de85bfc508
It seems two of the file system drivers we have in the tree, namely ufs and ext3, use a function called `skpc()'. The meaning of this function does not seem to be documented in FreeBSD, but it turns out one needs to be a VAX programmer to understand what it does. SPKC is an instruction on the VAX that does the opposite of memchr(). It searches for the non-equal character. Add a new function called memcchr() to the tree that has the following advantages over skpc(): - It has a name that makes more sense than skpc(). Just like strcspn() matches the complement of strspn(), memcchr() is the complement of memchr(). - It is faster than skpc(). Similar to our strlen() in libc, it compares entire words, instead of single bytes. It seems that for this routine this yields a sixfold performance increase on amd64. - It has a man page.
60 lines
1.9 KiB
Groff
60 lines
1.9 KiB
Groff
.\" Copyright (c) 2012 Ed Schouten <ed@FreeBSD.org>
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd January 1, 2012
|
|
.Dt MEMCCHR 9
|
|
.Os
|
|
.Sh NAME
|
|
.Nm memcchr
|
|
.Nd locate the complement of a byte in byte string
|
|
.Sh SYNOPSIS
|
|
.In sys/libkern.h
|
|
.Ft void *
|
|
.Fn memcchr "const void *b" "int c" "size_t len"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn memcchr
|
|
function locates the first occurrence of a byte unequal to
|
|
.Fa c
|
|
(converted to an
|
|
.Vt "unsigned char" )
|
|
in string
|
|
.Fa b .
|
|
.Sh RETURN VALUES
|
|
The
|
|
.Fn memcchr
|
|
function return a pointer to the byte located, or NULL if no such byte
|
|
exists within
|
|
.Fa len
|
|
bytes.
|
|
.Sh SEE ALSO
|
|
.Xr memchr 3
|
|
.Sh HISTORY
|
|
The
|
|
.Fn memcchr
|
|
function first appeared in
|
|
.Fx 10.0 .
|