trjhtr

Previously asked here.

The code is now available on GitHub.

Since the previous review I have added unit tests.

Since it is big it will come in a couple of parts.

Part 1 | Part 2 | Part 3 | Part 4

Part 4

Printing strings and integers did not work the same way on streams as they did in printf(). So I had to write some special handling code to deal with these types to get the unit tests to all work.

printToStream.h

#ifndef THORSANVIL_IOUTIL_PRINT_TO_STREAM_H
#define THORSANVIL_IOUTIL_PRINT_TO_STREAM_H

#include "FormatInfo.h"
#include "printIntToStream.h"
#include "printStringToStream.h"

#include <ostream>

namespace ThorsAnvil::IOUtil


template<typename T>
inline void printToStreamDefault(std::ostream& s, T const& arg, FormatInfo const&)

 s << arg;


/* Template method for everything apart from integers */
template<typename T>
inline
typename std::enable_if<!std::is_integral<T>::value>::type
printToStream(std::ostream& s, T const& arg, FormatInfo const& info)

 // Just use the standard stream printing methods.
 // Below we special case Int and string handling (floats work as expected).
 printToStreamDefault(s, arg, info);


/*
 * As a char is an integer we need to detect this case
 * and call the standard printing functions for Type::Char
 *
 * But we can also print an integer using a char in which case we need to convert the char to an integer
 * before we can print it. Below are helper functions to convert Char to Int when printing a char as an
 * an integer.
 */
template<typename T>
struct CharIntConverter

 using Integer = T;
;
template<>
struct CharIntConverter<char>

 using Integer = int;
;
template<>
struct CharIntConverter<unsigned char>

 using Integer = unsigned int;
;


template<typename T>
inline
typename std::enable_if<std::is_integral<T>::value>::type
printToStream(std::ostream& s, T const& arg, FormatInfo const& info)

 if (info.type == Type::Char)
 
 printToStreamDefault(s, static_cast<char>(arg), info);
 
 else
 
 printIntToStream(s, static_cast<typename CharIntConverter<T>::Integer>(arg), info);
 


// C-String
inline void printToStream(std::ostream& s, char const* const& arg, FormatInfo const& info)

 printStringToStream(s, arg, info);





#endif

PrintStringToStream.h

#ifndef THORSANVIL_IOUTIL_PRINT_STRING_TO_STREAM_H
#define THORSANVIL_IOUTIL_PRINT_STRING_TO_STREAM_H

#include "FormatInfo.h"
#include "printToStream.h"

namespace ThorsAnvil::IOUtil


inline void printStringToStream(std::ostream& s, char const* const& arg, FormatInfo const& info)

 if (info.precision == -1)
 
 s << arg;
 
 else
 
 s.width(0);
 std::size_t padding = (info.precision >= info.width) ? 0 : (info.width - info.precision);
 if (!info.leftJustify)
 
 for (std::size_t loop = 0; loop < padding; ++loop)
 
 s.put(' ');
 
 
 for (std::size_t loop = 0; arg[loop] != '' && loop < info.precision; ++loop)
 
 s.put(arg[loop]);
 
 if (info.leftJustify)
 
 for (std::size_t loop = 0; loop < padding; ++loop)
 
 s.put(' ');
 
 
 

PrintIntToStream

#ifndef THORSANVIL_IOUTIL_PRINT_INT_TO_STREAM_H
#define THORSANVIL_IOUTIL_PRINT_INT_TO_STREAM_H

#include "FormatInfo.h"
#include "printToStream.h"

#include <ostream>
#include <cmath>

namespace ThorsAnvil::IOUtil


inline long long absm(long long arg) return std::abs(arg);
inline long absm(long arg) return std::abs(arg);
inline int absm(int arg) return std::abs(arg);
inline unsigned long long absm(unsigned long long arg) return arg;
inline unsigned long absm(unsigned long arg) return arg;
inline unsigned int absm(unsigned int arg) return arg;

template<typename T>
inline void printIntToStream(std::ostream& s, T arg, FormatInfo const& info)

 static long double const logFor16 = std::log10(16.0L);
 static long double const logFor10 = std::log10(10.0L);
 static long double const logFor08 = std::log10(8.0L);

 double const& logBase = s.flags() & std::ios_base::oct ? logFor08 : s.flags() & std::ios_base::hex ? logFor16 : logFor10;

 if (info.width == 0 && info.precision == -1)
 
 s << arg;
 
 else
 arg != 0)
 
 s << absm(arg);
 
 // Add spaces after number to make it fit in width.
 if (info.leftJustify)
 
 for (std::size_t loop = 0; loop < padding; ++loop)
 
 s.put(' ');
 
 
 




#endif