internal/ceres/integral_types.h

// Ceres Solver - A fast non-linear least squares minimizer
// Copyright 2015 Google Inc. All rights reserved.
// http://ceres-solver.org/
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// Author: keir@google.com (Keir Mierle)
//
// Portable typedefs for various fixed-size integers. Uses template
// metaprogramming instead of fragile compiler defines.

#ifndef CERES_INTERNAL_INTEGRAL_TYPES_H_
#define CERES_INTERNAL_INTEGRAL_TYPES_H_

namespace ceres {
namespace internal {

// Compile time ternary on types.
template<bool kCondition, typename kTrueType, typename kFalseType>
struct Ternary {
  typedef kTrueType type;
};
template<typename kTrueType, typename kFalseType>
struct Ternary<false, kTrueType, kFalseType> {
  typedef kFalseType type;
};

#define CERES_INTSIZE(TYPE) \
    typename Ternary<sizeof(TYPE) * 8 == kBits, TYPE,

template<int kBits>
struct Integer {
  typedef
      CERES_INTSIZE(char)
      CERES_INTSIZE(short)
      CERES_INTSIZE(int)
      CERES_INTSIZE(long int)
      CERES_INTSIZE(long long)
      void>::type >::type >::type >::type >::type
      type;
};

template<int kBits>
struct UnsignedInteger {
  typedef
      CERES_INTSIZE(unsigned char)
      CERES_INTSIZE(unsigned short)
      CERES_INTSIZE(unsigned int)
      CERES_INTSIZE(unsigned long int)
      CERES_INTSIZE(unsigned long long)
      void>::type >::type >::type >::type >::type
      type;
};

#undef CERES_INTSIZE

typedef Integer< 8>::type int8;
typedef Integer<32>::type int32;
typedef Integer<64>::type int64;

typedef UnsignedInteger< 8>::type uint8;
typedef UnsignedInteger<16>::type uint16;
typedef UnsignedInteger<32>::type uint32;
typedef UnsignedInteger<64>::type uint64;

}  // namespace internal
}  // namespace ceres

#endif  // CERES_INTERNAL_INTEGRAL_TYPES_H_