dlib C++ Library - Miscellaneous

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- Version: 17.12

Last Modified: Nov 10, 2008

# Miscellaneous

This page documents library components that don't really fit in anywhere else. They all basically follow the same conventions as the rest of the library. So to get a pipe for example you would need to write something like `typedef dlib::pipe::kernel_1a pipe_type;` and from then on make your pipes like `pipe_type my_pipe(pipe_size);`.

Objects

- bit_stream
- byte_orderer
- copy_functor
- error
- logger
- member_function_pointer
- memory_manager
- memory_manager_global
- memory_manager_stateless
- pipe
- std_allocator
- sync_extension
- timeout
- timer
- uint16
- uint32
- uint64
- uint8

Global Functions

- deserialize
- serialize
- zero_extend_cast

Testing

- dlib_testing_suite

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# bit_stream

This object represents a middle man between a user and the iostream classes that allows single bits to be read/written easily from/to the iostream classes
Specification: dlib/bit_stream/bit_stream_kernel_abstract.h
File to include: dlib/bit_stream.h
Implementations:

> bit_stream_kernel_1:
> This implementation is done by buffering single bits in the obvious way.

> kernel_1a | is a typedef for bit_stream_kernel_1
> kernel_1a_c | is a typedef for kernel_1a that checks its preconditions.

## Extensions to bit_stream

bit_stream_multi:
This extension gives a bit_stream object the ability to read/write multible bits at a time.
Specification: dlib/bit_stream/bit_stream_multi_abstract.h
Implementations:

> bit_stream_multi_1:
> This implementation is done by calling the read/write functions in the bit_stream kernel.

> multi_1a | is a typedef for bit_stream_kernel_1 extended by bit_stream_multi_1
> multi_1a_c | is a typedef for multi_1a that checks its preconditions.

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# byte_orderer

This object provides a simple type safe mechanism to convert data to and from network and host byte orders. I.e. to convert things between big and little endian byte ordering.
Specification: dlib/byte_orderer/byte_orderer_kernel_abstract.h
File to include: dlib/byte_orderer.h
Implementations:

> byte_orderer_kernel_1:
> This implementation is done in the obvious way.

> kernel_1a | is a typedef for byte_orderer_kernel_1

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# copy_functor

This is a templated function object that makes coppies of something.
Specification: dlib/algs.h
File to include: dlib/algs.h
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# deserialize

This is actually a set of overloaded functions which provide the ability to restore an object's state from an input stream. Currently all dlib container classes, non pointer C++ intrinsics, std::string, std::vector, std::map, std::complex, dlib::bigint, dlib::uint64, C style arrays, and dlib::vector objects are serializable.
Specification: dlib/serialize.h
File to include: dlib/serialize.h
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# dlib_testing_suite

This library comes with a command line driven regression test suite. All the testing code is located in the dlib/test folder. If you want to build it and test the library on your system you can use the makefile at dlib/test/makefile (you may have to edit it to make it work on your system) or use the CMake CMakeLists.txt file at dlib/test/CMakeLists.txt to build it.

What you may find more useful however is the testing framework itself. It uses a faily simple and modular design. Each test is contained in its own cpp file and when compiled into the program it automatically shows up in the list of tests to run. If you want to use the testing framework all you need to do is add the files dlib/test/tester.h, dlib/test/tester.cpp, and dlib/test/main.cpp to your project and then add cpp files that contain your tests (see dlib/test/example.cpp and dlib/test/example_args.cpp for some examples).

From the command line you can choose to run all the installed tests, enable or disable the loggers, set various logging levels, specify how many times to run the tests, or pick just one or two tests to run at a time rather than the entire suite.

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# error

This is the base exception class from which all exceptions in this library inherit.
Specification: dlib/error.h
File to include: dlib/error.h
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# logger

This component is a logging output stream in the style of the log4j logger available for Java. Note that unlike most other objects in this library there is only one implementation. Thus, to create instances of the logger you would simply write logger my_logger("some_name");.
Specification: dlib/logger/logger_kernel_abstract.h
File to include: dlib/logger.h
Code Examples: 1, 2, 3

## Extensions to logger

config_file:
This extension provides the configure_loggers_from_file() function which reads a configuration file from disk that sets up all your loggers.
Specification: dlib/logger/logger_config_file.h

extra_logger_headers:
This extension contains additional logger headers you may chose to use instead of the default one.
Specification: dlib/logger/extra_logger_headers.h
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# member_function_pointer

This object represents a member function pointer. It is useful because instances of this object can be created without needing to know the type of object whose member function we will be calling.
Specification: dlib/member_function_pointer/member_function_pointer_kernel_abstract.h
File to include: dlib/member_function_pointer.h
Code Examples: 1
Implementations:

> member_function_pointer_kernel_1:
> This implementation is done using type erasure and placement new. This means that it never allocates memory on the heap and instead stores everything on the stack.

