scanner.h

#ifndef SCANNER_H_62B23520_7C8E_11DE_8A39_0800200C9A66
#define SCANNER_H_62B23520_7C8E_11DE_8A39_0800200C9A66

#if defined(_MSC_VER) ||                                            \
    (defined(__GNUC__) && (__GNUC__ == 3 && __GNUC_MINOR__ >= 4) || \
     (__GNUC__ >= 4))  // GCC supports "pragma once" correctly since 3.4
#pragma once
#endif

#include <cstddef>
#include <ios>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>

#include "ptr_vector.h"
#include "stream.h"
#include "token.h"
#include "yaml-cpp/mark.h"

namespace YAML {
class Node;
class RegEx;

class Scanner {
 public:
  Scanner(std::istream &in);
  ~Scanner();

  // token queue management (hopefully this looks kinda stl-ish)
  bool empty();
  void pop();
  Token &peek();
  Mark mark() const;

 private:
  struct IndentMarker {
    enum INDENT_TYPE { MAP, SEQ, NONE };
    enum STATUS { VALID, INVALID, UNKNOWN };
    IndentMarker(int column_, INDENT_TYPE type_)
        : column(column_), type(type_), status(VALID), pStartToken(0) {}

    int column;
    INDENT_TYPE type;
    STATUS status;
    Token *pStartToken;
  };

  enum FLOW_MARKER { FLOW_MAP, FLOW_SEQ };

 private:
  // scanning
  void EnsureTokensInQueue();
  void ScanNextToken();
  void ScanToNextToken();
  void StartStream();
  void EndStream();
  Token *PushToken(Token::TYPE type);

  bool InFlowContext() const { return !m_flows.empty(); }
  bool InBlockContext() const { return m_flows.empty(); }
  std::size_t GetFlowLevel() const { return m_flows.size(); }

  Token::TYPE GetStartTokenFor(IndentMarker::INDENT_TYPE type) const;
  IndentMarker *PushIndentTo(int column, IndentMarker::INDENT_TYPE type);
  void PopIndentToHere();
  void PopAllIndents();
  void PopIndent();
  int GetTopIndent() const;

  // checking input
  bool CanInsertPotentialSimpleKey() const;
  bool ExistsActiveSimpleKey() const;
  void InsertPotentialSimpleKey();
  void InvalidateSimpleKey();
  bool VerifySimpleKey();
  void PopAllSimpleKeys();

  void ThrowParserException(const std::string &msg) const;

  bool IsWhitespaceToBeEaten(char ch);
  const RegEx &GetValueRegex() const;

  struct SimpleKey {
    SimpleKey(const Mark &mark_, std::size_t flowLevel_);

    void Validate();
    void Invalidate();

    Mark mark;
    std::size_t flowLevel;
    IndentMarker *pIndent;
    Token *pMapStart, *pKey;
  };

  // and the tokens
  void ScanDirective();
  void ScanDocStart();
  void ScanDocEnd();
  void ScanBlockSeqStart();
  void ScanBlockMapSTart();
  void ScanBlockEnd();
  void ScanBlockEntry();
  void ScanFlowStart();
  void ScanFlowEnd();
  void ScanFlowEntry();
  void ScanKey();
  void ScanValue();
  void ScanAnchorOrAlias();
  void ScanTag();
  void ScanPlainScalar();
  void ScanQuotedScalar();
  void ScanBlockScalar();

 private:
  // the stream
  Stream INPUT;

  // the output (tokens)
  std::queue<Token> m_tokens;

  // state info
  bool m_startedStream, m_endedStream;
  bool m_simpleKeyAllowed;
  bool m_canBeJSONFlow;
  std::stack<SimpleKey> m_simpleKeys;
  std::stack<IndentMarker *> m_indents;
  ptr_vector<IndentMarker> m_indentRefs;  // for "garbage collection"
  std::stack<FLOW_MARKER> m_flows;
};
}

#endif  // SCANNER_H_62B23520_7C8E_11DE_8A39_0800200C9A66