IT-SC book: Advanced CORBA Programming with C++ in Software

Creation Code-39 in Software IT-SC book: Advanced CORBA Programming with C++
IT-SC book: Advanced CORBA Programming with C++
Code 3/9 Maker In Visual C#.NET
Using Barcode printer for .NET framework Control to generate, create ANSI/AIM Code 39 image in .NET framework applications.
sequence element, we transmit 8 bytes, so the sparse version is more efficient if at least half the elements are zeros Note that IDL provides no performance guarantees for sequences and arrays Instead, the run-time performance for sequences and arrays depends on the language mapping The C++ mapping guarantees random array access in constant time because it maps IDL arrays to C++ arrays For sequences, the C++ mapping provides no performance guarantees Most C++ mapping implementations provide constant-time performance for random access to sequences However, constant-time performance is not guaranteed by the specification 478 Recursive Types Even though IDL does not have pointers to data, it supports recursive data types Recursion is legal only for structures and unions In either case, recursion is expressed as an anonymous sequence of the incomplete (recursive) type
Creating Code39 In .NET Framework
Using Barcode creator for ASP.NET Control to generate, create USS Code 39 image in ASP.NET applications.
Recursion Via Structures
Create Code 3/9 In VS .NET
Using Barcode drawer for .NET Control to generate, create Code 39 Full ASCII image in VS .NET applications.
Structures can contain data members that are sequences of the structure under definition, making the structure definition recursive Here is an example:
Code 3/9 Drawer In VB.NET
Using Barcode printer for .NET framework Control to generate, create Code 39 Full ASCII image in .NET applications.
struct Node { long sequence<Node> }; value; children;
EAN / UCC - 14 Creation In VS .NET
Using Barcode encoder for VS .NET Control to generate, create UCC-128 image in .NET applications.
This code defines a data structure consisting of nodes, in which each node contains a long value and a number of descendant nodes Such constructs can be used to express arbitrary complexity graphs, such as expression trees; leaf nodes, which have an outdegree of one, are indicated by an empty descendant sequence
Data Matrix Printer In Visual C#
Using Barcode generation for .NET framework Control to generate, create ECC200 image in .NET applications.
Recursion Via Unions
EAN-13 Generator In Java
Using Barcode generator for Java Control to generate, create GS1 - 13 image in Java applications.
A recursive sequence must have an incomplete structure or union type as its element type (Node in the preceding example) The sequence can be bounded or unbounded Here is another example that defines an expression tree for bitwise and logical operators on long values:
European Article Number 13 Encoder In .NET Framework
Using Barcode printer for ASP.NET Control to generate, create EAN-13 image in ASP.NET applications.
enum OpType { OP_AND, OP_OR, OP_NOT, OP_BITAND, OP_BITOR, OP_BITXOR, OP_BITNOT }; enum NodeKind { LEAF_NODE, UNARY_NODE, BINARY_NODE }; union Node switch (NodeKind) { case LEAF_NODE: long value; case UNARY_NODE: struct UnaryOp {
Printing Barcode In .NET Framework
Using Barcode creation for ASP.NET Control to generate, create barcode image in ASP.NET applications.
IT-SC book: Advanced CORBA Programming with C++
Scan EAN 13 In .NET Framework
Using Barcode reader for .NET Control to read, scan read, scan image in .NET framework applications.
OpType sequence<Node, 1> } u_op; case BINARY_NODE: struct BinaryOp { OpType sequence<Node, 2> } bin_op; };
UPCA Recognizer In .NET Framework
Using Barcode decoder for .NET Control to read, scan read, scan image in VS .NET applications.
op; child;
Bar Code Generator In Java
Using Barcode creation for Java Control to generate, create bar code image in Java applications.
op; children;
Generating Bar Code In Visual C#
Using Barcode encoder for VS .NET Control to generate, create bar code image in .NET framework applications.
Note that in this example, the incomplete type for the recursion is a union (instead of a struct) and that bounded sequences are used The use of bounded sequences is not mandatory but it improves the type safety of the specification (It does not make sense for a unary node to have more than one descendant and for a binary node to have more than two descendants, so we might as well express this) However, we cannot enforce at the type level that a binary node must have exactly two descendants The following attempt to achieve this is simply illegal IDL because recursion must be expressed via a sequence:
USS Code 39 Creation In C#
Using Barcode drawer for Visual Studio .NET Control to generate, create Code 39 Extended image in .NET applications.
// case BINARY_NODE: struct BinaryOp { OpType op; Node children[2]; // Illegal recursion, not a sequence } bin_op; //
Generating UCC-128 In .NET
Using Barcode generator for ASP.NET Control to generate, create GTIN - 128 image in ASP.NET applications.
Finally, note that the operator enumerators in this example are named OP_AND, OP_OR, and so on (instead of AND, OR, and so on) This is because AND and OR are keywords in several implementation languages, and that causes awkward language mappings (Remember that standard C++ has added quite a few new keywords, among them and and or)
Encode Barcode In Java
Using Barcode generation for Java Control to generate, create barcode image in Java applications.
Multilevel Recursion
ECC200 Generator In VS .NET
Using Barcode creator for .NET Control to generate, create Data Matrix image in Visual Studio .NET applications.
Recursion can extend over more than one level Here is an example that shows the recursion on the incomplete type TwoLevelRecursive nested inside another structure definition:
Make Barcode In .NET Framework
Using Barcode generator for ASP.NET Control to generate, create barcode image in ASP.NET applications.
struct TwoLevelRecursive { string id; struct Nested { long value; sequence<TwoLevelRecursive> children; } data; };
Bar Code Generator In VS .NET
Using Barcode creation for .NET Control to generate, create bar code image in .NET applications.
Mutually Recursive Structures
ANSI/AIM Code 128 Drawer In VB.NET
Using Barcode printer for .NET Control to generate, create USS Code 128 image in .NET framework applications.
IT-SC book: Advanced CORBA Programming with C++
Occasionally, you may find yourself in a situation when you want to implement mutually recursive structures along the following lines:
// Not legal IDL! typedef something Adata; typedef whatever Bdata; struct Astruct { Adata sequence<Bstruct, 1> }; struct Bstruct { Bdata sequence<Astruct, 1> }; // Data specific to A's // Data specific to B's data; nested; // Illegal - undefined Bstruct data; nested;
This need typically arises during legacy application integration, when existing C or C++ interfaces are translated into IDL The problem can also arise with automated translation algorithms, such as ASN1 to IDL conversion Unfortunately, the preceding IDL is illegal It is impossible to create mutually recursive structures as shown; the compiler complains when you try to use type Bstruct before it is defined A forward declaration does not solve the problem because IDL does not permit forward declarations for anything except interfaces However, you can use a union to achieve the desired semantics:
typedef something Adata; // Data specific to A's typedef whatever Bdata; // Data specific to B's enum StructType { A_TYPE, B_TYPE }; union ABunion switch (StructType) { case A_TYPE: struct Acontents { Bdata data; sequence<ABunion, 1> nested; } A_member; case B_TYPE: struct Bcontents { Adata data; sequence<ABunion, 1> nested; } B_member; };
This definition is not pretty because it loses some type safety (At the type level, it is not enforced that an A must always contain a B and that a B must always contain an A) However, it works and adequately expresses the requirement 479 Constant Definitions and Literals IDL permits the definition of constants Syntax and semantics are identical to C++; you can define floating-point, integer, character, string, Boolean, octet, and enumerated constants[1] IDL does not allow you to define a constant of type any nor a user-defined complex type Here are some examples of legal constants: