From 74fe778476c50e1d94ba92cda3559775898fcc4c Mon Sep 17 00:00:00 2001
From: rui-mo <rui.mo@intel.com>
Date: Mon, 26 Feb 2024 16:43:30 +0800
Subject: [PATCH] Support locate function

---
 velox/functions/sparksql/Register.cpp         |  6 ++-
 velox/functions/sparksql/String.h             | 49 ++++++++++++++++++-
 velox/functions/sparksql/tests/StringTest.cpp | 33 +++++++++++++
 3 files changed, 86 insertions(+), 2 deletions(-)

diff --git a/velox/functions/sparksql/Register.cpp b/velox/functions/sparksql/Register.cpp
index bd748af7dadfd..ebff668609b42 100644
--- a/velox/functions/sparksql/Register.cpp
+++ b/velox/functions/sparksql/Register.cpp
@@ -221,13 +221,17 @@ void registerFunctions(const std::string& prefix) {
   registerCompareFunctions(prefix);
   registerBitwiseFunctions(prefix);
 
-  // String sreach function
+  // String search function
   registerFunction<StartsWithFunction, bool, Varchar, Varchar>(
       {prefix + "startswith"});
   registerFunction<EndsWithFunction, bool, Varchar, Varchar>(
       {prefix + "endswith"});
   registerFunction<ContainsFunction, bool, Varchar, Varchar>(
       {prefix + "contains"});
+  registerFunction<LocateFunction, int32_t, Varchar, Varchar>(
+      {prefix + "locate"});
+  registerFunction<LocateFunction, int32_t, Varchar, Varchar, int32_t>(
+      {prefix + "locate"});
 
   registerFunction<TrimSpaceFunction, Varchar, Varchar>({prefix + "trim"});
   registerFunction<TrimFunction, Varchar, Varchar, Varchar>({prefix + "trim"});
diff --git a/velox/functions/sparksql/String.h b/velox/functions/sparksql/String.h
index ad135b71ee76c..af1f5160ddaad 100644
--- a/velox/functions/sparksql/String.h
+++ b/velox/functions/sparksql/String.h
@@ -253,7 +253,6 @@ struct StartsWithFunction {
       result = false;
     } else {
       result = str1.substr(0, str2.length()) == str2;
-      ;
     }
     return true;
   }
@@ -284,6 +283,54 @@ struct EndsWithFunction {
   }
 };
 
+/// locate function
+/// locate(string, string) -> integer
+/// locate(string, string, integer) -> integer
+/// Returns the position of the first occurrence of 'substr' in given string
+/// after position 'start'.
+template <typename T>
+struct LocateFunction {
+  VELOX_DEFINE_FUNCTION_TYPES(T);
+
+  FOLLY_ALWAYS_INLINE bool doCall(
+      out_type<int32_t>& result,
+      const arg_type<Varchar>* substr,
+      const arg_type<Varchar>* str,
+      int32_t start) {
+    if (substr == nullptr || str == nullptr) {
+      return false;
+    }
+    const auto inputStr = (*str).str();
+    std::size_t found =
+        inputStr.find_first_of((*substr).data(), start - 1, (*substr).size());
+    if (found != std::string::npos) {
+      result = found + 1;
+    } else {
+      result = 0;
+    }
+    return true;
+  }
+
+  FOLLY_ALWAYS_INLINE bool callNullable(
+      out_type<int32_t>& result,
+      const arg_type<Varchar>* substr,
+      const arg_type<Varchar>* str) {
+    return doCall(result, substr, str, 1);
+  }
+
+  FOLLY_ALWAYS_INLINE bool callNullable(
+      out_type<int32_t>& result,
+      const arg_type<Varchar>* substr,
+      const arg_type<Varchar>* str,
+      const arg_type<int32_t>* start) {
+    if (start == nullptr || *start < 1) {
+      result = 0;
+      return true;
+    }
+    return doCall(result, substr, str, *start);
+  }
+};
+
 /// Returns the substring from str before count occurrences of the delimiter
 /// delim. If count is positive, everything to the left of the final delimiter
 /// (counting from the left) is returned. If count is negative, everything to
diff --git a/velox/functions/sparksql/tests/StringTest.cpp b/velox/functions/sparksql/tests/StringTest.cpp
index dc2bfadf619f5..ceefac436632f 100644
--- a/velox/functions/sparksql/tests/StringTest.cpp
+++ b/velox/functions/sparksql/tests/StringTest.cpp
@@ -120,6 +120,19 @@ class StringTest : public SparkFunctionBaseTest {
     return evaluateOnce<bool>("contains(c0, c1)", str, pattern);
   }
 
+  std::optional<int32_t> locate(
+      const std::optional<std::string>& substr,
+      const std::optional<std::string>& str) {
+    return evaluateOnce<int32_t>("locate(c0, c1)", substr, str);
+  }
+
+  std::optional<int32_t> locate(
+      const std::optional<std::string>& substr,
+      const std::optional<std::string>& str,
+      const std::optional<int32_t>& start) {
+      return evaluateOnce<int32_t>("locate(c0, c1, c2)", substr, str, start);
+  }
+
   std::optional<std::string> substring(
       std::optional<std::string> str,
       std::optional<int32_t> start) {
@@ -405,6 +418,26 @@ TEST_F(StringTest, endsWith) {
   EXPECT_EQ(endsWith(std::nullopt, "abc"), std::nullopt);
 }
 
+TEST_F(StringTest, locate) {
+  EXPECT_EQ(locate("aa", "aaads"), 1);
+  EXPECT_EQ(locate("aa", "aaads", 0), 0);
+  EXPECT_EQ(locate("aa", "aaads", 1), 1);
+  EXPECT_EQ(locate("aa", "aaads", 2), 2);
+  EXPECT_EQ(locate("aa", "aaads", 3), 0);
+  EXPECT_EQ(locate("de", "aaads"), 0);
+  EXPECT_EQ(locate("de", "aaads", 2), 0);
+  EXPECT_EQ(locate("", ""), 1);
+  EXPECT_EQ(locate("", "", 3), 1);
+  EXPECT_EQ(locate("", "aaads"), 0);
+  EXPECT_EQ(locate("", "aaads", 2), 0);
+  EXPECT_EQ(locate("aa", ""), 0);
+  EXPECT_EQ(locate("aa", "", 2), 0);
+  EXPECT_EQ(locate("zz", "aaads", std::nullopt), 0);
+  EXPECT_EQ(locate("aa", std::nullopt), std::nullopt);
+  EXPECT_EQ(locate(std::nullopt, "aaads"), std::nullopt);
+  EXPECT_EQ(locate(std::nullopt, std::nullopt, std::nullopt), 0);
+}
+
 TEST_F(StringTest, substringIndex) {
   EXPECT_EQ(substringIndex("www.apache.org", ".", 3), "www.apache.org");
   EXPECT_EQ(substringIndex("www.apache.org", ".", 2), "www.apache");