> kernel_1a | is a typedef for member_function_pointer_kernel_1
> kernel_1a_c | is a typedef for kernel_1a that checks its preconditions.

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# memory_manager

This object represents a memory pool.
Specification: dlib/memory_manager/memory_manager_kernel_abstract.h
File to include: dlib/memory_manager.h
Implementations:

> memory_manager_kernel_1:
> This memory manager implementation allocates objects one at a time when there are allocation requests. Then when there is a deallocate request the returning object is placed into a list of free blocks if that list has less than max_pool_size blocks in it. Subsequent allocation requests will be serviced by drawing from the free list whenever it isn't empty. Array allocations, on the other hand, are not managed at all but are passed directly on to new and delete.

> When this object's max_pool_size template parameter is set to 0 it simply calls new and delete directly and doesn't function as a memory pool.

> kernel_1a | is a typedef for memory_manager_kernel_1 with a max_pool_size of 0
> kernel_1b | is a typedef for memory_manager_kernel_1 with a max_pool_size of 10
> kernel_1c | is a typedef for memory_manager_kernel_1 with a max_pool_size of 100
> kernel_1d | is a typedef for memory_manager_kernel_1 with a max_pool_size of 1000
> kernel_1e | is a typedef for memory_manager_kernel_1 with a max_pool_size of 10000
> kernel_1f | is a typedef for memory_manager_kernel_1 with a max_pool_size of 100000

> memory_manager_kernel_2:
> This memory manager implementation allocates memory in blocks of chunk_size*sizeof(T) bytes. All the sizeof(T) subblocks are kept in a linked list of free memory blocks and are given out whenever an allocation request occurs. Also, memory is not freed until this object is destructed. Also note that array allocations are not managed at all but are passed directly on to new and delete.

> kernel_2a | is a typedef for memory_manager_kernel_2 with a chunk_size of 10
> kernel_2b | is a typedef for memory_manager_kernel_2 with a chunk_size of 100
> kernel_2c | is a typedef for memory_manager_kernel_2 with a chunk_size of 1000
> kernel_2d | is a typedef for memory_manager_kernel_2 with a chunk_size of 10000
> kernel_2e | is a typedef for memory_manager_kernel_2 with a chunk_size of 100000

> memory_manager_kernel_3:
> This memory manager implementation allocates memory in blocks of chunk_size*sizeof(T) bytes. All the sizeof(T) subblocks are kept in a linked list of free memory blocks and are given out whenever an allocation request occurs. Note that array allocations are managed. So this object is just like kernel_2 but it also pools memory from array allocations (chunk_size has no effect with respect to array allocations, each array is allocated one at a time). Also, memory is not freed until this object is destructed.

> kernel_3a | is a typedef for memory_manager_kernel_3 with a chunk_size of 10
> kernel_3b | is a typedef for memory_manager_kernel_3 with a chunk_size of 100
> kernel_3c | is a typedef for memory_manager_kernel_3 with a chunk_size of 1000
> kernel_3d | is a typedef for memory_manager_kernel_3 with a chunk_size of 10000
> kernel_3e | is a typedef for memory_manager_kernel_3 with a chunk_size of 100000

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# memory_manager_global

This object represents some kind of global memory manager or memory pool.
Specification: dlib/memory_manager_global/memory_manager_global_kernel_abstract.h
File to include: dlib/memory_manager_global.h
Implementations:

> memory_manager_global_kernel_1:
> This is implemented in the obvious way. See the code for details.

> kernel_1a | is a typedef for memory_manager_global_kernel_1

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# memory_manager_stateless

This object represents some kind of stateless memory manager or memory pool. Stateless means that all instances (instances of the same type that is) of this object are identical and can be used interchangably. Note that implementations are allowed to have some shared global state such as a global memory pool. This object is also thread safe.
Specification: dlib/memory_manager_stateless/memory_manager_stateless_kernel_abstract.h
File to include: dlib/memory_manager_stateless.h
Implementations:

> memory_manager_stateless_kernel_1:
> This implementation just calls new and delete. So it doesn't do anything special.

> kernel_1a | is a typedef for memory_manager_stateless_kernel_1

> memory_manager_stateless_kernel_2:
> This implementation uses a global instance of a memory_manager object guarded by a mutex as its implementation.

