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Last Modified:
Jan 03, 2011

Containers



Many of these containers were inspired by the RESOLVE/C++ course sequence at Ohio State. As such, most of the objects do not support copying in any form, only swapping is allowed. That is, when objects are added or removed from any of these containers they are swapped in and out, not copied.

This allows you to do things like have containers of containers of containers without encountering the overhead of the massive copying that would likely result if you did the same thing with the STL. It also means you can store objects that are not copyable inside these containers, which is not something you can do with the STL.

To use any of these containers all you need to do is #include the file indicated in the short section about the component you would like to use. Then pick which implementation you would like and typedef it to something nice. Here is an example of creating a typedef for a set of integers using the first kernel implementation.
typedef dlib::set<int>::kernel_1a set_of_ints;. Or as another example, if you wanted to make an expandable array of ints you might say
typedef dlib::array<int>::expand_1d_c array_of_ints;.

Note that it is assumed by these containers that swap() and operator< do not throw. They may not function correctly if this assumption is broken. Also note that the built in types (int, long, char, etc.) and std::string will not cause operator< or swap() to throw.

Note also that most of the containers inherit from the enumerable interface. Thus, all the member functions inherited from enumerable are defined in the enumerable class and their documentation is not repeated in each container's documentation. This includes the size() member function in each container.


Objects
Interfaces
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any



This object is basically a type-safe version of a void*. In particular, it is a container which can contain only one object but the object may be of any type.

It is somewhat like the type_safe_union except you don't have to declare the set of possible content types beforehand. So in some sense this is like a less type-strict version of the type_safe_union.



Specification: dlib/any/any_abstract.h
File to include: dlib/any.h

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any_decision_function



This object is a version of dlib::any that is restricted to containing elements which are some kind of function object with an operator() with the following signature: scalar_type operator()(const sample_type&) const

It is intended to be used to contain dlib::decision_function objects and other types which represent learned decision functions. It allows you to write code which contains and processes these decision functions without needing to know the specific types of decision functions used.



Specification: dlib/any/any_decision_function_abstract.h
File to include: dlib/any.h

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any_trainer



This object is a version of dlib::any that is restricted to containing elements which are some kind of object with a .train() method compatible with the following signature:
 decision_function train(
      const std::vector<sample_type>& samples,
      const std::vector<scalar_type>& labels
   ) const
Where decision_function is a type capable of being stored in an any_decision_function object.

any_trainer is intended to be used to contain objects such as the svm_nu_trainer and other similar types which represent supervised machine learning algorithms. It allows you to write code which contains and processes these trainer objects without needing to know the specific types of trainer objects used.



Specification: dlib/any/any_trainer_abstract.h
File to include: dlib/any.h

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array



This object is just like a C style array and the accessor functions operate in constant time.

Specification: dlib/array/array_kernel_abstract.h
File to include: dlib/array.h

Implementations:
array_kernel_1:
This implementation is done using an array of pointers, each of which point to small sections of the array. This implementation allows the array to use only about as much memory as it needs at any given time. It does not use the memory_manager at all.
kernel_1a
is a typedef for array_kernel_1
kernel_1a_c
is a typedef for kernel_1a that checks its preconditions.
array_kernel_2:
This implementation is done using a single array of max_size() elements. So this is just a simple layer on top of a C style array. It uses the memory_manager for all memory allocations.
kernel_2a
is a typedef for array_kernel_2
kernel_2a_c
is a typedef for kernel_2a that checks its preconditions.

Extensions to array

array_expand

This extension gives an array the ability to expand its size() beyond its max_size() without clearing out all its elements. It also adds a set of pop/push_back() functions similar to the ones in the std::vector object.

Specification: dlib/array/array_expand_abstract.h

Implementations:
array_expand_1:
This is implemented by creating a new bigger array if max_size() isn't big enough, swapping everything into that new array, and then swapping that array with *this.
expand_1a
is a typedef for array_sort_1a extended by array_expand_1
expand_1a_c
is a typedef for expand_1a that checks its preconditions.
expand_1b
is a typedef for array_sort_1b extended by array_expand_1
expand_1b_c
is a typedef for expand_1b that checks its preconditions.
expand_1c
is a typedef for array_sort_2a extended by array_expand_1
expand_1c_c
is a typedef for expand_1c that checks its preconditions.
expand_1d
is a typedef for array_sort_2b extended by array_expand_1
expand_1d_c
is a typedef for expand_1d that checks its preconditions.
array_sort

This extension gives an array the ability to sort its contents.

