add template specializations to avoid DATAPTR use

Author: kevinushey

ChangeLog

@@ -1,3 +1,8 @@
+2024-06-11  Kevin Ushey  <[email protected]>
+
+	* inst/include/Rcpp/internal/r_vector.h: Use template specializations to
+	avoid DATAPTR usage
+
 2024-06-02  Dirk Eddelbuettel  <[email protected]>
 
 	* inst/include/Rcpp/internal/export.h: More R_xlen_t switching

inst/NEWS.Rd

@@ -9,9 +9,11 @@
     \itemize{
       \item Set R_NO_REMAP if not already defined (Dirk in \ghpr{1296})
       \item Add variadic templates to be used instead of generated code
-      (Andrew Johnson in \ghpr{1303}
+      (Andrew Johnson in \ghpr{1303})
       \item Count variables were switches to \code{size_t} to avoid warnings
       about conversion-narrowing (Dirk in \ghpr{1307})
+      \item Rcpp now avoids the usage of the (non-API) DATAPTR function when
+      accessing the contents of Rcpp Vector objects where possible.
     }
     \item Changes in Rcpp Deployment:
     \itemize{

inst/include/Rcpp/internal/r_vector.h

@@ -32,6 +32,21 @@ typename Rcpp::traits::storage_type<RTYPE>::type* r_vector_start(SEXP x) {
     return reinterpret_cast<pointer>(dataptr(x));
 }
 
+// add specializations to avoid use of dataptr
+#define RCPP_VECTOR_START_IMPL(__RTYPE__, __ACCESSOR__)                                              \
+    template <>                                                                                      \
+    inline typename Rcpp::traits::storage_type<__RTYPE__>::type* r_vector_start<__RTYPE__>(SEXP x) { \
+        return __ACCESSOR__(x);                                                                      \
+    }
+
+RCPP_VECTOR_START_IMPL(LGLSXP,  LOGICAL);
+RCPP_VECTOR_START_IMPL(INTSXP,  INTEGER);
+RCPP_VECTOR_START_IMPL(RAWSXP,  RAW);
+RCPP_VECTOR_START_IMPL(CPLXSXP, COMPLEX);
+RCPP_VECTOR_START_IMPL(REALSXP, REAL);
+
+#undef RCPP_VECTOR_START_IMPL
+
 /**
  * The value 0 statically casted to the appropriate type for
  * the given SEXP type