toml11/toml/serializer.hpp
2019-05-29 21:22:32 +09:00

527 lines
16 KiB
C++

// Copyright Toru Niina 2019.
// Distributed under the MIT License.
#ifndef TOML11_SERIALIZER_HPP
#define TOML11_SERIALIZER_HPP
#include "value.hpp"
#include "lexer.hpp"
#include <limits>
#include <cstdio>
namespace toml
{
struct serializer
{
serializer(const std::size_t w = 80,
const int float_prec = std::numeric_limits<toml::floating>::max_digits10,
const bool can_be_inlined = false,
std::vector<toml::key> ks = {})
: can_be_inlined_(can_be_inlined), float_prec_(float_prec), width_(w),
keys_(std::move(ks))
{}
~serializer() = default;
std::string operator()(const toml::boolean& b) const
{
return b ? "true" : "false";
}
std::string operator()(const integer i) const
{
return std::to_string(i);
}
std::string operator()(const toml::floating f) const
{
const auto fmt = "%.*g";
const auto bsz = std::snprintf(nullptr, 0, fmt, this->float_prec_, f);
std::vector<char> buf(bsz + 1, '\0'); // +1 for null character(\0)
std::snprintf(buf.data(), buf.size(), fmt, this->float_prec_, f);
std::string token(buf.begin(), std::prev(buf.end()));
if(token.back() == '.') // 1. => 1.0
{
token += '0';
}
const auto e = std::find_if(token.cbegin(), token.cend(),
[](const char c) -> bool {
return c == 'E' || c == 'e';
});
if(e == token.cend())
{
return token; // there is no exponent part. just return it.
}
// zero-prefix in an exponent is not allowed in TOML.
// remove it if it exists.
bool sign_exists = false;
std::size_t zero_prefix = 0;
for(auto iter = std::next(e), iend = token.cend(); iter != iend; ++iter)
{
if(*iter == '+' || *iter == '-'){sign_exists = true; continue;}
if(*iter == '0'){zero_prefix += 1;}
else {break;}
}
if(zero_prefix != 0)
{
const auto offset = std::distance(token.cbegin(), e) +
(sign_exists ? 2 : 1);
token.erase(offset, zero_prefix);
}
return token;
}
std::string operator()(const string& s) const
{
if(s.kind == string_t::basic)
{
if(std::find(s.str.cbegin(), s.str.cend(), '\n') != s.str.cend())
{
// if linefeed is contained, make it multiline-string.
const std::string open("\"\"\"\n");
const std::string close("\\\n\"\"\"");
return open + this->escape_ml_basic_string(s.str) + close;
}
// no linefeed. try to make it oneline-string.
std::string oneline = this->escape_basic_string(s.str);
if(oneline.size() + 2 < width_ || width_ < 2)
{
const std::string quote("\"");
return quote + oneline + quote;
}
// the line is too long compared to the specified width.
// split it into multiple lines.
std::string token("\"\"\"\n");
while(!oneline.empty())
{
if(oneline.size() < width_)
{
token += oneline;
oneline.clear();
}
else if(oneline.at(width_-2) == '\\')
{
token += oneline.substr(0, width_-2);
token += "\\\n";
oneline.erase(0, width_-2);
}
else
{
token += oneline.substr(0, width_-1);
token += "\\\n";
oneline.erase(0, width_-1);
}
}
return token + std::string("\\\n\"\"\"");
}
else // the string `s` is literal-string.
{
if(std::find(s.str.cbegin(), s.str.cend(), '\n') != s.str.cend() ||
std::find(s.str.cbegin(), s.str.cend(), '\'') != s.str.cend() )
{
const std::string open("'''\n");
const std::string close("'''");
return open + s.str + close;
}
else
{
const std::string quote("'");
return quote + s.str + quote;
}
}
}
std::string operator()(const local_date& d) const
{
std::ostringstream oss;
oss << d;
return oss.str();
}
std::string operator()(const local_time& t) const
{
std::ostringstream oss;
oss << t;
return oss.str();
}
std::string operator()(const local_datetime& dt) const
{
std::ostringstream oss;
oss << dt;
return oss.str();
}
std::string operator()(const offset_datetime& odt) const
{
std::ostringstream oss;
oss << odt;
return oss.str();
}
std::string operator()(const array& v) const
{
if(!v.empty() && v.front().is_table())// v is an array of tables
{
// if it's not inlined, we need to add `[[table.key]]`.
