From f1dc2f4775a35e1b3c1edc2d0aee3e2bc22d1e6a Mon Sep 17 00:00:00 2001
From: Alexey Milovidov <milovidov@yandex-team.ru>
Date: Fri, 3 Apr 2015 19:16:02 +0300
Subject: [PATCH] dbms: fixed error [#METR-15387].

---
 .../DB/Functions/FunctionsStringSearch.h      | 19 +++++++++++++------
 .../0_stateless/00144_empty_regexp.reference  |  2 ++
 .../0_stateless/00144_empty_regexp.sql        |  2 ++
 .../0_stateless/00145_empty_likes.reference   | 16 ++++++++++++++++
 .../queries/0_stateless/00145_empty_likes.sql | 18 ++++++++++++++++++
 5 files changed, 51 insertions(+), 6 deletions(-)
 create mode 100644 dbms/tests/queries/0_stateless/00144_empty_regexp.reference
 create mode 100644 dbms/tests/queries/0_stateless/00144_empty_regexp.sql
 create mode 100644 dbms/tests/queries/0_stateless/00145_empty_likes.reference
 create mode 100644 dbms/tests/queries/0_stateless/00145_empty_likes.sql

diff --git a/dbms/include/DB/Functions/FunctionsStringSearch.h b/dbms/include/DB/Functions/FunctionsStringSearch.h
index 50c65394f47..351fb47f1ef 100644
--- a/dbms/include/DB/Functions/FunctionsStringSearch.h
+++ b/dbms/include/DB/Functions/FunctionsStringSearch.h
@@ -395,14 +395,21 @@ struct MatchImpl
 
 			if (required_substring.empty())
 			{
-				size_t prev_offset = 0;
-				for (size_t i = 0; i < size; ++i)
+				if (!regexp->getRE2())	/// Пустой регексп. Всегда матчит.
 				{
-					res[i] = revert ^ regexp->getRE2()->Match(
-						re2_st::StringPiece(reinterpret_cast<const char *>(&data[prev_offset]), offsets[i] - prev_offset - 1),
-						0, offsets[i] - prev_offset - 1, re2_st::RE2::UNANCHORED, nullptr, 0);
+					memset(&res[0], 1, size * sizeof(res[0]));
+				}
+				else
+				{
+					size_t prev_offset = 0;
+					for (size_t i = 0; i < size; ++i)
+					{
+						res[i] = revert ^ regexp->getRE2()->Match(
+							re2_st::StringPiece(reinterpret_cast<const char *>(&data[prev_offset]), offsets[i] - prev_offset - 1),
+							0, offsets[i] - prev_offset - 1, re2_st::RE2::UNANCHORED, nullptr, 0);
 
-					prev_offset = offsets[i];
+						prev_offset = offsets[i];
+					}
 				}
 			}
 			else
diff --git a/dbms/tests/queries/0_stateless/00144_empty_regexp.reference b/dbms/tests/queries/0_stateless/00144_empty_regexp.reference
new file mode 100644
index 00000000000..6ed281c757a
--- /dev/null
+++ b/dbms/tests/queries/0_stateless/00144_empty_regexp.reference
@@ -0,0 +1,2 @@
+1
+1
diff --git a/dbms/tests/queries/0_stateless/00144_empty_regexp.sql b/dbms/tests/queries/0_stateless/00144_empty_regexp.sql
new file mode 100644
index 00000000000..004b1c8ef9e
--- /dev/null
+++ b/dbms/tests/queries/0_stateless/00144_empty_regexp.sql
@@ -0,0 +1,2 @@
+SELECT match(materialize('Hello'), '');
+SELECT match('Hello', '');
diff --git a/dbms/tests/queries/0_stateless/00145_empty_likes.reference b/dbms/tests/queries/0_stateless/00145_empty_likes.reference
new file mode 100644
index 00000000000..5b87d5441e4
--- /dev/null
+++ b/dbms/tests/queries/0_stateless/00145_empty_likes.reference
@@ -0,0 +1,16 @@
+0
+1
+1
+1
+1
+0
+1
+1
+0
+1
+1
+1
+1
+0
+1
+1
diff --git a/dbms/tests/queries/0_stateless/00145_empty_likes.sql b/dbms/tests/queries/0_stateless/00145_empty_likes.sql
new file mode 100644
index 00000000000..e1b4adf0118
--- /dev/null
+++ b/dbms/tests/queries/0_stateless/00145_empty_likes.sql
@@ -0,0 +1,18 @@
+SELECT materialize('Hello') LIKE '';
+SELECT materialize('Hello') LIKE '%';
+SELECT materialize('Hello') LIKE '%%';
+SELECT materialize('Hello') LIKE '%%%';
+SELECT materialize('Hello') LIKE '%_%';
+SELECT materialize('Hello') LIKE '_';
+SELECT materialize('Hello') LIKE '_%';
+SELECT materialize('Hello') LIKE '%_';
+
+SELECT 'Hello' LIKE '';
+SELECT 'Hello' LIKE '%';
+SELECT 'Hello' LIKE '%%';
+SELECT 'Hello' LIKE '%%%';
+SELECT 'Hello' LIKE '%_%';
+SELECT 'Hello' LIKE '_';
+SELECT 'Hello' LIKE '_%';
+SELECT 'Hello' LIKE '%_';
+