Merge pull request #432 from thirdwing/subsetter

fix the error in subset under gc. close #431

Author: eddelbuettel

ChangeLog

@@ -1,3 +1,9 @@
+2016-01-30 Qiang Kou <qkou@umail.iu.edu>
+
+        * inst//include/Rcpp/vector/Subsetter.h: fix the error under gc
+        * inst/unitTests/cpp/Vector.cpp : Add tests
+        * inst/unitTests/runit.Vector.R : Idem
+
 2016-01-29  Dirk Eddelbuettel  <edd@debian.org>
 
         * vignettes/Rcpp-FAQ.Rnw (Rcpp): Add new entry about required TeXlive

inst/include/Rcpp/vector/Subsetter.h

@@ -144,9 +144,13 @@ class SubsetProxy {
     #endif
 
     void get_indices( traits::identity< traits::int2type<INTSXP> > t ) {
-        indices = INTEGER(rhs);
-        indices_n = rhs_n;
-        check_indices(indices, rhs_n, lhs_n);
+        indices.reserve(rhs_n);
+        int* ptr = INTEGER(rhs);
+        check_indices(ptr, rhs_n, lhs_n);
+        for (int i=0; i < rhs_n; ++i) {
+            indices.push_back( rhs[i] );
+        }
+        indices_n = rhs_n;        
     }
 
     void get_indices( traits::identity< traits::int2type<REALSXP> > t ) {
@@ -215,13 +219,7 @@ class SubsetProxy {
     int lhs_n;
     int rhs_n;
 
-    // we want to reuse the indices if an IntegerVector is passed in; otherwise,
-    // we construct a std::vector<int> to hold the indices
-    typename traits::if_<
-        RHS_RTYPE == INTSXP,
-        int*,
-        std::vector<int>
-    >::type indices;
+    std::vector<int> indices;
 
     // because of the above, we keep track of the size
     int indices_n;

inst/unitTests/cpp/Vector.cpp

@@ -823,3 +823,8 @@ String vec_print_integer(IntegerVector v) {
     buf << v;
     return buf.str();
 }
+
+// [[Rcpp::export]]
+IntegerVector vec_subset(IntegerVector x, IntegerVector y) {
+    return x[y - 1];
+}

inst/unitTests/runit.Vector.R

@@ -720,5 +720,14 @@ if (.runThisTest) {
         s <- vec_print_character(v)
         checkEquals(s, '"a" "b" "c" "d"')
     }
+
+    test.IntegerVector.subset.under.gc <- function() {
+        x <- 1:1E6
+        y <- 1:1E6
+        gctorture(TRUE)
+        z <- vec_subset(x, y)
+        gctorture(FALSE)
+        checkEquals(x[y], z)
+    }
 }