suffix functions: ignore trailing slashes.

Another requirements tweak to short-suffix and long-suffix:
ignore one or more trailing slashes, instead of just one.
This harmonizes with base-name, which does same, that
requirement being copies from the POSIX basename utility.

* stream.c (short_suffix, long_suffix): If sl points to a
trailing slash which is the start of a suffix that consists of
nothing but trailing slashes, then we pretend it isn't there.

* tests/018/path.tl: Adjusted two existing test cases, and
added more.

* txr.1: Documented.

3 files changed, 27 insertions, 9 deletions

diff --git a/stream.c b/stream.c
index a2f4baf1..4f4edbe3 100644
--- a/stream.c
+++ b/stream.c
@@ -5042,8 +5042,9 @@ val short_suffix(val name, val alt_in)
   const wchar_t *str = c_str(name, self);
   const wchar_t *dot = wcsrchr(str, '.');
   const wchar_t *sl = if3(dot, wcspbrk(dot + 1, psc), 0);
+  int sl_trail = if3(sl, sl[wcsspn(sl, psc)] == 0, 0);
 
-  if (!dot || (sl && sl[1]) || dot == str || wcschr(psc, dot[-1])) {
+  if (!dot || (sl && sl[1] && !sl_trail) || dot == str || wcschr(psc, dot[-1])) {
     return default_null_arg(alt_in);
   } else {
     wchar_t *suff = chk_strdup(dot);
@@ -5063,7 +5064,7 @@ val long_suffix(val name, val alt_in)
   {
     const wchar_t *sl;
 
-    while (dot && (sl = wcspbrk(dot, psc)) && sl[1])
+    while (dot && (sl = wcspbrk(dot, psc)) && sl[1] && sl[wcsspn(sl, psc)] != 0)
       dot = wcschr(sl + 1, '.');
 
     if (dot && (dot == str || wcschr(psc, dot[-1])))
@@ -5074,7 +5075,7 @@ val long_suffix(val name, val alt_in)
     } else {
       wchar_t *suff = chk_strdup(dot);
       if (sl)
-      suff[sl - dot] = 0;
+        suff[sl - dot] = 0;
       return string_own(suff);
     }
   }
diff --git a/tests/018/path.tl b/tests/018/path.tl
index 96298dfd..937d2d6e 100644
--- a/tests/018/path.tl
+++ b/tests/018/path.tl
@@ -49,7 +49,12 @@
   (short-suffix ".a/b/.b/") nil
   (short-suffix ".a/b/c.b") ".b"
   (short-suffix ".a/b/c.b/") ".b"
-  (short-suffix ".a/b/c.b//") nil)
+  (short-suffix ".a/b/c.b//") ".b"
+  (short-suffix ".a/b/c.b///") ".b"
+  (short-suffix ".a/b/c.") "."
+  (short-suffix ".a/b/c./") "."
+  (short-suffix ".a/b/c.//") "."
+  (short-suffix ".a/b/c.///") ".")
 
 (mtest
   (long-suffix "/") nil
@@ -67,7 +72,16 @@
   (long-suffix "a.b/c.d.e/") ".d.e"
   (long-suffix "a.b/c.d.e/f") nil
   (long-suffix "a.b/c.d.e/f.g.h") ".g.h"
-  (long-suffix "a.b/c.d.e//") nil)
+  (long-suffix "a.b/c.d.e//") ".d.e"
+  (long-suffix "a.b/c.d.e///") ".d.e"
+  (long-suffix "a.b/c.d.") ".d."
+  (long-suffix "a.b/c.d./") ".d."
+  (long-suffix "a.b/c.d.//") ".d."
+  (long-suffix "a.b/c.d.///") ".d."
+  (long-suffix "a.b/c.") "."
+  (long-suffix "a.b/c./") "."
+  (long-suffix "a.b/c.//") "."
+  (long-suffix "a.b/c.///") ".")
 
 (mtest
   (base-name "") ""
diff --git a/txr.1 b/txr.1
index 4b7e7236..d963097d 100644
--- a/txr.1
+++ b/txr.1
@@ -57406,10 +57406,10 @@ If a suffix delimiter is present, then the long or short suffix is the
 substring of
 .meta path
 which includes the delimiting period and all characters which follow,
-except that if the last character of
+except that if
 .meta path
-is a path separator character, that character is omitted from the
-returned suffix.
+ends in a sequence of one or more path separator characters,
+those characters are omitted from the returned suffix.
 
 If multiple periods occur in the last component of the path,
 the delimiter for the long suffix is the leftmost period and
@@ -57428,7 +57428,8 @@ For the purpose of identifying the last component of
 .metn path ,
 if
 .meta path
-ends in a path-separator character, then that character is removed.
+ends a sequence of one or more path-separator characters, then those
+characters are removed from consideration.
 If the remaining string contains path-separator characters, then
 the last component consists of that portion of it which follows
 the rightmost path-separator character. Otherwise, the last component
@@ -57446,6 +57447,7 @@ extracted from this last component.
   (short-suffix "abc" "") -> ""
   (short-suffix "abc.") -> "."
   (short-suffix "abc.tar") -> ".tar"
+  (short-suffix "abc.tar///") -> ".tar"
   (short-suffix "abc.tar.gz") -> ".gz"
   (short-suffix "abc.tar.gz/") -> ".gz"
   (short-suffix "x.y.z/abc.tar.gz/") -> ".gz"
@@ -57458,6 +57460,7 @@ extracted from this last component.
   (long-suffix "/.abc") -> nil
   (long-suffix "abc.") -> "."
   (long-suffix "abc.tar") -> ".tar"
+  (long-suffix "abc.tar///") -> ".tar"
   (long-suffix "abc.tar.gz") -> ".tar.gz"
   (long-suffix "abc.tar.gz/") -> ".tar.gz"
   (long-suffix "x.y.z/abc.tar.gz/") -> ".tar.gz"