Fixes for DataFrame::nrows(), following @romainfrancois commit (closes #120)

kevinushey · kevinushey · commit dedec9d2fa76 · 2014-02-23T14:34:06.000-08:00
diff --git a/ChangeLog b/ChangeLog
@@ -1,3 +1,7 @@
+2014-02-23  Kevin Ushey <kevinushey@gmail.com>
+
+        * inst/include/Rcpp/DataFrame.h: better nrows behavior
+
 2014-02-17  Romain Francois <romain@r-enthusiasts.com>
 
         * inst/include/Rcpp/traits/un_pointer.h: fix bug in un_pointer for object<T>
diff --git a/inst/NEWS.Rd b/inst/NEWS.Rd
@@ -15,6 +15,8 @@
       as the vector .sort() method. These fixes ensure that sugar functions
       depending on IndexHash (unique, sort_unique, match) will now properly
       handle NA and NaN values for numeric vectors.
+      \item DataFrame::nrows now more accurately mimics R's internal behavior
+      (checks the row.names attribute)
     }
     \item Changes in Rcpp Attributes
       \itemize{
diff --git a/inst/include/Rcpp/DataFrame.h b/inst/include/Rcpp/DataFrame.h
@@ -60,7 +60,12 @@ namespace Rcpp{
         }
                 
         inline int nrows() const {
-            return Rf_length( VECTOR_ELT(Parent::get__(), 0) );     
+            SEXP rn = Rf_getAttrib( Parent::get__(), R_RowNamesSymbol );
+            if (TYPEOF(rn) == INTSXP && LENGTH(rn) == 2 && INTEGER(rn)[0] == NA_INTEGER)
+                return INTEGER(rn)[1];
+            if (Rf_isNull(rn))
+                return 0;
+            return LENGTH(rn);
         }
         
         static DataFrame_Impl create(){ 

Original file line number	Diff line number	Diff line change
`@@ -15,6 +15,8 @@`
`15`	`15`	`as the vector .sort() method. These fixes ensure that sugar functions`
`16`	`16`	`depending on IndexHash (unique, sort_unique, match) will now properly`
`17`	`17`	`handle NA and NaN values for numeric vectors.`
	`18`	`+ \item DataFrame::nrows now more accurately mimics R's internal behavior`
	`19`	`+ (checks the row.names attribute)`
`18`	`20`	`}`
`19`	`21`	`\item Changes in Rcpp Attributes`
`20`	`22`	`\itemize{`
Original file line number	Diff line number	Diff line change
`@@ -60,7 +60,12 @@ namespace Rcpp{`
`60`	`60`	`}`
`61`	`61`
`62`	`62`	`inline int nrows() const {`
`63`		`- return Rf_length( VECTOR_ELT(Parent::get__(), 0) );`
	`63`	`+ SEXP rn = Rf_getAttrib( Parent::get__(), R_RowNamesSymbol );`
	`64`	`+ if (TYPEOF(rn) == INTSXP && LENGTH(rn) == 2 && INTEGER(rn)[0] == NA_INTEGER)`
	`65`	`+ return INTEGER(rn)[1];`
	`66`	`+ if (Rf_isNull(rn))`
	`67`	`+ return 0;`
	`68`	`+ return LENGTH(rn);`
`64`	`69`	`}`
`65`	`70`
`66`	`71`	`static DataFrame_Impl create(){`