blog posting [1].
- Use word-sized test for unaligned pointer before working
the hard way.
Memory page boundary is always integral multiple of a word
alignment boundary. Therefore, if we can access memory
referenced by pointer p, then (p & ~word mask) must be also
accessible.
- Better utilization of multi-issue processor's ability of
concurrency.
The previous implementation utilized a formular that must be
executed sequentially. However, the ~, & and - operations can
actually be caculated at the same time when the operand were
different and unrelated.
The original Hacker's Delight formular also offered consistent
performance regardless whether the input would contain
characters with their highest-bit set, as it catches real
nul characters only.
These two optimizations has shown further improvements over the
previous implementation on microbenchmarks on i386 and amd64 CPU
including Pentium 4, Core Duo 2 and i7.
[1] http://vger.kernel.org/~davem/cgi-bin/blog.cgi/2010/03/08#strlen_1
MFC after: 1 month
wcscasecmp(), and wcsncasecmp().
- Make some previously non-standard extensions visible
if POSIX_VISIBLE >= 200809.
- Use restrict qualifiers in stpcpy().
- Declare off_t and size_t in stdio.h.
- Bump __FreeBSD_version in case the new symbols (particularly
getline()) cause issues with ports.
Reviewed by: standards@
reducing branches and doing word-sized operation.
The idea is taken from J.T. Conklin's x86_64 optimized version of strlen(3)
for NetBSD, and reimplemented in C by me.
Discussed on: -arch@
Copyright attribution is kept the same as in original NetBSD source.
Submitted by: Florian Smeets <flo kasimir com>
Obtained from: NetBSD
MFC after: 2 weeks
on long long arguments.
Reviewed by: bde (previous version, that included asm implementation
for all ffs and fls functions on i386 and amd64)
MFC after: 2 weeks
It is the binary equivalent to strstr(3).
void *memmem(const void *big, size_t big_len,
const void *little, size_t little_len);
Submitted by: Pascal Gloor <pascal.gloor at spale.com>
MFC after: 3 days
implementations inspired by the ones in DragonFly. Unlike the
DragonFly versions, these have a small data cache footprint, and my
tests show that they're never slower than the old code except when the
charset or the span is 0 or 1 characters. This implementation is
generally faster than DragonFly until either the charset or the span
gets in the ballpark of 32 to 64 characters.
http://www.opengroup.org/onlinepubs/009695399/functions/swab.html
the prototype for swab() should be in <unistd.h> and not in <string.h>.
Move it, and update to match SUS. Leave the prototype in string.h for
now, for backwards compat.
PR: 74751
Submitted by: Craig Rodrigues <rodrigc@crodrigues.org>
Discussed with: das
almost identical.
* Merge strchr(3) and strrchr(3) to strchr(3) since the two functions
are almost identical.
* Make the wording of index(3) and strchr(3) more similar.
* mdoc(7) cleanup.
Submitted by: SUZUKI Koichi <metal@gc5.so-net.ne.jp>, keramida, myself
PR: docs/32054
Reviewed by: ru
Approved by: ceri (mentor)
technique) so that we don't wind up calling into an application's
version if the application defines them.
Inspired by: qpopper's interfering and buggy version of strlcpy
As a side effect, it makes the code easier to read and requires less
pointer arithmetic.
Test by: strerror regression test
Submitted by: Tim Kientzle <kientzle@acm.org>
o Fix an English error (comma splice) and poorly worded sentence.
o Fix KNF ordering of variables (pointers come before arithmetic types).
o Restore hand-optimization of sizeof()-1, instead of strlen().
o Remove unneeded local variables in strerror_r().
Test by: strerror regression test
Requested by: bde
Reviewed by: bde
strerror_r(). Doing this allows us to ensure that strerror_r() always
fills the supplied buffer regardless of EINVAL or ERANGE errors.
strerror()'s semantics have changed slightly such that an argument of
0 is now considered invalid and errno is set to EINVAL.
Remove internal regression test for strerror() and strerror_r(). This
will be reincarnated in src/tools/regression/lib/libc/string.
In strerror(3), add a comment about strerror()'s bogus return type.
PR: 44356
more efficient. The problem with the previous implementation was that it
calculated the length of the first argument ("big") with wcslen() when
it was not necessary.
two major bugs:
- off-by-one overflow when the length of the source string exceeds or
equals the destination buffer size.
- old version was not padding the destination buffer with null wide chars
bcopy(3) functions are prototyped in <strings.h> and not in
<string.h> anymore.
- Add a sentence about that to the respective HISTORY sections.
In the C source files:
- Include <string.h> or <strings.h> depending on what function
is to be compiled.
- Use ANSI-C function definitions.
.In string.h
with
.In strings.h
and adding a sentence to the HISTORY section.
- Use an ANSI-C function definition.
- Include <strings.h> instead of <string.h>.
- Apply style(9): Put a space after return keywords.
in the ANSI-C format.
- Change the code a bit to hopefully save some cycles.
I.e. (simplified) change
a = b + 1;
while (--b & 0x7)
/* ... */
to
a = b;
for (; b & 0x7; b--)
/* ... */
and
while (--a >= 0)
/* ... */
to
for (; a > 0; a--)
/* ... */
- Equip two function arguments of swab() with the 'restrict'
type qualifier in form of the '__restrict' macro. This is
specified by POSIX.1-2001.
<strings.h> as the associated header file.
The prototypes have been moved there from <string.h> because
POSIX.1-2001 said so.
- Conditionally include either <strings.h> or <string.h> based
on whether the [r]index() or str[r]chr() functions are
compiled, respectively.
- Style(9) tells us to
- put a space after the return keyword
- to check for a NUL character without using the ! operator.
- use NULL instead of (type *)NULL where the compiler knows
the type.
Apply these rules.
- Rather use ANSI-C function definitions than K&R ones.
- For index(3), correct second function argument's type; it was
declared to be a `const char' before and is now an `int'.
is <strings.h> and not <string.h> anymore.
- Tell the reader about this change in the HISTORY section.
- Switch to use an ANSI-C function definition.
- Include <strings.h> instead of <string.h> in the source file.
the prototypes for both functions are now in the <strings.h>
header, as required by IEEE Std 1003.1-2001.
- Add one sentence about that in the HISTORY section.
- Include <strings.h> in the source file to have the prototypes
in scope when the _ANSI_SOURCE macro is defined.
concatenation and copy functions using the '__restrict' macro.
This is to satisfy IEEE Std 1003-1.2001.
- Use ANSI-C function definitions.
- Add the 'restrict' keyword to the manual pages, too.
to the function definition of strxfrm(3) in form of our
'__restrict' macro.
- Use an ANSI-C function definition for strxfrm(3).
- Change the manual page accordingly.
the first revision of strcpy(3)'s section is included, but should be
removed as the Security Architecture document is committed and
completed.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, NAI Labs
This will be trimmed as the FreeBSD Security Architecture document
is fleshed out and committed.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, NAI Labs
more careful about reporting truncation with ERANGE in strerror_r.
Set errno to EINVAL for "unknown" errnum in strerror as required
by P1003.1-200x Draft June 14, 2001.
More carefully document the handling of strerrbuf when errors
(ERANGE, EINVAL) are encountered in strerror_r.
Reviewed by: bde (ongoing discussion)
number of characters that are searched. This is especially useful
with file operations and non-NUL terminated strings.
Silence from: -audit, -hackers
MFC after: 5 days
