Binary data

Functions
M_uint8 *	M_bin_wrap (const M_uint8 *value, size_t len)
M_uint8 *	M_bin_wrapeddup (const M_uint8 *value)
void *	M_bin_wrapeddup_vp (const void *value)
const M_uint8 *	M_bin_unwrap (const M_uint8 *value, size_t *len)
M_uint8 *	M_bin_unwrapdup (const M_uint8 *value, size_t *len)

Detailed Description

Allows for wrapping binary data into a data type that includes both length and data. This is to allow binary data to be passed around as a single pointer instead of having to manage the data separate from the length.

Binary data of form data, len will be wrapped into len+data. The length prefix is always fixed as 8. 8 was chosen instead of sizeof(size_t) because 32bit Solaris Sparc sizeof(size_t) is 4 but alignment is 8. 8 is also sizeof(size_t) on 64bit platforms.

Example:

M_uint8  data[3] = { 1, 2, 3 };
M_uint8 *wd;
M_uint8 *wd_dup;
size_t   len;
 
wd     = M_bin_wrap(data, 3);
wd_dup = M_bin_wrapeddup(wd);
 
M_free(wd);
wd = M_bin_unwrapdup(wd_dup, &len);
 
M_free(wd);
M_free(wd_dup);
 
M_printf(len='%zu'\n", len);

Function Documentation

M_bin_wrap()

M_uint8 * M_bin_wrap	(	const M_uint8 *	value,
		size_t	len
	)

Duplicate a binary value with the length prepended.

Parameters

[in]	value	The binary data.
[in]	len	The length of value.

Returns

Allocated memory of len+data of length len+sizeof(len). Where sizeof(size_t) is typically 8.

M_bin_wrapeddup()

M_uint8 * M_bin_wrapeddup

(

const M_uint8 *

value

)

Duplicates binary data that has the length prepended.

The data would have to have been created using M_bin_wrap. The prepended length is used to determine how much memory to duplicate.

Parameters

[in]

value

Wrapped binary data to duplicate.

Returns

Copy of wrapped data (len+data).

M_bin_wrapeddup_vp()

void * M_bin_wrapeddup_vp

(

const void *

value

)

Duplicates data that has the length prepended.

The data would have to have been created using M_bin_wrap. The prepended length is used to determine how much memory to duplicate. This function should be considered unsafe and is only provided as a convience to avoid casting if the data is not an M_uint8.

Parameters

[in]

value

Wrapped binary data to duplicate.

Returns

Copy of wrapped data (len+data).

See also

M_bin_wrapeddup

M_bin_unwrap()

const M_uint8 * M_bin_unwrap	(	const M_uint8 *	value,
		size_t *	len
	)

Unwrap wrapped binary data.

Parameters

[in]	value	Wrapped binary data.
[out]	len	The length of the binary data.

Returns

Pointer to start of data within value.

M_bin_unwrapdup()

M_uint8 * M_bin_unwrapdup	(	const M_uint8 *	value,
		size_t *	len
	)

Unwrap wrapped binary data and return a copy of the data.

Parameters

[in]	value	Wrapped binary data.
[out]	len	The length of the binary data.

Returns

Allocated memory with a copy of data from value. The prepended length will not be duplicated.