C++ Range-V3 dividing an audio stream into Chunks - c++

Question

I am reading a wav file,and pushing the data in a std::array in the end.
I need to make some operation on the chunks of data. So I thought this is a good opportunity to learn Eric Niebler's ranges.
I saw view_facade in manual page under "custom ranges" section but than I saw this question: link . Now I am not sure how to make a custom range class. Can anybody help me about that? The code below shows what I am trying to achieve.
#include <iostream>
#include <range/v3/all.hpp>
using namespace ranges;
using namespace std;
struct A
{
static constexpr size_t MAX_SIZE = 100000;
A ()
{
for ( size_t i = 0; i < MAX_SIZE; i++)
data[i] = i;
size = MAX_SIZE;
}
auto begin() const { return data.begin(); }
auto end() const { return data.end(); }
std::array< double , MAX_SIZE > data;
size_t size;
};
int main()
{
A instance;
RANGES_FOR(auto chunk, view::all(instance) | view::chunk(256)) {
}
return 0;
}
Part of compile output:
14:47:23: Running steps for project tryOuts...
14:47:23: Configuration unchanged, skipping qmake step.
14:47:23: Starting: "C:\Qt\Tools\mingw491_32\bin\mingw32-make.exe"
C:/Qt/Tools/mingw491_32/bin/mingw32-make -f Makefile.Debug
mingw32-make[1]: Entering directory 'C:/Users/Erdem/Documents/build-tryOuts-Desktop_Qt_5_4_2_MinGW_32bit-Debug'
g++ -c -pipe -fno-keep-inline-dllexport -std=gnu++1y -pthread -lpthread -O3 -g -frtti -Wall -Wextra -fexceptions -mthreads -DUNICODE -I"..\tryOuts" -I"." -I"..\..\..\..\range-v3-master\include" -I"D:\cvOutNoIPP\install\include" -I"..\..\..\..\Qt\5.4\mingw491_32\mkspecs\win32-g++" -o debug\main.o ..\tryOuts\main.cpp
In file included from ..\..\..\..\range-v3-master\include/range/v3/utility/iterator.hpp:28:0,
from ..\..\..\..\range-v3-master\include/range/v3/begin_end.hpp:24,
from ..\..\..\..\range-v3-master\include/range/v3/core.hpp:17,
from ..\..\..\..\range-v3-master\include/range/v3/all.hpp:17,
from ..\tryOuts\main.cpp:2:
..\..\..\..\range-v3-master\include/range/v3/utility/basic_iterator.hpp:445:22: error: 'constexpr const T& ranges::v3::basic_mixin<Cur>::get() const' cannot be overloaded
T const &get() const noexcept
^
------------ Update -------------------------------------------
If I add
CONFIG += c++14 the code almost compiles except auto return type deduction errors below :
main.cpp:22: deduced return type only available with -std=c++1y or -std=gnu++1y
to avoid those errors I am using CONFIG += c++1y.But in this case I am getting bunch of errors that I post in first place. I know from D language so called "Voldemort Types" are important, I don't want to give up return type deduction. Which flag in gcc should I use?

Answer 1

I'm still learning the range library myself, but my understanding is that things that expose STL-compatible begin() and end() methods can be used as a view. So for example, with your Reader class you could have
struct Reader {
// ...
auto begin() const { return rawData.begin(); }
auto end() const { return rawData.end(); }
};
You could then use view::all() to create a view around the Reader, something like
Reader r;
RANGES_FOR(auto chunk, view::all(r) | view::chunk(256)) {
...
}
As I say, I'm still learning the library myself, but hopefully this will help.