read-until-match: streamline get_char calls.

Similarly to what was done in get_csv, we optimize he
use of get_char and unget_char. I see a 7.5% speed
improvement in a simple benchmark of the awk macro
with the record separator rs set to #/\n/.

* regex.c (scan_until_common): Obtain the strm_ops
operations of the stream, and pull the low level
get_char and unget_char virtual operations from it.
Call these directly in the loop. Thereby, we avoid
all the type checking overhead in these functions.

1 files changed, 7 insertions, 3 deletions

diff --git a/regex.c b/regex.c
index a5c187ff..ebd7b2f4 100644
--- a/regex.c
+++ b/regex.c
@@ -3197,6 +3197,10 @@ static val scan_until_common(val self, val regex, val stream_in,
   val match = nil;
   val stream = default_arg(stream_in, std_input);
   val include_match = default_null_arg(include_match_in);
+  struct strm_ops *ops = coerce(struct strm_ops *,
+                                cobj_ops(self, stream, stream_cls));
+  val (*get_char)(val) = ops->get_char;
+  val (*unget_char)(val, val) = ops->unget_char;
 
   regex_machine_init(self, &regm, regex);
 
@@ -3219,13 +3223,13 @@ static val scan_until_common(val self, val regex, val stream_in,
 
     switch (regex_machine_feed(&regm, c_chr(ch))) {
     case REGM_FAIL:
-      unget_char(ch, stream);
+      unget_char(stream, ch);
 
       if (match)
         goto out_match;
 
       while (stack)
-        unget_char(rcyc_pop(&stack), stream);
+        unget_char(stream, rcyc_pop(&stack));
 
       ch = get_char(stream);
 
@@ -3259,7 +3263,7 @@ static val scan_until_common(val self, val regex, val stream_in,
   if (nil) {
 out_match:
     while (stack && stack != match)
-      unget_char(rcyc_pop(&stack), stream);
+      unget_char(stream, rcyc_pop(&stack));
     if (accum && !out)
       out = null_string;
     if (include_match)