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#include "cru/base/io/BufferStream.h"
#include "cru/base/io/Stream.h"
namespace cru::io {
BufferStream::BufferStream(const BufferStreamOptions& options)
: Stream(false, true, true) {
block_size_ = options.GetBlockSizeOrDefault();
max_block_count_ = options.GetMaxBlockCount();
eof_written_ = false;
}
BufferStream::~BufferStream() {}
Index BufferStream::DoRead(std::byte* buffer, Index offset, Index size) {
std::unique_lock lock(mutex_);
read_cv_.wait(lock, [this] {
return eof_written_ || !buffer_list_.empty() || IsClosed();
});
CheckClosed();
if (buffer_list_.empty() && eof_written_) {
return kEOF;
}
auto full_previously = max_block_count_ > 0 &&
buffer_list_.size() == max_block_count_ &&
buffer_list_.back().IsFull();
Index read = 0;
while (!buffer_list_.empty()) {
auto& stream_buffer = buffer_list_.front();
auto this_read = stream_buffer.Read(buffer + offset + read, size - read);
if (stream_buffer.IsEmpty()) {
buffer_list_.pop_front();
}
read += this_read;
if (read == size) {
break;
}
}
if (full_previously && buffer_list_.size() < max_block_count_) {
write_cv_.notify_all();
}
return read;
}
Index BufferStream::DoWrite(const std::byte* buffer, Index offset, Index size) {
std::unique_lock lock(mutex_);
write_cv_.wait(lock, [this] {
return eof_written_ || max_block_count_ <= 0 ||
buffer_list_.size() < max_block_count_ ||
!buffer_list_.back().IsFull() || IsClosed();
});
CheckClosed();
if (eof_written_) {
throw StreamIOException(
this, "Stream has been set eof. Can't write to it any more.");
}
auto empty_previously = buffer_list_.empty();
Index written = 0;
if (empty_previously) {
buffer_list_.push_back(Block(block_size_));
}
while (true) {
if (buffer_list_.back().IsFull()) {
if (max_block_count_ > 0 && buffer_list_.size() == max_block_count_) {
break;
}
buffer_list_.push_back(Block(block_size_));
}
auto& stream_buffer = buffer_list_.back();
auto this_written =
stream_buffer.Write(buffer + offset + written, size - written);
written += this_written;
if (written == size) {
break;
}
}
if (empty_previously) {
read_cv_.notify_all();
}
return written;
}
void BufferStream::DoClose() {
std::unique_lock lock(mutex_);
buffer_list_.clear();
read_cv_.notify_all();
write_cv_.notify_all();
}
void BufferStream::WriteEof() {
std::unique_lock lock(mutex_);
eof_written_ = true;
read_cv_.notify_all();
write_cv_.notify_all();
}
BufferStream::Block::Block(Index size)
: buffer(new std::byte[size]), size(size), start(0), end(0) {}
BufferStream::Block::Block(Block&& other) noexcept
: buffer(other.buffer),
size(other.size),
start(other.start),
end(other.end) {
other.buffer = nullptr;
other.size = other.start = other.end = 0;
}
BufferStream::Block& BufferStream::Block::operator=(Block&& other) noexcept {
if (this != &other) {
delete[] buffer;
buffer = other.buffer;
size = other.size;
start = other.start;
end = other.end;
other.buffer = nullptr;
other.size = other.start = other.end = 0;
}
return *this;
}
BufferStream::Block::~Block() { delete[] buffer; }
Index BufferStream::Block::Read(std::byte* des, Index si) {
si = std::min(si, end - start);
std::memcpy(des, buffer + start, si);
start += si;
return si;
}
Index BufferStream::Block::Write(const std::byte* src, Index si) {
si = std::min(si, size - end);
std::memcpy(buffer + end, src, si);
end += si;
return si;
}
bool BufferStream::Block::IsFull() const { return end == size; }
bool BufferStream::Block::IsEmpty() const { return end == start; }
} // namespace cru::io
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