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#include "uline.hh"
#include "check.hh"
#include <algorithm>
#include <array>
#include <cassert>
#include <cstdint>
#include <cstring>
#include <expected>
#include <memory>
#include <string_view>
#include <utility>
namespace {
template <typename T, typename Reader>
class UnicodeReader {
public:
UnicodeReader(std::unique_ptr<Reader> reader, size_t max_len,
std::array<T, 2> line_terminators)
: reader_(std::move(reader)),
max_len_(max_len),
line_terminators_(line_terminators),
buffer_(std::make_unique_for_overwrite<T[]>(
check::add(max_len, static_cast<size_t>(2)))),
rptr_(buffer_.get()),
wptr_(buffer_.get()),
search_(rptr_),
end_(buffer_.get() + check::add(max_len, static_cast<size_t>(2))) {}
[[nodiscard]]
std::expected<std::basic_string_view<T>, line::ReadError> read() {
while (true) {
search_ = std::find_first_of(search_, wptr_, line_terminators_.begin(),
line_terminators_.end());
if (search_ < wptr_) {
if (std::cmp_greater(search_ - rptr_, max_len_)) {
return line(max_len_, 0);
}
size_t tlen;
if (*search_ == line_terminators_[1]) {
tlen = 1;
} else {
if (search_ + 1 == wptr_) {
make_space_if_needed();
auto got = fill();
if (got.has_value()) {
if (got.value() == 0) {
return line(search_ - rptr_, 1);
}
} else {
return std::unexpected(line::ReadError(got.error()));
}
}
if (search_[1] == line_terminators_[1]) {
tlen = 2;
} else {
tlen = 1;
}
}
return line(search_ - rptr_, tlen);
}
if (std::cmp_greater_equal(wptr_ - rptr_, max_len_)) {
return line(max_len_, 0);
}
make_space_if_needed();
auto got = fill();
if (got.has_value()) {
if (got.value() == 0) {
if (rptr_ == wptr_) {
return std::unexpected(line::ReadError());
}
return line(wptr_ - rptr_, 0);
}
} else {
return std::unexpected(line::ReadError(got.error()));
}
}
}
[[nodiscard]] uint64_t number() const { return number_; }
private:
std::basic_string_view<T> line(size_t len, size_t terminator_len) {
assert(len <= max_len_);
auto ret = std::basic_string_view<T>(rptr_, len);
rptr_ += len + terminator_len;
search_ = rptr_;
++number_;
return ret;
}
void make_space_if_needed() {
size_t free = rptr_ - buffer_.get();
if (free == 0)
return;
size_t avail = end_ - wptr_;
if (avail > 1024)
return;
memmove(buffer_.get(), rptr_, (wptr_ - rptr_) * sizeof(T));
search_ -= free;
wptr_ -= free;
rptr_ = buffer_.get();
}
std::expected<size_t, io::ReadError> fill() {
auto ret = reader_->read(wptr_, (end_ - wptr_) * sizeof(T));
if (ret.has_value())
wptr_ += ret.value() / sizeof(T); // NOLINT(bugprone-sizeof-expression)
return ret;
}
std::unique_ptr<Reader> reader_;
size_t const max_len_;
std::array<T, 2> const line_terminators_;
uint64_t number_{0};
std::unique_ptr<T[]> buffer_;
T* rptr_;
T* wptr_;
T* search_;
T* const end_;
};
} // namespace
namespace u8::line {
namespace {
class ReaderImpl : public UnicodeReader<char, u8::Reader>,
public virtual Reader {
public:
ReaderImpl(std::unique_ptr<u8::Reader> reader, size_t max_len)
: UnicodeReader<char, u8::Reader>(std::move(reader), max_len,
{'\r', '\n'}) {}
[[nodiscard]]
std::expected<std::string_view, ::line::ReadError> read() override {
return UnicodeReader<char, u8::Reader>::read();
}
[[nodiscard]]
uint64_t number() const override {
return UnicodeReader<char, u8::Reader>::number();
}
};
} // namespace
[[nodiscard]]
std::unique_ptr<Reader> open(std::unique_ptr<u8::Reader> reader,
size_t max_len) {
return std::make_unique<ReaderImpl>(std::move(reader), max_len);
}
} // namespace u8::line
namespace u16::line {
namespace {
class ReaderImpl : public UnicodeReader<char16_t, u16::Reader>,
public virtual Reader {
public:
ReaderImpl(std::unique_ptr<u16::Reader> reader, size_t max_len)
: UnicodeReader<char16_t, u16::Reader>(std::move(reader), max_len,
{u'\r', u'\n'}) {}
[[nodiscard]]
std::expected<std::u16string_view, ::line::ReadError> read() override {
return UnicodeReader<char16_t, u16::Reader>::read();
}
[[nodiscard]]
uint64_t number() const override {
return UnicodeReader<char16_t, u16::Reader>::number();
}
};
} // namespace
[[nodiscard]]
std::unique_ptr<Reader> open(std::unique_ptr<u16::Reader> reader,
size_t max_len) {
return std::make_unique<ReaderImpl>(std::move(reader), max_len);
}
} // namespace u16::line
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