Crow/json.h
2014-04-17 10:06:41 -04:00

480 lines
14 KiB
C++

#pragma once
#include <iostream>
#include <string>
#include <unordered_map>
namespace flask
{
namespace json
{
enum class type : intptr_t
{
Null,
False,
True,
Number,
String,
List,
Object,
};
const char* json_type_str =
"\0\0\0\0\0\0\0\0"
"\1\0\0\0\0\0\0\0"
"\2\0\0\0\0\0\0\0"
"\3\0\0\0\0\0\0\0"
"\4\0\0\0\0\0\0\0"
"\5\0\0\0\0\0\0\0"
"\6\0\0\0\0\0\0\0";
struct r_string
{
operator std::string ()
{
return std::string(s_, e_);
}
char* s_;
char* e_;
};
struct rvalue
{
rvalue() {}
rvalue(type t)
: start_{json_type_str + 8*(int)t},
end_{json_type_str+8*(int)t+8}
{}
~rvalue()
{
deallocate();
}
void deallocate()
{
if (mem_)
{
delete[] mem_;
mem_ = nullptr;
}
}
type t() const
{
return *reinterpret_cast<const type*>(start_);
}
const void* data() const
{
return reinterpret_cast<const void*>(start_ + sizeof(intptr_t));
}
int i() const
{
if (t() != type::Number)
throw std::runtime_error("value is not number");
return static_cast<int>(*(double*)data());
}
double d() const
{
if (t() != type::Number)
throw std::runtime_error("value is not number");
return *(double*)data();
}
r_string s() const
{
if (t() != type::Number)
throw std::runtime_error("value is not number");
return {(char*)data(),(char*)data() + sizeof(char*)};
}
const char* start_{};
const char* end_{};
char* mem_{};
};
//inline rvalue decode(const std::string& s)
//{
//}
/*inline boost::optional<const rvalue> decode(const char* data, size_t size, bool partial = false)
{
static char* escaped = "\"\\\/\b\f\n\r\t"
const char* e = data + size;
auto ws_skip = [&]
{
while(data != e)
{
while(data != e && *data == ' ') ++data;
while(data != e && *data == '\t') ++data;
while(data != e && *data == '\r') ++data;
while(data != e && *data == '\n') ++data;
}
};
auto decode_string = [&]->boost::optional<rvalue>
{
ws_skip();
if (data == e || *data != '"')
return {};
while(data != e)
{
if (*data == '"')
{
}
else if (*data == '\\')
{
// TODO
//if (data+1 == e)
//return {};
//data += 2;
}
else
{
data ++;
}
}
};
auto decode_list = [&]->boost::optional<rvalue>
{
// TODO
};
auto decode_number = [&]->boost::optional<rvalue>
{
// TODO
};
auto decode_value = [&]->boost::optional<rvalue>
{
if (data == e)
return {};
switch(*data)
{
case '"':
emit_str_begin();
case '{':
case 't':
if (e-data >= 4 &&
data[1] == 'r' &&
data[2] == 'u' &&
data[3] == 'e')
return rvalue(type::True);
else
return {};
case 'f':
case 'n':
}
// TODO
return {};
};
auto decode_object =[&]->boost::optional<rvalue>
{
ws_skip();
if (data == e || *data != '{')
return {};
ws_skip();
if (data == e)
return {};
if (*data == '}')
return rvalue(type::Object);
while(1)
{
auto t = decode_string();
ws_skip();
if (data == e)
return {};
if (data != ':')
return {};
auto v = decode_value();
ws_skip();
if (data == e)
return {};
if (data == '}')
break;
if (data != ',')
return {};
}
// TODO build up object
throw std::runtime_error("Not implemented");
return rvalue(type::Object);
};
return decode_object();
}
}
}
}*/
class wvalue
{
public:
type t{type::Null};
private:
double d;
std::string s;
std::unique_ptr<std::vector<wvalue>> l;
std::unique_ptr<std::unordered_map<std::string, wvalue>> o;
public:
wvalue() {}
wvalue(wvalue&& r)
{
*this = std::move(r);
}
wvalue& operator = (wvalue&& r)
{
t = r.t;
d = r.d;
s = std::move(r.s);
l = std::move(r.l);
o = std::move(r.o);
