rapidjson::GenericPointer< ValueType, Allocator > 模板类 参考

Represents a JSON Pointer. Use Pointer for UTF8 encoding and default allocator. 更多...

`#include <pointer.h>`

## 类

struct | Token
| A token is the basic units of internal representation. 更多...

## Public 类型

typedef ValueType::EncodingType | EncodingType
| Encoding type from Value
typedef ValueType::Ch | Ch
| Character type from Value

## Public 成员函数

Constructors and destructor.
| GenericPointer (Allocator *allocator=0)
| Default constructor.
| GenericPointer (const Ch *source, Allocator *allocator=0)
| Constructor that parses a string or URI fragment representation. 更多...
| GenericPointer (const std::basic_string< Ch > &source, Allocator *allocator=0)
| Constructor that parses a string or URI fragment representation. 更多...
| GenericPointer (const Ch *source, size_t length, Allocator *allocator=0)
| Constructor that parses a string or URI fragment representation, with length of the source string. 更多...
| GenericPointer (const Token *tokens, size_t tokenCount)
| Constructor with user-supplied tokens. 更多...
| GenericPointer (const GenericPointer &rhs, Allocator *allocator=0)
| Copy constructor.
| ~GenericPointer ()
| Destructor.
GenericPointer & | operator= (const GenericPointer &rhs)
| Assignment operator.

## Append token

Allocator * | allocator
Allocator stackAllocator stackAllocator & | document
Allocator stackAllocator stackAllocator T const | defaultValue
GenericPointer | Append (const Token &token, Allocator *allocator=0) const
| Append a token and return a new Pointer 更多...
GenericPointer | Append (const Ch *name, SizeType length, Allocator *allocator=0) const
| Append a name token with length, and return a new Pointer 更多...
template<typename T >
| RAPIDJSON_DISABLEIF_RETURN ((internal::NotExpr< internal::IsSame< typename internal::RemoveConst< T >::Type, Ch > >),(GenericPointer)) Append(T *name
| Append a name token without length, and return a new Pointer 更多...
Allocator stackAllocator | RAPIDJSON_DISABLEIF_RETURN ((internal::OrExpr< internal::IsPointer< T >, internal::IsGenericValue< T > >),(ValueType &)) GetWithDefault(GenericDocument< EncodingType

## Set a value

T | value
T ValueType::AllocatorType &const | allocator
stackAllocator & | document
stackAllocator T const | value
ValueType & | Set (ValueType &root, ValueType &value, typename ValueType::AllocatorType &allocator) const
| Set a value in a subtree, with move semantics. 更多...
ValueType & | Set (ValueType &root, const ValueType &value, typename ValueType::AllocatorType &allocator) const
| Set a value in a subtree, with copy semantics.
ValueType & | Set (ValueType &root, const Ch *value, typename ValueType::AllocatorType &allocator) const
| Set a null-terminated string in a subtree.
ValueType & | Set (ValueType &root, const std::basic_string< Ch > &value, typename ValueType::AllocatorType &allocator) const
| Set a std::basic_string in a subtree.
template<typename T >
| RAPIDJSON_DISABLEIF_RETURN ((internal::OrExpr< internal::IsPointer< T >, internal::IsGenericValue< T > >),(ValueType &)) Set(ValueType &root
| Set a primitive value in a subtree. 更多...
template<typename stackAllocator >
ValueType & | Set (GenericDocument< EncodingType, typename ValueType::AllocatorType, stackAllocator > &document, ValueType &value) const
| Set a value in a document, with move semantics.
template<typename stackAllocator >
ValueType & | Set (GenericDocument< EncodingType, typename ValueType::AllocatorType, stackAllocator > &document, const ValueType &value) const
| Set a value in a document, with copy semantics.
template<typename stackAllocator >
ValueType & | Set (GenericDocument< EncodingType, typename ValueType::AllocatorType, stackAllocator > &document, const Ch *value) const
| Set a null-terminated string in a document.
template<typename stackAllocator >
ValueType & | Set (GenericDocument< EncodingType, typename ValueType::AllocatorType, stackAllocator > &document, const std::basic_string< Ch > &value) const
| Sets a std::basic_string in a document.
template<typename T , typename stackAllocator >
| RAPIDJSON_DISABLEIF_RETURN ((internal::OrExpr< internal::IsPointer< T >, internal::IsGenericValue< T > >),(ValueType &)) Set(GenericDocument< EncodingType
| Set a primitive value in a document. 更多...

## Swap a value

ValueType & | Swap (ValueType &root, ValueType &value, typename ValueType::AllocatorType &allocator) const
| Swap a value with a value in a subtree. 更多...
template<typename stackAllocator >
ValueType & | Swap (GenericDocument< EncodingType, typename ValueType::AllocatorType, stackAllocator > &document, ValueType &value) const
| Swap a value with a value in a document.
bool | Erase (ValueType &root) const
| Erase a value in a subtree. 更多...

