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util.h

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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(char)          { return  "%c"; }
00048 template<> inline const char *FmtString(unsigned char) { return  "%c"; }
00049 
00050 
00052 template<typename T> inline PGSTD::string ToString(const T &Obj)
00053 {
00054   // TODO: Find a decent way to determine max string length at compile time!
00055   char Buf[500];
00056   sprintf(Buf, FmtString(Obj), Obj);
00057   return PGSTD::string(Buf);
00058 }
00059 
00060 template<> inline PGSTD::string ToString(const PGSTD::string &Obj) {return Obj;}
00061 template<> inline PGSTD::string ToString(const char *const &Obj) { return Obj; }
00062 
00063 template<> inline PGSTD::string ToString(const bool &Obj) 
00064 { 
00065   return ToString(unsigned(Obj));
00066 }
00067 
00068 template<> inline PGSTD::string ToString(const short &Obj)
00069 {
00070   return ToString(int(Obj));
00071 }
00072 
00073 template<> inline PGSTD::string ToString(const unsigned short &Obj)
00074 {
00075   return ToString(unsigned(Obj));
00076 }
00077 
00078 
00079 template<typename T> inline void FromString(const char Str[], T &Obj)
00080 {
00081   if (!Str) throw PGSTD::runtime_error("Attempt to convert NULL string to " +
00082                                      PGSTD::string(typeid(T).name()));
00083 
00084   if (sscanf(Str, FmtString(Obj), &Obj) != 1)
00085     throw PGSTD::runtime_error("Cannot convert value '" + 
00086                              PGSTD::string(Str) + 
00087                              "' to " + typeid(T).name());
00088 }
00089 
00090 
00091 template<> inline void FromString(const char Str[], PGSTD::string &Obj)
00092 {
00093   if (!Str) 
00094     throw PGSTD::runtime_error("Attempt to convert NULL C string to C++ "
00095                                "string");
00096   Obj = Str;
00097 }
00098 
00099 
00100 template<> inline void FromString(const char Str[], const char *&Obj)
00101 {
00102   if (!Str)
00103     throw PGSTD::runtime_error("Attempt to read NULL string");
00104   Obj = Str;
00105 }
00106 
00107 template<> inline void FromString(const char Str[], bool &Obj)
00108 {
00109   if (!Str)
00110     throw PGSTD::runtime_error("Attempt to read NULL string");
00111 
00112   switch (Str[0])
00113   {
00114   case 0:
00115   case 'f':
00116     Obj = false;
00117     break;
00118   case '0':
00119     {
00120       int I;
00121       FromString(Str, I);
00122       Obj = (I != 0);
00123     }
00124     break;
00125   default:
00126     Obj = true;
00127   }
00128 }
00129 
00130 
00133 template<typename T> PGSTD::string Quote(const T &Obj, bool EmptyIsNull=false);
00134 
00135 
00137 template<> inline PGSTD::string Quote(const PGSTD::string &Obj, 
00138                                       bool EmptyIsNull)
00139 {
00140   if (EmptyIsNull && Obj.empty()) return "null";
00141 
00142   PGSTD::string Result = "'";
00143 
00144 #ifdef HAVE_PQESCAPESTRING
00145 
00146   char *const Buf = new char[2*Obj.size() + 1];
00147   try
00148   {
00149     PQescapeString(Buf, Obj.c_str(), Obj.size());
00150     Result += Buf;
00151   }
00152   catch (const PGSTD::exception &)
00153   {
00154     delete [] Buf;
00155     throw;
00156   }
00157   delete [] Buf;
00158 
00159 #else
00160 
00161   for (PGSTD::string::size_type i=0; i < Obj.size(); ++i)
00162   {
00163     if (isgraph(Obj[i]))
00164     {
00165       switch (Obj[i])
00166       {
00167       case '\'':
00168       case '\\':
00169         Result += '\\';
00170       }
00171       Result += Obj[i];
00172     }
00173     else
00174     {
00175         char s[5];
00176         snprintf(s, 5, "\\%03hho", Obj[i]);
00177         Result.append(s, 4);
00178     }
00179   }
00180 
00181 #endif
00182 
00183   return Result + '\'';
00184 }
00185 
00186 
00189 template<> inline PGSTD::string Quote(const char *const & Obj, 
00190                                       bool EmptyIsNull)
00191 {
00192   if (!Obj) return "null";
00193   return Quote(PGSTD::string(Obj), EmptyIsNull);
00194 }
00195 
00196 
00200 template<typename T> inline PGSTD::string Quote(const T &Obj, bool EmptyIsNull)
00201 {
00202   return Quote(ToString(Obj), EmptyIsNull);
00203 }
00204 
00205 
00206 
00208 template<typename T> PGSTD::string Classname(const T *);
00209 
00210 
00216 template<typename GUEST>
00217 class Unique
00218 {
00219 public:
00220   Unique() : m_Guest(0) {}
00221 
00222   const GUEST *get() const throw () { return m_Guest; }
00223 
00224   void Register(const GUEST *G)
00225   {
00226     if (!G) throw PGSTD::logic_error("Internal libpqxx error: NULL " + 
00227                                      Classname(G));
00228     
00229     if (m_Guest)
00230     {
00231       if (G == m_Guest)
00232         throw PGSTD::logic_error(Classname(G) +
00233                                  " '" +
00234                                  G->Name() +
00235                                  "' started more than once without closing");
00236 
00237       throw PGSTD::logic_error("Started " + 
00238                                Classname(G) +
00239                                " '" + 
00240                                G->Name() + 
00241                                "' while '" +
00242                                m_Guest->Name() +
00243                                "' was still active");
00244     }
00245     
00246     m_Guest = G;
00247   }
00248 
00249   void Unregister(const GUEST *G)
00250   {
00251     if (G != m_Guest)
00252     {
00253       if (!G) 
00254         throw PGSTD::logic_error("Closing NULL " + Classname(G));
00255       else if (!m_Guest)
00256         throw PGSTD::logic_error("Closing " + 
00257                                  Classname(G) +
00258                                  " '" +
00259                                  G->Name() +
00260                                  "' which wasn't open");
00261       else
00262         throw PGSTD::logic_error("Closing wrong " + 
00263                                  Classname(G) +
00264                                  "; expected '" +
00265                                  m_Guest->Name() +
00266                                  "' but got '" +
00267                                  G->Name() +
00268                                  "'");
00269     }
00270 
00271     m_Guest = 0;
00272   }
00273 
00274 private:
00275   const GUEST *m_Guest;
00276 
00277   // Not allowed:
00278   Unique(const Unique &);
00279   Unique &operator=(const Unique &);
00280 };
00281 
00282 }
00283 
00284 #endif
00285 

Generated on Thu Jan 2 20:15:21 2003 for libpqxx by doxygen1.3-rc2