Repeat

Introduction

xpp::io::Repeat is an infinite repeating byte reader. Every call to read() fills the buffer with the same byte and returns len. Never returns EOF — useful for benchmarks and generating padding data.

C++11-compatible (no coroutines). Satisfies the AsyncReader concept.

Example — .await()

#include <xpp/io/repeat.h>

auto r = xpp::io::repeat('A');
char buf[16];
ssize_t n = r.read(buf, sizeof(buf)).await();
// n == 16, buf = "AAAAAAAAAAAAAAAA"

How it works

Repeat stores a single byte and returns xpp::resolve(len) after filling the buffer with std::memset. No I/O, no state changes, no coroutine overhead.

API Reference

Usage Examples

Benchmark throughput — .await()

auto r = xpp::io::repeat();
auto s = xpp::io::sink();
xpp::io::copy(r, s).await();  // measures pure reader + copy throughput

Benchmark throughput — co_await (C++20)

auto r = xpp::io::repeat();
auto s = xpp::io::sink();
co_await xpp::io::copy(r, s);

Padding generation

// .await()
auto zeros = xpp::io::repeat(0);
char pad[1024];
zeros.read(pad, 1024).await();  // 1KB of zeros

// co_await (C++20)
auto zeros = xpp::io::repeat(0);
char pad[1024];
co_await zeros.read(pad, 1024);