printf.h

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#ifndef TAG_PRINTF_H
#define TAG_PRINTF_H

#include <iostream>
#include <iomanip>
#include <sstream>
#include <string>
#include <cctype>

#include <tag/tuple.h>

namespace tag
{
    #ifndef DOXYGEN_IGNORE_INTERNAL
    namespace Internal
    {

        // Code for parsing and interpreting printf style format specifiers.
        //Code for groking format strings
        struct format
        {
            enum
            {
                ALT = 1, ZP=2, LEFT=4, SPACE=8, SIGN=16, PERCENT=32, BAD=64,
                NO_PRECISION=-1, NO_WIDTH=-1
            };

            int flags;
            int  width, precision;
            char conversion;

            inline int parse(const std::string& fmt, int pos)
            {
                flags=0;
                width=NO_WIDTH;
                precision=NO_PRECISION;
                conversion=0;

                int s = fmt.size();

                if(pos == s)
                {
                    flags |= BAD;
                    return 0;
                }

                //Check for literal
                if(fmt[pos] == '%')
                {
                    flags = PERCENT;
                    return pos+1;
                }

                //Get flags (if any)
                for(; pos < s; pos++)
                {
                    char c = fmt[pos];

                    if(c == '#')
                        flags |= ALT;
                    else if(c == '0')
                        flags |= ZP;
                    else if(c == ' ')
                        flags |= SPACE;
                    else if(c == '-')
                        flags |= LEFT;
                    else if(c == '+')
                        flags |= SIGN;
                    else
                        break;
                }

                //Get width
                for(; pos < s; pos++)
                {
                    char c = fmt[pos];
                    if(isdigit(c))
                        if(width == NO_WIDTH)
                            width = c - '0';
                        else
                            width = width * 10 + (c-'0');
                    else
                        break;
                }

                //Check for a precison
                if(pos < s && fmt[pos] == '.')
                {
                    precision = 0;
                    pos++;

                    //Get width
                    for(; pos < s; pos++)
                    {
                        char c = fmt[pos];
                        if(isdigit(c))
                            precision = precision * 10 + (c-'0');
                        else
                            break;
                    }
                }

                //Now, this should be the conversion
                if(pos < s && isalpha(fmt[pos]))
                    conversion = fmt[pos++];
                else
                    flags = BAD;

                return pos;
            }
        };

        //To make it looks like ostream << format works
        template<class Char, class Traits> struct bound_format
        {
            bound_format(std::basic_ostream<Char, Traits>& os, const format& ff)
            :o(os), f(ff)
            {}

            std::basic_ostream<Char, Traits>& o;
            const format& f;
        };


        template<class Char, class Traits> bound_format<Char, Traits> operator<<(std::basic_ostream<Char, Traits>& o, const format& f)
        {
            return bound_format<Char, Traits>(o, f);
        }

        //Evaluate the result of osteram << format << X
        template<class Char, class Traits, class C> std::basic_ostream<Char, Traits>& operator<<(bound_format<Char,Traits> f, const C& c)
        {
            using std::ios;
            using namespace std;

            bool precision_is_max_width=0;


            //Save old stream state.
            int old_p = f.o.precision();
            Char old_fill = f.o.fill();
            ios::fmtflags old_flags = f.o.flags();

            //Conversion specific tricks
            //Defaults
            f.o.unsetf(ios::floatfield | ios::boolalpha);
            f.o.setf(ios::dec);
            f.o.fill(' ');

            //Process conversion characters. These can affect the formatting
            //parameters below.
            switch(f.f.conversion)
            {
                case 'f':
                case 'F':
                    f.o.setf(ios::fixed);
                    break;

                case 'e':
                case 'E':
                    f.o.setf(ios::scientific);
                    break;

                case 'g':
                case 'G':
                    f.o.unsetf(ios::floatfield);
                    break;

                case 'x':
                case 'X':
                    f.o << hex;
                    break;

                case 'o':
                case 'O':
                    f.o << oct;
                    break;

                case 'b':
                case 'B':
                    f.o << boolalpha;
                    break;

                case 's':
                case 'S':
                    precision_is_max_width=1;
                    break;

                case 'k':
                case 'K':
                    return f.o;
                    break;
            }



            if(f.f.width != format::NO_WIDTH)
                f.o.width(f.f.width);

            if(f.f.flags & format::ZP && !(f.f.flags & format::LEFT))
                f.o.fill('0');

            if(f.f.flags & format::SIGN)
                f.o.setf(ios::showpos);
            else
                f.o.unsetf(ios::showpos);

