[bug-diffutils] bug#33144: Replace some loops with str functions

[Kapus, Timotej]

Hi, 

I'm writing a program analysis that tries to find and replace some loops with str* functions. I'm trying to see if these replacements are a useful refactoring or the loops are intentional. I noticed that diff has a couple of these loops and wrote a patch (pasted below) that changes this.

I find strspn easier to read, communicate intention and has less LOC, but would be interested to hear why you would like to keep the loops to.

Cheers,

Timotej

From 38e7030f127f567fd2d02f27663168dde4472d57 Mon Sep 17 00:00:00 2001

From: Timotej Kapus <address@hidden>

Date: Wed, 24 Oct 2018 23:47:22 +0100

Subject: [PATCH] maint: change 3 loops to strspn calls

  * src/ifdef.c: Change 3 loops to equivalent calls to strspn

---

 src/ifdef.c | 11 ++++-------

 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/src/ifdef.c b/src/ifdef.c

index 0ecc2c0..8046ac5 100644

--- a/src/ifdef.c

+++ b/src/ifdef.c

@@ -313,13 +313,10 @@ do_printf_spec (FILE *out, char const *spec,

   /* Scan printf-style SPEC of the form %[-'0]*[0-9]*(.[0-9]*)?[cdoxX].  */

   /* assert (*f == '%'); */

   f++;

-  while ((c = *f++) == '-' || c == '\'' || c == '0')

-    continue;

-  while (ISDIGIT (c))

-    c = *f++;

-  if (c == '.')

-    while (ISDIGIT (c = *f++))

-      continue;

+  f += strspn(f, "-\'0") + 1;

+  f += strspn(f, "0123456789") + 1;

+  if ((c = *f++) == '.')

+    f += strspn(f, "0123456789") + 1;

   c1 = *f++;

   switch (c)

--

2.7.4