Table of
Contents
Modern C++ Design: Generic Programming and Design Patterns Applied
By Andrei Alexandrescu
Publisher: Addison Wesley
Pub Date: February 01, 2001
ISBN: 0-201-70431-5
Pages: 352
Modern C++ Design is an important book. Fundamentally, it demonstrates 'generic
patterns' or 'pattern templates' as a powerful new way of creating extensible designs in
C++--a new way to combine templates and patterns that you may never have dreamt was
possible, but is. If your work involves C++ design and coding, you should read this book.
Highly recommended.-Herb Sutter
What's left to say about C++ that hasn't already been said? Plenty, it turns out.-From the
Foreword by John Vlissides
In Modern C++ Design, Andrei Alexandrescu opens new vistas for C++ programmers.
Displaying extraordinary creativity and programming virtuosity, Alexandrescu offers a
cutting-edge approach to design that unites design patterns, generic programming, and
C++, enabling programmers to achieve expressive, flexible, and highly reusable code.
This book introduces the concept of generic components-reusable design templates that
produce boilerplate code for compiler consumption-all within C++. Generic components
enable an easier and more seamless transition from design to application code, generate
code that better expresses the original design intention, and support the reuse of design
structures with minimal recoding.
The author describes the specific C++ techniques and features that are used in building
generic components and goes on to implement industrial strength generic components for
real-world applications. Recurring issues that C++ developers face in their day-to-day
activity are discussed in depth and implemented in a generic way. These include:
• Policy-based design for flexibility
• Partial template specialization
• Typelists-powerful type manipulation structures
• Patterns such as Visitor, Singleton, Command, and Factories
• Multi-method engines
For each generic component, the book presents the fundamental problems and design
options, and finally implements a generic solution.
In addition, an accompanying Web site, http://www.awl.com/cseng/titles/0-201-70431-5,
makes the code implementations available for the generic components in the book and
provides a free, downloadable C++ library, called Loki, created by the author. Loki
provides out-of-the-box functionality for virtually any C++ project.
TEAMFLY
Team-Fly
®
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Table of Content
Table of Content .................................................................................................................. i
Copyright............................................................................................................................. vi
Foreword............................................................................................................................ vii
Foreword............................................................................................................................. ix
Preface................................................................................................................................. x
Audience......................................................................................................................... xi
Loki.................................................................................................................................. xi
Organization.................................................................................................................. xii
Acknowledgments ...........................................................................................................xiii
Part I: Techniques................................................................................................................... 1
Chapter 1. Policy-Based Class Design........................................................................... 2
1.1 The Multiplicity of Software Design ...................................................................... 2
1.2 The Failure of the Do-It-All Interface .................................................................... 3
1.3 Multiple Inheritance to the Rescue? ..................................................................... 4
1.4 The Benefit of Templates ....................................................................................... 5
1.5 Policies and Policy Classes................................................................................... 6
1.6 Enriched Policies..................................................................................................... 9
1.7 Destructors of Policy Classes.............................................................................. 10
1.8 Optional Functionality Through Incomplete Instantiation................................ 11
1.9 Combining Policy Classes.................................................................................... 12
1.10 Customizing Structure with Policy Classes..................................................... 13
1.11 Compatible and Incompatible Policies............................................................. 14
1.12 Decomposing a Class into Policies .................................................................. 16
1.13 Summary .............................................................................................................. 17
Chapter 2. Techniques .................................................................................................... 19
2.1 Compile-Time Assertions..................................................................................... 19
2.2 Partial Template Specialization........................................................................... 22
2.3 Local Classes......................................................................................................... 23
2.4 Mapping Integral Constants to Types ................................................................ 24
2.5 Type-to-Type Mapping.......................................................................................... 26
2.6 Type Selection ....................................................................................................... 28
2.7 Detecting Convertibility and Inheritance at Compile Time .............................. 29
2.8 A Wrapper Around type_info.......................................................................... 32
2.9 NullType and EmptyType................................................................................ 34
2.10 Type Traits ........................................................................................................... 34
2.11 Summary .............................................................................................................. 40
Chapter 3. Typelists ......................................................................................................... 42
3.1 The Need for Typelists.......................................................................................... 42
3.2 Defining Typelists .................................................................................................. 43
