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#include "io_test_helper.hh"
#include "io.hh"
#include <algorithm>
#include <cstddef>
#include <expected>
#include <memory>
#include <utility>
namespace {
class BreakingReader : public io::Reader {
public:
BreakingReader(std::unique_ptr<io::Reader> reader, size_t offset,
io::ReadError error)
: reader_(std::move(reader)), offset_(offset), error_(error) {}
[[nodiscard]]
std::expected<size_t, io::ReadError> read(void* dst, size_t max) override {
if (offset_ == 0)
return std::unexpected(error_);
size_t avail = std::min(offset_, max);
auto ret = reader_->read(dst, avail);
if (ret.has_value()) {
offset_ -= ret.value();
}
return ret;
}
[[nodiscard]]
std::expected<size_t, io::ReadError> skip(size_t max) override {
if (offset_ == 0)
return std::unexpected(error_);
size_t avail = std::min(offset_, max);
auto ret = reader_->skip(avail);
if (ret.has_value()) {
offset_ -= ret.value();
}
return ret;
}
private:
std::unique_ptr<io::Reader> reader_;
size_t offset_;
io::ReadError const error_;
};
class MaxBlockReader : public io::Reader {
public:
MaxBlockReader(std::unique_ptr<io::Reader> reader, size_t max_block_size)
: reader_(std::move(reader)), max_block_size_(max_block_size) {}
[[nodiscard]]
std::expected<size_t, io::ReadError> read(void* dst, size_t max) override {
size_t avail = std::min(max_block_size_, max);
return reader_->read(dst, avail);
}
[[nodiscard]]
std::expected<size_t, io::ReadError> skip(size_t max) override {
size_t avail = std::min(max_block_size_, max);
return reader_->skip(avail);
}
private:
std::unique_ptr<io::Reader> reader_;
size_t const max_block_size_;
};
} // namespace
std::unique_ptr<io::Reader> io_make_breaking(std::unique_ptr<io::Reader> reader,
size_t offset,
io::ReadError error) {
return std::make_unique<BreakingReader>(std::move(reader), offset, error);
}
std::unique_ptr<io::Reader> io_make_max_block(
std::unique_ptr<io::Reader> reader, size_t max_block_size) {
return std::make_unique<MaxBlockReader>(std::move(reader), max_block_size);
}
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