## 详细描述

### template<typename ValueType, typename Allocator = CrtAllocator>
class rapidjson::GenericPointer< ValueType, Allocator >

Represents a JSON Pointer. Use Pointer for UTF8 encoding and default allocator.

This class implements RFC 6901 "JavaScript Object Notation (JSON) Pointer" (https://tools.ietf.org/html/rfc6901).

A JSON pointer is for identifying a specific value in a JSON document (GenericDocument). It can simplify coding of DOM tree manipulation, because it can access multiple-level depth of DOM tree with single API call.

After it parses a string representation (e.g. "/foo/0" or URI fragment representation (e.g. "#/foo/0") into its internal representation (tokens), it can be used to resolve a specific value in multiple documents, or sub-tree of documents.

Contrary to GenericValue, Pointer can be copy constructed and copy assigned. Apart from assignment, a Pointer cannot be modified after construction.

Although Pointer is very convenient, please aware that constructing Pointer involves parsing and dynamic memory allocation. A special constructor with user- supplied tokens eliminates these.

GenericPointer depends on GenericDocument and GenericValue.

模板参数

  ValueType | The value type of the DOM tree. E.g. GenericValue<UTF8<> >
  Allocator | The allocator type for allocating memory for internal representation.

注解
  GenericPointer uses same encoding of ValueType. However, Allocator of GenericPointer is independent of Allocator of Value.

## 构造及析构函数说明

## GenericPointer() [1/4]

template<typename ValueType , typename Allocator = CrtAllocator>

rapidjson::GenericPointer< ValueType, Allocator >::GenericPointer | ( | const Ch * | source,
|  | Allocator * | allocator = `0`
| ) |  |

inline explicit

Constructor that parses a string or URI fragment representation.

参数

  source | A null-terminated, string or URI fragment representation of JSON pointer.
  allocator | User supplied allocator for this pointer. If no allocator is provided, it creates a self-owned one.

## GenericPointer() [2/4]

template<typename ValueType , typename Allocator = CrtAllocator>

rapidjson::GenericPointer< ValueType, Allocator >::GenericPointer | ( | const std::basic_string< Ch > & | source,
|  | Allocator * | allocator = `0`
| ) |  |

inline explicit

Constructor that parses a string or URI fragment representation.

参数

  source | A string or URI fragment representation of JSON pointer.
  allocator | User supplied allocator for this pointer. If no allocator is provided, it creates a self-owned one.

注解
  Requires the definition of the preprocessor symbol RAPIDJSON_HAS_STDSTRING.

## GenericPointer() [3/4]

template<typename ValueType , typename Allocator = CrtAllocator>

rapidjson::GenericPointer< ValueType, Allocator >::GenericPointer | ( | const Ch * | source,
|  | size_t | length,
|  | Allocator * | allocator = `0`
| ) |  |

inline

Constructor that parses a string or URI fragment representation, with length of the source string.

参数

  source | A string or URI fragment representation of JSON pointer.
  length | Length of source.
  allocator | User supplied allocator for this pointer. If no allocator is provided, it creates a self-owned one.

注解
  Slightly faster than the overload without length.

## GenericPointer() [4/4]

template<typename ValueType , typename Allocator = CrtAllocator>

rapidjson::GenericPointer< ValueType, Allocator >::GenericPointer | ( | const Token * | tokens,
|  | size_t | tokenCount
| ) |  |

inline

Constructor with user-supplied tokens.

This constructor let user supplies const array of tokens. This prevents the parsing process and eliminates allocation. This is preferred for memory constrained environments.

参数

  tokens | An constant array of tokens representing the JSON pointer.
  tokenCount | Number of tokens.

Example

#define NAME(s) { s, sizeof(s) / sizeof(s[0]) - 1, kPointerInvalidIndex }
#define INDEX(i) { #i, sizeof(#i) - 1, i }
static const Pointer::Token kTokens[] = { NAME("foo"), INDEX(123) };
static const Pointer p(kTokens, sizeof(kTokens) / sizeof(kTokens[0]));
// Equivalent to static const Pointer p("/foo/123");
#undef NAME
#undef INDEX

## 成员函数说明

## Append() [1/2]

template<typename ValueType , typename Allocator = CrtAllocator>

GenericPointer rapidjson::GenericPointer< ValueType, Allocator >::Append | ( | const Ch * | name,
|  | SizeType | length,
|  | Allocator * | allocator = `0`
| ) |  | const

inline

Append a name token with length, and return a new Pointer

参数

  name | Name to be appended.
  length | Length of name.
  allocator | Allocator for the newly return Pointer.

返回
  A new Pointer with appended token.

## Append() [2/2]

template<typename ValueType , typename Allocator = CrtAllocator>

GenericPointer rapidjson::GenericPointer< ValueType, Allocator >::Append | ( | const Token & | token,
|  | Allocator * | allocator = `0`
| ) |  | const

inline

Append a token and return a new Pointer

参数

  token | Token to be appended.
  allocator | Allocator for the newly return Pointer.

