From 5339293fb868a0273507f6f9de705b2babd8dad5 Mon Sep 17 00:00:00 2001
From: glass <glass@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Fri, 2 Aug 2013 14:56:39 +0000
Subject: [PATCH] * array.c (rb_ary_zip): performance improvement by avoiding  
 array creation if rb_block_arity() > 1.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42336 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 ChangeLog |  5 +++++
 array.c   | 44 ++++++++++++++++++++++++++++++--------------
 2 files changed, 35 insertions(+), 14 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 9e668d8ba6..1c342313d5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri Aug  2 23:54:11 2013  Masaki Matsushita  <glass.saga@gmail.com>
+
+	* array.c (rb_ary_zip): performance improvement by avoiding
+	  array creation if rb_block_arity() > 1.
+
 Fri Aug  2 23:50:53 2013  Tanaka Akira  <akr@fsij.org>
 
 	* bignum.c (power_cache_get_power): Appry bigtrunc to the result of
diff --git a/array.c b/array.c
index 3d999e8879..b1ce74f98a 100644
--- a/array.c
+++ b/array.c
@@ -3146,7 +3146,7 @@ take_items(VALUE obj, long n)
 static VALUE
 rb_ary_zip(int argc, VALUE *argv, VALUE ary)
 {
-    int i, j;
+    int i, j, block_given, arity = 0;
     long len;
     VALUE result = Qnil;
 
@@ -3154,24 +3154,40 @@ rb_ary_zip(int argc, VALUE *argv, VALUE ary)
     for (i=0; i<argc; i++) {
 	argv[i] = take_items(argv[i], len);
     }
-    if (!rb_block_given_p()) {
+
+    block_given = rb_block_given_p();
+    if (block_given)
+	arity = rb_block_arity();
+    else
 	result = rb_ary_new2(len);
-    }
 
-    for (i=0; i<RARRAY_LEN(ary); i++) {
-	VALUE tmp = rb_ary_new2(argc+1);
+    if (block_given && arity > 1) {
+	int yield_argc = argc + 1;
+	VALUE *yield_argv = ALLOC_N(VALUE, yield_argc);
 
-	rb_ary_push(tmp, rb_ary_elt(ary, i));
-	for (j=0; j<argc; j++) {
-	    rb_ary_push(tmp, rb_ary_elt(argv[j], i));
-	}
-	if (NIL_P(result)) {
-	    rb_yield(tmp);
-	}
-	else {
-	    rb_ary_push(result, tmp);
+	for (i=0; i<RARRAY_LEN(ary); i++) {
+	    yield_argv[0] = RARRAY_AREF(ary, i);
+	    for (j=0; j<argc; j++) {
+		yield_argv[j+1] = rb_ary_elt(argv[j], i);
+	    }
+	    rb_yield_values2(yield_argc, yield_argv);
 	}
     }
+    else {
+	for (i=0; i<RARRAY_LEN(ary); i++) {
+	    VALUE tmp = rb_ary_new2(argc+1);
+
+	    rb_ary_push(tmp, RARRAY_AREF(ary, i));
+	    for (j=0; j<argc; j++) {
+		rb_ary_push(tmp, rb_ary_elt(argv[j], i));
+	    }
+	    if (block_given)
+		rb_yield(tmp);
+	    else
+		rb_ary_push(result, tmp);
+	}
+    }
+
     return result;
 }