libpqxx: strconv.hxx Source File

libpqxx 4.0.1

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strconv.hxx
1 /*-------------------------------------------------------------------------
2 *
3 * FILE
4 * pqxx/stringconv.hxx
5 *
6 * DESCRIPTION
7 * String conversion definitions for libpqxx
8 * DO NOT INCLUDE THIS FILE DIRECTLY; include pqxx/stringconv instead.
9 *
10 * Copyright (c) 2008-2011, Jeroen T. Vermeulen <jtv@xs4all.nl>
11 *
12 * See COPYING for copyright license. If you did not receive a file called
13 * COPYING with this source code, please notify the distributor of this mistake,
14 * or contact the author.
15 *
16 *-------------------------------------------------------------------------
17 */
18 #ifndef PQXX_H_STRINGCONV
19 #define PQXX_H_STRINGCONV
20
21 #include "pqxx/compiler-public.hxx"
22
23 #include <sstream>
24 #include <stdexcept>
25
26
27 namespace pqxx
28 {
29
41
43
46 template<typename T> struct string_traits {};
47
48 namespace internal
49 {
51 void PQXX_LIBEXPORT PQXX_NORETURN throw_null_conversion(
52 const PGSTD::string &type);
53 } // namespace pqxx::internal
54
55 #define PQXX_DECLARE_STRING_TRAITS_SPECIALIZATION(T) \
56 template<> struct PQXX_LIBEXPORT string_traits<T> \
57 { \
58 typedef T subject_type; \
59 static const char *name() { return #T; } \
60 static bool has_null() { return false; } \
61 static bool is_null(T) { return false; } \
62 static T null() \
63 { internal::throw_null_conversion(name()); return subject_type(); } \
64 static void from_string(const char Str[], T &Obj); \
65 static PGSTD::string to_string(T Obj); \
66 };
67
68 PQXX_DECLARE_STRING_TRAITS_SPECIALIZATION(bool)
69
70 PQXX_DECLARE_STRING_TRAITS_SPECIALIZATION(short)
71 PQXX_DECLARE_STRING_TRAITS_SPECIALIZATION(unsigned short)
72 PQXX_DECLARE_STRING_TRAITS_SPECIALIZATION(int)
73 PQXX_DECLARE_STRING_TRAITS_SPECIALIZATION(unsigned int)
74 PQXX_DECLARE_STRING_TRAITS_SPECIALIZATION(long)
75 PQXX_DECLARE_STRING_TRAITS_SPECIALIZATION(unsigned long)
76 #ifdef PQXX_HAVE_LONG_LONG
77 PQXX_DECLARE_STRING_TRAITS_SPECIALIZATION(long long)
78 PQXX_DECLARE_STRING_TRAITS_SPECIALIZATION(unsigned long long)
79 #endif
80
81 PQXX_DECLARE_STRING_TRAITS_SPECIALIZATION(float)
82 PQXX_DECLARE_STRING_TRAITS_SPECIALIZATION(double)
83 #ifdef PQXX_HAVE_LONG_DOUBLE
84 PQXX_DECLARE_STRING_TRAITS_SPECIALIZATION(long double)
85 #endif
86
87 #undef PQXX_DECLARE_STRING_TRAITS_SPECIALIZATION
88
90 template<> struct PQXX_LIBEXPORT string_traits<const char *>
91 {
92 static const char *name() { return "const char *"; }
93 static bool has_null() { return true; }
94 static bool is_null(const char *t) { return !t; }
95 static const char *null() { return NULL; }
96 static void from_string(const char Str[], const char *&Obj) { Obj = Str; }
97 static PGSTD::string to_string(const char *Obj) { return Obj; }
98 };
99
101 template<> struct PQXX_LIBEXPORT string_traits<char *>
102 {
103 static const char *name() { return "char *"; }
104 static bool has_null() { return true; }
105 static bool is_null(const char *t) { return !t; }
106 static const char *null() { return NULL; }
107
108 // Don't allow this conversion since it breaks const-safety.
