#include "chunked_response_stream.h"

const rs::httpserver::Stream::byte rs::httpserver::ChunkedResponseStream::endOfLine_[2] = { '\r', '\n' };

const rs::httpserver::Stream::byte rs::httpserver::ChunkedResponseStream::endOfBlocks_[5] = { '0', '\r', '\n', '\r', '\n' };

int rs::httpserver::ChunkedResponseStream::Write(const byte* buffer, int offset, int count) {

auto blocks = count / Config::MaxResponseChunkSize;

auto overflow = count % Config::MaxResponseChunkSize;

for (int i = 0; i < blocks; i++) {

stream_.Write(&maxBlockSizeHeader_[0], 0, maxBlockSizeHeader_.size());

stream_.Write(buffer, offset, Config::MaxResponseChunkSize);

stream_.Write(endOfLine_, 0, sizeof(endOfLine_));

offset += Config::MaxResponseChunkSize;

position_ += Config::MaxResponseChunkSize;

length_ += Config::MaxResponseChunkSize;

}

if (overflow > 0) {

auto header = GetHeader(overflow);

stream_.Write(&header[0], 0, header.size());

stream_.Write(buffer, offset, overflow);

stream_.Write(endOfLine_, 0, sizeof(endOfLine_));

position_ += overflow;

length_ += overflow;

}

return count;

}

void rs::httpserver::ChunkedResponseStream::Flush() {

stream_.Write(endOfBlocks_, 0, sizeof(endOfBlocks_));

stream_.Flush();

}

std::vector<rs::httpserver::Stream::byte> rs::httpserver::ChunkedResponseStream::GetHeader(int blockSize) {

if (blockSize <= 0) {

return std::vector<Stream::byte>({'0', '\r', '\n'});

} else {

auto chars = 0;

while ((blockSize >> (4 * chars)) > 0) ++chars;

std::vector<Stream::byte> buffer(chars + 2);

for (auto i = 0; i < chars; ++i) {

auto index = chars - 1 - i;

buffer[index] = (blockSize >> (4 * i)) & 0x0f;

buffer[index] += buffer[index] > 9 ? ('a' - 10) : '0';

}

buffer[chars] = '\r';

buffer[chars + 1] = '\n';

return buffer;

}

}