.fp 5 CW

.de Af

.ds ;G \\*(;G\\f\\$1\\$3\\f\\$2

.if !\\$4 .Af \\$2 \\$1 "\\$4" "\\$5" "\\$6" "\\$7" "\\$8" "\\$9"

..

.de aF

.ie \\$3 .ft \\$1

.el \{\

.ds ;G \&

.nr ;G \\n(.f

.Af "\\$1" "\\$2" "\\$3" "\\$4" "\\$5" "\\$6" "\\$7" "\\$8" "\\$9"

\\*(;G

.ft \\n(;G \}

..

.de L

.aF 5 \\n(.f "\\$1" "\\$2" "\\$3" "\\$4" "\\$5" "\\$6" "\\$7"

..

.de LR

.aF 5 1 "\\$1" "\\$2" "\\$3" "\\$4" "\\$5" "\\$6" "\\$7"

..

.de RL

.aF 1 5 "\\$1" "\\$2" "\\$3" "\\$4" "\\$5" "\\$6" "\\$7"

..

.de EX \" start example

.ta 1i 2i 3i 4i 5i 6i

.PP

.RS

.PD 0

.ft 5

.nf

..

.de EE \" end example

.fi

.ft

.PD

.RE

.PP

..

.TH SWAP 3

.SH NAME

swap \- integral representation conversion routines

.SH SYNOPSIS

.L "#include <swap.h>"

.sp

.L "int swapop(const void* internal, const void* external, int width);

.L "int_max swapget(int op, const void* from, int width);"

.L "void* swapput(int op, void* to, int width, int_max value);"

.L "void* swapmem(int op, const void* from, void* to, size_t n);"

.SH DESCRIPTION

These routines convert integral constants between internal and

external representations.

They are used to handle binary data generated by foreign programs.

New binary data representations should use the compact canonical form

provided by the

.IR sfio (3)

routines

.L sfputu

and

.LR sgetu .

.PP

.L swapop

returns the swap operation required to convert the

.L width

byte integer

.L external

to the

.L width

byte integer

.LR internal .

The swap operation is a bit mask:

.TP

.L 0

No swapping necessary.

.TP

.L 1

Swap byte

.L 0

with byte

.LR 1 .

.TP

.L 2

Swap bytes

.L 0

and

.L 1

with bytes

.L 2

and

.LR 3 .

.TP

.L 4

Swap bytes

.L 0-3

with bytes

.LR 4-7 ,

and so on.

The largest native integral type is defined by the macro

.L int_max

in the header

.L <int.h>

described in

.IR int (3).

.PP

.L swapget

returns the

.L width

byte integer in the buffer

.LR from ,

swapped according to

.LR op .

.PP

.L swapput

copies the

.L width

byte integer

.L value

into the buffer

.LR to ,

swapped according to

.LR op .

.L to

is returned.

.PP

.L swapmem

swaps

.L n

bytes from the buffer

.L from

to the buffer

.L to

according to

.LR op .

.L to

and

.L from

may be the same.

.SH "SEE ALSO"

int(3)