/*

Copyright (C) 2004-2019 John W. Eaton

This file is part of Octave.

Octave is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

Octave is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with Octave; see the file COPYING.  If not, see
<https://www.gnu.org/licenses/>.

*/

#if defined (HAVE_CONFIG_H)
#  include "config.h"
#endif

#include <limits>

#include "str-vec.h"
#include "quit.h"

#include "defun.h"
#include "error.h"
#include "ov.h"
#include "ov-uint64.h"
#include "ov-uint32.h"
#include "ov-uint16.h"
#include "ov-uint8.h"
#include "ov-int64.h"
#include "ov-int32.h"
#include "ov-int16.h"
#include "ov-int8.h"
#include "ov-float.h"
#include "ov-scalar.h"
#include "ov-re-mat.h"
#include "ov-bool.h"

#include <functional>

#if ! defined (HAVE_CXX_BITWISE_OP_TEMPLATES)
namespace std
{
  template <typename T>
  struct bit_and
  {
  public:
    T operator() (const T & op1, const T & op2) const { return (op1 & op2); }
  };

  template <typename T>
  struct bit_or
  {
  public:
    T operator() (const T & op1, const T & op2) const { return (op1 | op2); }
  };

  template <typename T>
  struct bit_xor
  {
  public:
    T operator() (const T & op1, const T & op2) const { return (op1 ^ op2); }
  };
}
#endif

template <typename OP, typename T>
octave_value
bitopxx (const OP& op, const std::string& fname,
         const Array<T>& x, const Array<T>& y)
{
  int nelx = x.numel ();
  int nely = y.numel ();

  bool is_scalar_op = (nelx == 1 || nely == 1);

  dim_vector dvx = x.dims ();
  dim_vector dvy = y.dims ();

  bool is_array_op = (dvx == dvy);

  if (! is_array_op && ! is_scalar_op)
    error ("%s: size of X and Y must match, or one operand must be a scalar",
           fname.c_str ());

  Array<T> result;

  if (nelx != 1)
    result.resize (dvx);
  else
    result.resize (dvy);

  for (int i = 0; i < nelx; i++)
    if (is_scalar_op)
      for (int k = 0; k < nely; k++)
        result(i+k) = op (x(i), y(k));
    else
      result(i) = op (x(i), y(i));

  return result;
}

// Trampoline function, instantiates the proper template above, with
// reflective information hardwired.  We can't hardwire this information
// in Fbitxxx DEFUNs below, because at that moment, we still don't have
// information about which integer types we need to instantiate.
template <typename T>
octave_value
bitopx (const std::string& fname, const Array<T>& x, const Array<T>& y)
{
  if (fname == "bitand")
    return bitopxx (std::bit_and<T>(), fname, x, y);
  if (fname == "bitor")
    return bitopxx (std::bit_or<T>(), fname, x, y);

  //else (fname == "bitxor")
  return bitopxx (std::bit_xor<T>(), fname, x, y);
}

static inline int
bitop_arg_is_int (const octave_value& arg)
{
  return (arg.class_name () != octave_scalar::static_class_name ()
          && arg.class_name () != octave_float_scalar::static_class_name ()
          && arg.class_name () != octave_bool::static_class_name ());
}

static inline int
bitop_arg_is_bool (const octave_value& arg)
{
  return arg.class_name () == octave_bool::static_class_name ();
}

static inline int
bitop_arg_is_float (const octave_value& arg)
{
  return arg.class_name () == octave_float_scalar::static_class_name ();
}

octave_value
bitop (const std::string& fname, const octave_value_list& args)
{
  if (args.length () != 2)
    print_usage ();

  octave_value retval;

  if (args(0).class_name () == octave_scalar::static_class_name ()
      || args(0).class_name () == octave_float_scalar::static_class_name ()
      || args(0).class_name () == octave_bool::static_class_name ()
      || args(1).class_name () == octave_scalar::static_class_name ()
      || args(1).class_name () == octave_float_scalar::static_class_name ()
      || args(1).class_name () == octave_bool::static_class_name ())
    {
      bool arg0_is_int = bitop_arg_is_int (args(0));
      bool arg1_is_int = bitop_arg_is_int (args(1));

      bool arg0_is_bool = bitop_arg_is_bool (args(0));
      bool arg1_is_bool = bitop_arg_is_bool (args(1));

      bool arg0_is_float = bitop_arg_is_float (args(0));
      bool arg1_is_float = bitop_arg_is_float (args(1));