Specification: dlib/array/array_sort_abstract.h

Implementations:
array_sort_1:
This is a version of the QuickSort algorithm. It swaps the entire array into a C style array, sorts it and then swaps it back into the array object.
sort_1a
is a typedef for array_kernel_1a extended by array_sort_1
sort_1a_c
is a typedef for sort_1a that checks its preconditions.
sort_1b
is a typedef for array_kernel_2a extended by array_sort_1
sort_1b_c
is a typedef for sort_1b that checks its preconditions.
array_sort_2:
This is a version of the QuickSort algorithm.
sort_2a
is a typedef for array_kernel_1a extended by array_sort_2
sort_2a_c
is a typedef for sort_2a that checks its preconditions.
sort_2b
is a typedef for array_kernel_2a extended by array_sort_2
sort_2b_c
is a typedef for sort_2b that checks its preconditions.
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array2d



This object represents a 2-Dimensional array of objects.

Specification: dlib/array2d/array2d_kernel_abstract.h
File to include: dlib/array2d.h
Code Examples: 1

Implementations:
array2d_kernel_1:
This is implemented in the obvious way. See the source for details. It uses the memory_manager for all memory allocations.
kernel_1a
is a typedef for array2d_kernel_1
kernel_1a_c
is a typedef for kernel_1a that checks its preconditions.
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binary_search_tree



This object represents a data dictionary that is built on top of some kind of binary search tree.

Specification: dlib/binary_search_tree/binary_search_tree_kernel_abstract.h
File to include: dlib/binary_search_tree.h

Implementations:
binary_search_tree_kernel_1:
This implementation is done using an AVL binary search tree. It uses the memory_manager for all memory allocations.
kernel_1a
is a typedef for binary_search_tree_kernel_1
kernel_1a_c
is a typedef for kernel_1a that checks its preconditions.
binary_search_tree_kernel_2:
This implementation is done using a red-black binary search tree. It uses the memory_manager for all memory allocations.
kernel_2a
is a typedef for binary_search_tree_kernel_2
kernel_2a_c
is a typedef for kernel_2a that checks its preconditions.
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directed_graph



This object represents a directed graph which is a set of nodes with directed edges connecting various nodes.

Specification: dlib/directed_graph/directed_graph_kernel_abstract.h
File to include: dlib/directed_graph.h

Implementations:
directed_graph_kernel_1:
This is implemented using std::vector to contain all the nodes and edges.
kernel_1a
is a typedef for directed_graph_kernel_1
kernel_1a_c
is a typedef for kernel_1a that checks its preconditions.
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enumerable



This object is an abstract class which represents an interface for iterating over all the elements of a container.

Specification: dlib/interfaces/enumerable.h
File to include: dlib/interfaces/enumerable.h

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graph



This object represents a graph which is a set of nodes with undirected edges connecting various nodes.

Specification: dlib/graph/graph_kernel_abstract.h
File to include: dlib/graph.h

Implementations:
graph_kernel_1:
This is implemented using std::vector to contain all the nodes and edges.
kernel_1a
is a typedef for graph_kernel_1
kernel_1a_c
is a typedef for kernel_1a that checks its preconditions.
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hash_map



This object represents a hashed mapping of items of type domain onto items of type range.

Specification: dlib/hash_map/hash_map_kernel_abstract.h
File to include: dlib/hash_map.h

Implementations:
hash_map_kernel_1:
This implementation is done using a hash_table object. It uses the memory_manager for all memory allocations.
kernel_1a
is a typedef for hash_map_kernel_1 that uses hash_table_kernel_1a
kernel_1a_c
is a typedef for kernel_1a that checks its preconditions.
kernel_1b
is a typedef for hash_map_kernel_1 that uses hash_table_kernel_2a
kernel_1b_c
is a typedef for kernel_1b that checks its preconditions.
kernel_1c
is a typedef for hash_map_kernel_1 that uses hash_table_kernel_2b
kernel_1c_c
is a typedef for kernel_1c that checks its preconditions.
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hash_set



This object represents a hashed unordered and unaddressed collection of unique items.

