//===-- Core Structures for scanf ------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_LIBC_SRC_STDIO_SCANF_CORE_CORE_STRUCTS_H
#define LLVM_LIBC_SRC_STDIO_SCANF_CORE_CORE_STRUCTS_H

#include "src/__support/CPP/bitset.h"
#include "src/__support/CPP/string_view.h"
#include "src/__support/macros/config.h"

#include <inttypes.h>
#include <stddef.h>

namespace LIBC_NAMESPACE_DECL {
namespace scanf_core {

// These length modifiers match the length modifiers in the format string, which
// is why they are formatted differently from the rest of the file.
enum class LengthModifier { hh, h, l, ll, j, z, t, L, NONE };

enum FormatFlags : uint8_t {
  NONE = 0x00,
  NO_WRITE = 0x01, // *
  ALLOCATE = 0x02, // m
};

struct FormatSection {
  bool has_conv;

  cpp::string_view raw_string;

  // Format Specifier Values
  FormatFlags flags = FormatFlags::NONE;
  LengthModifier length_modifier = LengthModifier::NONE;
  int max_width = -1;

  // output_ptr is nullptr if and only if the NO_WRITE flag is set.
  void *output_ptr = nullptr;

  char conv_name;

  cpp::bitset<256> scan_set;

  LIBC_INLINE bool operator==(const FormatSection &other) {
    if (has_conv != other.has_conv)
      return false;

    if (raw_string != other.raw_string)
      return false;

    if (has_conv) {
      if (!((static_cast<uint8_t>(flags) ==
             static_cast<uint8_t>(other.flags)) &&
            (max_width == other.max_width) &&
            (length_modifier == other.length_modifier) &&
            (conv_name == other.conv_name)))
        return false;

      // If the pointers are used, then they should be equal. If the NO_WRITE
      // flag is set or the conversion is %, then the pointers are not used.
      // If the pointers are used and they are not equal, return false.

      if (!(((flags & FormatFlags::NO_WRITE) != 0) || (conv_name == '%') ||
            (output_ptr == other.output_ptr)))
        return false;

      if (conv_name == '[')
        return scan_set == other.scan_set;
    }
    return true;
  }
};

enum ErrorCodes : int {
  // This is the value to be returned by conversions when no error has occurred.
  READ_OK = 0,
  // These are the scanf return values for when an error has occurred. They are
  // all negative, and should be distinct.
  FILE_READ_ERROR = -1,
  FILE_STATUS_ERROR = -2,
  MATCHING_FAILURE = -3,
  ALLOCATION_FAILURE = -4,
};
} // namespace scanf_core
} // namespace LIBC_NAMESPACE_DECL

#endif // LLVM_LIBC_SRC_STDIO_SCANF_CORE_CORE_STRUCTS_H