      if (! (arg0_is_int || arg1_is_int))
        {
          if (arg0_is_bool && arg1_is_bool)
            {
              boolNDArray x (args(0).bool_array_value ());
              boolNDArray y (args(1).bool_array_value ());

              retval = bitopx (fname, x, y).bool_array_value ();
            }
          else if (arg0_is_float && arg1_is_float)
            {
              uint64NDArray x (args(0).float_array_value ());
              uint64NDArray y (args(1).float_array_value ());

              retval = bitopx (fname, x, y).float_array_value ();
            }
          else if (! (arg0_is_float || arg1_is_float))
            {
              uint64NDArray x (args(0).array_value ());
              uint64NDArray y (args(1).array_value ());

              retval = bitopx (fname, x, y).array_value ();
            }
          else
            {
              int p = (arg0_is_float ? 1 : 0);
              int q = (arg0_is_float ? 0 : 1);

              uint64NDArray x (args(p).array_value ());
              uint64NDArray y (args(q).float_array_value ());

              retval = bitopx (fname, x, y).float_array_value ();
            }
        }
      else
        {
          int p = (arg0_is_int ? 1 : 0);
          int q = (arg0_is_int ? 0 : 1);

          NDArray dx = args(p).array_value ();

          if (args(q).type_id () == octave_uint64_matrix::static_type_id ()
              || args(q).type_id () == octave_uint64_scalar::static_type_id ())
            {
              uint64NDArray x (dx);
              uint64NDArray y = args(q).uint64_array_value ();

              retval = bitopx (fname, x, y);
            }
          else if (args(q).type_id () == octave_uint32_matrix::static_type_id ()
                   || args(q).type_id () == octave_uint32_scalar::static_type_id ())
            {
              uint32NDArray x (dx);
              uint32NDArray y = args(q).uint32_array_value ();

              retval = bitopx (fname, x, y);
            }
          else if (args(q).type_id () == octave_uint16_matrix::static_type_id ()
                   || args(q).type_id () == octave_uint16_scalar::static_type_id ())
            {
              uint16NDArray x (dx);
              uint16NDArray y = args(q).uint16_array_value ();

              retval = bitopx (fname, x, y);
            }
          else if (args(q).type_id () == octave_uint8_matrix::static_type_id ()
                   || args(q).type_id () == octave_uint8_scalar::static_type_id ())
            {
              uint8NDArray x (dx);
              uint8NDArray y = args(q).uint8_array_value ();

              retval = bitopx (fname, x, y);
            }
          else if (args(q).type_id () == octave_int64_matrix::static_type_id ()
                   || args(q).type_id () == octave_int64_scalar::static_type_id ())
            {
              int64NDArray x (dx);
              int64NDArray y = args(q).int64_array_value ();

              retval = bitopx (fname, x, y);
            }
          else if (args(q).type_id () == octave_int32_matrix::static_type_id ()
                   || args(q).type_id () == octave_int32_scalar::static_type_id ())
            {
              int32NDArray x (dx);
              int32NDArray y = args(q).int32_array_value ();

              retval = bitopx (fname, x, y);
            }
          else if (args(q).type_id () == octave_int16_matrix::static_type_id ()
                   || args(q).type_id () == octave_int16_scalar::static_type_id ())
            {
              int16NDArray x (dx);
              int16NDArray y = args(q).int16_array_value ();

              retval = bitopx (fname, x, y);
            }
          else if (args(q).type_id () == octave_int8_matrix::static_type_id ()
                   || args(q).type_id () == octave_int8_scalar::static_type_id ())
            {
              int8NDArray x (dx);
              int8NDArray y = args(q).int8_array_value ();

              retval = bitopx (fname, x, y);
            }
          else
            error ("%s: invalid operand type", fname.c_str ());
        }
    }
  else if (args(0).class_name () == args(1).class_name ())
    {
      if (args(0).type_id () == octave_uint64_matrix::static_type_id ()
          || args(0).type_id () == octave_uint64_scalar::static_type_id ())
        {
          uint64NDArray x = args(0).uint64_array_value ();
          uint64NDArray y = args(1).uint64_array_value ();

          retval = bitopx (fname, x, y);
        }
      else if (args(0).type_id () == octave_uint32_matrix::static_type_id ()
               || args(0).type_id () == octave_uint32_scalar::static_type_id ())
        {
          uint32NDArray x = args(0).uint32_array_value ();
          uint32NDArray y = args(1).uint32_array_value ();

          retval = bitopx (fname, x, y);
        }
      else if (args(0).type_id () == octave_uint16_matrix::static_type_id ()
               || args(0).type_id () == octave_uint16_scalar::static_type_id ())
        {
          uint16NDArray x = args(0).uint16_array_value ();
          uint16NDArray y = args(1).uint16_array_value ();