// but if it can be inlined, we need `table.key = [...]`.
if(this->can_be_inlined_)
{
std::string token;
if(!keys_.empty())
{
token += this->serialize_key(keys_.back());
token += " = ";
}
bool width_exceeds = false;
token += "[\n";
for(const auto& item : v)
{
const auto t =
this->make_inline_table(item.cast<value_t::Table>());
if(t.size() + 1 > width_ || // +1 for the last comma {...},
std::find(t.cbegin(), t.cend(), '\n') != t.cend())
{
width_exceeds = true;
break;
}
token += t;
token += ",\n";
}
if(!width_exceeds)
{
token += "]\n";
return token;
}
// if width_exceeds, serialize it as [[array.of.tables]].
}
std::string token;
for(const auto& item : v)
{
token += "[[";
token += this->serialize_dotted_key(keys_);
token += "]]\n";
token += this->make_multiline_table(item.cast<value_t::Table>());
}
return token;
}
if(v.empty())
{
return std::string("[]");
}
// not an array of tables. normal array. first, try to make it inline.
{
const auto inl = this->make_inline_array(v);
if(inl.size() < this->width_ &&
std::find(inl.cbegin(), inl.cend(), '\n') == inl.cend())
{
return inl;
}
}
// if the length exceeds this->width_, print multiline array
std::string token;
std::string current_line;
token += "[\n";
for(const auto& item : v)
{
auto next_elem = toml::visit(*this, item);
// newline between array-value and comma is not allowed
if(next_elem.back() == '\n'){next_elem.pop_back();}
if(current_line.size() + next_elem.size() + 1 < this->width_)
{
current_line += next_elem;
current_line += ',';
}
else if(current_line.empty())
{
// the next elem cannot be within the width.
token += next_elem;
token += ",\n";
// keep current line empty
}
else // current_line has some tokens and it exceeds width
{
assert(current_line.back() == ',');
token += current_line;
token += '\n';
current_line = next_elem;
current_line += ',';
}
}
if(!current_line.empty())
{
if(current_line.back() != '\n') {current_line += '\n';}
token += current_line;
}
token += "]\n";
return token;
}
std::string operator()(const table& v) const
{
if(this->can_be_inlined_)
{
std::string token;
if(!this->keys_.empty())
{
token += this->serialize_key(this->keys_.back());
token += " = ";
}
token += this->make_inline_table(v);
if(token.size() < this->width_)
{
return token;
}
}
std::string token;
if(!keys_.empty())
{
token += '[';
token += this->serialize_dotted_key(keys_);
token += "]\n";
}
token += this->make_multiline_table(v);
return token;
}
private:
std::string serialize_key(const toml::key& key) const
{
detail::location<toml::key> loc(key, key);
detail::lex_unquoted_key::invoke(loc);
if(loc.iter() == loc.end())
{
return key; // all the tokens are consumed. the key is unquoted-key.
}
std::string token("\"");
token += this->escape_basic_string(key);
token += "\"";
return token;
}
std::string serialize_dotted_key(const std::vector<toml::key>& keys) const
{
std::string token;
if(keys.empty()){return token;}
for(const auto& k : keys)
{
token += this->serialize_key(k);
token += '.';
}
token.erase(token.size() - 1, 1); // remove trailing `.`
return token;
}
std::string escape_basic_string(const std::string& s) const
{
//XXX assuming `s` is a valid utf-8 sequence.