109 // static void from_string(const char Str[], char *&Obj);
110
111 static PGSTD::string to_string(char *Obj) { return Obj; }
112 };
113
115 template<size_t N> struct PQXX_LIBEXPORT string_traits<char[N]>
116 {
117 static const char *name() { return "char[]"; }
118 static bool has_null() { return true; }
119 static bool is_null(const char t[]) { return !t; }
120 static const char *null() { return NULL; }
121 static PGSTD::string to_string(const char Obj[]) { return Obj; }
122 };
123
125
128 template<size_t N> struct PQXX_LIBEXPORT string_traits<const char[N]>
129 {
130 static const char *name() { return "char[]"; }
131 static bool has_null() { return true; }
132 static bool is_null(const char t[]) { return !t; }
133 static const char *null() { return NULL; }
134 static PGSTD::string to_string(const char Obj[]) { return Obj; }
135 };
136
137
138 template<> struct PQXX_LIBEXPORT string_traits<PGSTD::string>
139 {
140 static const char *name() { return "string"; }
141 static bool has_null() { return false; }
142 static bool is_null(const PGSTD::string &) { return false; }
143 static PGSTD::string null()
144 { internal::throw_null_conversion(name()); return PGSTD::string(); }
145 static void from_string(const char Str[], PGSTD::string &Obj) { Obj=Str; }
146 static PGSTD::string to_string(const PGSTD::string &Obj) { return Obj; }
147 };
148
149 template<> struct PQXX_LIBEXPORT string_traits<const PGSTD::string>
150 {
151 static const char *name() { return "const string"; }
152 static bool has_null() { return false; }
153 static bool is_null(const PGSTD::string &) { return false; }
154 static const PGSTD::string null()
155 { internal::throw_null_conversion(name()); return PGSTD::string(); }
156 static const PGSTD::string to_string(const PGSTD::string &Obj) { return Obj; }
157 };
158
159 template<> struct PQXX_LIBEXPORT string_traits<PGSTD::stringstream>
160 {
161 static const char *name() { return "stringstream"; }
162 static bool has_null() { return false; }
163 static bool is_null(const PGSTD::stringstream &) { return false; }
164 static PGSTD::stringstream null()
165 {
166 internal::throw_null_conversion(name());
167 // No, dear compiler, we don't need a return here.
168 throw 0;
169 }
170 static void from_string(const char Str[], PGSTD::stringstream &Obj)
171 { Obj.clear(); Obj << Str; }
172 static PGSTD::string to_string(const PGSTD::stringstream &Obj)
173 { return Obj.str(); }
174 };
175
176
177 // TODO: Implement date conversions
178
180
192 template<typename T>
193 inline void from_string(const char Str[], T &Obj)
194 {
195 if (!Str)
196 throw PGSTD::runtime_error("Attempt to read NULL string");
197 string_traits<T>::from_string(Str, Obj);
198 }
199
200
202
208 template<typename T> inline void from_string(const char Str[], T &Obj, size_t)
209 {
210 return from_string(Str, Obj);
211 }
212
213 template<>
214 inline void from_string<PGSTD::string>(const char Str[],
215 PGSTD::string &Obj,
216 size_t len) //[t0]
217 {
218 if (!Str)
219 throw PGSTD::runtime_error("Attempt to read NULL string");
220 Obj.assign(Str, len);
221 }
222
223 template<typename T>
224 inline void from_string(const PGSTD::string &Str, T &Obj) //[t45]
225 { from_string(Str.c_str(), Obj); }
226
227 template<typename T>
228 inline void from_string(const PGSTD::stringstream &Str, T &Obj) //[t0]
229 { from_string(Str.str(), Obj); }
230
231 template<> inline void
232 from_string(const PGSTD::string &Str, PGSTD::string &Obj) //[t46]
233 { Obj = Str; }
234
235
236 namespace internal
237 {
239 inline int digit_to_number(char c) throw () { return c-'0'; }
240 inline char number_to_digit(int i) throw () { return static_cast<char>(i+'0'); }
241 } // namespace pqxx::internal
242
243
245
249 template<typename T> inline PGSTD::string to_string(const T &Obj)
250 { return string_traits<T>::to_string(Obj); }
251
253
254 } // namespace pqxx
255
256 #endif
257