Main Page   Namespace List   Class Hierarchy   Alphabetical List   Compound List   File List   Namespace Members   Compound Members   File Members   Related Pages  

util.h

Go to the documentation of this file.
00001 /*-------------------------------------------------------------------------
00002  *
00003  *   FILE
00004  *      pqxx/util.h
00005  *
00006  *   DESCRIPTION
00007  *      Various utility definitions for libpqxx
00008  *
00009  * Copyright (c) 2001-2003, Jeroen T. Vermeulen <jtv@xs4all.nl>
00010  *
00011  *-------------------------------------------------------------------------
00012  */
00013 #ifndef PQXX_UTIL_H
00014 #define PQXX_UTIL_H
00015 
00016 #include "pqxx/compiler.h"
00017 
00018 #include <cstdio>
00019 #include <stdexcept>
00020 #include <string>
00021 #include <typeinfo>
00022 
00023 extern "C"
00024 {
00025 #include "libpq-fe.h"
00026 }
00027 
00028 
00029 namespace pqxx
00030 {
00031 typedef long Result_size_type;
00032 typedef int Tuple_size_type;
00033 
00036 template<typename T> inline const char *FmtString(T);
00037 
00038 // Not implemented to prevent accidents with irregular meaning of argument:
00039 // template<> inline const char *FmtString(const char *&) { return "%s"; }
00040 
00041 template<> inline const char *FmtString(int)           { return  "%i"; }
00042 template<> inline const char *FmtString(long)          { return "%li"; }
00043 template<> inline const char *FmtString(unsigned)      { return  "%u"; }
00044 template<> inline const char *FmtString(unsigned long) { return "%lu"; }
00045 template<> inline const char *FmtString(float)         { return  "%f"; }
00046 template<> inline const char *FmtString(double)        { return "%lf"; }
00047 template<> inline const char *FmtString(long double)   { return "%Lf"; }
00048 template<> inline const char *FmtString(char)          { return  "%c"; }
00049 template<> inline const char *FmtString(unsigned char) { return  "%c"; }
00050 
00051 
00053 template<typename T> inline PGSTD::string ToString(const T &Obj)
00054 {
00055   // TODO: Find a decent way to determine max string length at compile time!
00056   char Buf[500];
00057   sprintf(Buf, FmtString(Obj), Obj);
00058   return PGSTD::string(Buf);
00059 }
00060 
00061 template<> inline PGSTD::string ToString(const PGSTD::string &Obj) {return Obj;}
00062 template<> inline PGSTD::string ToString(const char *const &Obj) { return Obj; }
00063 
00064 template<> inline PGSTD::string ToString(const bool &Obj) 
00065 { 
00066   return ToString(unsigned(Obj));
00067 }
00068 
00069 template<> inline PGSTD::string ToString(const short &Obj)
00070 {
00071   return ToString(int(Obj));
00072 }
00073 
00074 template<> inline PGSTD::string ToString(const unsigned short &Obj)
00075 {
00076   return ToString(unsigned(Obj));
00077 }
00078 
00079 
00080 template<typename T> inline void FromString(const char Str[], T &Obj)
00081 {
00082   if (!Str) throw PGSTD::runtime_error("Attempt to convert NULL string to " +
00083                                      PGSTD::string(typeid(T).name()));
00084 
00085   if (sscanf(Str, FmtString(Obj), &Obj) != 1)
00086     throw PGSTD::runtime_error("Cannot convert value '" + 
00087                              PGSTD::string(Str) + 
00088                              "' to " + typeid(T).name());
00089 }
00090 
00091 
00092 template<> inline void FromString(const char Str[], PGSTD::string &Obj)
00093 {
00094   if (!Str) 
00095     throw PGSTD::runtime_error("Attempt to convert NULL C string to C++ "
00096                                "string");
00097   Obj = Str;
00098 }
00099 
00100 
00101 template<> inline void FromString(const char Str[], const char *&Obj)
00102 {
00103   if (!Str)
00104     throw PGSTD::runtime_error("Attempt to read NULL string");
00105   Obj = Str;
00106 }
00107 
00108 template<> inline void FromString(const char Str[], bool &Obj)
00109 {
00110   if (!Str)
00111     throw PGSTD::runtime_error("Attempt to read NULL string");
00112 
00113   switch (Str[0])
00114   {
00115   case 0:
00116   case 'f':
00117     Obj = false;
00118     break;
00119   case '0':
00120     {
00121       int I;
00122       FromString(Str, I);
00123       Obj = (I != 0);
00124     }
00125     break;
00126   default:
00127     Obj = true;
00128   }
00129 }
00130 
00131 
00134 template<typename T> PGSTD::string Quote(const T &Obj, bool EmptyIsNull=false);
00135 
00136 
00138 template<> inline PGSTD::string Quote(const PGSTD::string &Obj, 
00139                                       bool EmptyIsNull)
00140 {
00141   if (EmptyIsNull && Obj.empty()) return "null";
00142 
00143   PGSTD::string Result;
00144   Result.reserve(Obj.size() + 2);
00145   Result += "'";
00146 
00147 #ifdef HAVE_PQESCAPESTRING
00148 
00149   char *const Buf = new char[2*Obj.size() + 1];
00150   try
00151   {
00152     PQescapeString(Buf, Obj.c_str(), Obj.size());
00153     Result += Buf;
00154   }
00155   catch (const PGSTD::exception &)
00156   {
00157     delete [] Buf;
00158     throw;
00159   }
00160   delete [] Buf;
00161 
00162 #else
00163 
00164   for (PGSTD::string::size_type i=0; i < Obj.size(); ++i)
00165   {
00166     if (isgraph(Obj[i]))
00167     {
00168       switch (Obj[i])
00169       {
00170       case '\'':
00171       case '\\':
00172         Result += '\\';
00173       }
00174       Result += Obj[i];
00175     }
00176     else
00177     {
00178         char s[10];
00179         sprintf(s, 
00180                 "\\%03o", 
00181                 static_cast<unsigned int>(static_cast<unsigned char>(Obj[i])));
00182         Result.append(s, 4);
00183     }
00184   }
00185 
00186 #endif
00187 
00188   return Result + '\'';
00189 }
00190 
00191 
00194 template<> inline PGSTD::string Quote(const char *const & Obj, 
00195                                       bool EmptyIsNull)
00196 {
00197   if (!Obj) return "null";
00198   return Quote(PGSTD::string(Obj), EmptyIsNull);
00199 }
00200 
00201 
00205 template<typename T> inline PGSTD::string Quote(const T &Obj, bool EmptyIsNull)
00206 {
00207   return Quote(ToString(Obj), EmptyIsNull);
00208 }
00209 
00210 
00211 
00213 template<typename T> PGSTD::string Classname(const T *);
00214 
00215 
00221 template<typename GUEST>
00222 class Unique
00223 {
00224 public:
00225   Unique() : m_Guest(0) {}
00226 
00227   const GUEST *get() const throw () { return m_Guest; }
00228 
00229   void Register(const GUEST *G)
00230   {
00231     if (!G) throw PGSTD::logic_error("Internal libpqxx error: NULL " + 
00232                                      Classname(G));
00233     
00234     if (m_Guest)
00235     {
00236       if (G == m_Guest)
00237         throw PGSTD::logic_error(Classname(G) +
00238                                  " '" +
00239                                  G->Name() +
00240                                  "' started more than once without closing");
00241 
00242       throw PGSTD::logic_error("Started " + 
00243                                Classname(G) +
00244                                " '" + 
00245                                G->Name() + 
00246                                "' while '" +
00247                                m_Guest->Name() +
00248                                "' was still active");
00249     }
00250     
00251     m_Guest = G;
00252   }
00253 
00254   void Unregister(const GUEST *G)
00255   {
00256     if (G != m_Guest)
00257     {
00258       if (!G) 
00259         throw PGSTD::logic_error("Closing NULL " + Classname(G));
00260       else if (!m_Guest)
00261         throw PGSTD::logic_error("Closing " + 
00262                                  Classname(G) +
00263                                  " '" +
00264                                  G->Name() +
00265                                  "' which wasn't open");
00266       else
00267         throw PGSTD::logic_error("Closing wrong " + 
00268                                  Classname(G) +
00269                                  "; expected '" +
00270                                  m_Guest->Name() +
00271                                  "' but got '" +
00272                                  G->Name() +
00273                                  "'");
00274     }
00275 
00276     m_Guest = 0;
00277   }
00278 
00279 private:
00280   const GUEST *m_Guest;
00281 
00282   // Not allowed:
00283   Unique(const Unique &);
00284   Unique &operator=(const Unique &);
00285 };
00286 
00287 }
00288 
00289 #endif
00290 

Generated on Fri Feb 28 19:23:32 2003 for libpqxx by doxygen1.3-rc3