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
|
// This file provides utility functions for use with STL map-like data
// structures, such as std::map and hash_map. Some functions will also work with
// sets, such as ContainsKey().
#ifndef TENSORFLOW_LIB_GTL_MAP_UTIL_H_
#define TENSORFLOW_LIB_GTL_MAP_UTIL_H_
#include <stddef.h>
#include <iterator>
#include <memory>
#include <string>
#include <utility>
#include <vector>
namespace tensorflow {
namespace gtl {
// Returns a pointer to the const value associated with the given key if it
// exists, or NULL otherwise.
template <class Collection>
const typename Collection::value_type::second_type* FindOrNull(
const Collection& collection,
const typename Collection::value_type::first_type& key) {
typename Collection::const_iterator it = collection.find(key);
if (it == collection.end()) {
return 0;
}
return &it->second;
}
// Same as above but returns a pointer to the non-const value.
template <class Collection>
typename Collection::value_type::second_type* FindOrNull(
Collection& collection, // NOLINT
const typename Collection::value_type::first_type& key) {
typename Collection::iterator it = collection.find(key);
if (it == collection.end()) {
return 0;
}
return &it->second;
}
// Returns the pointer value associated with the given key. If none is found,
// NULL is returned. The function is designed to be used with a map of keys to
// pointers.
//
// This function does not distinguish between a missing key and a key mapped
// to a NULL value.
template <class Collection>
typename Collection::value_type::second_type FindPtrOrNull(
const Collection& collection,
const typename Collection::value_type::first_type& key) {
typename Collection::const_iterator it = collection.find(key);
if (it == collection.end()) {
return typename Collection::value_type::second_type();
}
return it->second;
}
// Returns a const reference to the value associated with the given key if it
// exists, otherwise returns a const reference to the provided default value.
//
// WARNING: If a temporary object is passed as the default "value,"
// this function will return a reference to that temporary object,
// which will be destroyed at the end of the statement. A common
// example: if you have a map with string values, and you pass a char*
// as the default "value," either use the returned value immediately
// or store it in a string (not string&).
template <class Collection>
const typename Collection::value_type::second_type& FindWithDefault(
const Collection& collection,
const typename Collection::value_type::first_type& key,
const typename Collection::value_type::second_type& value) {
typename Collection::const_iterator it = collection.find(key);
if (it == collection.end()) {
return value;
}
return it->second;
}
// Inserts the given key and value into the given collection if and only if the
// given key did NOT already exist in the collection. If the key previously
// existed in the collection, the value is not changed. Returns true if the
// key-value pair was inserted; returns false if the key was already present.
template <class Collection>
bool InsertIfNotPresent(Collection* const collection,
const typename Collection::value_type& vt) {
return collection->insert(vt).second;
}
// Same as above except the key and value are passed separately.
template <class Collection>
bool InsertIfNotPresent(
Collection* const collection,
const typename Collection::value_type::first_type& key,
const typename Collection::value_type::second_type& value) {
return InsertIfNotPresent(collection,
typename Collection::value_type(key, value));
}
// Looks up a given key and value pair in a collection and inserts the key-value
// pair if it's not already present. Returns a reference to the value associated
// with the key.
template <class Collection>
typename Collection::value_type::second_type& LookupOrInsert(
Collection* const collection, const typename Collection::value_type& vt) {
return collection->insert(vt).first->second;
}
// Same as above except the key-value are passed separately.
template <class Collection>
typename Collection::value_type::second_type& LookupOrInsert(
Collection* const collection,
const typename Collection::value_type::first_type& key,
const typename Collection::value_type::second_type& value) {
return LookupOrInsert(collection,
typename Collection::value_type(key, value));
}
} // namespace gtl
} // namespace tensorflow
#endif // TENSORFLOW_LIB_GTL_MAP_UTIL_H_
|
