psemek/libs/audio/source/effect/loop.cpp

69 lines
1.4 KiB
C++

#include <psemek/audio/effect/loop.hpp>
#include <psemek/audio/duplicate.hpp>
namespace psemek::audio
{
namespace
{
struct loop_impl
: stream
{
loop_impl(track_ptr dup, std::optional<std::size_t> count)
: dup_(std::move(dup))
, stream_(dup_->stream())
, count_(count)
{}
std::optional<std::size_t> length() const override
{
if (count_)
return (*stream_->length()) * (*count_);
return std::nullopt;
}
std::size_t read(float * data, std::size_t sample_count) override
{
std::size_t result = 0;
while (result < sample_count && (!count_ || repeated_ < *count_))
{
auto need = sample_count - result;
auto count = stream_->read(data + result, need);
result += count;
if (count < need)
{
++repeated_;
stream_ = dup_->stream();
}
}
return result;
}
std::size_t played() const override
{
return stream_->played() + (*stream_->length()) * repeated_;
}
private:
track_ptr dup_;
stream_ptr stream_;
std::optional<std::size_t> count_;
std::size_t repeated_ = 0;
};
}
stream_ptr loop(track_ptr track, std::optional<std::size_t> count)
{
return std::make_shared<loop_impl>(track, count);
}
stream_ptr loop(stream_ptr stream, std::optional<std::size_t> count)
{
if (!stream->length())
return stream;
return loop(make_duplicator(std::move(stream)), count);
}
}