utils.h File Reference

General purpose utility functions. More...

#include "common.h"

Go to the source code of this file.

Macros
#define	cx_for_n(varname, n)   for (size_t varname = 0 ; (varname) < (n) ; (varname)++)
	Convenience macro for a for loop that counts from zero to n-1.
#define	cx_swap_ptr(left, right)   do {void *cx_tmp_swap_var = left; left = right; right = cx_tmp_swap_var;} while(0)
	Convenience macro for swapping two pointers.
#define	cx_szmul(a, b, result)   cx_szmul_impl(a, b, result)
	Performs a multiplication of size_t values and checks for overflow.
#define	cx_stream_bcopy(src, dest, rfnc, wfnc, buf, bufsize)    cx_stream_bncopy(src, dest, rfnc, wfnc, buf, bufsize, SIZE_MAX)
	Reads data from a stream and writes it to another stream.
#define	cx_stream_copy(src, dest, rfnc, wfnc)    cx_stream_ncopy(src, dest, rfnc, wfnc, SIZE_MAX)
	Reads data from a stream and writes it to another stream.

Functions
int	cx_szmul_impl (size_t a, size_t b, size_t *result)
	Performs a multiplication of size_t values and checks for overflow.
size_t	cx_stream_bncopy (void *src, void *dest, cx_read_func rfnc, cx_write_func wfnc, char *buf, size_t bufsize, size_t n)
	Reads data from a stream and writes it to another stream.
size_t	cx_stream_ncopy (void *src, void *dest, cx_read_func rfnc, cx_write_func wfnc, size_t n)
	Reads data from a stream and writes it to another stream.

Detailed Description

General purpose utility functions.

Author

Mike Becker

Olaf Wintermann

Version

3.0

Copyright

2-Clause BSD License

Macro Definition Documentation

cx_stream_bcopy

#define cx_stream_bcopy	(		src,
			dest,
			rfnc,
			wfnc,
			buf,
			bufsize
	)		cx_stream_bncopy(src, dest, rfnc, wfnc, buf, bufsize, SIZE_MAX)

Reads data from a stream and writes it to another stream.

Parameters

src	the source stream
dest	the destination stream
rfnc	the read function
wfnc	the write function
buf	a pointer to the copy buffer or NULL if a buffer shall be implicitly created on the heap
bufsize	the size of the copy buffer - if buf is NULL you can set this to zero to let the implementation decide

Returns

total number of bytes copied

cx_stream_copy

#define cx_stream_copy	(		src,
			dest,
			rfnc,
			wfnc
	)		cx_stream_ncopy(src, dest, rfnc, wfnc, SIZE_MAX)

Reads data from a stream and writes it to another stream.

The data is temporarily stored in a stack allocated buffer.

Parameters

src	the source stream
dest	the destination stream
rfnc	the read function
wfnc	the write function

Returns

total number of bytes copied

cx_szmul

#define cx_szmul	(		a,
			b,
			result
	)		cx_szmul_impl(a, b, result)

Performs a multiplication of size_t values and checks for overflow.

Parameters

a	first operand
b	second operand
result	a pointer to a size_t, where the result should be stored

Returns

zero, if no overflow occurred and the result is correct, non-zero otherwise

Function Documentation

cx_stream_bncopy()

size_t cx_stream_bncopy	(	void *	src,
		void *	dest,
		cx_read_func	rfnc,
		cx_write_func	wfnc,
		char *	buf,
		size_t	bufsize,
		size_t	n
	)

Reads data from a stream and writes it to another stream.

Parameters

src	the source stream
dest	the destination stream
rfnc	the read function
wfnc	the write function
buf	a pointer to the copy buffer or NULL if a buffer shall be implicitly created on the heap
bufsize	the size of the copy buffer - if buf is NULL you can set this to zero to let the implementation decide
n	the maximum number of bytes that shall be copied. If this is larger than bufsize, the content is copied over multiple iterations.

Returns

the total number of bytes copied

cx_stream_ncopy()

size_t cx_stream_ncopy	(	void *	src,
		void *	dest,
		cx_read_func	rfnc,
		cx_write_func	wfnc,
		size_t	n
	)

Reads data from a stream and writes it to another stream.

The data is temporarily stored in a stack allocated buffer.

Parameters

src	the source stream
dest	the destination stream
rfnc	the read function
wfnc	the write function
n	the maximum number of bytes that shall be copied.

Returns

total number of bytes copied

cx_szmul_impl()

int cx_szmul_impl	(	size_t	a,
		size_t	b,
		size_t *	result
	)

Performs a multiplication of size_t values and checks for overflow.

This is a custom implementation in case there is no compiler builtin available.

Parameters

a	first operand
b	second operand
result	a pointer to a size_t where the result should be stored

Returns

zero, if no overflow occurred and the result is correct, non-zero otherwise