          retval = bitopx (fname, x, y);
        }
      else if (args(0).type_id () == octave_uint8_matrix::static_type_id ()
               || args(0).type_id () == octave_uint8_scalar::static_type_id ())
        {
          uint8NDArray x = args(0).uint8_array_value ();
          uint8NDArray y = args(1).uint8_array_value ();

          retval = bitopx (fname, x, y);
        }
      else if (args(0).type_id () == octave_int64_matrix::static_type_id ()
               || args(0).type_id () == octave_int64_scalar::static_type_id ())
        {
          int64NDArray x = args(0).int64_array_value ();
          int64NDArray y = args(1).int64_array_value ();

          retval = bitopx (fname, x, y);
        }
      else if (args(0).type_id () == octave_int32_matrix::static_type_id ()
               || args(0).type_id () == octave_int32_scalar::static_type_id ())
        {
          int32NDArray x = args(0).int32_array_value ();
          int32NDArray y = args(1).int32_array_value ();

          retval = bitopx (fname, x, y);
        }
      else if (args(0).type_id () == octave_int16_matrix::static_type_id ()
               || args(0).type_id () == octave_int16_scalar::static_type_id ())
        {
          int16NDArray x = args(0).int16_array_value ();
          int16NDArray y = args(1).int16_array_value ();

          retval = bitopx (fname, x, y);
        }
      else if (args(0).type_id () == octave_int8_matrix::static_type_id ()
               || args(0).type_id () == octave_int8_scalar::static_type_id ())
        {
          int8NDArray x = args(0).int8_array_value ();
          int8NDArray y = args(1).int8_array_value ();

          retval = bitopx (fname, x, y);
        }
      else
        error ("%s: invalid operand type", fname.c_str ());
    }
  else
    error ("%s: must have matching operand types", fname.c_str ());

  return retval;
}

DEFUN (bitand, args, ,
       doc: /* -*- texinfo -*-
@deftypefn {} {} bitand (@var{x}, @var{y})
Return the bitwise AND of non-negative integers.

@var{x}, @var{y} must be in the range [0,intmax]
@seealso{bitor, bitxor, bitset, bitget, bitcmp, bitshift, intmax, flintmax}
@end deftypefn */)
{
  return bitop ("bitand", args);
}

/*
%!# Function bitand is tested as part of bitxor BIST tests
*/

DEFUN (bitor, args, ,
       doc: /* -*- texinfo -*-
@deftypefn {} {} bitor (@var{x}, @var{y})
Return the bitwise OR of non-negative integers @var{x} and @var{y}.

@seealso{bitor, bitxor, bitset, bitget, bitcmp, bitshift, intmax, flintmax}
@end deftypefn */)
{
  return bitop ("bitor", args);
}

/*
%!# Function bitor is tested as part of bitxor BIST tests
*/

DEFUN (bitxor, args, ,
       doc: /* -*- texinfo -*-
@deftypefn {} {} bitxor (@var{x}, @var{y})
Return the bitwise XOR of non-negative integers @var{x} and @var{y}.

@seealso{bitand, bitor, bitset, bitget, bitcmp, bitshift, intmax, flintmax}
@end deftypefn */)
{
  return bitop ("bitxor", args);
}

/*
%!assert (bitand (true, false), false)
%!assert (bitor  (true, false), true)
%!assert (bitxor (true, false), true)

%!assert (bitand (true, true), true)
%!assert (bitor  (true, true), true)
%!assert (bitxor (true, true), false)

%!assert (bitand (true, 5), 1)

%!assert (bitand (true, false), false)
%!assert (bitand (true, true), true)
%!assert (bitand (true, false), false)
%!assert (bitand (true, false), false)

## Test idx_arg.length () == 0
%!error <size of X and Y must match> bitand ([0 0 0], [1 0])
%!error <size of X and Y must match> bitand ([0; 0; 0], [0 0 0])
*/

template <typename T>
static int64_t
max_mantissa_value ()
{
  return (static_cast<int64_t> (1) << std::numeric_limits<T>::digits) - 1;
}

static int64_t
bitshift (double a, int n, int64_t mask)
{
  // In the name of bug-for-bug compatibility.
  if (a < 0)
    return -bitshift (-a, n, mask);

  if (n > 0)
    return (static_cast<int64_t> (a) << n) & mask;
  else if (n < 0)
    return (static_cast<int64_t> (a) >> -n) & mask;
  else
    return static_cast<int64_t> (a) & mask;
}

static int64_t
bitshift (float a, int n, int64_t mask)
{
  // In the name of bug-for-bug compatibility.
  if (a < 0)
    return -bitshift (-a, n, mask);

  if (n > 0)
    return (static_cast<int64_t> (a) << n) & mask;
  else if (n < 0)
    return (static_cast<int64_t> (a) >> -n) & mask;
  else
    return static_cast<int64_t> (a) & mask;
}

// Note that the bitshift operators are undefined if shifted by more
// bits than in the type, so we need to test for the size of the
// shift.