Specification: dlib/hash_set/hash_set_kernel_abstract.h
File to include: dlib/hash_set.h

Implementations:
hash_set_kernel_1:
This implementation is done using a hash_table object. It uses the memory_manager for all memory allocations.
kernel_1a
is a typedef for hash_set_kernel_1 that uses hash_table_kernel_1a
kernel_1a_c
is a typedef for kernel_1a that checks its preconditions.
kernel_1b
is a typedef for hash_set_kernel_1 that uses hash_table_kernel_2a
kernel_1b_c
is a typedef for kernel_1b that checks its preconditions.
kernel_1c
is a typedef for hash_set_kernel_1 that uses hash_table_kernel_2b
kernel_1c_c
is a typedef for kernel_1c that checks its preconditions.
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hash_table



This object represents a data dictionary that is built on top of some kind of hash table.

Specification: dlib/hash_table/hash_table_kernel_abstract.h
File to include: dlib/hash_table.h

Implementations:
hash_table_kernel_1:
This implementation is done using singly linked lists as hashing buckets. It uses the memory_manager for all memory allocations.
kernel_1a
is a typedef for hash_table_kernel_1.
kernel_1a_c
is a typedef for kernel_1a that checks its preconditions.
hash_table_kernel_2:
This implementation is done using binary_search_tree objects as hashing buckets. It uses the memory_manager for all memory allocations.
kernel_2a
is a typedef for hash_table_kernel_2 that uses binary_search_tree_kernel_1
kernel_2a_c
is a typedef for kernel_2a that checks its preconditions.
kernel_2b
is a typedef for hash_table_kernel_2 that uses binary_search_tree_kernel_2
kernel_2b_c
is a typedef for kernel_2b that checks its preconditions.
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map



This object represents a mapping of items of type domain onto items of type range.

Specification: dlib/map/map_kernel_abstract.h
File to include: dlib/map.h

Implementations:
map_kernel_1:
This is implemented using the binary_search_tree component. It uses the memory_manager for all memory allocations.
kernel_1a
is a typedef for map_kernel_1 that uses binary_search_tree_kernel_1
kernel_1a_c
is a typedef for kernel_1a that checks its preconditions.
kernel_1b
is a typedef for map_kernel_1 that uses binary_search_tree_kernel_2
kernel_1b_c
is a typedef for kernel_1b that checks its preconditions.
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map_pair



This object is an abstract class which represents an interface for accessing a pair from a container such as the map, hash_table, etc.

Specification: dlib/interfaces/map_pair.h
File to include: dlib/interfaces/map_pair.h

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matrix



This is a 2D matrix object that enables you to write code that deals with matrices using a simple syntax similar to what can be written in MATLAB. It is implemented using the expression templates technique which allows it to eliminate the temporary matrix objects that would normally be returned from expressions such as M = A+B+C+D; Normally each invocation of the + operator would construct and return a temporary matrix object but using this technique we can avoid creating all these temporary objects and receive a large speed boost.

This object is also capable of using BLAS and LAPACK libraries such as ATLAS or the Intel MKL when available. To enable BLAS support all you have to do is #define DLIB_USE_BLAS and then make sure you link your application with your BLAS library. Similarly, to enable LAPACK support just #define DLIB_USE_LAPACK and link to your LAPACK library. Finally, the use of BLAS and LAPACK is transparent to the user, that is, the dlib matrix object uses BLAS and LAPACK internally to optimize various operations while still allowing the user to use a simple MATLAB like syntax.

Note that the cmake files that come with dlib know how to link a project with ATLAS or the Intel MKL if you are building on a linux system. The cmake files may also work in a few other cases as well but I haven't tested any others. But in any case, by no means are you required to use the dlib cmake files.

It is also worth noting that all the preconditions of every function related to the matrix object are checked by DLIB_ASSERT statements and thus can be enabled by #defining ENABLE_ASSERTS or DEBUG. Doing this will cause your program to run slower but should catch any usage errors.

Finally, you don't need to #include anything to get the matrix extensions listed below. They are included by the dlib/matrix.h file for you.