3.3 Linearizing Typelist Creation ............................................................................... 45
3.4 Calculating Length................................................................................................. 45
3.5 Intermezzo.............................................................................................................. 46
3.6 Indexed Access ..................................................................................................... 47
3.7 Searching Typelists............................................................................................... 48
3.8 Appending to Typelists ......................................................................................... 49
3.9 Erasing a Type from a Typelist............................................................................ 50
3.10 Erasing Duplicates .............................................................................................. 51
3.11 Replacing an Element in a Typelist.................................................................. 52
3.12 Partially Ordering Typelists................................................................................ 53
3.13 Class Generation with Typelists........................................................................ 56
3.14 Summary .............................................................................................................. 65
3.15 Typelist Quick Facts...................................................................................... 66
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Chapter 4. Small-Object Allocation................................................................................ 68
4.1 The Default Free Store Allocator ........................................................................ 68
4.2 The Workings of a Memory Allocator................................................................. 69
4.3 A Small-Object Allocator ...................................................................................... 70
4.4 Chunks ................................................................................................................... 71
4.5 The Fixed-Size Allocator...................................................................................... 74
4.6 The SmallObjAllocator Class...................................................................... 77
4.7 A Hat Trick.............................................................................................................. 79
4.8 Simple, Complicated, Yet Simple in the End..................................................... 81
4.9 Administrivia........................................................................................................... 82
4.10 Summary .............................................................................................................. 83
4.11 Small-Object Allocator Quick Facts.................................................................. 83
Part II: Components.............................................................................................................. 85
Chapter 5. Generalized Functors................................................................................... 86
5.1 The Command Design Pattern............................................................................ 86
5.2 Command in the Real World................................................................................ 89
5.3 C++ Callable Entities ............................................................................................ 89
5.4 The Functor Class Template Skeleton ........................................................... 91
5.5 Implementing the Forwarding Functor::operator() ............................... 95
5.6 Handling Functors ................................................................................................. 96
5.7 Build One, Get One Free...................................................................................... 98
5.8 Argument and Return Type Conversions .......................................................... 99
5.9 Handling Pointers to Member Functions.......................................................... 101
5.10 Binding................................................................................................................ 104
5.11 Chaining Requests............................................................................................ 106
5.12 Real-World Issues I: The Cost of Forwarding Functions ............................ 107
5.13 Real-World Issues II: Heap Allocation ........................................................... 108
5.14 Implementing Undo and Redo with Functor .............................................. 110
5.15 Summary ............................................................................................................ 110
5.16 Functor Quick Facts....................................................................................... 111
Chapter 6. Implementing Singletons ........................................................................... 113
6.1 Static Data + Static Functions != Singleton..................................................... 113
6.2 The Basic C++ Idioms Supporting Singletons ................................................ 114
6.3 Enforcing the Singleton's Uniqueness ............................................................. 116
6.4 Destroying the Singleton .................................................................................... 116
6.5 The Dead Reference Problem........................................................................... 118
6.6 Addressing the Dead Reference Problem (I): The Phoenix Singleton........ 120
6.7 Addressing the Dead Reference Problem (II): Singletons with Longevity.. 122
6.8 Implementing Singletons with Longevity.......................................................... 125
6.9 Living in a Multithreaded World......................................................................... 128
6.10 Putting It All Together....................................................................................... 130
6.11 Working with SingletonHolder.................................................................. 134
6.12 Summary ............................................................................................................ 136
6.13 SingletonHolder Class Template Quick Facts....................................... 136
Chapter 7. Smart Pointers............................................................................................. 138
7.1 Smart Pointers 101 ............................................................................................. 138
7.2 The Deal ............................................................................................................... 139
7.3 Storage of Smart Pointers.................................................................................. 140
7.4 Smart Pointer Member Functions..................................................................... 142
7.5 Ownership-Handling Strategies ........................................................................ 143