#define DO_BITSHIFT(T)                                                  \
  double d1, d2;                                                        \
                                                                        \
  if (! n.all_integers (d1, d2))                                        \
    error ("bitshift: K must be a scalar or array of integers");        \
                                                                        \
  int m_nel = m.numel ();                                               \
  int n_nel = n.numel ();                                               \
                                                                        \
  bool is_scalar_op = (m_nel == 1 || n_nel == 1);                       \
                                                                        \
  dim_vector m_dv = m.dims ();                                          \
  dim_vector n_dv = n.dims ();                                          \
                                                                        \
  bool is_array_op = (m_dv == n_dv);                                    \
                                                                        \
  if (! is_array_op && ! is_scalar_op)                                  \
    error ("bitshift: size of A and N must match, or one operand must be a scalar"); \
                                                                        \
  T ## NDArray result;                                                  \
                                                                        \
  if (m_nel != 1)                                                       \
    result.resize (m_dv);                                               \
  else                                                                  \
    result.resize (n_dv);                                               \
                                                                        \
  for (int i = 0; i < m_nel; i++)                                       \
    if (is_scalar_op)                                                   \
      for (int k = 0; k < n_nel; k++)                                   \
        if (static_cast<int> (n(k)) >= bits_in_type)                    \
          result(i+k) = 0;                                              \
        else                                                            \
          result(i+k) = bitshift (m(i), static_cast<int> (n(k)), mask); \
    else                                                                \
      if (static_cast<int> (n(i)) >= bits_in_type)                      \
        result(i) = 0;                                                  \
      else                                                              \
        result(i) = bitshift (m(i), static_cast<int> (n(i)), mask);     \
                                                                        \
  retval = result;

#define DO_UBITSHIFT(T, N)                              \
  do                                                    \
    {                                                   \
      int bits_in_type = octave_ ## T :: nbits ();      \
      T ## NDArray m = m_arg.T ## _array_value ();      \
      octave_ ## T mask = octave_ ## T::max ();         \
      if ((N) < bits_in_type)                           \
        mask = bitshift (mask, (N) - bits_in_type);     \
      else if ((N) < 1)                                 \
        mask = 0;                                       \
      DO_BITSHIFT (T);                                  \
    }                                                   \
  while (0)

#define DO_SBITSHIFT(T, N)                              \
  do                                                    \
    {                                                   \
      int bits_in_type = octave_ ## T :: nbits ();      \
      T ## NDArray m = m_arg.T ## _array_value ();      \
      octave_ ## T mask = octave_ ## T::max ();         \
      if ((N) < bits_in_type)                           \
        mask = bitshift (mask, (N) - bits_in_type);     \
      else if ((N) < 1)                                 \
        mask = 0;                                       \
      /* FIXME: 2's complement only? */                 \
      mask = mask | octave_ ## T :: min ();             \
      DO_BITSHIFT (T);                                  \
    }                                                   \
  while (0)

DEFUN (bitshift, args, ,
       doc: /* -*- texinfo -*-
@deftypefn  {} {} bitshift (@var{a}, @var{k})
@deftypefnx {} {} bitshift (@var{a}, @var{k}, @var{n})
Return a @var{k} bit shift of @var{n}-digit unsigned integers in @var{a}.

A positive @var{k} leads to a left shift; A negative value to a right shift.

If @var{n} is omitted it defaults to 64.
@var{n} must be in the range [1,64].