            if(f.f.flags & format::LEFT)
                f.o.setf(ios::left);
            else
                f.o.setf(ios::internal);

            if(f.f.flags * format::ALT)
                f.o.setf(ios::showbase | ios::showpoint);
            else
                f.o.unsetf(ios::showbase | ios::showpoint);


            if(isupper(f.f.conversion))
                f.o.setf(ios::uppercase);
            else
                f.o.unsetf(ios::uppercase);


            if(f.f.precision != format::NO_PRECISION && ! precision_is_max_width)
                f.o.precision(f.f.precision);

            if(precision_is_max_width && f.f.precision != format::NO_PRECISION)
            {
                ostringstream tmp;
                tmp.copyfmt(f.o);

                //Since we're doing the truncation by hand, then there should be
                //no width specification
                tmp << setw(0) << c;

                f.o << tmp.str().substr(0, f.f.precision);
            }
            else
                f.o << c;


            //Reset values
            f.o.precision(old_p);
            f.o.fill(old_fill);
            f.o.setf(old_flags);

            return f.o;
        }

        //This parses a format tring and uses it to print a typelist. The typelist has to be
        //accessed in reverse order, since the last element added to the typelist is the
        //one at the start of the list. Since lists are produced with (Fmt, a, b, c), that means
        //that c would be accessed first. To make it look like printf, a needs to be accessed first.
        template<class C, class D, int i, int max> struct print_typelist
        {
            static void print(std::ostream& o, const std::string& fmt, int fpos, const T_list<C,D>& l)
            {
                size_t ppos;

                while(1)
                {
                    ppos = fmt.find('%', fpos);

                    if(ppos == fmt.npos)
                    {
                        //No more format specifiers, so output the rest of the string
                        o <<  &fmt[fpos];
                        return;
                    }

                    //else output the strung up to the specifier
                    o  << fmt.substr(fpos, ppos - fpos);

                    //Parse the format string
                    format f;
                    int pos = f.parse(fmt, ppos+1);

                    if(f.flags & format::PERCENT)
                    {
                        o << '%';
                        fpos = pos;
                        continue;
                    }
                    else if(f.flags & format::BAD)
                    {
                        o  << "<Malformed format>" << &fmt[ppos];
                        return ;
                    }
                    else
                    {
                        o << f << l.template index<i>();
                        print_typelist<C,D, i+1, max>::print(o, fmt, pos, l);
                        return;
                    }
                }
            }

        };

        template<class C, class D, int max> struct print_typelist<C, D, max, max>
        {
            static void print(std::ostream& o, const std::string& fmt, int fpos, const T_list<C,D>&)
            {
                size_t ppos;

                while(1)
                {
                    ppos = fmt.find('%', fpos);

                    if(ppos == fmt.npos)
                    {
                        //No more format specifiers, so output the rest of the string
                        o <<  &fmt[fpos];
                        return;
                    }

                    //else output the strung up to the specifier
                    o  << fmt.substr(fpos, ppos - fpos);

                    //Parse the format string
                    format f;
                    int pos = f.parse(fmt, ppos+1);

                    if(f.flags & format::PERCENT)
                    {
                        o << '%';
                        fpos = pos;
                        continue;
                    }
                    else if(f.flags & format::BAD)
                    {
                        o  << "<Malformed format>" << &fmt[ppos];
                        return ;
                    }
                    else
                    {
                        o << "<Missing value>";
                        fpos = pos;
                        continue;
                    }
                }
            }
        };
    }
    #endif



    template<class A, class B, class C, class D> void vfPrintf(std::basic_ostream<A, B>& o, const std::string fmt, const T_list<C,D>& l)
    {
        Internal::print_typelist<C, D, 0, T_list<C,D>::elements >::print(o, fmt, 0, l);
    }

    template<class C, class D> void vPrintf(const std::string fmt, const T_list<C,D>& l)
    {
        vfPrintf(std::cout, fmt, l);
    }

    template<class C, class D> std::string vsPrintf(const std::string& fmt, const T_list<C,D>& l)
    {
        std::ostringstream o;
        vfPrintf(o, fmt, l);
        return o.str();
    }

    static const T_ListEnd Fmt=TupleHead;

    //Old cvs version has by-hand variable argument list up to 10 args
}

#define Printf(A, ...) vPrintf(A, (tag::Fmt,## __VA_ARGS__))

#define fPrintf(A,B, ...) vfPrintf(A,B, (tag::Fmt,## __VA_ARGS__))

#define sPrintf(A, ...) vsPrintf(A, (tag::Fmt,## __VA_ARGS__))
#endif