[GitHub] [arrow] wesm commented on a change in pull request #7593: ARROW-9160: [C++] Implement contains for exact matches

[GitBox <gi...@apache.org>]

wesm commented on a change in pull request #7593:
URL: https://github.com/apache/arrow/pull/7593#discussion_r447982219



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File path: cpp/src/arrow/compute/kernels/scalar_string.cc
##########
@@ -387,16 +380,20 @@ using ContainsExactState = OptionsWrapper<ContainsExactOptions>;
 
 template <typename Type>
 struct ContainsExact {
+  using offset_type = typename Type::offset_type;
   static void Exec(KernelContext* ctx, const ExecBatch& batch, Datum* out) {
-    ContainsExactOptions arg =
-        checked_cast<const ContainsExactState&>(*ctx->state()).options;
-    auto transform_func =
-        std::bind(TransformContainsExact<typename Type::offset_type>,
-                  reinterpret_cast<const uint8_t*>(arg.pattern.c_str()),
-                  arg.pattern.length(), std::placeholders::_1, std::placeholders::_2,
-                  std::placeholders::_3, std::placeholders::_4);
-
-    StringBoolTransform<Type>(ctx, batch, transform_func, out);
+    ContainsExactOptions arg = ContainsExactState::Get(ctx);
+    const uint8_t* pat = reinterpret_cast<const uint8_t*>(arg.pattern.c_str());
+    const int64_t pat_size = arg.pattern.length();
+    StringBoolTransform<Type>(
+        ctx, batch,
+        [pat, pat_size](const void* offsets, const uint8_t* data, int64_t length,
+                        int64_t output_offset, uint8_t* output) {
+          TransformContainsExact<offset_type>(
+              pat, pat_size, reinterpret_cast<const offset_type*>(offsets), data, length,
+              output_offset, output);
+        },

Review comment:
       I hope you don't mind, this seemed simpler to me




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