return *this;
}
void clear()
{
t = type::Null;
l.reset();
o.reset();
}
void reset()
{
t = type::Null;
l.reset();
o.reset();
}
wvalue& operator = (std::nullptr_t)
{
reset();
return *this;
}
wvalue& operator = (bool value)
{
reset();
if (value)
t = type::True;
else
t = type::False;
return *this;
}
wvalue& operator = (double value)
{
reset();
t = type::Number;
d = value;
return *this;
}
wvalue& operator = (uint16_t value)
{
reset();
t = type::Number;
d = (double)value;
return *this;
}
wvalue& operator = (int16_t value)
{
reset();
t = type::Number;
d = (double)value;
return *this;
}
wvalue& operator = (uint32_t value)
{
reset();
t = type::Number;
d = (double)value;
return *this;
}
wvalue& operator = (int32_t value)
{
reset();
t = type::Number;
d = (double)value;
return *this;
}
wvalue& operator = (uint64_t value)
{
reset();
t = type::Number;
d = (double)value;
return *this;
}
wvalue& operator = (int64_t value)
{
reset();
t = type::Number;
d = (double)value;
return *this;
}
wvalue& operator=(const char* str)
{
reset();
t = type::String;
s = str;
return *this;
}
wvalue& operator=(const std::string& str)
{
reset();
t = type::String;
s = str;
return *this;
}
wvalue& operator[](unsigned index)
{
if (t != type::List)
reset();
t = type::List;
if (!l)
l = std::move(std::unique_ptr<std::vector<wvalue>>(new std::vector<wvalue>{}));
l->resize(index+1);
return (*l)[index];
}
wvalue& operator[](const std::string& str)
{
if (t != type::Object)
reset();
t = type::Object;
if (!o)
o = std::move(
std::unique_ptr<
std::unordered_map<std::string, wvalue>
>(
new std::unordered_map<std::string, wvalue>{}));
return (*o)[str];
}
size_t estimate_length() const
{
switch(t)
{
case type::Null: return 4;
case type::False: return 5;
case type::True: return 4;
case type::Number: return 30;
case type::String: return 2+s.size()+s.size()/2;
case type::List:
{
size_t sum{};
if (l)
{
for(auto& x:*l)
{
sum += 1;
sum += x.estimate_length();
}
}
return sum+2;
}
case type::Object:
{
size_t sum{};
if (o)
{
for(auto& kv:*o)
{
sum += 2;
sum += 2+kv.first.size()+kv.first.size()/2;
sum += kv.second.estimate_length();
}
}
return sum+2;
}
}
return 1;
}
friend void encode_internal(const wvalue& v, std::string& out);
friend std::string encode(const wvalue& v);
};
void encode_string(const std::string& str, std::string& out)
{
// TODO escaping
out.push_back('"');
out += str;
out.push_back('"');
}
void encode_internal(const wvalue& v, std::string& out)
{
switch(v.t)
{
case type::Null: out += "null"; break;
case type::False: out += "false"; break;
case type::True: out += "true"; break;
case type::Number: out += boost::lexical_cast<std::string>(v.d); break;
case type::String: encode_string(v.s, out); break;
case type::List:
{
out.push_back('[');
if (v.l)
{
bool first = true;
for(auto& x:*v.l)
{
if (!first)
{
out.push_back(',');
}
first = false;
encode_internal(x, out);
}
}
out.push_back(']');
}
break;
case type::Object:
{
out.push_back('{');
if (v.o)
{
bool first = true;
for(auto& kv:*v.o)
{
if (!first)
{
out.push_back(',');
}
first = false;
encode_string(kv.first, out);
out.push_back(':');
encode_internal(kv.second, out);
}
}
out.push_back('}');
}
break;
}
}
std::string encode(const wvalue& v)
{
std::string ret;
ret.reserve(v.estimate_length());
encode_internal(v, ret);
return ret;
}
//std::vector<boost::asio::const_buffer> encode_ref(wvalue& v)
//{
//}
}
}