scanner-utils: optimize one-line comments

Compose files have a lot of those.

Signed-off-by: Ran Benita <ran234@gmail.com>

src/compose/parser.c

@@ -134,7 +134,7 @@ skip_more_whitespace_and_comments:
 
     /* Skip comments. */
     if (chr(s, '#')) {
-        while (!eof(s) && !eol(s)) next(s);
+        skip_to_eol(s);
         goto skip_more_whitespace_and_comments;
     }
 

src/scanner-utils.h

@@ -102,6 +102,15 @@ eol(struct scanner *s)
     return peek(s) == '\n';
 }
 
+static inline void
+skip_to_eol(struct scanner *s)
+{
+    const char *nl = memchr(s->s + s->pos, '\n', s->len - s->pos);
+    const size_t new_pos = nl ? (size_t) (nl - s->s) : s->len;
+    s->column += new_pos - s->pos;
+    s->pos = new_pos;
+}
+
 static inline char
 next(struct scanner *s)
 {

src/xkbcomp/rules.c

@@ -85,7 +85,7 @@ skip_more_whitespace_and_comments:
 
     /* Skip comments. */
     if (lit(s, "//")) {
-        while (!eof(s) && !eol(s)) next(s);
+        skip_to_eol(s);
     }
 
     /* New line. */

src/xkbcomp/scanner.c

@@ -69,7 +69,7 @@ skip_more_whitespace_and_comments:
 
     /* Skip comments. */
     if (lit(s, "//") || chr(s, '#')) {
-        while (!eof(s) && !eol(s)) next(s);
+        skip_to_eol(s);
         goto skip_more_whitespace_and_comments;
     }