[GitHub] [arrow] nealrichardson commented on a change in pull request #7514: ARROW-6235: [R] Implement conversion from arrow::BinaryArray to R character vector

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

nealrichardson commented on a change in pull request #7514:
URL: https://github.com/apache/arrow/pull/7514#discussion_r448483516



##########
File path: r/src/array_from_vector.cpp
##########
@@ -918,6 +923,97 @@ class Time64Converter : public TimeConverter<Time64Type> {
   }
 };
 
+template <typename Builder>
+class BinaryVectorConverter : public VectorConverter {
+ public:
+  ~BinaryVectorConverter() {}
+
+  Status Init(ArrayBuilder* builder) {
+    typed_builder_ = checked_cast<Builder*>(builder);
+    return Status::OK();
+  }
+
+  Status Ingest(SEXP obj) {
+    ARROW_RETURN_IF(TYPEOF(obj) != VECSXP, Status::RError("Expecting a list"));
+    R_xlen_t n = XLENGTH(obj);
+
+    // Reserve enough space before appending
+    int64_t size = 0;
+    for (R_xlen_t i = 0; i < n; i++) {
+      SEXP obj_i = VECTOR_ELT(obj, i);
+      if (!Rf_isNull(obj_i)) {
+        ARROW_RETURN_IF(TYPEOF(obj_i) != RAWSXP,
+                        Status::RError("Expecting a raw vector"));
+        size += XLENGTH(obj_i);
+      }
+    }
+    RETURN_NOT_OK(typed_builder_->Reserve(size));
+
+    // append
+    for (R_xlen_t i = 0; i < n; i++) {
+      SEXP obj_i = VECTOR_ELT(obj, i);
+      if (Rf_isNull(obj_i)) {
+        RETURN_NOT_OK(typed_builder_->AppendNull());
+      } else {
+        RETURN_NOT_OK(typed_builder_->Append(RAW(obj_i), XLENGTH(obj_i)));
+      }
+    }
+    return Status::OK();
+  }
+
+  Status GetResult(std::shared_ptr<arrow::Array>* result) {
+    return typed_builder_->Finish(result);
+  }
+
+ private:
+  Builder* typed_builder_;
+};
+
+template <typename Builder>
+class StringVectorConverter : public VectorConverter {
+ public:
+  ~StringVectorConverter() {}
+
+  Status Init(ArrayBuilder* builder) {
+    typed_builder_ = checked_cast<Builder*>(builder);
+    return Status::OK();
+  }
+
+  Status Ingest(SEXP obj) {
+    ARROW_RETURN_IF(TYPEOF(obj) != STRSXP,
+                    Status::RError("Expecting a character vector"));
+    R_xlen_t n = XLENGTH(obj);
+
+    // Reserve enough space before appending
+    int64_t size = 0;
+    for (R_xlen_t i = 0; i < n; i++) {
+      SEXP string_i = STRING_ELT(obj, i);
+      if (string_i != NA_STRING) {
+        size += XLENGTH(string_i);
+      }
+    }
+    RETURN_NOT_OK(typed_builder_->Reserve(size));
+
+    // append
+    for (R_xlen_t i = 0; i < n; i++) {
+      SEXP string_i = STRING_ELT(obj, i);
+      if (string_i == NA_STRING) {
+        RETURN_NOT_OK(typed_builder_->AppendNull());
+      } else {
+        RETURN_NOT_OK(typed_builder_->Append(CHAR(string_i), XLENGTH(string_i)));

Review comment:
       I fixed this; will deal with efficiency/redundancy in a followup.




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