> kernel_2_1a | is a typedef for memory_manager_stateless_kernel_2 that uses memory_manager_1a
> kernel_2_1b | is a typedef for memory_manager_stateless_kernel_2 that uses memory_manager_1b
> kernel_2_1c | is a typedef for memory_manager_stateless_kernel_2 that uses memory_manager_1c
> kernel_2_1d | is a typedef for memory_manager_stateless_kernel_2 that uses memory_manager_1d
> kernel_2_1e | is a typedef for memory_manager_stateless_kernel_2 that uses memory_manager_1e
> kernel_2_1f | is a typedef for memory_manager_stateless_kernel_2 that uses memory_manager_1f
> kernel_2_2a | is a typedef for memory_manager_stateless_kernel_2 that uses memory_manager_2a
> kernel_2_2b | is a typedef for memory_manager_stateless_kernel_2 that uses memory_manager_2b
> kernel_2_2c | is a typedef for memory_manager_stateless_kernel_2 that uses memory_manager_2c
> kernel_2_2d | is a typedef for memory_manager_stateless_kernel_2 that uses memory_manager_2d
> kernel_2_2e | is a typedef for memory_manager_stateless_kernel_2 that uses memory_manager_2e
> kernel_2_3a | is a typedef for memory_manager_stateless_kernel_2 that uses memory_manager_3a
> kernel_2_3b | is a typedef for memory_manager_stateless_kernel_2 that uses memory_manager_3b
> kernel_2_3c | is a typedef for memory_manager_stateless_kernel_2 that uses memory_manager_3c
> kernel_2_3d | is a typedef for memory_manager_stateless_kernel_2 that uses memory_manager_3d
> kernel_2_3e | is a typedef for memory_manager_stateless_kernel_2 that uses memory_manager_3e

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# pipe

This is a first in first out queue with a fixed maximum size containing items of type T. It is suitable for passing objects between threads.
Specification: dlib/pipe/pipe_kernel_abstract.h
File to include: dlib/pipe.h
Code Examples: 1
Implementations:

> pipe_kernel_1:
> This implementation is done using a circular buffer in the obvious way. See the source for details.

> kernel_1a | is a typedef for pipe_kernel_1

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# serialize

This is actually a set of overloaded functions which provide the ability to save an object's state to an output stream. Currently all dlib container classes, non pointer C++ intrinsics, std::string, std::vector, std::map, std::complex, dlib::bigint, dlib::uint64, C style arrays, and dlib::vector objects are serializable.
Specification: dlib/serialize.h
File to include: dlib/serialize.h
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# std_allocator

This object is an implementation of an allocator that conforms to the C++ standard requirements for allocator objects. The M template argument is one of the dlib memory manager objects and this allocator implementation will do all of its memory allocations using whatever dlib memory manager you supply.

Thus, using this allocator object you can use any of the dlib memory manager objects with the containers in the STL or with any other object that requires an STL style allocator object.

Specification: dlib/std_allocator.h
File to include: dlib/std_allocator.h
Code Examples: 1
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# sync_extension

This object represents a general extension to any object. This object gives any object which it extends an integrated rmutex and rsignaler object. The extended object will then be able to be treated as if it was also a rmutex and rsignaler.
Specification: dlib/sync_extension/sync_extension_kernel_abstract.h
File to include: dlib/sync_extension.h
Implementations:

> sync_extension_kernel_1:
> This is implemented using a rmutex and rsignaler in the obvious way.

> kernel_1a | is a typedef for sync_extension_kernel_1

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# timeout

This object provides a simple way to implement a timeout.
Specification: dlib/timeout/timeout_kernel_abstract.h
File to include: dlib/timeout.h
Implementations:

> timeout_kernel_1:
> This is implemented in the obvious way using virtual functions and templates.

> kernel_1a | is a typedef for timeout_kernel_1

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# timer

This object represents a timer that will call a given member function repeatedly at regular intervals.
Specification: dlib/timer/timer_kernel_abstract.h
File to include: dlib/timer.h
Code Examples: 1
Implementations:

> timer_kernel_1:
> This is implemented in the obvious way.

> kernel_1a | is a typedef for timer_kernel_1

> timer_kernel_2:
> This implemenation has a single master thread that does all the waiting. This master thread creates and dispatches threads to specific timer objects when they need to run their action functions. When a timer object isn't executing its action function then it doesn't have any thread allocated to it at all. So it is much more efficient than timer_kernel_1.

> kernel_2a | is a typedef for timer_kernel_2

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# uint16

This is just a typedef for a 16 bit unsigned integer.
Specification: dlib/uintn.h
File to include: dlib/uintn.h
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# uint32

This is just a typedef for a 32 bit unsigned integer.
Specification: dlib/uintn.h
File to include: dlib/uintn.h
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# uint64

This is just a typedef for a 64 bit unsigned integer.
Specification: dlib/uintn.h
File to include: dlib/uintn.h
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# uint8

This is just a typedef for an 8 bit unsigned integer.
Specification: dlib/uintn.h
File to include: dlib/uintn.h
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# zero_extend_cast

This is a global function that performs a zero extending cast from one integral type to another integral type.
Specification: dlib/uintn.h
File to include: dlib/uintn.h