From: Akim Demaille <akim@epita.fr>
Date: Fri, 28 Apr 2000 09:46:55 +0000 (+0000)
Subject: mawk suffers a severe performance loss when using `sub' with a
X-Git-Tag: autoconf-2.50~957
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2df476bb0c9b56c8c9fcf164188422ed0d881f0a;p=thirdparty%2Fautoconf.git

mawk suffers a severe performance loss when using `sub' with a
changing value.  On the `configure' script of the fileutils:
mawk '{ sub (/foo/, foo++) }'                  -> 14s.
mawk '{ if ($0 ~ /foo/) sub (/foo/, foo++) }'  -> 0.03s.
mawk '{ sub (/foo/, foo) }'                    -> 0.03s.

* autoconf.sh (task script, AWK script): Run `sub (__oline__,
oline)' only in the lines that match `__oline__'.
Suggested by Paul Eggert.
---

diff --git a/ChangeLog b/ChangeLog
index 79e153173..173933bb6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,15 @@
+2000-04-28  Akim Demaille  <akim@epita.fr>
+
+	mawk suffers a severe performance loss when using `sub' with a
+	changing value.  On the `configure' script of the fileutils:
+	mawk '{ sub (/foo/, foo++) }'                  -> 14s.
+	mawk '{ if ($0 ~ /foo/) sub (/foo/, foo++) }'  -> 0.03s.
+	mawk '{ sub (/foo/, foo) }'                    -> 0.03s.
+
+	* autoconf.sh (task script, AWK script): Run `sub (__oline__,
+	oline)' only in the lines that match `__oline__'.
+	Suggested by Paul Eggert.
+
 2000-04-28  Akim Demaille  <akim@epita.fr>
 
 	* autoconf.sh (options handling::-W*): Strip two leading chars, not
diff --git a/autoconf.in b/autoconf.in
index d5e296e33..db19c30e1 100644
--- a/autoconf.in
+++ b/autoconf.in
@@ -308,8 +308,9 @@ case $task in
         }
       duplicate = 0
       oline++
-      while (sub(/__oline__/, oline))
-        continue
+      if ($0 ~ /__oline__/)
+        while (sub(/__oline__/, oline))
+          continue
       while (sub(/@<:@/, "["))
         continue
       while (sub(/@:>@/, "]"))
diff --git a/autoconf.sh b/autoconf.sh
index d5e296e33..db19c30e1 100644
--- a/autoconf.sh
+++ b/autoconf.sh
@@ -308,8 +308,9 @@ case $task in
         }
       duplicate = 0
       oline++
-      while (sub(/__oline__/, oline))
-        continue
+      if ($0 ~ /__oline__/)
+        while (sub(/__oline__/, oline))
+          continue
       while (sub(/@<:@/, "["))
         continue
       while (sub(/@:>@/, "]"))
diff --git a/bin/autoconf.in b/bin/autoconf.in
index d5e296e33..db19c30e1 100644
--- a/bin/autoconf.in
+++ b/bin/autoconf.in
@@ -308,8 +308,9 @@ case $task in
         }
       duplicate = 0
       oline++
-      while (sub(/__oline__/, oline))
-        continue
+      if ($0 ~ /__oline__/)
+        while (sub(/__oline__/, oline))
+          continue
       while (sub(/@<:@/, "["))
         continue
       while (sub(/@:>@/, "]"))