mystring.h

Go to the documentation of this file.

 
/***********************************************************************
 Copyright (c) 1998 by Kevin Atkinson, (c) 1999-2001 by MySQL AB, and
 (c) 2004-2008 by Educational Technology Resources, Inc.  Others may
 also hold copyrights on code in this file.  See the CREDITS.txt file
 in the top directory of the distribution for details.
 
 This file is part of MySQL++.
 
 MySQL++ is free software; you can redistribute it and/or modify it
 under the terms of the GNU Lesser General Public License as published
 by the Free Software Foundation; either version 2.1 of the License, or
 (at your option) any later version.
 
 MySQL++ is distributed in the hope that it will be useful, but WITHOUT
 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
 License for more details.
 
 You should have received a copy of the GNU Lesser General Public
 License along with MySQL++; if not, write to the Free Software
 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
 USA
***********************************************************************/
 
#if !defined(MYSQLPP_MYSTRING_H)
#define MYSQLPP_MYSTRING_H
 
#include "common.h"
 
#include "datetime.h"
#include "exceptions.h"
#include "null.h"
#include "sql_buffer.h"
 
#include <string>
#include <sstream>
#include <limits>
 
#include <stdlib.h>
#include <string.h>
 
namespace mysqlpp {
 
#if !defined(DOXYGEN_IGNORE)
// Doxygen will not generate documentation for this section.
 
namespace detail
{
        template<typename T, bool is_signed = std::numeric_limits<T>::is_signed>
        struct conv_promotion;
 
        template<>
        struct conv_promotion<float>
        {
                typedef double type;
        };
 
        template<>
        struct conv_promotion<double>
        {
                typedef double type;
        };
 
#       if !defined(NO_LONG_LONGS)
        template<>
        struct conv_promotion<unsigned long long>
        {
                typedef unsigned long long type;
        };
 
        template<>
        struct conv_promotion<long long>
        {
                typedef long long type;
        };
#       endif
 
        // preserve existing behaviour, char converted as signed long
        template<>
        struct conv_promotion<char>
        {
                typedef long type;
        };
 
        // all other types use signed/unsigned long
 
        template<typename T>
        struct conv_promotion<T, true>
        {
                typedef long type;
        };
 
        template<typename T>
        struct conv_promotion<T, false>
        {
                typedef unsigned long type;
        };
} // namespace detail
 
class MYSQLPP_EXPORT SQLTypeAdapter;
#endif // !defined(DOXYGEN_IGNORE)
 
 
class MYSQLPP_EXPORT String
{
public:
        typedef const char value_type;
 
        typedef size_t size_type;
 
        typedef const char* const_iterator;
 
        typedef const_iterator iterator;
 
#if !defined(DOXYGEN_IGNORE)
// Doxygen will not generate documentation for this section.
        typedef int difference_type;
        typedef const char* const_pointer;
        typedef const_pointer pointer;
#endif // !defined(DOXYGEN_IGNORE)
 
        String() :
        buffer_()
        {
        }
 
        String(const String& other) :
        buffer_(other.buffer_)
        {
        }
 
        explicit String(const char* str, size_type len,
                        mysql_type_info type = mysql_type_info::string_type,
                        bool is_null = false) :
        buffer_(new SQLBuffer(str, len, type, is_null))
        {
        }
 
        explicit String(const std::string& str,
                        mysql_type_info type = mysql_type_info::string_type,
                        bool is_null = false) :
        buffer_(new SQLBuffer(str.data(), static_cast<size_type>(str.length()),
                        type, is_null))
        {
        }
 
        explicit String(const char* str,
                        mysql_type_info type = mysql_type_info::string_type,
                        bool is_null = false) :
        buffer_(new SQLBuffer(str, static_cast<size_type>(strlen(str)),
                        type, is_null))
        {
        }
 
        ~String() { }
 
        void assign(const char* str, size_type len,
                        mysql_type_info type = mysql_type_info::string_type,
                        bool is_null = false)
        {
                buffer_ = new SQLBuffer(str, len, type, is_null);
        }
 
        void assign(const std::string& str,
                        mysql_type_info type = mysql_type_info::string_type,
                        bool is_null = false)
        {
                buffer_ = new SQLBuffer(str.data(),
                                static_cast<size_type>(str.length()), type, is_null);
        }
 
        void assign(const char* str,
                        mysql_type_info type = mysql_type_info::string_type,
                        bool is_null = false)
        {
                buffer_ = new SQLBuffer(str, static_cast<size_type>(strlen(str)),
                                type, is_null);
        }
 
        char at(size_type pos) const;
 
        const_iterator begin() const { return data(); }
 
        const char* c_str() const { return data(); }
        
#if defined(MYSQLPP_PLATFORM_VISUAL_CPP)
// Squish VC++ warning about "possible loss of data" for these conversions
#   pragma warning(disable: 4244)
#endif
 
        template <class Type>
        Type conv(Type) const
        {
                // Conversions are done using one of double/long/ulong/llong/ullong
                // so we call a helper function to do the work using that type.
                // This reduces the amount of template code instantiated.
                typedef typename detail::conv_promotion<Type>::type conv_type;
                return do_conv<conv_type>(typeid(Type).name());
        }
 
