CxxUtils::pointer_list_base::allocator Class Reference

Very simple allocator for use with pointer_list. More...

#include <pointer_list.h>

Inheritance diagram for CxxUtils::pointer_list_base::allocator:

Collaboration diagram for CxxUtils::pointer_list_base::allocator:

Classes
struct	chunk
	One memory allocation chunk. More...

Public Member Functions
	allocator (size_t nelt, size_t nblock, unsigned long end_mask, unsigned long end_offs)
	Constructor. More...
	~allocator ()
	Destructor. Deletes all blocks from this allocator. More...
list_block *	allocate ()
	Allocate a new block. More...
size_t	nelt () const
	Return the number of pointers per block (excluding the end-pointer). More...
size_t	nchunks () const
	Return the current number of allocated chunks. More...
bool	at_end (const void *p) const
	Test if P is pointing at the end-pointer of a block. More...

Private Member Functions
void	refill ()
	Allocate a new chunk of blocks. More...

Private Attributes
size_t	m_nelt
	Number of elements per block (excluding the end-pointer). More...
size_t	m_nblock
	Number of blocks per chunk. More...
chunk *	m_chunks
	Most recent chunk allocated. More...
size_t	m_nthis
	Number of blocks allocated so far from that chunk. More...
size_t	m_nchunks
	Current number of allocated chunks. More...
unsigned long	m_end_mask
	Mask for testing for an end pointer. More...
unsigned long	m_end_offs
	Offset for testing for an end pointer. More...

Detailed Description

Very simple allocator for use with pointer_list.

We allocate large chunks and divide them up into list_block's. We don't support deleting individual elements; instead, everything is deleted when the allocator is. The chunks are chained together to allow for this.

The total size of a block should be a power of two, and blocks must be aligned to this boundary.

Definition at line 94 of file pointer_list.h.

Constructor & Destructor Documentation

allocator()

CxxUtils::pointer_list_base::allocator::allocator	(	size_t	nelt,
		size_t	nblock,
		unsigned long	end_mask,
		unsigned long	end_offs
	)

Constructor.

Parameters

nelt	Number of pointers per block (excluding the end pointer). Must be one less than a power of two.
nblock	Number of blocks to allocate per chunk.
end_mask	Mask to use for end-of-block test.
end_offs	Offset to use for end-of-block test.
nelt	Number of pointers per block. (excluding the end pointer).
nblock	Number of blocks to allocate per chunk.
end_mask	Mask to use for end-of-block test.
end_offs	Offset to use for end-of-block test.

Definition at line 29 of file pointer_list.cxx.

  : m_nelt (nelt),
    m_nblock (nblock),
    m_chunks (0),
    m_nthis (nblock),
    m_nchunks (0),
    m_end_mask (end_mask),
    m_end_offs (end_offs)
{
}

~allocator()

CxxUtils::pointer_list_base::allocator::~allocator

(

)

Destructor. Deletes all blocks from this allocator.

Destructor.

Deletes all blocks from this allocator.

Definition at line 47 of file pointer_list.cxx.

{
  // Loop over the chunks, deleting each one.
  chunk* ch = m_chunks;
  while (ch) {
    chunk* next = ch->m_next;
    delete [] reinterpret_cast<char*> (ch);
    ch = next;
  }
}

Member Function Documentation

allocate()

list_block* CxxUtils::pointer_list_base::allocator::allocate

(

)

Allocate a new block.

at_end()

bool CxxUtils::pointer_list_base::allocator::at_end

(

const void *

p

)

const

Test if P is pointing at the end-pointer of a block.

nchunks()

size_t CxxUtils::pointer_list_base::allocator::nchunks

(

)

const

Return the current number of allocated chunks.

nelt()

size_t CxxUtils::pointer_list_base::allocator::nelt

(

)

const

Return the number of pointers per block (excluding the end-pointer).

refill()

void CxxUtils::pointer_list_base::allocator::refill ( )

private

Allocate a new chunk of blocks.

Definition at line 62 of file pointer_list.cxx.

{
  char* p = new char
    [(sizeof(chunk) + m_nblock*list_block::size(m_nelt)) +
     list_block::size(m_nelt)-1];
  chunk* ch = reinterpret_cast<chunk*> (p);
 
  // Align.
  unsigned long pp = reinterpret_cast<unsigned long> (ch+1);
  pp = (pp + m_end_mask) & ~m_end_mask;
  ch->m_blocks = reinterpret_cast<list_block*> (pp);
 
  ch->m_next = m_chunks;
  m_chunks = ch;
  ++m_nchunks;
 
  // No blocks allocated so far from this chunk.
  m_nthis = 0;
}

Member Data Documentation

m_chunks

chunk* CxxUtils::pointer_list_base::allocator::m_chunks

private

Most recent chunk allocated.

Definition at line 149 of file pointer_list.h.

m_end_mask

unsigned long CxxUtils::pointer_list_base::allocator::m_end_mask

private

Mask for testing for an end pointer.

Definition at line 158 of file pointer_list.h.

m_end_offs

unsigned long CxxUtils::pointer_list_base::allocator::m_end_offs

private

Offset for testing for an end pointer.

Definition at line 161 of file pointer_list.h.

m_nblock

size_t CxxUtils::pointer_list_base::allocator::m_nblock

private

Number of blocks per chunk.

Definition at line 146 of file pointer_list.h.

m_nchunks

size_t CxxUtils::pointer_list_base::allocator::m_nchunks

private

Current number of allocated chunks.

Definition at line 155 of file pointer_list.h.

m_nelt

size_t CxxUtils::pointer_list_base::allocator::m_nelt

private

Number of elements per block (excluding the end-pointer).

Definition at line 143 of file pointer_list.h.

m_nthis

size_t CxxUtils::pointer_list_base::allocator::m_nthis

private

Number of blocks allocated so far from that chunk.

Definition at line 152 of file pointer_list.h.

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The documentation for this class was generated from the following files:

• pointer_list.h
• pointer_list.cxx