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| AutoBuffer () |
| the default constructor
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| AutoBuffer (const AutoBuffer< _Tp, fixed_size > &buf) |
| the copy constructor
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| AutoBuffer (size_t _size) |
| constructor taking the real buffer size
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| ~AutoBuffer () |
| destructor. calls deallocate()
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void | allocate (size_t _size) |
| allocates the new buffer of size _size. if the _size is small enough, stack-allocated buffer is used
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_Tp * | data () |
| returns pointer to the real buffer, stack-allocated or heap-allocated
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const _Tp * | data () const |
| returns read-only pointer to the real buffer, stack-allocated or heap-allocated
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void | deallocate () |
| deallocates the buffer if it was dynamically allocated
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| operator _Tp * () |
| returns pointer to the real buffer, stack-allocated or heap-allocated
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| operator const _Tp * () const |
| returns read-only pointer to the real buffer, stack-allocated or heap-allocated
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AutoBuffer< _Tp, fixed_size > & | operator= (const AutoBuffer< _Tp, fixed_size > &buf) |
| the assignment operator
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void | resize (size_t _size) |
| resizes the buffer and preserves the content
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size_t | size () const |
| returns the current buffer size
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template<typename
_Tp, size_t fixed_size = 1024/sizeof(_Tp)+8>
class cv::AutoBuffer< _Tp, fixed_size >
Automatically Allocated Buffer Class.
The class is used for temporary buffers in functions and methods. If a temporary buffer is usually small (a few K's of memory), but its size depends on the parameters, it makes sense to create a small fixed-size array on stack and use it if it's large enough. If the required buffer size is larger than the fixed size, another buffer of sufficient size is allocated dynamically and released after the processing. Therefore, in typical cases, when the buffer size is small, there is no overhead associated with malloc()/free(). At the same time, there is no limit on the size of processed data.
This is what AutoBuffer does. The template takes 2 parameters - type of the buffer elements and the number of stack-allocated elements. Here is how the class is used:
{
...
}
Automatically Allocated Buffer Class.
Definition utility.hpp:102
_Tp buf[(fixed_size > 0) ? fixed_size :1]
pre-allocated buffer. At least 1 element to confirm C++ standard requirements
Definition utility.hpp:150
n-dimensional dense array class
Definition mat.hpp:950
int rows
the number of rows and columns or (-1, -1) when the matrix has more than 2 dimensions
Definition mat.hpp:2424