返回
  A new Pointer with appended token.

## Erase()

template<typename ValueType , typename Allocator = CrtAllocator>

bool rapidjson::GenericPointer< ValueType, Allocator >::Erase | ( | ValueType & | root | ) | const

inline

Erase a value in a subtree.

参数

  root | Root value of a DOM sub-tree to be resolved. It can be any value other than document root.

返回
  Whether the resolved value is found and erased.

注解
  Erasing with an empty pointer `Pointer`(""), i.e. the root, always fail and return false.

## RAPIDJSON_DISABLEIF_RETURN() [1/3]

template<typename ValueType , typename Allocator = CrtAllocator>
template<typename T >

rapidjson::GenericPointer< ValueType, Allocator >::RAPIDJSON_DISABLEIF_RETURN | ( | (internal::NotExpr< internal::IsSame< typename internal::RemoveConst< T >::Type, Ch > >) | ,
|  | (GenericPointer< ValueType, Allocator >) |
| ) |  |

Append a name token without length, and return a new Pointer

参数

  name | Name (const Ch*) to be appended.
  allocator | Allocator for the newly return Pointer.

返回
  A new Pointer with appended token.

## RAPIDJSON_DISABLEIF_RETURN() [2/3]

template<typename ValueType , typename Allocator = CrtAllocator>
template<typename T , typename stackAllocator >

rapidjson::GenericPointer< ValueType, Allocator >::RAPIDJSON_DISABLEIF_RETURN | ( | (internal::OrExpr< internal::IsPointer< T >, internal::IsGenericValue< T > >) | ,
|  | (ValueType &) |
| ) |  |

Set a primitive value in a document.

模板参数

  T | Either Type, `int`, `unsigned`, `int64_t`, `uint64_t`, `bool`

## RAPIDJSON_DISABLEIF_RETURN() [3/3]

template<typename ValueType , typename Allocator = CrtAllocator>
template<typename T >

rapidjson::GenericPointer< ValueType, Allocator >::RAPIDJSON_DISABLEIF_RETURN | ( | (internal::OrExpr< internal::IsPointer< T >, internal::IsGenericValue< T > >) | ,
|  | (ValueType &) |
| ) |  | &

Set a primitive value in a subtree.

模板参数

  T | Either Type, `int`, `unsigned`, `int64_t`, `uint64_t`, `bool`

## Set()

template<typename ValueType , typename Allocator = CrtAllocator>

ValueType& rapidjson::GenericPointer< ValueType, Allocator >::Set | ( | ValueType & | root,
|  | ValueType & | value,
|  | typename ValueType::AllocatorType & | allocator
| ) |  | const

inline

Set a value in a subtree, with move semantics.

It creates all parents if they are not exist or types are different to the tokens. So this function always succeeds but potentially remove existing values.

参数

  root | Root value of a DOM sub-tree to be resolved. It can be any value other than document root.
  value | Value to be set.
  allocator | Allocator for creating the values if the specified value or its parents are not exist.

参见
  Create()

## Swap()

template<typename ValueType , typename Allocator = CrtAllocator>

ValueType& rapidjson::GenericPointer< ValueType, Allocator >::Swap | ( | ValueType & | root,
|  | ValueType & | value,
|  | typename ValueType::AllocatorType & | allocator
| ) |  | const

inline

Swap a value with a value in a subtree.

It creates all parents if they are not exist or types are different to the tokens. So this function always succeeds but potentially remove existing values.

参数

  root | Root value of a DOM sub-tree to be resolved. It can be any value other than document root.
  value | Value to be swapped.
  allocator | Allocator for creating the values if the specified value or its parents are not exist.

参见
  Create()

## 类成员变量说明

## allocator

template<typename ValueType , typename Allocator = CrtAllocator>

T ValueType::AllocatorType& const rapidjson::GenericPointer< ValueType, Allocator >::allocator

初始值:
{
return Create(root, allocator) = ValueType(value).Move()

## defaultValue

template<typename ValueType , typename Allocator = CrtAllocator>

Allocator stackAllocator stackAllocator T const rapidjson::GenericPointer< ValueType, Allocator >::defaultValue

初始值:
{
return GetWithDefault(document, defaultValue, document.GetAllocator())

## value

template<typename ValueType , typename Allocator = CrtAllocator>

stackAllocator T const rapidjson::GenericPointer< ValueType, Allocator >::value

初始值:
{
return Create(document) = value

该类的文档由以下文件生成:

- include/rapidjson/fwd.h
- include/rapidjson/pointer.h

rapidjson::Pointer
GenericPointer< Value, CrtAllocator > Pointer
GenericPointer for Value (UTF-8, default allocator).
Definition: fwd.h:126