std::hash<Rcpp::String>. close #84

ChangeLog

@@ -1,3 +1,9 @@
+2015-12-12  Qiang Kou <qkou@umail.iu.edu>
+
+        * inst/include/Rcpp/String.h: std::hash<Rcpp::String>
+        * inst/unitTests/cpp/wrap.cpp: Unit tests
+        * inst/unitTests/runit.wrap.R: Unit tests
+
 2015-12-04  Qiang Kou <qkou@umail.iu.edu>
 
         * inst/include/Rcpp/vector/Matrix.h: Add math operators between matrix

inst/include/Rcpp/String.h

@@ -556,4 +556,24 @@ namespace Rcpp {
 
 } // Rcpp
 
+/** hash can be in std or std::tr1 */
+#if defined(RCPP_USING_CXX11) || defined(HAS_TR1)
+namespace std
+{
+#ifndef RCPP_USING_CXX11
+namespace tr1 {
+#endif
+    template <>
+    struct hash<Rcpp::String>
+    {
+        size_t operator()(const Rcpp::String & s) const{
+            return hash<string>()(s.get_cstring());
+        }
+    };
+#ifndef RCPP_USING_CXX11
+}
+#endif
+}
+#endif
+
 #endif

inst/unitTests/cpp/wrap.cpp

@@ -168,6 +168,10 @@ SEXP nonnull_const_char(){
     return wrap(p) ;
 }
 
+#ifdef RCPP_USING_CXX11
+// [[Rcpp::plugins(cpp11)]]
+#endif
+
 // [[Rcpp::export]]
 IntegerVector unordered_map_string_int(){
     RCPP_UNORDERED_MAP< std::string, int > m ;
@@ -177,6 +181,25 @@ IntegerVector unordered_map_string_int(){
     return wrap(m);
 }
 
+// [[Rcpp::export]]
+IntegerVector unordered_map_rcpp_string_int(StringVector v){
+    RCPP_UNORDERED_MAP< String, int > m ;
+    m[v[0]] = 200;
+    m[v[1]] = 100;
+    m[v[2]] = 300;
+    return wrap(m);
+}
+
+// [[Rcpp::export]]
+LogicalVector unordered_set_rcpp_string(StringVector x) {
+    RCPP_UNORDERED_SET<String> seen;
+    LogicalVector out(x.size());
+    for (int i = 0; i < x.size(); i++) {
+        out[i] = !seen.insert(x[i]).second;
+    }
+    return out;
+}
+
 // [[Rcpp::export]]
 NumericVector unordered_map_string_double(){
     RCPP_UNORDERED_MAP<std::string,double> m ;

inst/unitTests/runit.wrap.R

@@ -108,6 +108,18 @@ if (.runThisTest) {
         checkEquals( res[["c"]], 300L,  msg = "wrap( tr1::unordered_map<string,int>) " )
     }
 
+    test.wrap.unordered.map.rcpp.string.int <- function(){
+        res <- unordered_map_rcpp_string_int(c("a", "b", "c"))
+        checkEquals( res[["a"]], 200L,  msg = "wrap( tr1::unordered_map<Rcpp::String,int>) " )
+        checkEquals( res[["b"]], 100L,  msg = "wrap( tr1::unordered_map<Rcpp::String,int>) " )
+        checkEquals( res[["c"]], 300L,  msg = "wrap( tr1::unordered_map<Rcpp::String,int>) " )
+    }
+
+    test.unordered.set.rcpp.string <- function(){
+        checkEquals(unordered_set_rcpp_string(c("a", "b", "c", "b")),
+            c(FALSE, FALSE, FALSE, TRUE), msg = "wrap( tr1::unordered_set<Rcpp::String>) " )
+    }
+
     test.wrap.unordered.map.string.double <- function(){
         res <- unordered_map_string_double()
         checkEquals( res[["a"]], 200,  msg = "wrap( tr1::unordered_map<string,double>) " )