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FCbWriter

A writer for compact binary object, arrays, and fields.

Unreal Engine C++ API Reference > Runtime > Core > Serialization

Inheritance Hierarchy

References

   
Module Core
Header /Engine/Source/Runtime/Core/Public/Serialization/CompactBinaryWriter.h
Include #include "Serialization/CompactBinaryWriter.h"

Syntax

class FCbWriter

Remarks

A writer for compact binary object, arrays, and fields.

The writer produces a sequence of fields that can be saved to a provided memory buffer or into a new owned buffer. The typical use case is to write a single object, which can be accessed by calling Save().AsObject() or Save(Buffer).AsObjectView().

The writer will assert on most incorrect usage and will always produce valid compact binary if provided with valid input. The writer does not check for invalid UTF-8 string encoding, object fields with duplicate names, or invalid compact binary being copied from another source.

It is most convenient to use the streaming API for the writer, as demonstrated in the example.

When writing a small amount of compact binary data, TCbWriter can be more efficient as it uses a fixed-size stack buffer for storage before spilling onto the heap.

Example:

FCbObject WriteObject() { TCbWriter<256> Writer; Writer.BeginObject();

Writer << "Resize" << true; Writer << "MaxWidth" << 1024; Writer << "MaxHeight" << 1024;

Writer.BeginArray(); Writer << "FormatA" << "FormatB" << "FormatC"; Writer.EndArray();

Writer.EndObject(); return Writer.Save().AsObject(); }

Constructors

  Type Name Description
Public function    
Public function  

FCbWriter ( const FCbWriter&
)

  
Protected function  

FCbWriter ( int64 InitialSize
)

 Private flags that are public to work with ENUM_CLASS_FLAGS.

Destructors

  Type Name Description
Public function    

Functions

  Type Name Description
Public function void

AddArray ( FUtf8StringView Name,
const FCbArray& Value
)

 Copy the value (not the name) of an existing array. Holds a reference if owned.
Public function void

AddArray ( FUtf8StringView Name,
const FCbArrayView& Value
)

 Copy the value (not the name) of an existing array.
Public function void

AddArray ( const FCbArrayView& Value
)

  
Public function void

AddArray ( const FCbArray& Value
)

  
Public function void

AddAttachment ( const FCbAttachment& Attachment
)

  
Public function void

AddAttachment ( FUtf8StringView Name,
const FCbAttachment& Attachment
)

 Write a field referencing the attachment by its hash.
Public function void

AddBinary ( FUtf8StringView Name,
const FCompositeBuffer& Value
)

  
Public function void

AddBinary ( FUtf8StringView Name,
const FSharedBuffer& Value
)

 Write a binary field by copying the buffer. Holds a reference if owned.
Public function void

AddBinary ( const void* Value,
uint64 Size
)

  
Public function void

AddBinary ( FMemoryView Value
)

  
Public function void

AddBinary ( const FSharedBuffer& Value
)

  
Public function void

AddBinary ( const FCompositeBuffer& Value
)

 Write a binary field by copying Size bytes from Value.
Public function void

AddBinary ( FUtf8StringView Name,
const void* Value,
uint64 Size
)

 Write a binary field by copying Size bytes from Value.
Public function void

AddBinary ( FUtf8StringView Name,
FMemoryView Value
)

 Write a binary field by copying the view.
Public function void

AddBinaryAttachment ( const FIoHash& Value
)

  
Public function void

AddBinaryAttachment ( FUtf8StringView Name,
const FIoHash& Value
)

 Write a field referencing a binary attachment by its hash.
Public function void

AddBool ( bool bValue
)

  
Public function void

AddBool ( FUtf8StringView Name,
bool bValue
)

 Write a bool field.
Public function void

AddCustom ( uint64 TypeId,
FMemoryView Value
)

  
Public function void

AddCustom ( FUtf8StringView TypeName,
FMemoryView Value
)

  
Public function void

AddCustom ( FUtf8StringView FieldName,
uint64 TypeId,
FMemoryView Value
)

 Write a custom field with an integer sub-type identifier.
Public function void

AddCustom ( FUtf8StringView FieldName,
FUtf8StringView TypeName,
FMemoryView Value
)

 Write a custom field with a string sub-type identifier.
Public function void

AddDateTime ( FUtf8StringView Name,
FDateTime Value
)

 Write a date/time field.
Public function void Write a date/time field.
Public function void

AddDateTimeTicks ( FUtf8StringView Name,
int64 Ticks
)

 Write a date/time field with the specified count of 100ns ticks since the epoch.
Public function void

AddDateTimeTicks ( int64 Ticks
)

  
Public function void

AddField ( FUtf8StringView Name,
const FCbField& Value
)

 Copy the value (not the name) of an existing field. Holds a reference if owned.
Public function void

AddField ( FUtf8StringView Name,
const FCbFieldView& Value
)

 Copy the value (not the name) of an existing field.
Public function void

AddField ( const FCbFieldView& Value
)

  
Public function void

AddField ( const FCbField& Value
)

  
Public function void

AddFloat ( float Value
)

  
Public function void

AddFloat ( double Value
)

  
Public function void

AddFloat ( FUtf8StringView Name,
float Value
)

 Write a float field from a 32-bit float value.
Public function void

AddFloat ( FUtf8StringView Name,
double Value
)

 Write a float field from a 64-bit float value.
Public function void

AddHash ( FUtf8StringView Name,
const FIoHash& Value
)

 Write a hash field.
Public function void

AddHash ( const FIoHash& Value
)

  
Public function void

AddInteger ( int32 Value
)

  
Public function void

AddInteger ( int64 Value
)

  
Public function void

AddInteger ( uint32 Value
)

  
Public function void

AddInteger ( uint64 Value
)

