diff.h

#ifndef SOURCEMETA_CORE_DIFF_H_
#define SOURCEMETA_CORE_DIFF_H_
 
#ifndef SOURCEMETA_CORE_DIFF_EXPORT
#include <sourcemeta/core/diff_export.h>
#endif
 
#include <cstddef>     // std::size_t
#include <cstdint>     // std::uint8_t
#include <functional>  // std::function
#include <ostream>     // std::ostream
#include <string_view> // std::string_view
#include <vector>      // std::vector

 
namespace sourcemeta::core {

struct Diff {
  enum class Mode : std::uint8_t {
    Line
  };

  enum class Algorithm : std::uint8_t {
    Myers
  };

  enum class Format : std::uint8_t {
    Unified
  };

  struct Operation {
    enum class Type : std::uint8_t {
      Equal,
      Delete,
      Insert
    };

    Type type;
    std::size_t original_start;
    std::size_t original_end;
    std::size_t modified_start;
    std::size_t modified_end;
 
    auto operator==(const Operation &) const noexcept -> bool = default;
  };

  struct FormatOptions {
    enum class LineType : std::uint8_t {
      HeaderOriginal,
      HeaderModified,
      Hunk,
      Context,
      Delete,
      Insert,
      NoNewline
    };

    using LineWriter =
        std::function<void(std::ostream &stream, LineType type,
                           std::string_view prefix, std::string_view content)>;

    std::string_view original_label{"a"};
    std::string_view modified_label{"b"};
    std::size_t context{3};
    LineWriter line_writer{};
  };

  std::vector<std::string_view> original;
  std::vector<std::string_view> modified;
  std::vector<Operation> operations;
  bool original_ends_with_newline{true};
  bool modified_ends_with_newline{true};
};

SOURCEMETA_CORE_DIFF_EXPORT
auto diff(const std::string_view original, const std::string_view modified,
          const Diff::Mode mode, const Diff::Algorithm algorithm) -> Diff;

SOURCEMETA_CORE_DIFF_EXPORT
auto stringify(const Diff &document, std::ostream &stream,
               const Diff::Format format,
               const Diff::FormatOptions &options = {}) -> void;
 
} // namespace sourcemeta::core
 
#endif