[GitHub] [arrow] pitrou commented on a change in pull request #12504: ARROW-15763: [C++] Improve CSV writer

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

pitrou commented on a change in pull request #12504:
URL: https://github.com/apache/arrow/pull/12504#discussion_r815964918



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File path: cpp/src/arrow/csv/writer.cc
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@@ -328,6 +351,26 @@ class QuotedColumnPopulator : public ColumnPopulator {
   }
 
  private:
+  // Returns true if there's no quote in the string array
+  // similar to std::find, but with much better performance
+  static bool NoQuoteInArray(const StringArray& array) {
+    const uint8_t* data = array.raw_data() + array.value_offset(0);
+    const int64_t buffer_size = array.total_values_length();
+    const uint8_t* const data_end = data + buffer_size;
+
+    for (int64_t i = 0; i < buffer_size / 16; ++i) {
+      bool r = false;
+      for (int i = 0; i < 16; ++i) {
+        r |= data[i] == '"';
+      }

Review comment:
       How does this compare to simply using `memchr`? At least on glibc it should be heavily optimized. I have no idea on macOS or Windows.




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