view buf_resize.3 @ 17:2694997c4c90

buf: add a test against SIZE_MAX when doubling While here, explain more what the code does at some points.
author David Demelier <markand@malikania.fr>
date Wed, 16 Dec 2020 16:12:31 +0100
parents b1991ee4451d
children 939fe74cd80a
line wrap: on
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.\"
.\" buf_resize.3 -- simple string buffer for C
.\"
.\" Copyright (c) 2019-2020 David Demelier <markand@malikania.fr>
.\"
.\" Permission to use, copy, modify, and/or distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd October 29, 2019-2020
.Dt BUF_RESIZE 3
.Os
.\" NAME
.Sh NAME
.Nm buf_resize
.Nd change string length
.\" SYNOPSIS
.Sh SYNOPSIS
.In buf.h
.Ft bool
.Fn buf_resize "struct buf *b" "size_t size" "char c"
.\" DESCRIPTION
.Sh DESCRIPTION
Change the buffer length specified by
.Fa b
to the new
.Fa size
and optionally fill new space with character
.Fa c .
.Pp
This function serves two purposes, it can reduce the string length if the
.Fa size
argument is smaller than current
.Fa b
length or it can increase it and fill the new region with
.Fa c .
In the first case, the function never fails in the second it may need to
reallocate data which could fail if no memory is available.
.Pp
Note that in constrast to
.Fn buf_shrink
function, the
.Fn buf_resize
function never reallocate data if the new size is smaller, you may want to call
.Fn buf_shrink
if memory should be released.
.\" RETURN VALUE
.Sh RETURN VALUE
The
.Fn buf_resize
function returns false in case of error and
.Va errno
is set to indicate the error.
.\" ERRORS
.Sh ERRORS
.Bl -tag -width Er
.It Bq Er ENOMEM
Couldn't allocate more memory.
.El
.\" SEE ALSO
.Sh SEE ALSO
.Xr libbuf 3 ,
.Xr buf_resize 3 ,
.Xr buf_shrink 3
.\" AUTHORS
.Sh AUTHORS
The
.Nm libbuf
library was written by
.An David Demelier <markand@malikania.fr>