eyalroz / strf

Work on a CUDA adaptation of the strf C++ formatting library

Strf

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Version: 0.10.2 documentation: http://robhz786.github.io/strf/doc/quick_reference.html

Strf is a header-only C++14 formatting library that

• is highly extensible.
• is highly customizable
• is fast
• is locale independent. ( Not aways an advantange, but usually ).
• supports encoding conversion.

Overview

#include <cassert>
#include <iostream>
#include <strf.hpp> // The whole library is included in this header

void samples()
{
    // basic example:
    int value = 255;
    std::string s = strf::to_string(value, " in hexadecimal is ", strf::hex(value));
    assert(s == "255 in hexadecimal is ff");


    // more formatting:  operator>(int width) : align to rigth
    //                   operator~()          : show base
    //                   p(int)               : precision
    s = strf::to_string( "---"
                       , ~strf::hex(255).p(4).fill(U'.') > 10
                       , "---" );
    assert(s == "---....0x00ff---");


    // ranges
    int array[] = {20, 30, 40};
    s = strf::to_string( "--[", strf::separated_range(array, " / "), "]--");
    assert(s == "--[20 / 30 / 40]--");


    // range with formatting
    s = strf::to_string( "--["
                       , ~strf::hex(strf::separated_range(array, ", ")).p(4)
                       , "]--");
    assert(s == "--[0x0014, 0x001e, 0x0028]--");


    // join: align a group of argument as one:
    s = strf::to_string( "---"
                       , strf::join_center(30, U'.')( value
                                                    , " in hexadecimal is "
                                                    , strf::hex(value) )
                       , "---" );
    assert(s == "---...255 in hexadecimal is ff...---");


    // numeric punctuation ( using facets )
    auto punct_facet = strf::monotonic_grouping<base>{3}.thousands_sep(U'.');
    s = strf::to_string .with(punct_facet) (100000000000ll);
    assert(s == "100.000.000.000");


    // encoding conversion
    auto s_utf8 = strf::to_u8string( strf::cv(u"aaa-")
                                   , strf::cv(U"bbb-")
                                   , strf::cv( "\x80\xA4"
                                   , strf::windows_1252<char>() ) );
    assert(s_utf8 == u8"aaa-bbb-\u20AC\u00A4");


    // string append
    strf::assign(s) ("aaa", "bbb");
    strf::append(s) ("ccc", "ddd");
    assert(s == "aaabbbcccddd");


    // other output types
    char buff[500];
    strf::to(buff) (value, " in hexadecimal is ", strf::hex(value));
    strf::to(stdout) ("Hello, ", "World", '!');
    strf::to(std::cout.rdbuf()) ("Hello, ", "World", '!');
    std::u16string s16 = strf::to_u16string( value
                                           , u" in hexadecimal is "
                                           , strf::hex(value) );


    // alternative syntax:
    s = strf::to_string.tr("{} in hexadecimal is {}", value, strf::hex(value));
    assert(s == "255 in hexadecimal is ff");
}

Acknowledgments

• This library uses Ryu to print floating-points. Thanks to Ulf Adams for creating such a great algorithm and providing a C implementation. It saved me a ton of work.
• Thanks to Eyal Rozenberg --- the author of cuda-kat library --- for enabling strf to work on CUDA.

Compilers

In its current state, Strf is known to work with the following compilers:

• Clang 3.8 (with --std=c++14 option )
• GCC 6 (with --std=c++14 option )
• Visual Studio 2017 15.8

To-do

• Documentation
• Make it possible to use it as a static library.
• More input types:
  • Hexadecimal floating-points.
  • bool ( currently converted to int and printed as 0 or 1 )
  • char32_t ( converting from UTF-32 to the output encoding )
• More encodings:
  • CESU-8,
  • Modified UTF-8
  • ISO 8859-x
  • Windows-125x
• Enable the user to customize how the width is calculated in input strings.
• Support encoding conversion in Tr-string.