On 01/03/2014 08:40 PM, Алексей Шилин wrote:
> Looks like I was overly cautious about decrementing an unsigned...
>
> size_t n = bytes_read;
> while (n)
> {
> if (all_lines)
> n -= n ? 1 : 0; // ...here.
> else
>
> As it is under `while (n)' statement, n is always true here, and thus the
> ternary operator, though makes no
> harm, is needless, and the whole line can be replaced with just `n--;'. Sorry
> for that.
>
> The fixed version of the original patch is attached.
>
I've updated the patch to also handle the pipe case,
and I added a test. Will push soon.
thanks,
Pádraig.
>From b1387eb3e922398ab90cf6aa63cac6dea37971fb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=D0=90=D0=BB=D0=B5=D0=BA=D1=81=D0=B5=D0=B9=20=D0=A8=D0=B8=D0?=
=?UTF-8?q?=BB=D0=B8=D0=BD?= <[email protected]>
Date: Wed, 29 Jan 2014 01:23:46 +0000
Subject: [PATCH] head: fix --lines=-0 outputting nothing if no newline at EOF
* src/head.c (elide_tail_lines_pipe): Just output all input in
this case to avoid the issue and also avoid redundant '\n' processing.
(elide_tail_lines_seekable): Likewise.
* tests/misc/head-elide-tail.pl: Add tests for no '\n' at EOF.
* NEWS: Mention the fix.
Fixes http://bugs.gnu.org/16329
---
NEWS | 4 ++++
src/head.c | 27 +++++++++++++++++++++------
tests/misc/head-elide-tail.pl | 7 +++++--
3 files changed, 30 insertions(+), 8 deletions(-)
diff --git a/NEWS b/NEWS
index e091d18..f86e589 100644
--- a/NEWS
+++ b/NEWS
@@ -14,6 +14,10 @@ GNU coreutils NEWS -*- outline -*-
when reading the SELinux context for a file.
[bug introduced in coreutils-8.22]
+ head --lines=-0, when the input does not contain a trailing '\n',
+ now copies all input to stdout. Previously nothing was output in this case.
+ [bug introduced with the --lines=-N feature in coreutils-5.0.1]
+
ln -sf now replaces symbolic links whose targets can't exist. Previously
it would display an error, requiring --no-dereference to avoid the issue.
[bug introduced in coreutils-5.3.0]
diff --git a/src/head.c b/src/head.c
index ddaa990..ef368d7 100644
--- a/src/head.c
+++ b/src/head.c
@@ -501,6 +501,13 @@ elide_tail_lines_pipe (const char *filename, int fd, uintmax_t n_elide)
n_read = safe_read (fd, tmp->buffer, BUFSIZ);
if (n_read == 0 || n_read == SAFE_READ_ERROR)
break;
+
+ if (! n_elide)
+ {
+ fwrite (tmp->buffer, 1, n_read, stdout);
+ continue;
+ }
+
tmp->nbytes = n_read;
tmp->nlines = 0;
tmp->next = NULL;
@@ -636,8 +643,11 @@ elide_tail_lines_seekable (const char *pretty_filename, int fd,
return false;
}
+ /* n_lines == 0 case needs special treatment. */
+ const bool all_lines = !n_lines;
+
/* Count the incomplete line on files that don't end with a newline. */
- if (bytes_read && buffer[bytes_read - 1] != '\n')
+ if (n_lines && bytes_read && buffer[bytes_read - 1] != '\n')
--n_lines;
while (1)
@@ -647,11 +657,16 @@ elide_tail_lines_seekable (const char *pretty_filename, int fd,
size_t n = bytes_read;
while (n)
{
- char const *nl;
- nl = memrchr (buffer, '\n', n);
- if (nl == NULL)
- break;
- n = nl - buffer;
+ if (all_lines)
+ n -= 1;
+ else
+ {
+ char const *nl;
+ nl = memrchr (buffer, '\n', n);
+ if (nl == NULL)
+ break;
+ n = nl - buffer;
+ }
if (n_lines-- == 0)
{
/* Found it. */
diff --git a/tests/misc/head-elide-tail.pl b/tests/misc/head-elide-tail.pl
index 758e1c9..3c178d6 100755
--- a/tests/misc/head-elide-tail.pl
+++ b/tests/misc/head-elide-tail.pl
@@ -52,6 +52,8 @@ my @Tests =
['elide-l2', "--lines=-1", {IN=>"a"}, {OUT=>''}],
['elide-l3', "--lines=-1", {IN=>"a\nb"}, {OUT=>"a\n"}],
['elide-l4', "--lines=-1", {IN=>"a\nb\n"}, {OUT=>"a\n"}],
+ ['elide-l5', "--lines=-0", {IN=>"a\nb\n"}, {OUT=>"a\nb\n"}],
+ ['elide-l6', "--lines=-0", {IN=>"a\nb"}, {OUT=>"a\nb"}],
);
if ($ENV{RUN_EXPENSIVE_TESTS})
@@ -80,9 +82,10 @@ if ($ENV{RUN_EXPENSIVE_TESTS})
}
$s =~ s/(.)/$1\n/g;
- for my $file_size (0..20)
+ $s .= 'u'; # test without trailing '\n'
+ for my $file_size (0..21)
{
- for my $n_elide (0..20)
+ for my $n_elide (0..21)
{
my $input = substr $s, 0, 2 * $file_size;
my $out_len = $n_elide < $file_size ? $file_size - $n_elide : 0;
--
1.7.7.6