Specification: dlib/matrix/matrix_abstract.h
File to include: dlib/matrix.h
Code Examples: 1, 2


Extensions to matrix

matrix_la

This extension contains linear algebra functions to calculate QR, LU, Cholesky, eigenvalue, and singular value decompositions. It also contains a few other miscellaneous functions that solve systems of equations or calculate values derived from the above decompositions.

Specification: dlib/matrix/matrix_la_abstract.h
matrix_math_functions

This extension contains mathematical functions that operate on each element of a matrix independently.

Specification: dlib/matrix/matrix_math_functions_abstract.h
matrix_sub_expressions

This extension contains a number of functions for dealing with sub-matrices.

Specification: dlib/matrix/matrix_subexp_abstract.h
matrix_utilities

This extension contains miscellaneous utility functions for manipulating matrix objects.

Specification: dlib/matrix/matrix_utilities_abstract.h
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queue



This object represents a first in first out queue.

Specification: dlib/queue/queue_kernel_abstract.h
File to include: dlib/queue.h
Code Examples: 1

Implementations:
queue_kernel_1:
This is implemented in the obvious way using a singly linked list. It does not use the memory_manager at all.
kernel_1a
is a typedef for queue_kernel_1
kernel_1a_c
is a typedef for kernel_1a that checks its preconditions.
queue_kernel_2:
This is implemented using a singly linked list and each node in the list contains block_size (a template parameter) elements. It uses the memory_manager for all memory allocations.
kernel_2a
is a typedef for queue_kernel_2 with a block_size of 20
kernel_2a_c
is a typedef for kernel_2a that checks its preconditions.
kernel_2b
is a typedef for queue_kernel_2 with a block_size of 100
kernel_2b_c
is a typedef for kernel_2b that checks its preconditions.

Extensions to queue

queue_sort

This extension gives a queue the ability to sort its contents.

Specification: dlib/queue/queue_sort_abstract.h

Implementations:
queue_sort_1:
This is a version of the QuickSort algorithm.
sort_1a
is a typedef for queue_kernel_1a extended by queue_sort_1
sort_1a_c
is a typedef for sort_1a that checks its preconditions.
sort_1b
is a typedef for queue_kernel_2a extended by queue_sort_1
sort_1b_c
is a typedef for sort_1b that checks its preconditions.
sort_1c
is a typedef for queue_kernel_2b extended by queue_sort_1
sort_1c_c
is a typedef for sort_1c that checks its preconditions.
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reference_counter



This object represents a container for an object and provides reference counting capabilities for the object it contains.

Specification: dlib/reference_counter/reference_counter_kernel_abstract.h
File to include: dlib/reference_counter.h

Implementations:
reference_counter_kernel_1:
This implementation is done using pointers in the obvious way.
kernel_1a
is a typedef for reference_counter_kernel_1
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reference_wrapper



This is a simple object that just holds a reference to another object. It is useful because it can serve as a kind of "copyable reference".

Specification: dlib/ref.h
File to include: dlib/ref.h
Code Examples: 1

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remover



This is a set of interfaces which gives the ability to remove all the items in a container without actually knowing what kind of container contains them.

Specification: dlib/interfaces/remover.h
File to include: dlib/interfaces/remover.h

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scoped_ptr



This is a implementation of the scoped_ptr class found in the Boost C++ library. It is a simple smart pointer class which guarantees that the pointer contained within it will always be deleted. The class does not permit copying and so does not do any kind of reference counting. Thus it is very simple and quite fast.

Specification: dlib/smart_pointers/scoped_ptr_abstract.h
File to include: dlib/smart_pointers.h

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sequence



This object represents an ordered sequence of items, each item is associated with an integer value. The items are numbered from 0 to the number of items in the sequence minus 1.

Specification: dlib/sequence/sequence_kernel_abstract.h
File to include: dlib/sequence.h

Implementations:
sequence_kernel_1:
This is implemented as an AVL binary search tree. Accessing(or adding or removing) an element always takes O(log n) time. It uses the memory_manager for all memory allocations.
kernel_1a
is a typedef for sequence_kernel_1
kernel_1a_c
is a typedef for kernel_1a that checks its preconditions.
sequence_kernel_2:
This implementation is done using a doubly linked list in the shape of a ring. It will remember the last element accessed(or added or removed) and give O(1) access time to the elements just left and right of it. Aside from that, accessing(or adding or removing) a random element will take O(n) and in the worst case it will take time proportional to the size of the sequence/2.

