Use read-only pointers in memcpy

Author: MichaelChirico

src/dogroups.c

@@ -541,11 +541,11 @@ SEXP growVector(SEXP x, const R_len_t newlen)
     return newx;
   }
   switch (TYPEOF(x)) {
-  case RAWSXP:  memcpy(RAW(newx),     RAW(x),     len*SIZEOF(x)); break;
-  case LGLSXP:  memcpy(LOGICAL(newx), LOGICAL(x), len*SIZEOF(x)); break;
-  case INTSXP:  memcpy(INTEGER(newx), INTEGER(x), len*SIZEOF(x)); break;
-  case REALSXP: memcpy(REAL(newx),    REAL(x),    len*SIZEOF(x)); break;
-  case CPLXSXP: memcpy(COMPLEX(newx), COMPLEX(x), len*SIZEOF(x)); break;
+  case RAWSXP:  memcpy(RAW(newx),     RAW_RO(x),     len*SIZEOF(x)); break;
+  case LGLSXP:  memcpy(LOGICAL(newx), LOGICAL_RO(x), len*SIZEOF(x)); break;
+  case INTSXP:  memcpy(INTEGER(newx), INTEGER_RO(x), len*SIZEOF(x)); break;
+  case REALSXP: memcpy(REAL(newx),    REAL_RO(x),    len*SIZEOF(x)); break;
+  case CPLXSXP: memcpy(COMPLEX(newx), COMPLEX_RO(x), len*SIZEOF(x)); break;
   case STRSXP : {
     const SEXP *xd = SEXPPTR_RO(x);
     for (int i=0; i<len; ++i)