Rcpp Version 0.12.12
LazyVector.h
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1 // -*- mode: C++; c-indent-level: 4; c-basic-offset: 4; indent-tabs-mode: nil; -*-
2 //
3 // LazyVector.h: Rcpp R/C++ interface class library -- lazy vectors
4 //
5 // Copyright (C) 2010 - 2012 Dirk Eddelbuettel and Romain Francois
6 //
7 // This file is part of Rcpp.
8 //
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21 
22 #ifndef Rcpp__vector__LazyVector_h
23 #define Rcpp__vector__LazyVector_h
24 
25 namespace Rcpp{
26 namespace internal{
27 
28 template <typename VECTOR>
29 class LazyVector{
30 public:
31  typedef typename VECTOR::r_type r_type ;
33 
34  LazyVector( const VECTOR& vec_ ) : vec(vec_), n(vec_.size()), data(n), known(n,false){}
35 
36  inline stored_type operator[]( R_xlen_t i) const {
37  stored_type res ;
38  if( ! known[i] ) {
39  data[i] = res = vec[i] ;
40  known[i] = true ;
41  } else {
42  res = data[i] ;
43  }
44  return res ;
45  }
46 
47 private:
48  const VECTOR& vec ;
49  R_xlen_t n ;
50  mutable std::vector<stored_type> data ;
51  mutable std::vector<bool> known ;
52 } ;
53 
54 template <int RTYPE>
55 class LazyVector< Rcpp::Vector<RTYPE> >{
56 public:
58  typedef typename VECTOR::Proxy Proxy ;
59 
60  LazyVector( const VECTOR& vec_) : vec(vec_){}
61  inline Proxy operator[]( R_xlen_t i) const { return vec[i] ; }
62 
63 private:
64  const VECTOR& vec ;
65 } ;
66 
67 
68 } // internal
69 } // Rcpp
70 #endif
std::vector< stored_type > data
Definition: LazyVector.h:50
std::vector< bool > known
Definition: LazyVector.h:51
LazyVector(const VECTOR &vec_)
Definition: LazyVector.h:34
stored_type operator[](R_xlen_t i) const
Definition: LazyVector.h:36
VECTOR::r_type r_type
Definition: LazyVector.h:31
traits::r_vector_proxy< RTYPE >::type Proxy
Definition: Vector.h:43
Rcpp API.
Definition: algo.h:28
Rcpp::traits::storage_type< r_type::value >::type stored_type
Definition: LazyVector.h:32