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Merge pull request #40 from aburgh/incremental

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Parse streams incrementally.
This commit is contained in:
Niels 2015-03-24 17:57:40 +01:00
commit 50e06a7bd1
1 changed files with 50 additions and 18 deletions
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68
src/json.hpp.re2c
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@ -1739,6 +1739,12 @@ class basic_json
return parser(s).parse();
}
/// deserialize from stream
static basic_json parse(std::istream& i)
{
return parser(i).parse();
}
/// deserialize from stream
friend std::istream& operator>>(std::istream& i, basic_json& j)
{
@ -3112,11 +3118,20 @@ class basic_json
/// constructor with a given buffer
inline lexer(const string_t& s) noexcept
: m_content(reinterpret_cast<const lexer_char_t*>(s.c_str()))
: m_buffer(s), m_stream(nullptr)
{
m_content = reinterpret_cast<const lexer_char_t*>(s.c_str());
m_start = m_cursor = m_content;
m_limit = m_content + s.size();
}
inline lexer(std::istream* s) noexcept
: m_stream(s)
{
getline(*m_stream, m_buffer);
m_content = reinterpret_cast<const lexer_char_t*>(m_buffer.c_str());
m_start = m_cursor = m_content;
m_limit = m_content + m_buffer.size();
}
/// default constructor
inline lexer() = default;
@ -3242,7 +3257,7 @@ class basic_json
inline token_type scan() noexcept
{
// pointer for backtracking information
const lexer_char_t* m_marker = nullptr;
m_marker = nullptr;
// remember the begin of the token
m_start = m_cursor;
@ -3252,10 +3267,11 @@ class basic_json
re2c:define:YYCURSOR = m_cursor;
re2c:define:YYLIMIT = m_limit;
re2c:define:YYMARKER = m_marker;
re2c:define:YYFILL = "{ yyfill(); }";
re2c:yyfill:parameter = 0;
re2c:indent:string = " ";
re2c:indent:top = 1;
re2c:labelprefix = "basic_json_parser_";
re2c:yyfill:enable = 0;
// whitespace
ws = [ \t\n\r]+;
@ -3305,6 +3321,28 @@ class basic_json
// anything else is an error
. { return token_type::parse_error; }
*/
}
/// append data from the stream to the internal buffer
void yyfill() noexcept
{
if (not m_stream or not *m_stream) return;
ssize_t offset_start = m_start - m_content;
ssize_t offset_marker = m_marker - m_start;
ssize_t offset_cursor = m_cursor - m_start;
m_buffer.erase(0, offset_start);
std::string line;
std::getline(*m_stream, line);
m_buffer += line;
m_content = reinterpret_cast<const lexer_char_t*>(m_buffer.c_str());
m_start = m_content;
m_marker = m_start + offset_marker;
m_cursor = m_start + offset_cursor;
m_limit = m_start + m_buffer.size() - 1;
}
/// return string representation of last read token
@ -3469,10 +3507,16 @@ class basic_json
}
private:
/// optional input stream
std::istream* m_stream;
/// the buffer
string_t m_buffer;
/// the buffer pointer
const lexer_char_t* m_content = nullptr;
/// pointer to he beginning of the current symbol
/// pointer to the beginning of the current symbol
const lexer_char_t* m_start = nullptr;
/// pointer for backtracking information
const lexer_char_t* m_marker = nullptr;
/// pointer to the current symbol
const lexer_char_t* m_cursor = nullptr;
/// pointer to the end of the buffer
@ -3486,25 +3530,15 @@ class basic_json
{
public:
/// constructor for strings
inline parser(const string_t& s) : m_buffer(s), m_lexer(m_buffer)
inline parser(const string_t& s) : m_lexer(s)
{
// read first token
get_token();
}
/// a parser reading from an input stream
inline parser(std::istream& _is)
inline parser(std::istream& _is) : m_lexer(&_is)
{
while (_is)
{
string_t input_line;
std::getline(_is, input_line);
m_buffer += input_line;
}
// initializer lexer
m_lexer = lexer(m_buffer);
// read first token
get_token();
}
@ -3690,8 +3724,6 @@ class basic_json
}
private:
/// the buffer
string_t m_buffer;
/// the type of the last read token
typename lexer::token_type last_token = lexer::token_type::uninitialized;
/// the lexer