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⚡️ added improvements (#365)

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1 parent 4bd3b1b commit 2773038cf9e3de7f043d0e03c1ee79fe1d49e667 @nlohmann committed Nov 26, 2016
Showing with 62 additions and 26 deletions.
  1. +1 −1 README.md
  2. +1 −1 benchmarks/benchmarks.cpp
  3. +30 −12 src/json.hpp
  4. +30 −12 src/json.hpp.re2c
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@@ -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!
@@ -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;
View
@@ -8719,8 +8719,22 @@ 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)
@@ -8729,23 +8743,23 @@ 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');
@@ -8756,7 +8770,7 @@ 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;
@@ -8843,7 +8857,11 @@ 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
View
@@ -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

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