From 30b6a77f86a35dab16b3bf9b815e089657fc6890 Mon Sep 17 00:00:00 2001 From: Michał Cichoń Date: Tue, 1 May 2012 16:05:17 +0200 Subject: Update build environment to comply with latest pianobar requirements. Replace gcrypt with blowfist library - this will allow us to keep pianobar.exe portable. --- json-c/src/json_object_iterator.c | 168 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 168 insertions(+) create mode 100644 json-c/src/json_object_iterator.c (limited to 'json-c/src/json_object_iterator.c') diff --git a/json-c/src/json_object_iterator.c b/json-c/src/json_object_iterator.c new file mode 100644 index 0000000..7066649 --- /dev/null +++ b/json-c/src/json_object_iterator.c @@ -0,0 +1,168 @@ +/** +******************************************************************************* +* @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 json-c forces clients to use its private data +* structures for JSON Object iteration. This API +* implementation corrects that by abstracting the +* private json-c details. +* +******************************************************************************* +*/ + +#include + +#include "json.h" +#include "json_object_private.h" + +#include "json_object_iterator.h" + +/** + * How It Works + * + * 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 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 + * in the list, which makes the iterator equivalent to the "end" + * iterator. + */ + +/// Our current representation of the "end" iterator; +/// +/// @note May not always be NULL +static const void* kObjectEndIterValue = NULL; + +/** + * **************************************************************************** + */ +struct json_object_iterator +json_object_iter_begin(struct json_object* obj) +{ + struct json_object_iterator iter; + struct lh_table* pTable; + + /// @note json_object_get_object will return NULL if passed NULL + /// or a non-json_type_object instance + pTable = json_object_get_object(obj); + JASSERT(NULL != pTable); + + /// @note For a pair-less Object, head is NULL, which matches our + /// definition of the "end" iterator + iter.opaque_ = pTable->head; + return iter; +} + +/** + * **************************************************************************** + */ +struct json_object_iterator +json_object_iter_end(const struct json_object* obj) +{ + struct json_object_iterator iter; + + JASSERT(NULL != obj); + JASSERT(json_object_is_type(obj, json_type_object)); + + iter.opaque_ = kObjectEndIterValue; + + return iter; +} + +/** + * **************************************************************************** + */ +void +json_object_iter_next(struct json_object_iterator* iter) +{ + JASSERT(NULL != iter); + JASSERT(kObjectEndIterValue != iter->opaque_); + + iter->opaque_ = ((struct lh_entry *)iter->opaque_)->next; +} + + +/** + * **************************************************************************** + */ +const char* +json_object_iter_peek_name(const struct json_object_iterator* iter) +{ + JASSERT(NULL != iter); + JASSERT(kObjectEndIterValue != iter->opaque_); + + return (const char*)(((struct lh_entry *)iter->opaque_)->k); +} + + +/** + * **************************************************************************** + */ +struct json_object* +json_object_iter_peek_value(const struct json_object_iterator* iter) +{ + JASSERT(NULL != iter); + JASSERT(kObjectEndIterValue != iter->opaque_); + + return (struct json_object*)(((struct lh_entry *)iter->opaque_)->v); +} + + +/** + * **************************************************************************** + */ +json_bool +json_object_iter_equal(const struct json_object_iterator* iter1, + const struct json_object_iterator* iter2) +{ + JASSERT(NULL != iter1); + JASSERT(NULL != iter2); + + return (iter1->opaque_ == iter2->opaque_); +} + + +/** + * **************************************************************************** + */ +struct json_object_iterator +json_object_iter_init_default(void) +{ + struct json_object_iterator iter; + + /** + * @note Make this a negative, invalid value, such that + * accidental access to it would likely be trapped by the + * hardware as an invalid address. + */ + iter.opaque_ = NULL; + + return iter; +} -- cgit v1.2.3