pack (Buffer Packing and Unpacking)

Overview

Platform- and endianness-independent buffer packing and unpacking.

For 16- and 32-bit integer packing and unpacking:

#include "etcpal/pack.h"

For 64-bit integer packing and unpacking:

#include "etcpal/pack64.h"

This module defines macros for packing and unpacking integer types to/from a byte buffer. They are architected in such a way that the endianness of the integer in the buffer is always known, regardless of the endianness of your platform.

For example:

uint8_t buf[4];
etcpal_pack_u32b(buf, 0x11223344); // Pack 32-bit value, big-endian
 
// buf now contains { 0x11, 0x22, 0x33, 0x44 }
 
uint32_t val = etcpal_unpack_u32b(&buf); // Unpack 32-bit value, big-endian
etcpal_pack_u32l(&buf, val); // Pack 32-bit value, little-endian
 
// buf now contains { 0x44, 0x33, 0x22, 0x11 }

Functions
int16_t	etcpal_unpack_i16b (const uint8_t *buf)
	Unpack an int16_t from a known big-endian buffer. More...
void	etcpal_pack_i16b (uint8_t *buf, int16_t val)
	Pack an int16_t to a known big-endian buffer. More...
int16_t	etcpal_unpack_i16l (const uint8_t *buf)
	Unpack an int16_t from a known little-endian buffer. More...
void	etcpal_pack_i16l (uint8_t *buf, int16_t val)
	Pack an int16_t to a known little-endian buffer. More...
uint16_t	etcpal_unpack_u16b (const uint8_t *buf)
	Unpack a uint16_t from a known big-endian buffer. More...
void	etcpal_pack_u16b (uint8_t *buf, uint16_t val)
	Pack a uint16_t to a known big-endian buffer. More...
uint16_t	etcpal_unpack_u16l (const uint8_t *buf)
	Unpack a uint16_t from a known little-endian buffer. More...
void	etcpal_pack_u16l (uint8_t *buf, uint16_t val)
	Pack a uint16_t to a known little-endian buffer. More...
int32_t	etcpal_unpack_i32b (const uint8_t *buf)
	Unpack an int32_t from a known big-endian buffer. More...
void	etcpal_pack_i32b (uint8_t *buf, int32_t val)
	Pack an int32_t to a known big-endian buffer. More...
int32_t	etcpal_unpack_i32l (const uint8_t *buf)
	Unpack an int32_t from a known little-endian buffer. More...
void	etcpal_pack_i32l (uint8_t *buf, int32_t val)
	Pack an int32_t to a known little-endian buffer. More...
uint32_t	etcpal_unpack_u32b (const uint8_t *buf)
	Unpack a uint32_t from a known big-endian buffer. More...
void	etcpal_pack_u32b (uint8_t *buf, uint32_t val)
	Pack a uint32_t to a known big-endian buffer. More...
uint32_t	etcpal_unpack_u32l (const uint8_t *buf)
	Unpack a uint32_t from a known little-endian buffer. More...
void	etcpal_pack_u32l (uint8_t *buf, uint32_t val)
	Pack a uint32_t to a known little-endian buffer. More...
int64_t	etcpal_unpack_i64b (const uint8_t *buf)
	Unpack an int64_t from a known big-endian buffer. More...
void	etcpal_pack_i64b (uint8_t *buf, int64_t val)
	Pack an int64_t to a known big-endian buffer. More...
int64_t	etcpal_unpack_i64l (const uint8_t *buf)
	Unpack an int64_t from a known little-endian buffer. More...
void	etcpal_pack_i64l (uint8_t *buf, int64_t val)
	Pack an int64_t to a known little-endian buffer. More...
uint64_t	etcpal_unpack_u64b (const uint8_t *buf)
	Unpack a uint64_t from a known big-endian buffer. More...
void	etcpal_pack_u64b (uint8_t *buf, uint64_t val)
	Pack a uint64_t to a known big-endian buffer. More...
uint64_t	etcpal_unpack_u64l (const uint8_t *buf)
	Unpack a uint64_t from a known little-endian buffer. More...
void	etcpal_pack_u64l (uint8_t *buf, uint64_t val)
	Pack a uint64_t to a known little-endian buffer. More...

Function Documentation

etcpal_pack_i16b()

void etcpal_pack_i16b	(	uint8_t *	buf,
		int16_t	val
	)

Pack an int16_t to a known big-endian buffer.

Parameters

buf	Pointer to the buffer into which to pack a value; must be at least 2 bytes in size.
val	Value to pack into the buffer.

etcpal_pack_i16l()

void etcpal_pack_i16l	(	uint8_t *	buf,
		int16_t	val
	)

Pack an int16_t to a known little-endian buffer.

Parameters

buf	Pointer to the buffer into which to pack a value; must be at least 2 bytes in size.
val	Value to pack into the buffer.

etcpal_pack_i32b()

void etcpal_pack_i32b	(	uint8_t *	buf,
		int32_t	val
	)

Pack an int32_t to a known big-endian buffer.

Parameters

buf	Pointer to the buffer into which to pack a value; must be at least 4 bytes in size.
val	Value to pack into the buffer.

etcpal_pack_i32l()

void etcpal_pack_i32l	(	uint8_t *	buf,
		int32_t	val
	)

Pack an int32_t to a known little-endian buffer.

Parameters

buf	Pointer to the buffer into which to pack a value; must be at least 4 bytes in size.
val	Value to pack into the buffer.

etcpal_pack_i64b()

void etcpal_pack_i64b	(	uint8_t *	buf,
		int64_t	val
	)

Pack an int64_t to a known big-endian buffer.

Parameters

buf	Pointer to the buffer into which to pack a value; must be at least 8 bytes in size.
val	Value to pack into the buffer.

etcpal_pack_i64l()

void etcpal_pack_i64l	(	uint8_t *	buf,
		int64_t	val
	)

Pack an int64_t to a known little-endian buffer.

