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⚡ added improvements (#365)

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This commit is contained in:
Niels Lohmann 2016-11-26 12:43:23 +01:00
parent 4bd3b1b0ef
commit 2773038cf9
4 changed files with 62 additions and 26 deletions
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2
README.md
View file

@ -500,7 +500,7 @@ I deeply appreciate the help of the following people.
- [Vladimir Petrigo](https://github.com/vpetrigo) made a SFINAE hack more readable.
- [Denis Andrejew](https://github.com/seeekr) fixed a grammar issue in the README file.
- [Pierre-Antoine Lacaze](https://github.com/palacaze) found a subtle bug in the `dump()` function.
- [TurpentineDistillery](https://github.com/TurpentineDistillery) pointed to [`std::locale::classic()`](http://en.cppreference.com/w/cpp/locale/locale/classic) to avoid too much locale joggling and found some nice performance improvements in the parser.
- [TurpentineDistillery](https://github.com/TurpentineDistillery) pointed to [`std::locale::classic()`](http://en.cppreference.com/w/cpp/locale/locale/classic) to avoid too much locale joggling, found some nice performance improvements in the parser and improved the benchmarking code.
Thanks a lot for helping out!

2
benchmarks/benchmarks.cpp
View file

@ -58,7 +58,7 @@ static void bench(benchpress::context& ctx,
for (size_t i = 0; i < ctx.num_iterations(); ++i)
{
// clear flags and rewind
// clear flags and rewind
istr.clear();
istr.seekg(0);
json j;

42
src/json.hpp
View file

@ -8719,8 +8719,22 @@ basic_json_parser_66:
*/
void fill_line_buffer(size_t n = 0)
{
// if line buffer is used, m_content points to its data
assert(m_line_buffer.empty()
or m_content == reinterpret_cast<const lexer_char_t*>(m_line_buffer.data()));
// if line buffer is used, m_limit is set past the end of its data
assert(m_line_buffer.empty()
or m_limit == m_content + m_line_buffer.size());
// pointer relationships
assert(m_content <= m_start);
assert(m_start <= m_cursor);
assert(m_cursor <= m_limit);
assert(m_marker == nullptr or m_marker <= m_limit);
// number of processed characters (p)
const auto offset_start = m_start - m_content;
const size_t num_processed_chars = static_cast<size_t>(m_start - m_content);
// offset for m_marker wrt. to m_start
const auto offset_marker = (m_marker == nullptr) ? 0 : m_marker - m_start;
// number of unprocessed characters (u)
@ -8729,23 +8743,23 @@ basic_json_parser_66:
// no stream is used or end of file is reached
if (m_stream == nullptr or m_stream->eof())
{
// skip this part if we are already using the line buffer
if (m_start != reinterpret_cast<const lexer_char_t*>(m_line_buffer.data()))
{
// copy unprocessed characters to line buffer
m_line_buffer.assign(m_start, m_limit);
m_cursor = m_limit;
}
// m_start may or may not be pointing into m_line_buffer at
// this point. We trust the standand library to do the right
// thing. See http://stackoverflow.com/q/28142011/266378
m_line_buffer.assign(m_start, m_limit);
// append n characters to make sure that there is sufficient
// space between m_cursor and m_limit
m_line_buffer.append(1, '\x00');
m_line_buffer.append(n - 1, '\x01');
if (n > 0)
{
m_line_buffer.append(n - 1, '\x01');
}
}
else
{
// delete processed characters from line buffer
m_line_buffer.erase(0, static_cast<size_t>(offset_start));
m_line_buffer.erase(0, num_processed_chars);
// read next line from input stream
m_line_buffer_tmp.clear();
std::getline(*m_stream, m_line_buffer_tmp, '\n');
@ -8756,7 +8770,7 @@ basic_json_parser_66:
}
// set pointers
m_content = reinterpret_cast<const lexer_char_t*>(m_line_buffer.c_str());
m_content = reinterpret_cast<const lexer_char_t*>(m_line_buffer.data());
assert(m_content != nullptr);
m_start = m_content;
m_marker = m_start + offset_marker;
@ -8843,7 +8857,11 @@ basic_json_parser_66:
auto e = std::find(i, m_cursor - 1, '\\');
if (e != i)
{
result.append(i, e);
// see https://github.com/nlohmann/json/issues/365#issuecomment-262874705
for (auto k = i; k < e; k++)
{
result.push_back(static_cast<typename string_t::value_type>(*k));
}
i = e - 1; // -1 because of ++i
}
else

42
src/json.hpp.re2c
View file

@ -7868,8 +7868,22 @@ class basic_json
*/
void fill_line_buffer(size_t n = 0)
{
// if line buffer is used, m_content points to its data
assert(m_line_buffer.empty()
or m_content == reinterpret_cast<const lexer_char_t*>(m_line_buffer.data()));
// if line buffer is used, m_limit is set past the end of its data
assert(m_line_buffer.empty()
or m_limit == m_content + m_line_buffer.size());
// pointer relationships
assert(m_content <= m_start);
assert(m_start <= m_cursor);
assert(m_cursor <= m_limit);
assert(m_marker == nullptr or m_marker <= m_limit);
// number of processed characters (p)
const auto offset_start = m_start - m_content;
const size_t num_processed_chars = static_cast<size_t>(m_start - m_content);
// offset for m_marker wrt. to m_start
const auto offset_marker = (m_marker == nullptr) ? 0 : m_marker - m_start;
// number of unprocessed characters (u)
@ -7878,23 +7892,23 @@ class basic_json
// no stream is used or end of file is reached
if (m_stream == nullptr or m_stream->eof())
{
// skip this part if we are already using the line buffer
if (m_start != reinterpret_cast<const lexer_char_t*>(m_line_buffer.data()))
{
// copy unprocessed characters to line buffer
m_line_buffer.assign(m_start, m_limit);
m_cursor = m_limit;
}
// m_start may or may not be pointing into m_line_buffer at
// this point. We trust the standand library to do the right
// thing. See http://stackoverflow.com/q/28142011/266378
m_line_buffer.assign(m_start, m_limit);
// append n characters to make sure that there is sufficient
// space between m_cursor and m_limit
m_line_buffer.append(1, '\x00');
m_line_buffer.append(n - 1, '\x01');
if (n > 0)
{
m_line_buffer.append(n - 1, '\x01');
}
}
else
{
// delete processed characters from line buffer
m_line_buffer.erase(0, static_cast<size_t>(offset_start));
m_line_buffer.erase(0, num_processed_chars);
// read next line from input stream
m_line_buffer_tmp.clear();
std::getline(*m_stream, m_line_buffer_tmp, '\n');
@ -7905,7 +7919,7 @@ class basic_json
}
// set pointers
m_content = reinterpret_cast<const lexer_char_t*>(m_line_buffer.c_str());
m_content = reinterpret_cast<const lexer_char_t*>(m_line_buffer.data());
assert(m_content != nullptr);
m_start = m_content;
m_marker = m_start + offset_marker;
@ -7992,7 +8006,11 @@ class basic_json
auto e = std::find(i, m_cursor - 1, '\\');
if (e != i)
{
result.append(i, e);
// see https://github.com/nlohmann/json/issues/365#issuecomment-262874705
for (auto k = i; k < e; k++)
{
result.push_back(static_cast<typename string_t::value_type>(*k));
}
i = e - 1; // -1 because of ++i
}
else