7.6 The Address-of Operator.................................................................................... 150
7.7 Implicit Conversion to Raw Pointer Types....................................................... 151
7.8 Equality and Inequality........................................................................................ 153
7.9 Ordering Comparisons........................................................................................ 157
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7.10 Checking and Error Reporting......................................................................... 159
7.11 Smart Pointers to const and const Smart Pointers ................................. 161
7.12 Arrays.................................................................................................................. 161
7.13 Smart Pointers and Multithreading ................................................................. 162
7.14 Putting It All Together....................................................................................... 165
7.15 Summary ............................................................................................................ 171
7.16 SmartPtr Quick Facts.................................................................................... 171
Chapter 8. Object Factories.......................................................................................... 173
8.1 The Need for Object Factories .......................................................................... 174
8.2 Object Factories in C++: Classes and Objects............................................... 175
8.3 Implementing an Object Factory....................................................................... 176
8.4 Type Identifiers .................................................................................................... 180
8.5 Generalization...................................................................................................... 181
8.6 Minutiae................................................................................................................. 184
8.7 Clone Factories.................................................................................................... 185
8.8 Using Object Factories with Other Generic Components ............................. 188
8.9 Summary............................................................................................................... 189
8.10 Factory Class Template Quick Facts.......................................................... 189
8.11 CloneFactory Class Template Quick Facts.............................................. 190
Chapter 9. Abstract Factory.......................................................................................... 191
9.1 The Architectural Role of Abstract Factory...................................................... 191
9.2 A Generic Abstract Factory Interface............................................................... 193
9.3 Implementing AbstractFactory................................................................... 196
9.4 A Prototype-Based Abstract Factory Implementation.................................... 199
9.5 Summary............................................................................................................... 202
9.6 AbstractFactory and ConcreteFactory Quick Facts......................... 203
Chapter 10. Visitor.......................................................................................................... 205
10.1 Visitor Basics ..................................................................................................... 205
10.2 Overloading and the Catch-All Function........................................................ 210
10.3 An Implementation Refinement: The Acyclic Visitor.................................... 211
10.4 A Generic Implementation of Visitor............................................................... 215
10.5 Back to the "Cyclic" Visitor............................................................................... 221
10.6 Hooking Variations............................................................................................ 223
10.7 Summary ............................................................................................................ 226
10.8 Visitor Generic Components Quick Facts ..................................................... 226
Chapter 11. Multimethods............................................................................................. 228
11.1 What Are Multimethods?.................................................................................. 228
11.2 When Are Multimethods Needed?.................................................................. 229
11.3 Double Switch-on-Type: Brute Force............................................................. 230
11.4 The Brute-Force Approach Automated.......................................................... 232
11.5 Symmetry with the Brute-Force Dispatcher .................................................. 237
11.6 The Logarithmic Double Dispatcher............................................................... 240
11.7 FnDispatcher and Symmetry...................................................................... 245
11.8 Double Dispatch to Functors........................................................................... 246
11.9 Converting Arguments: static_cast or dynamic_cast?..................... 248
11.10 Constant-Time Multimethods: Raw Speed ................................................. 252
11.11 BasicDispatcher and BasicFastDispatcher as Policies............. 255
11.12 Looking Forward ............................................................................................. 257
11.13 Summary.......................................................................................................... 258
11.14 Double Dispatcher Quick Facts .................................................................... 259
Appendix A. A Minimalist Multithreading Library....................................................... 262
A.1 A Critique of Multithreading ............................................................................... 262
A.2 Loki's Approach................................................................................................... 263
A.3 Atomic Operations on Integral Types .............................................................. 264
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A.4 Mutexes................................................................................................................ 265
A.5 Locking Semantics in Object-Oriented Programming ................................... 267
A.6 Optional volatile Modifier............................................................................. 269
A.7 Semaphores, Events, and Other Good Things .............................................. 269
A.8 Summary .............................................................................................................. 269
Bibliography..................................................................................................................... 270