It does not use the memory_manager at all.

kernel_2a
is a typedef for sequence_kernel_2
kernel_2a_c
is a typedef for kernel_2a that checks its preconditions.

Extensions to sequence

sequence_compare

This extension gives sequences the ability to compare themselves using operator< and operator==. Thus they can be used in the other container classes that require this ability. (maps, sets, etc.)

Specification: dlib/sequence/sequence_compare_abstract.h

Implementations:
sequence_compare_1:
The implementation is obvious. Click on the sequence_compare_1 link if you want to see.
compare_1a
is a typedef for sequence_kernel_1a extended by sequence_compare_1
compare_1a_c
is a typedef for compare_1a that checks its preconditions.
compare_1b
is a typedef for sequence_kernel_2a extended by sequence_compare_1
compare_1b_c
is a typedef for compare_1b that checks its preconditions.
sequence_sort

This extension gives a sequence the ability to sort its contents.

Specification: dlib/sequence/sequence_sort_abstract.h

Implementations:
sequence_sort_1:
This is a version of the QuickSort algorithm and it sorts sequences of less than 30 elements with a selection sort. This implementation is fastest when used with sequence_kernel_2 and fairly slow when used with sequence_kernel_1
sort_1a
is a typedef for sequence_kernel_2a extended by sequence_sort_1
sort_1a_c
is a typedef for sort_1a that checks its preconditions.
sequence_sort_2:
This is a version of the QuickSort algorithm. This implementation of sort is the best to use with sequence_kernel_1 objects but gives extremely poor performance with sequence_kernel_2 objects.
sort_2a
is a typedef for sequence_kernel_1a extended by sequence_sort_2
sort_2a_c
is a typedef for sort_2a that checks its preconditions.
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set



This object represents an unordered and unaddressed collection of unique items.

Specification: dlib/set/set_kernel_abstract.h
File to include: dlib/set.h

Implementations:
set_kernel_1:
This is implemented using the binary_search_tree component. It uses the memory_manager for all memory allocations.
kernel_1a
is a typedef for set_kernel_1 that uses binary_search_tree_kernel_1
kernel_1a_c
is a typedef for kernel_1a that checks its preconditions.
kernel_1b
is a typedef for set_kernel_1 that uses binary_search_tree_kernel_2
kernel_1b_c
is a typedef for kernel_1b that checks its preconditions.

Extensions to set

set_compare

This extension gives sets the ability to compare themselves using operator< and operator==. Thus they can be used in the other container classes that require this ability. (maps, sets, etc.)

Specification: dlib/set/set_compare_abstract.h

Implementations:
set_compare_1:
The implementation is obvious. Click on the set_compare_1 link if you want to see.
compare_1a
is a typedef for set_kernel_1a extended by set_compare_1
compare_1a_c
is a typedef for compare_1a that checks its preconditions.
compare_1b
is a typedef for set_kernel_1b extended by set_compare_1
compare_1b_c
is a typedef for compare_1b that checks its preconditions.
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shared_ptr



This object represents a reference counted smart pointer. Each shared_ptr contains a pointer to some object and when the last shared_ptr that points to the object is destructed or reset() then the object is guaranteed to be deleted.

This is an implementation of the std::tr1::shared_ptr template from the document ISO/IEC PDTR 19768, Proposed Draft Technical Report on C++ Library Extensions. The only deviation from that document is that this shared_ptr is declared inside the dlib namespace rather than std::tr1.



Specification: dlib/smart_pointers/shared_ptr_abstract.h
File to include: dlib/smart_pointers.h

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shared_ptr_thread_safe



This object represents a reference counted smart pointer just like shared_ptr except that it is threadsafe.



Specification: dlib/smart_pointers/shared_ptr_thread_safe_abstract.h
File to include: dlib/smart_pointers_thread_safe.h

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sliding_buffer



This object represents an array with the ability to rotate its contents left or right.

