signet::forge::Arena Class Reference

Bump-pointer arena allocator for batch Parquet reads. More...

#include <memory.hpp>

Public Member Functions
	Arena (size_t block_size=64 *1024)
	Construct an arena with the given default block size.
	~Arena ()=default
void *	allocate (size_t size, size_t alignment=8)
	Allocate aligned memory from the arena.
void *	allocate_zeroed (size_t size, size_t alignment=alignof(std::max_align_t))
	Allocate zero-initialized memory from the arena.
template<typename T >
T *	allocate_array (size_t count)
	Allocate a typed array of count elements from the arena.
const uint8_t *	copy (const uint8_t *data, size_t size)
	Copy raw bytes into the arena and return a pointer to the copy.
const char *	copy_string (const std::string &str)
	Copy a string into the arena (including null terminator).
size_t	bytes_used () const
	Total bytes allocated (excluding alignment padding).
void	reset ()
	Reset the arena, reusing all memory blocks without freeing them.
	Arena (const Arena &)=delete
	Non-copyable.
Arena &	operator= (const Arena &)=delete
	Non-copyable.
	Arena (Arena &&) noexcept=default
	Move-constructible.
Arena &	operator= (Arena &&) noexcept=default
	Move-assignable.

Detailed Description

Bump-pointer arena allocator for batch Parquet reads.

Maintains a list of memory blocks. Allocations bump a pointer within the current block; when a block is exhausted a new one is allocated. reset() recycles all blocks without freeing, making them available for reuse.

Non-copyable, movable. Thread-safety: not thread-safe – callers must synchronize externally if shared across threads.

See also

ColumnReader (primary consumer for zero-copy page decoding)

Definition at line 33 of file memory.hpp.

Constructor & Destructor Documentation

Arena() [1/3]

signet::forge::Arena::Arena ( size_t  block_size = 64 * 1024 )

inlineexplicit

Construct an arena with the given default block size.

Parameters

block_size

Default allocation block size in bytes (default 64 KiB).

Definition at line 37 of file memory.hpp.

~Arena()

signet::forge::Arena::~Arena ( )

default

Arena() [2/3]

signet::forge::Arena::Arena ( const Arena &  )

delete

Non-copyable.

Arena() [3/3]

signet::forge::Arena::Arena ( Arena &&  )

defaultnoexcept

Move-constructible.

Member Function Documentation

allocate()

void * signet::forge::Arena::allocate ( size_t  size, size_t  alignment = 8  )

inline

Allocate aligned memory from the arena.

Attempts to satisfy the allocation from the current block. If the current block cannot accommodate the request, a new block is allocated whose size is at least size + alignment or block_size_, whichever is larger.

Parameters

size	Number of bytes to allocate (0 returns nullptr).
alignment	Required alignment (must be a power of 2, default 8).

Returns

Pointer to the allocated memory, or nullptr if size is 0.

Definition at line 52 of file memory.hpp.

allocate_array()

template<typename T >

T * signet::forge::Arena::allocate_array ( size_t  count )

inline

Allocate a typed array of count elements from the arena.

Elements are not constructed (raw memory only). The alignment is derived from alignof(T).

Template Parameters

T	Element type.

Parameters

count

Number of elements (0 returns nullptr).

Returns

Pointer to the first element, or nullptr if count is 0.

Definition at line 107 of file memory.hpp.

allocate_zeroed()

void * signet::forge::Arena::allocate_zeroed ( size_t  size, size_t  alignment = alignof(std::max_align_t)  )

inline

Allocate zero-initialized memory from the arena.

CWE-908: Use of Uninitialized Resource — zeroing prevents information leaks from recycled arena blocks or stale heap memory.

Equivalent to allocate() followed by memset to zero. Useful for security-sensitive buffers where uninitialized memory could leak data.

Parameters

size	Number of bytes to allocate (0 returns nullptr).
alignment	Required alignment (must be a power of 2, default max_align_t).

Returns

Pointer to zero-filled memory, or nullptr if size is 0.

Definition at line 92 of file memory.hpp.

bytes_used()

size_t signet::forge::Arena::bytes_used ( ) const

inline

Total bytes allocated (excluding alignment padding).

Returns

Cumulative allocation count in bytes.

Definition at line 141 of file memory.hpp.

copy()

const uint8_t * signet::forge::Arena::copy ( const uint8_t *  data, size_t  size  )

inline

Copy raw bytes into the arena and return a pointer to the copy.

Parameters

data	Source bytes to copy (nullptr returns nullptr).
size	Number of bytes to copy (0 returns nullptr).

Returns

Pointer to the arena-owned copy, or nullptr on empty input.

Definition at line 119 of file memory.hpp.

copy_string()

const char * signet::forge::Arena::copy_string ( const std::string &  str )

inline

Copy a string into the arena (including null terminator).

Parameters

str	The string to copy.

Returns

Pointer to the null-terminated arena-owned copy.

Definition at line 131 of file memory.hpp.

operator=() [1/2]

Arena & signet::forge::Arena::operator= ( Arena &&  )

defaultnoexcept

Move-assignable.

operator=() [2/2]

Arena & signet::forge::Arena::operator= ( const Arena &  )

delete

Non-copyable.

reset()

void signet::forge::Arena::reset ( )

inline

Reset the arena, reusing all memory blocks without freeing them.

After reset, subsequent allocations reuse existing block memory. This avoids the cost of repeated malloc/free across batches.

Definition at line 147 of file memory.hpp.

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

• include/signet/memory.hpp