std::string retval;
for(const char c : s)
{
switch(c)
{
case '\\': {retval += "\\\\"; break;}
case '\"': {retval += "\\\""; break;}
case '\b': {retval += "\\b"; break;}
case '\t': {retval += "\\t"; break;}
case '\f': {retval += "\\f"; break;}
case '\n': {retval += "\\n"; break;}
case '\r': {retval += "\\r"; break;}
default : {retval += c; break;}
}
}
return retval;
}
std::string escape_ml_basic_string(const std::string& s) const
{
std::string retval;
for(auto i=s.cbegin(), e=s.cend(); i!=e; ++i)
{
switch(*i)
{
case '\\': {retval += "\\\\"; break;}
case '\"': {retval += "\\\""; break;}
case '\b': {retval += "\\b"; break;}
case '\t': {retval += "\\t"; break;}
case '\f': {retval += "\\f"; break;}
case '\n': {retval += "\n"; break;}
case '\r':
{
if(std::next(i) != e && *std::next(i) == '\n')
{
retval += "\r\n";
++i;
}
else
{
retval += "\\r";
}
break;
}
default: {retval += *i; break;}
}
}
return retval;
}
std::string make_inline_array(const array& v) const
{
std::string token;
token += '[';
bool is_first = true;
for(const auto& item : v)
{
if(is_first) {is_first = false;} else {token += ',';}
token += visit(serializer(std::numeric_limits<std::size_t>::max(),
this->float_prec_, true), item);
}
token += ']';
return token;
}
std::string make_inline_table(const table& v) const
{
assert(this->can_be_inlined_);
std::string token;
token += '{';
bool is_first = true;
for(const auto& kv : v)
{
// in inline tables, trailing comma is not allowed (toml-lang #569).
if(is_first) {is_first = false;} else {token += ',';}
token += this->serialize_key(kv.first);
token += '=';
token += visit(serializer(std::numeric_limits<std::size_t>::max(),
this->float_prec_, true), kv.second);
}
token += '}';
return token;
}
std::string make_multiline_table(const table& v) const
{
std::string token;
// print non-table stuff first. because after printing [foo.bar], the
// remaining non-table values will be assigned into [foo.bar], not [foo]
for(const auto kv : v)
{
if(kv.second.is_table() || is_array_of_tables(kv.second))
{
continue;
}
const auto key_and_sep = this->serialize_key(kv.first) + " = ";
const auto residual_width = (this->width_ > key_and_sep.size()) ?
this->width_ - key_and_sep.size() : 0;
token += key_and_sep;
token += visit(serializer(residual_width, this->float_prec_, true),
kv.second);
if(token.back() != '\n')
{
token += '\n';
}
}
// normal tables / array of tables
// after multiline table appeared, the other tables cannot be inline
// because the table would be assigned into the table.
// [foo]
// ...
// bar = {...} # <- bar will be a member of [foo].
bool multiline_table_printed = false;
for(const auto& kv : v)
{
if(!kv.second.is_table() && !is_array_of_tables(kv.second))
{
continue; // other stuff are already serialized. skip them.
}
std::vector<toml::key> ks(this->keys_);
ks.push_back(kv.first);
auto tmp = visit(serializer(
this->width_, this->float_prec_, !multiline_table_printed, ks),
kv.second);
if((!multiline_table_printed) &&
std::find(tmp.cbegin(), tmp.cend(), '\n') != tmp.cend())
{
multiline_table_printed = true;
}
else
{
// still inline tables only.
tmp += '\n';
}
token += tmp;
}
return token;
}
bool is_array_of_tables(const value& v) const
{
if(!v.is_array()) {return false;}
const auto& a = v.as_array();
return !a.empty() && a.front().is_table();
}
private:
bool can_be_inlined_;
int float_prec_;
std::size_t width_;
std::vector<toml::key> keys_;
};
inline std::string
format(const value& v, std::size_t w = 80,
int fprec = std::numeric_limits<toml::floating>::max_digits10,
bool force_inline = false)
{
// if value is a table, it is considered to be a root object.
// the root object can't be an inline table. so pass false. otherwise, true.
return visit(serializer(w, fprec, (!v.is_table()) || force_inline), v);
}
inline std::string
format(const table& t, std::size_t w = 80,
int fprec = std::numeric_limits<toml::floating>::max_digits10,
bool force_inline = false)
{
return serializer(w, fprec, force_inline)(t);
}
template<typename charT, typename traits>
std::basic_ostream<charT, traits>&
operator<<(std::basic_ostream<charT, traits>& os, const value& v)
{
// get status of std::setw().
const std::size_t w = os.width();
const int fprec = os.precision();
os.width(0);
// the root object can't be an inline table. so pass `false`.
os << visit(serializer(w, fprec, false), v);
return os;
}
template<typename charT, typename traits>
std::basic_ostream<charT, traits>&
operator<<(std::basic_ostream<charT, traits>& os, const table& v)
{
// get status of std::setw().
const std::size_t w = os.width();
const int fprec = os.precision();
os.width(0);
// the root object can't be an inline table. so pass `false`.
os << serializer(w, fprec, false)(v);
return os;
}
} // toml
#endif// TOML11_SERIALIZER_HPP