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always seek
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karasikov committed Mar 18, 2021
1 parent 89b5ca7 commit 9bd059f
Showing 1 changed file with 6 additions and 24 deletions.
30 changes: 6 additions & 24 deletions include/sdsl/int_vector_buffer.hpp
Original file line number Diff line number Diff line change
Expand Up @@ -48,8 +48,6 @@ class int_vector_buffer
std::unique_ptr<sdsl::isfstream> m_ifile { new sdsl::isfstream() };
std::unique_ptr<sdsl::osfstream> m_ofile { new sdsl::osfstream() };
std::streampos m_start;
std::streampos m_ifile_pos; // current byte position in m_ifile
std::streampos m_ofile_pos; // current byte position in m_ofile
std::string m_filename;
int_vector<t_width> m_buffer;
bool m_need_to_write = false;
Expand All @@ -71,17 +69,13 @@ class int_vector_buffer
util::set_to_value(m_buffer, 0);
} else {
std::streampos pos = m_offset+static_cast<std::streampos>(m_begin*width()/8);
if (m_ifile_pos != pos) {
m_ifile->seekg(pos);
m_ifile_pos = pos;
if (!m_ifile->good())
throw_error("seekg error");
}
m_ifile->seekg(pos);
if (!m_ifile->good())
throw_error("seekg error");
if (m_size-m_begin<m_buffersize)
util::set_to_value(m_buffer, 0);
uint64_t wb = std::min(m_buffersize*width(), (m_size-m_begin)*width()+7)/8;
m_ifile->read(reinterpret_cast<char*>(m_buffer.data()), wb);
m_ifile_pos += wb;
if (!m_ifile->good())
throw_error("read block error");
}
Expand All @@ -93,17 +87,13 @@ class int_vector_buffer
if (m_need_to_write) {
assert(m_ofile->is_open());
std::streampos pos = m_offset+static_cast<std::streampos>(m_begin*width()/8);
if (m_ofile_pos != pos) {
m_ofile->seekp(pos);
m_ofile_pos = pos;
if (!m_ofile->good())
throw_error("seekp error");
}
m_ofile->seekp(pos);
if (!m_ofile->good())
throw_error("seekp error");
uint64_t wb = std::min(m_buffersize*width(), (m_size-m_begin)*width()+7)/8;
m_ofile->write(reinterpret_cast<const char*>(m_buffer.data()), wb);
if (!m_ofile->good())
throw_error("write block error");
m_ofile_pos += wb;
m_ofile->flush();
if (!m_ofile->good())
throw_error("flush block error");
Expand Down Expand Up @@ -176,7 +166,6 @@ class int_vector_buffer
m_ofile->open(m_filename, mode|(m_start ? std::ios::in : std::ios::openmode(0))|std::ios::binary);
if (!m_ofile)
throw_error("Could not open file for write");
m_ofile_pos = 0;
}

m_ifile->open(m_filename, std::ios::in|std::ios::binary);
Expand All @@ -202,8 +191,6 @@ class int_vector_buffer
m_size = size/width();
}

m_ifile_pos = m_ifile->tellg();

if (buffer_size < 8u)
buffer_size = 8; // at least 8 bytes
m_buffersize = ((buffer_size*8+width()-1)/width()+7)/8*8;
Expand Down Expand Up @@ -289,7 +276,6 @@ class int_vector_buffer
}
}
m_ofile->flush();
m_ofile->seekp(m_ofile_pos);
if (!m_ofile->good())
throw_error("flush failed");
}
Expand All @@ -313,8 +299,6 @@ class int_vector_buffer
m_size = 0;
m_offset -= m_start;
m_start = 0;
m_ifile_pos = 0;
m_ofile_pos = 0;
// reset buffer
read_block(0);
}
Expand Down Expand Up @@ -391,8 +375,6 @@ class int_vector_buffer
std::swap(m_buffersize, ivb.m_buffersize);
std::swap(m_size, ivb.m_size);
std::swap(m_begin, ivb.m_begin);
std::swap(m_ifile_pos, ivb.m_ifile_pos);
std::swap(m_ofile_pos, ivb.m_ofile_pos);
}
}

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