1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
|
// Copyright (C) 2008-2018 Lorenzo Caminiti
// Distributed under the Boost Software License, Version 1.0 (see accompanying
// file LICENSE_1_0.txt or a copy at http://www.boost.org/LICENSE_1_0.txt).
// See: http://www.boost.org/doc/libs/release/libs/contract/doc/html/index.html
#include <boost/contract.hpp>
#include <vector>
#include <algorithm>
#include <iostream>
#include <cassert>
//[assertion_level_no_impl
// If valid iterator range (cannot implement in C++ but OK to use in AXIOM).
template<typename Iter>
bool valid(Iter first, Iter last); // Only declared, not actually defined.
//]
//[assertion_level_class_begin
template<typename T>
class vector {
//]
public:
typedef typename std::vector<T>::iterator iterator;
// Could program class invariants and contracts for the following.
iterator begin() { return vect_.begin(); }
iterator end() { return vect_.end(); }
unsigned capacity() const { return vect_.capacity(); }
bool operator==(vector const& other) { return vect_ == other.vect_; }
//[assertion_level_axiom
public:
iterator insert(iterator where, T const& value) {
iterator result;
boost::contract::old_ptr<unsigned> old_capacity =
BOOST_CONTRACT_OLDOF(capacity());
boost::contract::check c = boost::contract::public_function(this)
.postcondition([&] {
BOOST_CONTRACT_ASSERT(capacity() >= *old_capacity);
if(capacity() > *old_capacity) {
BOOST_CONTRACT_ASSERT_AXIOM(!valid(begin(), end()));
} else {
BOOST_CONTRACT_ASSERT_AXIOM(!valid(where, end()));
}
})
;
return result = vect_.insert(where, value);
}
//]
//[assertion_level_audit_old
public:
void swap(vector& other) {
boost::contract::old_ptr<vector> old_me, old_other;
#ifdef BOOST_CONTRACT_AUDITS
old_me = BOOST_CONTRACT_OLDOF(*this);
old_other = BOOST_CONTRACT_OLDOF(other);
#endif // Else, skip old value copies...
boost::contract::check c = boost::contract::public_function(this)
.postcondition([&] {
// ...and also skip related assertions.
BOOST_CONTRACT_ASSERT_AUDIT(*this == *old_other);
BOOST_CONTRACT_ASSERT_AUDIT(other == *old_me);
})
;
vect_.swap(other.vect_);
}
//]
//[assertion_level_class_end
/* ... */
private:
std::vector<T> vect_;
};
//]
//[assertion_level_audit
template<typename RandomIter, typename T>
RandomIter random_binary_search(RandomIter first, RandomIter last,
T const& value) {
RandomIter result;
boost::contract::check c = boost::contract::function()
.precondition([&] {
BOOST_CONTRACT_ASSERT(first <= last); // Default, not expensive.
// Expensive O(n) assertion (use AXIOM if prohibitive instead).
BOOST_CONTRACT_ASSERT_AUDIT(std::is_sorted(first, last));
})
.postcondition([&] {
if(result != last) BOOST_CONTRACT_ASSERT(*result == value);
})
;
/* ... */
//]
RandomIter begin = first, end = last;
while(begin < end) {
RandomIter middle = begin + ((end - begin) >> 1);
BOOST_CONTRACT_CHECK(*begin <= *middle || value < *middle ||
*middle < value);
if(value < *middle) end = middle;
else if(value > *middle) begin = middle + 1;
else return result = middle;
}
return result = last;
}
int main() {
vector<char> v;
v.insert(v.begin() + 0, 'a');
v.insert(v.begin() + 1, 'b');
v.insert(v.begin() + 2, 'c');
vector<char>::iterator i = random_binary_search(v.begin(), v.end(), 'b');
assert(i != v.end());
assert(*i == 'b');
vector<char> w;
w.insert(w.begin() + 0, 'x');
w.insert(w.begin() + 1, 'y');
w.swap(v);
assert(*(w.begin() + 0) == 'a');
assert(*(w.begin() + 1) == 'b');
assert(*(w.begin() + 2) == 'c');
return 0;
}
|