#if defined(MYSQLPP_PLATFORM_VISUAL_CPP)
#   pragma warning(default: 4244)
#endif
 
        template <class T, class B>
        Null<T, B> conv(Null<T, B>) const
        {
                if (is_null()) {
                        return Null<T, B>(null);
                }
                else {
                        return Null<T, B>(conv(T()));
                }
        }
 
        int compare(const String& other) const;
 
        int compare(const std::string& other) const;
 
        int compare(size_type pos, size_type num, std::string& other) const;
 
        int compare(const char* other) const;
 
        int compare(size_type pos, size_type num, const char* other) const;
 
        const char* data() const;
 
        bool empty() const { return size() == 0; }
        
        const_iterator end() const;
 
        bool escape_q() const;
 
        bool is_null() const;
 
        void it_is_null();
 
        size_type length() const;
        
        size_type max_size() const { return size(); }
 
        bool quote_q() const;
 
        size_type size() const { return length(); }
        
        void strip_leading_blanks(std::string& s) const
        {
                const char* pc = data();
                if (pc) {
                        size_type n = length();
                        while (n && (*pc == ' ')) {
                                ++pc;
                                --n;
                        }
 
                        s.assign(pc, n);
                }
                else {
                        s.clear();
                }
        }
 
        void to_string(std::string& s) const;
 
        mysql_type_info type() const
        {
                return buffer_ ? buffer_->type() : mysql_type_info::string_type;
        }
 
        String& operator =(const std::string& rhs)
        {
                buffer_ = new SQLBuffer(rhs.data(),
                                static_cast<size_type>(rhs.length()),
                                mysql_type_info::string_type, false);
 
                return *this;
        }
 
        String& operator =(const char* str)
        {
                buffer_ = new SQLBuffer(str,
                                static_cast<size_type>(strlen(str)),
                                mysql_type_info::string_type, false);
 
                return *this;
        }
 
        String& operator =(const String& other)
        {
                buffer_ = other.buffer_;
 
                return *this;
        }
 
        template <typename T>
        bool operator ==(const T& rhs) const
        {
                return compare(rhs) == 0;
        }
 
        bool operator ==(const mysqlpp::null_type&) const
        {
                return is_null();
        }
 
        template <typename T>
        bool operator !=(const T& rhs) const
        {
                return compare(rhs) != 0;
        }
 
        bool operator !=(const mysqlpp::null_type&) const
        {
                return !is_null();
        }
 
        char operator [](size_type pos) const { return at(pos); }
 
        operator const char*() const { return data(); }
        
        operator signed char() const
                        { return conv(static_cast<signed char>(0)); }
        
        operator unsigned char() const
                        { return conv(static_cast<unsigned char>(0)); }
        
        operator int() const
                        { return conv(static_cast<int>(0)); }
        
        operator unsigned int() const
                        { return conv(static_cast<unsigned int>(0)); }
        
        operator short int() const
                        { return conv(static_cast<short int>(0)); }
        
        operator unsigned short int() const
                        { return conv(static_cast<unsigned short int>(0)); }
        
        operator long int() const
                        { return conv(static_cast<long int>(0)); }
        
        operator unsigned long int() const
                        { return conv(static_cast<unsigned long int>(0)); }
        
#if !defined(NO_LONG_LONGS)
        operator longlong() const
                        { return conv(static_cast<longlong>(0)); }
        
        operator ulonglong() const
                        { return conv(static_cast<ulonglong>(0)); }
#endif
        
        operator float() const
                        { return conv(static_cast<float>(0)); }
        
        operator double() const
                        { return conv(static_cast<double>(0)); }
        
        operator bool() const { return buffer_ ? atoi(c_str()) : false; }
 
        operator Date() const { return buffer_ ? Date(*this) : Date(); }
 
        operator DateTime() const
                        { return buffer_ ? DateTime(*this) : DateTime(); }
 
        operator Time() const { return buffer_ ? Time(*this) : Time(); }
 
        template <class T, class B>
        operator Null<T, B>() const { return conv(Null<T, B>()); }
 
private:
        template <class Type>
        Type do_conv(const char* type_name) const
        {
                if (buffer_) {
                        std::stringstream buf;
                        buf.write(data(), static_cast<std::streamsize>(length()));
                        buf.imbue(std::locale::classic()); // "C" locale
                        Type num = Type();
                        