  
Public function void

AddInteger ( FUtf8StringView Name,
int32 Value
)

 Write an integer field.
Public function void

AddInteger ( FUtf8StringView Name,
uint32 Value
)

 Write an integer field.
Public function void

AddInteger ( FUtf8StringView Name,
int64 Value
)

 Write an integer field.
Public function void

AddInteger ( FUtf8StringView Name,
uint64 Value
)

 Write an integer field.
Public function void

AddNull ( FUtf8StringView Name
)

 Write a null field.
Public function void

AddNull ()

  
Public function void

AddObject ( FUtf8StringView Name,
const FCbObject& Value
)

 Copy the value (not the name) of an existing object. Holds a reference if owned.
Public function void

AddObject ( FUtf8StringView Name,
const FCbObjectView& Value
)

 Copy the value (not the name) of an existing object.
Public function void

AddObject ( const FCbObject& Value
)

  
Public function void

AddObject ( const FCbObjectView& Value
)

  
Public function void

AddObjectAttachment ( const FIoHash& Value
)

  
Public function void

AddObjectAttachment ( FUtf8StringView Name,
const FIoHash& Value
)

 Write a field referencing an object attachment by its hash.
Public function void

AddObjectId ( const FCbObjectId& Value
)

  
Public function void

AddObjectId ( FUtf8StringView Name,
const FCbObjectId& Value
)

 Write an ObjectId field.
Public function void

AddString ( FUtf8StringView Value
)

  
Public function void

AddString ( FUtf8StringView Name,
FWideStringView Value
)

 Write a string field by converting the UTF-16 value to UTF-8.
Public function void

AddString ( FWideStringView Value
)

  
Public function void

AddString ( FUtf8StringView Name,
FUtf8StringView Value
)

 Write a string field by copying the UTF-8 value.
Public function void

AddTimeSpan ( FUtf8StringView Name,
FTimespan Value
)

 Write a time span field.
Public function void Write a time span field.
Public function void

AddTimeSpanTicks ( FUtf8StringView Name,
int64 Ticks
)

 Write a time span field with the specified count of 100ns ticks.
Public function void

AddTimeSpanTicks ( int64 Ticks
)

  
Public function void

AddUuid ( FUtf8StringView Name,
const FGuid& Value
)

 Write a UUID field.
Public function void

AddUuid ( const FGuid& Value
)

  
Public function void  
Public function void

BeginArray ( FUtf8StringView Name
)

 Begin a new array. Must have a matching call to EndArray.
Public function void

BeginObject ( FUtf8StringView Name
)

 Begin a new object. Must have a matching call to EndObject.
Public function void  
Public function void End an array after its fields have been written.
Public function void End an object after its fields have been written.
Public function Const uint64 The size of buffer (in bytes) required to serialize the fields that have been written.
Public function void

Reset ()

 Empty the writer without releasing any allocated memory.
Public function Const FCbFieldViewIterator

Save ( FMutableMemoryView Buffer
)

 Serialize the field(s) to memory.
Public function Const FCbFieldIterator

Save ()

 Serialize the field(s) to an owned buffer and return it as an iterator.
Public function Const void

Save ( FArchive& Ar
)

 Serialize the field(s) to an archive.
Public function FCbWriter &

SetName ( FUtf8StringView Name
)

 Sets the name of the next field to be written.

Operators

  Type Name Description
Public function FCbWriter &

operator<< ( const FGuid& Value
)

  
Public function FCbWriter &

operator<< ( const FIoHash& Value
)

  
Public function FCbWriter &

operator<< ( FDateTime Value
)

  
Public function FCbWriter &

operator<< ( const FCbAttachment& Attachment
)

  
Public function FCbWriter &

operator<< ( bool Value
)

  
Public function FCbWriter &

operator<< ( double Value
)

  
Public function FCbWriter &

operator<< ( float Value
)

  
Public function FCbWriter &

operator<< ( uint64 Value
)

  
Public function FCbWriter &

operator<< ( uint32 Value
)

  
Public function FCbWriter &

operator<< ( int64 Value
)

  
Public function FCbWriter &

operator<< ( int32 Value
)

  
Public function FCbWriter &

operator<< ( const WIDECHAR* Value
)

  
Public function FCbWriter &

operator<< ( FWideStringView Value
)

  
Public function FCbWriter &

operator<< ( const ANSICHAR* NameOrValue
)

 Write the field name if valid in this state, otherwise write the string value.
Public function FCbWriter &

operator<< ( const FCbArray& Value
)

  
Public function FCbWriter &

operator<< ( const FCbArrayView& Value
)

  
Public function FCbWriter &

operator<< ( const FCbObject& Value
)

  
Public function FCbWriter &

operator<< ( const FCbObjectView& Value
)

  
Public function FCbWriter &

operator<< ( const FCbField& Value
)

  
Public function FCbWriter &

operator<< ( const FCbFieldView& Value
)

  
Public function FCbWriter &

operator<< ( const UTF8CHAR* NameOrValue
)

 Write the field name if valid in this state, otherwise write the string value.
Public function FCbWriter &

operator<< ( FName Value
)

  
Public function FCbWriter &

operator<< ( FUtf8StringView NameOrValue
)

 Write the field name if valid in this state, otherwise write the string value.
Public function FCbWriter &

operator<< ( FTimespan Value
)

  
Public function FCbWriter &

operator<< ( const TArray< T, Allocator >& Value
)

  
Public function FCbWriter &

operator<< ( nullptr_t
)

  
Public function FCbWriter &

operator<< ( const FCbObjectId& Value
)

  
Public function FCbWriter &

operator= ( const FCbWriter&
)

  

Enums

  Type Name Description
Public enum EStateFlags    

See Also

TCbWriter

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