1 Package Ctx APIs for C++

Ctx is the namespace for TCtx XML context related types and interfaces.

This chapter contains the following sections:

Ctx Datatypes
MemAllocator Interface
TCtx Interface

Ctx Datatypes

Table 1-1 summarizes the datatypes of the Ctx package.

CPXML2139 Table 1-1 Summary of Datatypes; Ctx Package

Datatype	Description
encoding	A single supported encoding.
encodings	An array of encodings.

CPXML2140

encoding

A single supported encoding.

CPXML2141Definition

typedef struct encoding {
   oratext *encname;
   oratext *encvalue;
} encoding;

CPXML2142

encodings

An array of encodings.

CPXML2143Definition

typedef struct encodings {
   unsigned num;
   encoding *enc; 
} encodings;

CPXML01020

MemAllocator Interface

Table 1-2 summarizes the methods available through the MemAllocator interface.

CPXML2144 Table 1-2 Summary of MemAllocator Methods; Ctx Package

Function	Summary
alloc()	Allocates memory of given size.
dealloc()	Deallocate memory pointed to by the argument.
~MemAllocator()	Virtual destructor - interface level handle to actual destructors.

CPXML2145

alloc()

This is a virtual member function that defines a prototype for user defined allocator functions

CPXML2146Syntax

virtual void* alloc(
   ub4 size) = 0;

Parameter	Description
size	memory size

CPXML2147

dealloc()

This is a virtual member function that defines a prototype for user defined deallocator functions. Such deallocators are supposed to deallocate memory allocated by the alloc member functions

CPXML2148Syntax

virtual void dealloc(
   void* ptr) = 0;

Parameter	Description
ptr	pointer to previously allocated memory

CPXML2149

~MemAllocator()

It provides an interface level handle to actual destructors that can be invoked without knowing their names or implementations

CPXML2150Syntax

virtual ~MemAllocator() {}

CPXML01030

TCtx Interface

Table 1-3 summarizes the methods available through the TCtx interface.

CPXML2151 Table 1-3 Summary of TCtx Methods; Ctx Package

Function	Summary
TCtx()	Class constructor.
getEncoding()	Get data encoding in use by XML context.
getErrHandler()	Get Error Handler provided by the user.
getMemAllocator()	Get memory allocator.
isSimple()	Get a flag that indicates if data encoding is simple.
isUnicode()	Get a flag indicating if data encoding is Unicode.
~TCtx()	Destructor - clears space and destroys the implementation.

CPXML2152

TCtx()

TCtx constructor. It throws XmlException if it fails to create a context object.

Syntax	Description
TCtx() throw (XMLException)	This constructor creates the context object and initializes it with default values of parameters.
TCtx( oratext* name, ErrorHandler* errh = NULL, MemAllocator* memalloc = NULL, encodings* encs = NULL) throw (XMLException)	This constructor creates the context object and initializes it with parameter values provided by the user.
TCtx( oratext* name, up4 inpblksize, ErrorIfs* errh = NULL, MemAllocator* memalloc = NULL, encodings* encs = NULL) throw (XMLException)	This constructor creates the context object and initializes it with parameter values provided by the user. Takes an additional parameter for memory block size from input source.

Parameter	Description
name	user defined name of the context
errh	user defined error handler
memalloc	user defined memory allocator
encs	user specified encodings
inpblksize	memory block size for input source

CPXML2153Returns

(TCtx) Context object

CPXML2154

getEncoding()

Returns data encoding in use by XML context. Ordinarily, the data encoding is chosen by the user, so this function is not needed. However, if the data encoding is not specified, and allowed to default, this function can be used to return the name of that default encoding.

CPXML2155Syntax

oratext* getEncoding() const;

CPXML2156Returns

(oratext *) name of data encoding

CPXML2157

getErrHandler()

This member functions returns Error Handler provided by the user when the context was created, or NULL if none were provided.

CPXML2158Syntax

ErrorHandler* getErrHandler() const;

CPXML2159Returns

(ErrorHandler *) Pointer to the Error Handler object, or NULL

CPXML2160

getMemAllocator()

This member function returns memory allocator provided by the user when the context was created, or default memory allocator. It is important that this memory allocator is used for all C level memory allocations

CPXML2161Syntax