MySQL  8.0.18
Source Code Documentation
string_type.h
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22 
23 #ifndef DD__STRING_TYPE
24 #define DD__STRING_TYPE
25 
26 #include <stddef.h>
27 #include <sstream>
28 #include <string>
29 #include <system_error>
30 
31 #include "sql/stateless_allocator.h" // Stateless_allocator
32 
33 namespace dd {
34 /**
35  Functor class which allocates memory for String_type. Implementation
36  uses my_malloc with key_memory_DD_String_type.
37 */
39  void *operator()(size_t s) const;
40 };
41 
43 
44 /**
45  Template alias for char-based std::basic_string.
46 */
47 template <class A>
48 using Char_string_template = std::basic_string<char, std::char_traits<char>, A>;
49 
51 
52 /**
53  Template alias for char-based std::basic_stringstream.
54  */
55 template <class A>
57  std::basic_stringstream<char, std::char_traits<char>, A>;
58 
59 /**
60  Instantiation of std::basic_stringstream with the same allocator as
61  String_type. This is needed since a std::basic_stringstream::str()
62  returns a basic_string allocated with its own allocator. Note that
63  this also means that it is diffcult to use a different PSI key for
64  the stream memory as that would mean the return type of
65  Stringstream_type::str() would be different and incompatible with
66  String_type.
67 
68  To work around this would require the creation of a temporary
69  String_type from the string returned from stringstream::str().
70 */
72 
73 template <typename LEX_STRING_TYPE>
74 String_type make_string_type(const LEX_STRING_TYPE &lst) {
75  return {lst.str, lst.length};
76 }
77 } // namespace dd
78 
79 namespace std {
80 
81 /**
82  Specialize std::hash for dd::String_type so that it can be
83  used with unordered_ containers. Uses our standard murmur3_32
84  implementation, and the same suitability restrictions apply.
85  @see murmur3_32
86 */
87 template <>
88 struct hash<dd::String_type> {
90  typedef size_t result_type;
91 
92  size_t operator()(const dd::String_type &s) const;
93 };
94 } // namespace std
95 #endif /* DD__STRING_TYPE */
Stateless_allocator< char, String_type_alloc > String_type_allocator
Definition: string_type.h:42
Char_string_template< String_type_allocator > String_type
Definition: string_type.h:50
size_t result_type
Definition: string_type.h:90
Functor class which allocates memory for String_type.
Definition: string_type.h:38
Definition: varlen_sort.h:182
dd::String_type argument_type
Definition: string_type.h:89
std::basic_stringstream< char, std::char_traits< char >, A > Char_stringstream_template
Template alias for char-based std::basic_stringstream.
Definition: string_type.h:57
void * operator()(size_t s) const
Definition: string_type.cc:33
String_type make_string_type(const LEX_STRING_TYPE &lst)
Definition: string_type.h:74
uint32_t hash(const void *key, size_t length, const uint32_t initval)
Definition: hash.c:121
Stateless_allocator is a C++ STL memory allocator skeleton based on Malloc_allocator, which assumes that a global free function can be used to allocate and deallocate memory, so that no state need to be kept by the allocator object.
Definition: stateless_allocator.h:91
Char_stringstream_template< String_type_allocator > Stringstream_type
Instantiation of std::basic_stringstream with the same allocator as String_type.
Definition: string_type.h:71
The version of the current data dictionary table definitions.
Definition: dictionary_client.h:39
std::basic_string< char, std::char_traits< char >, A > Char_string_template
Template alias for char-based std::basic_string.
Definition: string_type.h:48