* json_object_iter_end(obj, &itEnd);
* struct json_object* obj;
*
* obj = json_tokener_parse("{'first':'george', 'age':100}");
* it = json_object_iter_begin(obj);
* itEnd = json_object_iter_end(obj);
*
* while (!json_object_iter_equal(&it, &itEnd)) {
* printf("%s\n",
* json_object_iter_peek_name(&it));
* json_object_iter_next(&it);
* }
*
* struct json_object* obj = json_tokener_parse(
* "{'first':'george', 'age':100}");
* struct json_object_iterator it;
* bool iterable = json_object_iter_begin(&it);
* if (iterable) {
* do {
* printf("%s\n", json_object_iter_peek_name(&it));
* } while (json_object_iter_next(&it));
* }
* @endcode
*/
struct json_object_iterator
@@ -124,11 +111,11 @@ json_object_iter_begin(struct json_object* obj);
/** Retrieves the iterator that represents the position beyond the
* last pair of the given JSON Object instance.
*
* @note WARNING: Do NOT write code that assumes that the "end"
*
* @warning Do NOT write code that assumes that the "end"
* iterator value is NULL, even if it is so in a
* particular instance of the implementation.
*
*
* @note The reason we do not (and MUST NOT) provide
* "json_object_iter_is_end(json_object_iterator* iter)"
* type of API is because it would limit the underlying
@@ -140,11 +127,10 @@ json_object_iter_begin(struct json_object* obj);
* representation without burdening the iterator
* structure with unnecessary data.
*
* @note For performance reasons, memoize the "end" iterator prior
* @note For performance reasons, memorize the "end" iterator prior
* to any loop.
*
* @param obj JSON Object instance (MUST be of type
* json_type_object)
*
* @param obj JSON Object instance (MUST be of type json_object)
*
* @return json_object_iterator On return, the iterator refers
* to the "end" of the Object instance's pairs
@@ -155,12 +141,10 @@ struct json_object_iterator
json_object_iter_end(const struct json_object* obj);
/** Returns an iterator to the next pair, if any
*
* @note WARNING: Any modification of the underlying pair
* invalidates all iterators to that pair.
*
* @param iter Iterator that references a name/value pair;
*
*
* @warning Any modification of the underlying pair
* invalidates all iterators to that pair.
*
* @param iter [IN/OUT] Pointer to iterator that references a
* name/value pair; MUST be a valid, non-end iterator.
* WARNING: bad things will happen if invalid or "end"
@@ -177,13 +161,14 @@ json_object_iter_next(struct json_object_iterator* iter);
/** Returns a const pointer to the name of the pair referenced
* by the given iterator.
*
*
* @param iter pointer to iterator that references a name/value
* pair; MUST be a valid, non-end iterator.
* WARNING: bad things will happen if invalid or
* "end" iterator is passed.
*
* @return const char* Pointer to the name of the rerferenced
*
* @warning bad things will happen if an invalid or
* "end" iterator is passed.
*
* @return const char* Pointer to the name of the referenced
* name/value pair. The name memory belongs to the
* name/value pair, will be freed when the pair is
* deleted or modified, and MUST NOT be modified or
@@ -193,21 +178,22 @@ const char*
json_object_iter_peek_name(const struct json_object_iterator* iter);
/** Returns a pointer to the cjson instance representing the
/** Returns a pointer to the json-c instance representing the
* value of the referenced name/value pair, without altering
* the instance's reference count.
*
* @param iter pointer to iterator that references a name/value
* pair; MUST be a valid, non-end iterator.
* WARNING: bad things will happen if invalid or
*
* @param iter pointer to iterator that references a name/value
* pair; MUST be a valid, non-end iterator.
*
* @warning bad things will happen if invalid or
* "end" iterator is passed.
*
* @return struct json_object* Pointer to the cjson value
*
* @return struct json_object* Pointer to the json-c value
* instance of the referenced name/value pair; the
* value's reference count is not changed by this
* function: if you plan to hold on to this cjson node,
* function: if you plan to hold on to this json-c node,
* take a look at json_object_get() and
* json_object_put(). IMPORTANT: cjson API represents
* json_object_put(). IMPORTANT: json-c API represents
* the JSON Null value as a NULL json_object instance
* pointer.
*/
@@ -219,7 +205,7 @@ json_object_iter_peek_value(const struct json_object_iterator* iter);
* for end of iteration by comparing an iterator to the
* corresponding "end" iterator (that was derived from the same
* JSON Object instance).
*
*
* @note The reason we do not (and MUST NOT) provide
* "json_object_iter_is_end(json_object_iterator* iter)"
* type of API is because it would limit the underlying
@@ -228,15 +214,15 @@ json_object_iter_peek_value(const struct json_object_iterator* iter);
* the iterator structure). The equality test method, on
* the other hand, permits us to cleanly abstract pretty
* much any reasonable underlying representation.
*
*
* @param iter1 Pointer to first valid, non-NULL iterator
* @param iter2 POinter to second valid, non-NULL iterator
*
* @note WARNING: if a NULL iterator pointer or an uninitialized
* or invalid iterator, or iterators derived from
* different JSON Object instances are passed, bad things
* will happen!
*
*
* @warning if a NULL iterator pointer or an uninitialized
* or invalid iterator, or iterators derived from
* different JSON Object instances are passed, bad things
* will happen!
*
* @return bool non-zero if iterators are equal (i.e., both
* reference the same name/value pair or are both at
* "end"); zero if they are not equal.