llvm/unittests/ADT/MappedIteratorTest.cpp

   1 //===------ MappedIteratorTest.cpp - Unit tests for mapped_iterator -------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "llvm/ADT/STLExtras.h"
  10 #include "gtest/gtest.h"
  11
  12 using namespace llvm;
  13
  14 namespace {
  15
  16 TEST(MappedIteratorTest, ApplyFunctionOnDereference) {
  17   std::vector<int> V({0});
  18
  19   auto I = map_iterator(V.begin(), [](int X) { return X + 1; });
  20
  21   EXPECT_EQ(*I, 1) << "should have applied function in dereference";
  22 }
  23
  24 TEST(MappedIteratorTest, ApplyFunctionOnArrow) {
  25   struct S {
  26     int Z = 0;
  27   };
  28
  29   std::vector<int> V({0});
  30   S Y;
  31   S* P = &Y;
  32
  33   auto I = map_iterator(V.begin(), [&](int X) -> S& { return *(P + X); });
  34
  35   I->Z = 42;
  36
  37   EXPECT_EQ(Y.Z, 42) << "should have applied function during arrow";
  38 }
  39
  40 TEST(MappedIteratorTest, FunctionPreservesReferences) {
  41   std::vector<int> V({1});
  42   std::map<int, int> M({ {1, 1} });
  43
  44   auto I = map_iterator(V.begin(), [&](int X) -> int& { return M[X]; });
  45   *I = 42;
  46
  47   EXPECT_EQ(M[1], 42) << "assignment should have modified M";
  48 }
  49
  50 TEST(MappedIteratorTest, CustomIteratorApplyFunctionOnDereference) {
  51   struct CustomMapIterator
  52       : public llvm::mapped_iterator_base<CustomMapIterator,
  53                                           std::vector<int>::iterator, int> {
  54     using BaseT::BaseT;
  55
  56     /// Map the element to the iterator result type.
  57     int mapElement(int X) const { return X + 1; }
  58   };
  59
  60   std::vector<int> V({0});
  61
  62   CustomMapIterator I(V.begin());
  63
  64   EXPECT_EQ(*I, 1) << "should have applied function in dereference";
  65 }
  66
  67 TEST(MappedIteratorTest, CustomIteratorApplyFunctionOnArrow) {
  68   struct S {
  69     int Z = 0;
  70   };
  71   struct CustomMapIterator
  72       : public llvm::mapped_iterator_base<CustomMapIterator,
  73                                           std::vector<int>::iterator, S &> {
  74     CustomMapIterator(std::vector<int>::iterator it, S *P) : BaseT(it), P(P) {}
  75
  76     /// Map the element to the iterator result type.
  77     S &mapElement(int X) const { return *(P + X); }
  78
  79     S *P;
  80   };
  81
  82   std::vector<int> V({0});
  83   S Y;
  84
  85   CustomMapIterator I(V.begin(), &Y);
  86
  87   I->Z = 42;
  88
  89   EXPECT_EQ(Y.Z, 42) << "should have applied function during arrow";
  90 }
  91
  92 TEST(MappedIteratorTest, CustomIteratorFunctionPreservesReferences) {
  93   struct CustomMapIterator
  94       : public llvm::mapped_iterator_base<CustomMapIterator,
  95                                           std::vector<int>::iterator, int &> {
  96     CustomMapIterator(std::vector<int>::iterator it, std::map<int, int> &M)
  97         : BaseT(it), M(M) {}
  98
  99     /// Map the element to the iterator result type.
 100     int &mapElement(int X) const { return M[X]; }
 101
 102     std::map<int, int> &M;
 103   };
 104   std::vector<int> V({1});
 105   std::map<int, int> M({{1, 1}});
 106
 107   auto I = CustomMapIterator(V.begin(), M);
 108   *I = 42;
 109
 110   EXPECT_EQ(M[1], 42) << "assignment should have modified M";
 111 }
 112
 113 } // anonymous namespace