json/reader.cpp - master - RedResistance/JSonMall

json/reader.cpp
124 строки2 KB
Domovoi-Kuzma
templates
27 июл 2025, 01:22
27 июл 2025, 01:221c9b251
#include <cassert>
#include "reader.h"
#include "any_factory.h"
using namespace json;

reader::reader(std::ifstream& in, base_factory& fact):factory(fact), fin(in) {
	parse_field();
}
void reader::parse_field() {
	int ch = nextchar();
	fin.unget();
	if (ch == '{') {
		parse_object();
	}
	else if (ch == '[') {
		parse_array();
	}
	else if (ch >= '0' && ch <= '9') {
		factory.onInt(parse_int());
	}
	else if (is_letter(ch)) {
		factory.onString(parse_string());
	}
	else {
		throw std::string("unexpected character3 ")+char(ch);
	}
}

bool reader::is_letter(char ch) {
	return (ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z') || ch == '_';
}

void reader::skip_spaces() {
	while (fin) {
		int ch = fin.get();//-1 for eof
		if (!isspace(ch)) {
			fin.unget();
			break;
		}
	}
}

int reader::parse_int() {
	int tmp;
	fin >> tmp;
	return tmp;
}

std::string reader::parse_string() {
	std::string tmp;
	while (fin) {
		char ch = fin.get();//-1 for eof
		if (!is_letter(ch)) {
			fin.unget();
			break;
		}
		tmp += ch;
	}
	return tmp;
}


void reader::parse_array() {
	char ch = nextchar();
	assert(ch == '[');
	ch = nextchar();
	if (ch == ']') {
		return;
	}
	fin.unget();
	while (fin) {
		base_factory* element_factory = factory.onArrayItem();
		json::reader(fin, *element_factory);
		ch = nextchar();
		if (ch == ']') {
			return;
		}
		if (ch != ',')
			throw std::string("unexpected character2 ") + ch;//hit
		skip_spaces();
	}

}
void reader::parse_object() {
	char ch = nextchar();
	assert(ch == '{');
	ch = nextchar();
	if (ch == '}') {
		return;
	}
	fin.unget();

	while (fin) {
		std::string key = parse_string();
		ch = nextchar();
		if (ch != ':')
			throw std::string("unexpected character1 ") + ch;
		base_factory *field_factory = factory.onField(key), *deleted_factory = nullptr;
		if (field_factory == nullptr) {
			deleted_factory = field_factory = new any_factory;
		}
		json::reader(fin, *field_factory);
		delete deleted_factory;
		ch = nextchar();

		if (ch == '}') {
			return;
		}
		if (ch != ',')
			throw std::string("unexpected character2 ") + ch;//hit
		skip_spaces();
	}
	throw "unexpected end of object";
}

int reader::nextchar() {
	while (fin) {
		int ch = fin.get();//-1 for eof
		if (!isspace(ch)) {
			return ch;
		}
	}
	return -1;
}