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tablereader.hxx

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00001 /*-------------------------------------------------------------------------
00002  *
00003  *   FILE
00004  *      pqxx/tablereader.hxx
00005  *
00006  *   DESCRIPTION
00007  *      definition of the pqxx::tablereader class.
00008  *   pqxx::tablereader enables optimized batch reads from a database table
00009  *   DO NOT INCLUDE THIS FILE DIRECTLY; include pqxx/tablereader instead.
00010  *
00011  * Copyright (c) 2001-2005, Jeroen T. Vermeulen <jtv@xs4all.nl>
00012  *
00013  * See COPYING for copyright license.  If you did not receive a file called
00014  * COPYING with this source code, please notify the distributor of this mistake,
00015  * or contact the author.
00016  *
00017  *-------------------------------------------------------------------------
00018  */
00019 #include "pqxx/libcompiler.h"
00020 
00021 #include "pqxx/result"
00022 #include "pqxx/tablestream"
00023 
00024 /* Methods tested in eg. self-test program test001 are marked with "//[t1]"
00025  */
00026 
00027 namespace pqxx
00028 {
00029 
00031 
00045 class PQXX_LIBEXPORT tablereader : public tablestream
00046 {
00047 public:
00048   tablereader(transaction_base &,
00049       const PGSTD::string &RName,
00050       const PGSTD::string &Null=PGSTD::string());                       //[t6]
00051 
00053 
00055   template<typename ITER>
00056   tablereader(transaction_base &,
00057       const PGSTD::string &RName,
00058       ITER begincolumns,
00059       ITER endcolumns,
00060       const PGSTD::string &Null=PGSTD::string());                       //[t80]
00061 
00062   ~tablereader() throw ();                                              //[t6]
00063 
00064   template<typename TUPLE> tablereader &operator>>(TUPLE &);            //[t8]
00065 
00066   operator bool() const throw () { return !m_Done; }                    //[t6]
00067   bool operator!() const throw () { return m_Done; }                    //[t6]
00068 
00070 
00074   bool get_raw_line(PGSTD::string &Line);                               //[t8]
00075 
00076   template<typename TUPLE>
00077   void tokenize(PGSTD::string, TUPLE &) const;                          //[t8]
00078 
00080 
00087   virtual void complete();                                              //[t8]
00088 
00089 #ifdef PQXX_DEPRECATED_HEADERS
00090 
00091   bool GetRawLine(PGSTD::string &L) { return get_raw_line(L); }
00093   template<typename TUPLE> void Tokenize(PGSTD::string L, TUPLE &T) const
00094         { tokenize(L, T); }
00095 #endif
00096 
00097 private:
00098   void setup(transaction_base &T,
00099       const PGSTD::string &RName,
00100       const PGSTD::string &Columns=PGSTD::string());
00101   void reader_close();
00102   PGSTD::string extract_field(const PGSTD::string &,
00103       PGSTD::string::size_type &) const;
00104 
00105   bool m_Done;
00106 };
00107 
00108 
00109 // TODO: Find meaningful definition of input iterator
00110 
00111 
00112 template<typename ITER> inline
00113 tablereader::tablereader(transaction_base &T,
00114     const PGSTD::string &RName,
00115     ITER begincolumns,
00116     ITER endcolumns,
00117     const PGSTD::string &Null) :
00118   tablestream(T, RName, Null, "tablereader"),
00119   m_Done(true)
00120 {
00121   setup(T, RName, columnlist(begincolumns, endcolumns));
00122 }
00123 
00124 
00125 template<typename TUPLE>
00126 inline void tablereader::tokenize(PGSTD::string Line, TUPLE &T) const
00127 {
00128   PGSTD::back_insert_iterator<TUPLE> ins = PGSTD::back_inserter(T);
00129 
00130   // Filter and tokenize line, inserting tokens at end of T
00131   PGSTD::string::size_type here=0;
00132   while (here < Line.size()) *ins++ = extract_field(Line, here);
00133 }
00134 
00135 
00136 template<typename TUPLE>
00137 inline tablereader &pqxx::tablereader::operator>>(TUPLE &T)
00138 {
00139   PGSTD::string Line;
00140   if (get_raw_line(Line)) tokenize(Line, T);
00141   return *this;
00142 }
00143 
00144 
00145 } // namespace pqxx
00146 

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