Vkm::Engine::BitWriter Class Reference

Packs values to the bit into a byte buffer. More...

#include <bit_stream.h>

Public Member Functions
	BitWriter (std::vector< uint8_t > &bytes, size_t capacity)
	Write into bytes, filling at most capacity of them.
void	bits (uint32_t value, uint32_t width)
	Write the low width bits of value.
void	u64 (uint64_t value)
	Two words, high first, because the field width is capped at 32.
void	f32 (float value)
	A float as its exact bits, for the values quantisation would spoil.
void	append (const uint8_t *bytes, size_t count)
	Write count bits from bytes, starting at its first bit.
size_t	bitCount () const
	Bits written so far.
size_t	byteCount () const
	Whole bytes needed to carry what has been written.
bool	overflowed () const
	True when a write did not fit.
void	finish ()
	Flush the last partial byte into the buffer.

Detailed Description

Packs values to the bit into a byte buffer.

A field costs what it needs, not its type's size: a flag is one bit.

Bounded by the packet's size: a write past it sets a sticky overflow flag instead of growing, so a caller asks once whether it all fit. Bits gather in a 64-bit word; the last partial byte stays there until finish().

Constructor & Destructor Documentation

BitWriter()

Vkm::Engine::BitWriter::BitWriter ( std::vector< uint8_t > & bytes, size_t capacity )

inline

Write into bytes, filling at most capacity of them.

Parameters

bytes	Buffer to fill; emptied, then grown as bytes complete. Holds the whole stream only after finish().
capacity	The packet's ceiling, in bytes.

Member Function Documentation

bits()

void Vkm::Engine::BitWriter::bits ( uint32_t value, uint32_t width )

inline

Write the low width bits of value.

Parameters

value	Value to write; bits above width are ignored.
width	1 to 32.

append()

void Vkm::Engine::BitWriter::append ( const uint8_t * bytes, size_t count )

inline

Write count bits from bytes, starting at its first bit.

For splicing something already encoded, which is not a whole number of bytes.

Parameters

bytes	Buffer holding the encoded bits, first bit first.
count	Bits to take from it.

overflowed()

bool Vkm::Engine::BitWriter::overflowed ( ) const

inline

True when a write did not fit.

Sticky, so a caller tests once at the end.

Returns

Whether any write since construction was refused.

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

• net/wire/bit_stream.h