CS144Lab/libsponge/stream_reassembler.hh
2021-09-28 17:03:04 -07:00

52 lines
2.0 KiB
C++

#ifndef SPONGE_LIBSPONGE_STREAM_REASSEMBLER_HH
#define SPONGE_LIBSPONGE_STREAM_REASSEMBLER_HH
#include "byte_stream.hh"
#include <cstdint>
#include <string>
//! \brief A class that assembles a series of excerpts from a byte stream (possibly out of order,
//! possibly overlapping) into an in-order byte stream.
class StreamReassembler {
private:
// Your code here -- add private members as necessary.
ByteStream _output; //!< The reassembled in-order byte stream
size_t _capacity; //!< The maximum number of bytes
public:
//! \brief Construct a `StreamReassembler` that will store up to `capacity` bytes.
//! \note This capacity limits both the bytes that have been reassembled,
//! and those that have not yet been reassembled.
StreamReassembler(const size_t capacity);
//! \brief Receive a substring and write any newly contiguous bytes into the stream.
//!
//! The StreamReassembler will stay within the memory limits of the `capacity`.
//! Bytes that would exceed the capacity are silently discarded.
//!
//! \param data the substring
//! \param index indicates the index (place in sequence) of the first byte in `data`
//! \param eof the last byte of `data` will be the last byte in the entire stream
void push_substring(const std::string &data, const uint64_t index, const bool eof);
//! \name Access the reassembled byte stream
//!@{
const ByteStream &stream_out() const { return _output; }
ByteStream &stream_out() { return _output; }
//!@}
//! The number of bytes in the substrings stored but not yet reassembled
//!
//! \note If the byte at a particular index has been pushed more than once, it
//! should only be counted once for the purpose of this function.
size_t unassembled_bytes() const;
//! \brief Is the internal state empty (other than the output stream)?
//! \returns `true` if no substrings are waiting to be assembled
bool empty() const;
};
#endif // SPONGE_LIBSPONGE_STREAM_REASSEMBLER_HH