Specification: dlib/sliding_buffer/sliding_buffer_kernel_abstract.h
File to include: dlib/sliding_buffer.h

Implementations:
sliding_buffer_kernel_1:
This object is implemented using a C style array in the obvious way. See the code for details.
kernel_1a
is a typedef for sliding_buffer_kernel_1
kernel_1a_c
is a typedef for kernel_1a that checks its preconditions.
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stack



This object represents a last in first out stack.

Specification: dlib/stack/stack_kernel_abstract.h
File to include: dlib/stack.h

Implementations:
stack_kernel_1:
This implementation is done in the obvious way using a singly linked list. It uses the memory_manager for all memory allocations.
kernel_1a
is a typedef for stack_kernel_1
kernel_1a_c
is a typedef for kernel_1a that checks its preconditions.
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static_map



This object represents a mapping of items of type domain onto items of type range. The difference between this object and the normal map object is that it does not support adding or removing individual objects from itself. This allows implementations to focus on using less memory and achieving faster searching.

Specification: dlib/static_map/static_map_kernel_abstract.h
File to include: dlib/static_map.h

Implementations:
static_map_kernel_1:
This implementation is just a sorted array which can be searched using a binary search.
kernel_1a
is a typedef for static_map_kernel_1
kernel_1a_c
is a typedef for kernel_1a that checks its preconditions.
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static_set



This object represents an unordered and unaddressed collection of items. The difference between this object and the normal set object is that it does not support adding or removing individual objects from itself. This allows implementations to focus on using less memory and achieving faster searching.

Specification: dlib/static_set/static_set_kernel_abstract.h
File to include: dlib/static_set.h

Implementations:
static_set_kernel_1:
This implementation is just a sorted array which can be searched using a binary search.
kernel_1a
is a typedef for static_set_kernel_1
kernel_1a_c
is a typedef for kernel_1a that checks its preconditions.

Extensions to static_set

static_set_compare

This extension gives static_sets the ability to compare themselves using operator< and operator==. Thus they can be used in the other container classes that require this ability. (maps, static_sets, etc.)

Specification: dlib/static_set/static_set_compare_abstract.h

Implementations:
static_set_compare_1:
The implementation is obvious. Click on the static_set_compare_1 link if you want to see.
compare_1a
is a typedef for static_set_kernel_1a extended by static_set_compare_1
compare_1a_c
is a typedef for compare_1a that checks its preconditions.
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std_vector_c



This object is a simple wrapper around the std::vector object. It provides an identical interface but also checks the preconditions of each member function. That is, if you violate a requires clause the dlib::fatal_error exception is thrown.

Specification: dlib/stl_checked/std_vector_c_abstract.h
File to include: dlib/stl_checked.h

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tuple



This is an implementation of a very simple templated container object. It contains between 0 and 31 objects where each object is listed explicitly in the tuple's template arguments.

Note that there is only one implementation of this object so there aren't any different kernels to choose from when you create instances of the tuple object. So for example, you could declare a tuple of 3 ints using the following statement: dlib::tuple<int,int,int> t;



Specification: dlib/tuple/tuple_abstract.h
File to include: dlib/tuple.h

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type_safe_union



This object is a type safe analogue of the classic C union object. The type_safe_union, unlike a union, can contain non-POD types such as std::string.

It is also implemented without performing any heap memory allocations and instead it stores everything on the stack.



Specification: dlib/type_safe_union/type_safe_union_kernel_abstract.h
File to include: dlib/type_safe_union.h
Code Examples: 1

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unordered_pair



This object is very similar to the std::pair struct except unordered_pair is only capable of representing an unordered set of two items rather than an ordered list of two items like std::pair.

Specification: dlib/unordered_pair.h
File to include: dlib/unordered_pair.h

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weak_ptr



The weak_ptr class template stores a weak reference to an object that is already managed by a shared_ptr. To access the object, a weak_ptr can be converted to a shared_ptr using the member function lock().

This is an implementation of the std::tr1::weak_ptr template from the document ISO/IEC PDTR 19768, Proposed Draft Technical Report on C++ Library Extensions. The only deviation from that document is that this shared_ptr is declared inside the dlib namespace rather than std::tr1.



Specification: dlib/smart_pointers/weak_ptr_abstract.h
File to include: dlib/smart_pointers.h