xml.cpp

#include "xml.h"

#include <string_view>
#include <iostream>
using namespace std;

namespace Xml{

pair<string_view, string_view> Split(string_view line, char by) {
  size_t pos = line.find(by);
  string_view left = line.substr(0, pos);

  if (pos < line.size() && pos + 1 < line.size()) {
    return {left, line.substr(pos + 1)};
  } else {
    return {left, string_view()};
  }
}

string_view Lstrip(string_view line) {
  while (!line.empty() && isspace(line[0])) {
    line.remove_prefix(1);
  }
  return line;
}

string_view Unquote(string_view value) {
  if (!value.empty() && value.front() == '"') {
    value.remove_prefix(1);
  }
  if (!value.empty() && value.back() == '"') {
    value.remove_suffix(1);
  }
  return value;
}

Node LoadNode(istream& input) {
  string root_name;
  getline(input, root_name);

  Node root(root_name.substr(1, root_name.size() - 2), {});
  for (string line; getline(input, line) && Lstrip(line)[1] != '/'; ) {
    auto [node_name, attrs] = Split(Lstrip(line), ' ');
    attrs = Split(attrs, '>').first;
    unordered_map<string, string> node_attrs;
    while (!attrs.empty()) {
      auto [head, tail] = Split(attrs, ' ');
      auto [name, value] = Split(head, '=');
      if (!name.empty() && !value.empty()) {
        node_attrs[string(Unquote(name))] = string(Unquote(value));
      }
      attrs = tail;
    }

    root.AddChild(Node(string(node_name.substr(1)), move(node_attrs)));
  }
  return root;
}

Document Load(istream& input) {
  return Document{LoadNode(input)};
}

Node::Node(
  string name, unordered_map<string, string> attrs
) : name(move(name)), attrs(move(attrs)) {
}

const vector<Node>& Node::Children() const {
  return children;
}

Document::Document(Node root) : root(move(root)) {
}

const Node& Document::GetRoot() const {
  return root;
}

void Node::AddChild(Node node) {
  children.push_back(move(node));
}

string_view Node::Name() const {
  return name;
}

}