                        if (buf >> num) {
                                char c;
                                if (!(buf >> c)) {
                                        // Nothing left in buffer, so conversion complete,
                                        // and thus successful.
                                        return num;
                                }
 
                                if (c == '.' &&
                                                (typeid(Type) != typeid(float)) &&
                                                (typeid(Type) != typeid(double))) {
                                        // Conversion stopped on a decimal point -- locale
                                        // doesn't matter to MySQL -- so only way to succeed
                                        // is if it's an integer and everything following
                                        // the decimal is inconsequential.
                                        c = '0';        // handles '.' at end of string
                                        while (buf >> c && c == '0') /* spin */ ;
                                        if (buf.eof() && c == '0') {
                                                return num;  // only zeros after decimal point
                                        }
                                }
                        }
                        else if (buf.eof()) {
                                return num;  // nothing to convert, return default value
                        }
 
                        throw BadConversion(type_name, data(), 0, length());
                }
                else {
                        return 0;
                }
        }
 
        RefCountedBuffer buffer_;       
 
        friend class SQLTypeAdapter;
};
 
MYSQLPP_EXPORT std::ostream& operator <<(std::ostream& o,
                const String& in);
 
 
#if !defined(MYSQLPP_NO_BINARY_OPERS) && !defined(DOXYGEN_IGNORE)
// Ignore this section is MYSQLPP_NO_BINARY_OPERS is defined, or if this
// section is being parsed by Doxygen.  In the latter case, it's ignored
// because Doxygen doesn't understand it correctly, and we can't be
// bothered to explain it to Doxygen.
 
#define oprsw(opr, other, conv) \
        inline other operator opr (String x, other y) \
                        { return static_cast<conv>(x) opr y; } \
        inline other operator opr (other x, String y) \
                        { return x opr static_cast<conv>(y); }
 
#define operator_binary(other, conv) \
        oprsw(+, other, conv) \
        oprsw(-, other, conv) \
        oprsw(*, other, conv) \
        oprsw(/, other, conv)
 
#define operator_binary_int(other, conv) \
        operator_binary(other, conv) \
        oprsw(%, other, conv) \
        oprsw(&, other, conv) \
        oprsw(^, other, conv) \
        oprsw(|, other, conv) \
        oprsw(<<, other, conv) \
        oprsw(>>, other, conv)
 
// Squish more complaints about possible loss of data
#if defined(MYSQLPP_PLATFORM_VISUAL_CPP)
#       pragma warning(disable: 4244)
#endif
 
operator_binary(float, double)
operator_binary(double, double)
 
operator_binary_int(char, long int)
operator_binary_int(int, long int)
operator_binary_int(short int, long int)
operator_binary_int(long int, long int)
 
operator_binary_int(unsigned char, unsigned long int)
operator_binary_int(unsigned int, unsigned long int)
operator_binary_int(unsigned short int, unsigned long int)
operator_binary_int(unsigned long int, unsigned long int)
 
#if defined(MYSQLPP_PLATFORM_VISUAL_CPP)
#       pragma warning(default: 4244)
#endif
 
#if !defined(NO_LONG_LONGS)
operator_binary_int(longlong, longlong)
operator_binary_int(ulonglong, ulonglong)
#endif // !defined(NO_LONG_LONGS)
#endif // !defined(MYSQLPP_NO_BINARY_OPERS) && !defined(DOXYGEN_IGNORE)
 
 
#if !defined(DOXYGEN_IGNORE)
// Doxygen isn't smart enough to recognize these template
// specializations.  Maybe it's the MYSQLPP_EXPORT tags?
 
template <> MYSQLPP_EXPORT bool String::conv(bool) const;
 
template <> MYSQLPP_EXPORT String String::conv(String) const;
 
template <> MYSQLPP_EXPORT std::string String::conv(std::string) const;
 
template <> MYSQLPP_EXPORT Date String::conv(Date) const;
 
template <> MYSQLPP_EXPORT DateTime String::conv(DateTime) const;
 
template <> MYSQLPP_EXPORT Time String::conv(Time) const;
 
#endif // !defined(DOXYGEN_IGNORE)
 
} // end namespace mysqlpp
 
#endif // !defined(MYSQLPP_MYSTRING_H)