[PATCH 7/7] rev: use string printing rather than character output

Sami Kerola
2013-07-28T21:11:46Z

Fliping a string in memory, and printing it with multibyte output
function makes the command about 1/3 quicker.

Signed-off-by: Sami Kerola <kerolasa@iki.fi>
---
text-utils/rev.c | 21 +++++++++++++--------
1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/text-utils/rev.c b/text-utils/rev.c
index 1c44036..85e1630 100644
--- a/text-utils/rev.c
+++ b/text-utils/rev.c
@@ -86,10 +86,20 @@ static void __attribute__ ((__noreturn__)) usage(FILE * out)
exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
}

+static void reverse_str(wchar_t *str, size_t n)
+{
+ size_t i;
+
+ for (i = 0; i < n / 2; ++i) {
+ wchar_t tmp = str[i];
+ str[i] = str[n - 1 - i];
+ str[n - 1 - i] = tmp;
+ }
+}
+
int main(int argc, char *argv[])
{
char *filename = "stdin";
- wchar_t *t;
size_t len, bufsiz = BUFSIZ;
FILE *fp = stdin;
int ch, rval = EXIT_SUCCESS;
@@ -153,13 +163,8 @@ int main(int argc, char *argv[])

len = wcslen(buf);
}
-
- if (*(t = buf + len - 1) == '\n')
- --t;
- for ( ; buf <= t; --t)
- putwchar(*t);
- if (!feof(fp))
- putwchar('\n');
+ reverse_str(buf, len - 1);
+ fputws(buf, stdout);
}
if (ferror(fp)) {
warn("%s", filename);
--
1.8.3.4