Parameters

buf	Pointer to the buffer into which to pack a value; must be at least 8 bytes in size.
val	Value to pack into the buffer.

etcpal_pack_u16b()

void etcpal_pack_u16b	(	uint8_t *	buf,
		uint16_t	val
	)

Pack a uint16_t to a known big-endian buffer.

Parameters

buf	Pointer to the buffer into which to pack a value; must be at least 2 bytes in size.
val	Value to pack into the buffer.

etcpal_pack_u16l()

void etcpal_pack_u16l	(	uint8_t *	buf,
		uint16_t	val
	)

Pack a uint16_t to a known little-endian buffer.

Parameters

buf	Pointer to the buffer into which to pack a value; must be at least 2 bytes in size.
val	Value to pack into the buffer.

etcpal_pack_u32b()

void etcpal_pack_u32b	(	uint8_t *	buf,
		uint32_t	val
	)

Pack a uint32_t to a known big-endian buffer.

Parameters

buf	Pointer to the buffer into which to pack a value; must be at least 4 bytes in size.
val	Value to pack into the buffer.

etcpal_pack_u32l()

void etcpal_pack_u32l	(	uint8_t *	buf,
		uint32_t	val
	)

Pack a uint32_t to a known little-endian buffer.

Parameters

buf	Pointer to the buffer into which to pack a value; must be at least 4 bytes in size.
val	Value to pack into the buffer.

etcpal_pack_u64b()

void etcpal_pack_u64b	(	uint8_t *	buf,
		uint64_t	val
	)

Pack a uint64_t to a known big-endian buffer.

Parameters

buf	Pointer to the buffer into which to pack a value; must be at least 8 bytes in size.
val	Value to pack into the buffer.

etcpal_pack_u64l()

void etcpal_pack_u64l	(	uint8_t *	buf,
		uint64_t	val
	)

Pack a uint64_t to a known little-endian buffer.

Parameters

buf	Pointer to the buffer into which to pack a value; must be at least 8 bytes in size.
val	Value to pack into the buffer.

etcpal_unpack_i16b()

int16_t etcpal_unpack_i16b

(

const uint8_t *

buf

)

Unpack an int16_t from a known big-endian buffer.

Parameters

buf	Pointer to the buffer from which to unpack a value; must be at least 2 bytes in size.

Returns

Unpacked value.

etcpal_unpack_i16l()

int16_t etcpal_unpack_i16l

(

const uint8_t *

buf

)

Unpack an int16_t from a known little-endian buffer.

Parameters

buf	Pointer to the buffer from which to unpack a value; must be at least 2 bytes in size.

Returns

Unpacked value.

etcpal_unpack_i32b()

int32_t etcpal_unpack_i32b

(

const uint8_t *

buf

)

Unpack an int32_t from a known big-endian buffer.

Parameters

buf	Pointer to the buffer from which to unpack a value; must be at least 4 bytes in size.

Returns

Unpacked value.

etcpal_unpack_i32l()

int32_t etcpal_unpack_i32l

(

const uint8_t *

buf

)

Unpack an int32_t from a known little-endian buffer.

Parameters

buf	Pointer to the buffer from which to unpack a value; must be at least 4 bytes in size.

Returns

Unpacked value.

etcpal_unpack_i64b()

int64_t etcpal_unpack_i64b

(

const uint8_t *

buf

)

Unpack an int64_t from a known big-endian buffer.

Parameters

buf	Pointer to the buffer from which to unpack a value; must be at least 8 bytes in size.

Returns

Unpacked value.

etcpal_unpack_i64l()

int64_t etcpal_unpack_i64l

(

const uint8_t *

buf

)

Unpack an int64_t from a known little-endian buffer.

Parameters

buf	Pointer to the buffer from which to unpack a value; must be at least 8 bytes in size.

Returns

Unpacked value.

etcpal_unpack_u16b()

uint16_t etcpal_unpack_u16b

(

const uint8_t *

buf

)

Unpack a uint16_t from a known big-endian buffer.

Parameters

buf	Pointer to the buffer from which to unpack a value; must be at least 2 bytes in size.

Returns

Unpacked value.

etcpal_unpack_u16l()

uint16_t etcpal_unpack_u16l

(

const uint8_t *

buf

)

Unpack a uint16_t from a known little-endian buffer.

Parameters

buf	Pointer to the buffer from which to unpack a value; must be at least 2 bytes in size.

Returns

Unpacked value.

etcpal_unpack_u32b()

uint32_t etcpal_unpack_u32b

(

const uint8_t *

buf

)

Unpack a uint32_t from a known big-endian buffer.

Parameters

buf	Pointer to the buffer from which to unpack a value; must be at least 4 bytes in size.

Returns

Unpacked value.

etcpal_unpack_u32l()

uint32_t etcpal_unpack_u32l

(

const uint8_t *

buf

)

Unpack a uint32_t from a known little-endian buffer.

Parameters

buf	Pointer to the buffer from which to unpack a value; must be at least 4 bytes in size.

Returns

Unpacked value.

etcpal_unpack_u64b()

uint64_t etcpal_unpack_u64b

(

const uint8_t *

buf

)

Unpack a uint64_t from a known big-endian buffer.

Parameters

buf	Pointer to the buffer from which to unpack a value; must be at least 8 bytes in size.

Returns

Unpacked value.

etcpal_unpack_u64l()

uint64_t etcpal_unpack_u64l

(

const uint8_t *

buf

)

Unpack a uint64_t from a known little-endian buffer.

Parameters

buf	Pointer to the buffer from which to unpack a value; must be at least 8 bytes in size.

Returns

Unpacked value.