terse::CharInputStreamBuf< TStream, BufferSize > Class Template Reference

#include <CharInputStreamBuf.h>

Inheritance diagram for terse::CharInputStreamBuf< TStream, BufferSize >:

Collaboration diagram for terse::CharInputStreamBuf< TStream, BufferSize >:

Public Types
using	PosType = std::streambuf::pos_type
using	OffType = std::streambuf::off_type
using	CharType = std::streambuf::char_type
using	IntType = std::streambuf::int_type
using	TraitsType = std::streambuf::traits_type

Public Member Functions
	CharInputStreamBuf (TStream *stream_)
std::streamsize	xsgetn (CharType *destination, std::streamsize size) override
IntType	underflow () override
std::streamsize	showmanyc () override

Private Attributes
TStream *	stream
std::array< char, BufferSize >	buffer

Member Typedef Documentation

CharType

template<class TStream , std::size_t BufferSize = 4096ul>

using terse::CharInputStreamBuf< TStream, BufferSize >::CharType = std::streambuf::char_type

IntType

template<class TStream , std::size_t BufferSize = 4096ul>

using terse::CharInputStreamBuf< TStream, BufferSize >::IntType = std::streambuf::int_type

OffType

template<class TStream , std::size_t BufferSize = 4096ul>

using terse::CharInputStreamBuf< TStream, BufferSize >::OffType = std::streambuf::off_type

PosType

template<class TStream , std::size_t BufferSize = 4096ul>

using terse::CharInputStreamBuf< TStream, BufferSize >::PosType = std::streambuf::pos_type

TraitsType

template<class TStream , std::size_t BufferSize = 4096ul>

using terse::CharInputStreamBuf< TStream, BufferSize >::TraitsType = std::streambuf::traits_type

Constructor & Destructor Documentation

CharInputStreamBuf()

template<class TStream , std::size_t BufferSize = 4096ul>

terse::CharInputStreamBuf< TStream, BufferSize >::CharInputStreamBuf ( TStream *  stream_ )

inlineexplicit

                                                      : stream{stream_}, buffer{} {
            char* bufferEnd = buffer.data() + buffer.size();
            setg(bufferEnd, bufferEnd, bufferEnd);
        }

References terse::CharInputStreamBuf< TStream, BufferSize >::buffer.

Member Function Documentation

showmanyc()

template<class TStream , std::size_t BufferSize = 4096ul>

std::streamsize terse::CharInputStreamBuf< TStream, BufferSize >::showmanyc ( )

inlineoverride

                                           {
            return static_cast<std::streamsize>(stream->size() - stream->tell());
        }

References terse::CharInputStreamBuf< TStream, BufferSize >::stream.

underflow()

template<class TStream , std::size_t BufferSize = 4096ul>

IntType terse::CharInputStreamBuf< TStream, BufferSize >::underflow ( )

inlineoverride

                                     {
            if (gptr() < egptr()) {
                return TraitsType::to_int_type(*gptr());
            }
 
            char* base = buffer.data();
            char* start = base;
            // Initially eback() == buffer.end() , but if that's not the case, buffer has already been
            // filled before, in which case first copy the data from the put-back area (located at the end of
            // the buffer) into the beginning of the buffer, making them the next characters to be read from it.
            // Put-back area is just one byte in this implementation currently.
            if (eback() == base) {
                std::memcpy(base, egptr() - 1ul, 1ul);
                ++start;
            }
 
            // Now fill the rest of the buffer after the put-back area is moved to the beginning of the buffer
            const std::size_t bytesRead = stream->read(start, buffer.size() - static_cast<std::size_t>(start - base));
            if (bytesRead == 0ul) {
                return TraitsType::eof();
            }
 
            setg(base, start, start + bytesRead);
            return TraitsType::to_int_type(*gptr());
        }

References terse::CharInputStreamBuf< TStream, BufferSize >::buffer, and terse::CharInputStreamBuf< TStream, BufferSize >::stream.

Referenced by terse::CharInputStreamBuf< TStream, BufferSize >::xsgetn().

xsgetn()

template<class TStream , std::size_t BufferSize = 4096ul>

std::streamsize terse::CharInputStreamBuf< TStream, BufferSize >::xsgetn ( CharType *  destination, std::streamsize  size  )

inlineoverride

                                                                                 {
            if (size <= 0) {
                return 0;
            }
 
            std::streamsize bytesNeeded = size;
 
            // Exhaust buffer contents first
            if (gptr() < egptr()) {
                const std::size_t bytesInBuffer = static_cast<std::size_t>(egptr() - gptr());
                const std::size_t bytesToCopy = std::min(static_cast<std::size_t>(bytesNeeded), bytesInBuffer);
                std::memcpy(destination, gptr(), bytesToCopy);
                destination += bytesToCopy;
                bytesNeeded -= static_cast<std::streamsize>(bytesToCopy);
                gbump(static_cast<IntType>(bytesToCopy));
            }
 
            // If there are still bytes needed (more data than buffer contained), read the rest directly from the stream
            if (bytesNeeded > 0) {
                const auto bytesRead =
                    static_cast<std::streamsize>(stream->read(destination, static_cast<std::size_t>(bytesNeeded)));
                bytesNeeded -= bytesRead;
            }
 
            // Refill buffer for subsequent accesses (if possible)
            underflow();
 
            return size - bytesNeeded;
        }

References terse::CharInputStreamBuf< TStream, BufferSize >::stream, and terse::CharInputStreamBuf< TStream, BufferSize >::underflow().

Member Data Documentation

buffer

template<class TStream , std::size_t BufferSize = 4096ul>

std::array<char, BufferSize> terse::CharInputStreamBuf< TStream, BufferSize >::buffer

private

Referenced by terse::CharInputStreamBuf< TStream, BufferSize >::CharInputStreamBuf(), and terse::CharInputStreamBuf< TStream, BufferSize >::underflow().

stream

template<class TStream , std::size_t BufferSize = 4096ul>

TStream* terse::CharInputStreamBuf< TStream, BufferSize >::stream

private

Referenced by terse::CharInputStreamBuf< TStream, BufferSize >::showmanyc(), terse::CharInputStreamBuf< TStream, BufferSize >::underflow(), and terse::CharInputStreamBuf< TStream, BufferSize >::xsgetn().

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The documentation for this class was generated from the following file:

• CharInputStreamBuf.h