C++ (Cpp) GuardMap::begin Examples

Example #1

// Merge adjacent blocks with identical guards.
static void mergeGuards(std::deque<std::string>& file_lines, GuardMap& guard_map) {
  if (guard_map.size() < 2) {
    return;
  }

  auto current = guard_map.begin();
  auto next = current;
  ++next;

  while (next != guard_map.end()) {
    if (current->second != next->second) {
      ++current;
      ++next;
      continue;
    }

    // Scan from the end of current to the beginning of next.
    bool in_block_comment = false;
    bool valid = true;

    FileLocation current_location = current->first.end;
    FileLocation end_location = next->first.start;

    auto nextLine = [&current_location]() {
      ++current_location.line;
      current_location.column = 1;
    };

    auto nextCol = [&file_lines, &current_location, &nextLine]() {
      if (current_location.column == file_lines[current_location.column - 1].length()) {
        nextLine();
      } else {
        ++current_location.column;
      }
    };

    // The end location will point to the semicolon, which we don't want to read, so skip it.
    nextCol();

    while (current_location < end_location) {
      const std::string& line = file_lines[current_location.line - 1];
      size_t line_index = current_location.column - 1;

      if (in_block_comment) {
        size_t pos = line.find("*/", line_index);
        if (pos == std::string::npos) {
          D("Didn't find block comment terminator, skipping line\n");
          nextLine();
          continue;
        } else {
          D("Found block comment terminator\n");
          in_block_comment = false;
          current_location.column = pos + 2;
          nextCol();
          continue;
        }
      } else {
        size_t pos = line.find_first_not_of(" \t", line_index);
        if (pos == std::string::npos) {
          nextLine();
          continue;
        }

        current_location.column = pos + 1;
        if (line[pos] != '/') {
          D("Trailing character '%c' is not a slash: %s\n", line[pos], line.substr(pos).c_str());
          valid = false;
          break;
        }

        nextCol();
        if (line.length() <= pos + 1) {
          // Trailing slash at the end of a line?
          D("Trailing slash at end of line\n");
          valid = false;
          break;
        }

        if (line[pos + 1] == '/') {
          // C++ style comment
          nextLine();
        } else if (line[pos + 1] == '*') {
          // Block comment
          nextCol();
          in_block_comment = true;
          D("In a block comment\n");
        } else {
          // Garbage?
          D("Unexpected output after /: %s\n", line.substr(pos).c_str());
          valid = false;
          break;
        }
      }
    }

    if (!valid) {
      D("Not merging blocks %s and %s\n", to_string(current->first).c_str(),
        to_string(next->first).c_str());
      ++current;
      ++next;
      continue;
    }

    D("Merging blocks %s and %s\n", to_string(current->first).c_str(),
      to_string(next->first).c_str());

    Location merged = current->first;
    merged.end = next->first.end;

    DeclarationAvailability avail = current->second;

    guard_map.erase(current);
    guard_map.erase(next);
    bool dummy;
    std::tie(current, dummy) = guard_map.insert(std::make_pair(merged, avail));
    next = current;
    ++next;
  }
}