@example
@group
bitshift (eye (3), 1)
@result{}
@group
2 0 0
0 2 0
0 0 2
@end group

bitshift (10, [-2, -1, 0, 1, 2])
@result{} 2   5  10  20  40
@c FIXME: restore this example when third arg is allowed to be an array.
@c
@c
@c bitshift ([1, 10], 2, [3,4])
@c @result{} 4  8
@end group
@end example
@seealso{bitand, bitor, bitxor, bitset, bitget, bitcmp, intmax, flintmax}
@end deftypefn */)
{
  int nargin = args.length ();

  if (nargin < 2 || nargin > 3)
    print_usage ();

  NDArray n = args(1).xarray_value ("bitshift: K must be a scalar or array of integers");

  int nbits = 64;

  if (nargin == 3)
    {
      // FIXME: for compatibility, we should accept an array or a scalar
      //        as the third argument.
      if (args(2).numel () > 1)
        error ("bitshift: N must be a scalar integer");

      nbits = args(2).xint_value ("bitshift: N must be an integer");

      if (nbits < 0)
        error ("bitshift: N must be positive");
    }

  octave_value retval;

  octave_value m_arg = args(0);
  std::string cname = m_arg.class_name ();

  if (cname == "double")
    {
      static const int bits_in_mantissa
        = std::numeric_limits<double>::digits;

      nbits = (nbits < bits_in_mantissa ? nbits : bits_in_mantissa);
      int64_t mask = max_mantissa_value<double> ();
      if (nbits < bits_in_mantissa)
        mask = mask >> (bits_in_mantissa - nbits);
      int bits_in_type = sizeof (double)
                         * std::numeric_limits<unsigned char>::digits;
      NDArray m = m_arg.array_value ();
      DO_BITSHIFT ();
    }
  else if (cname == "uint8")
    DO_UBITSHIFT (uint8, nbits < 8 ? nbits : 8);
  else if (cname == "uint16")
    DO_UBITSHIFT (uint16, nbits < 16 ? nbits : 16);
  else if (cname == "uint32")
    DO_UBITSHIFT (uint32, nbits < 32 ? nbits : 32);
  else if (cname == "uint64")
    DO_UBITSHIFT (uint64, nbits < 64 ? nbits : 64);
  else if (cname == "int8")
    DO_SBITSHIFT (int8, nbits < 8 ? nbits : 8);
  else if (cname == "int16")
    DO_SBITSHIFT (int16, nbits < 16 ? nbits : 16);
  else if (cname == "int32")
    DO_SBITSHIFT (int32, nbits < 32 ? nbits : 32);
  else if (cname == "int64")
    DO_SBITSHIFT (int64, nbits < 64 ? nbits : 64);
  else if (cname == "single")
    {
      static const int bits_in_mantissa
        = std::numeric_limits<float>::digits;
      nbits = (nbits < bits_in_mantissa ? nbits : bits_in_mantissa);
      int64_t mask = max_mantissa_value<float> ();
      if (nbits < bits_in_mantissa)
        mask = mask >> (bits_in_mantissa - nbits);
      int bits_in_type = sizeof (float)
                         * std::numeric_limits<unsigned char>::digits;
      FloatNDArray m = m_arg.float_array_value ();
      DO_BITSHIFT (Float);
    }
  else
    error ("bitshift: not defined for %s objects", cname.c_str ());

  return retval;
}

/*
%!assert (bitshift (uint8  (16), 1),  uint8 ( 32))
%!assert (bitshift (uint16 (16), 2), uint16 ( 64))
%!assert (bitshift (uint32 (16), 3), uint32 (128))
%!assert (bitshift (uint64 (16), 4), uint64 (256))
%!assert (bitshift (uint8 (255), 1), uint8 (254))

%!error <K must be a scalar or array of integers> bitshift (16, 1.5)
%!error bitshift (16, {1})
%!error <N must be a scalar integer> bitshift (10, [-2 -1 0 1 2], [1 1 1 1 1])
%!error <N must be positive> bitshift (10, [-2 -1 0 1 2], -1)
*/

DEFUN (flintmax, args, ,
       doc: /* -*- texinfo -*-
@deftypefn  {} {} flintmax ()
@deftypefnx {} {} flintmax ("double")
@deftypefnx {} {} flintmax ("single")
@deftypefnx {} {} flintmax (@var{var})
Return the largest integer that can be represented consecutively in a
floating point value.

The input is either a string specifying a floating point type, or it is an
existing floating point variable @var{var}.

The default type is @qcode{"double"}, but @qcode{"single"} is a valid option.
On IEEE 754 compatible systems, @code{flintmax} is @w{@math{2^{53}}} for
@qcode{"double"} and @w{@math{2^{24}}} for @qcode{"single"}.

Example Code - query an existing variable

@example
@group
x = single (1);
flintmax (x)
  @result{} 16777216
@end group
@end example

@seealso{intmax, realmax, realmin}
@end deftypefn */)
{
  int nargin = args.length ();

  if (nargin > 1)
    print_usage ();

  std::string cname = "double";
  if (nargin == 1)
    {
      if (args(0).is_string ())
        cname = args(0).string_value ();
      else if (args(0).isfloat ())
        cname = args(0).class_name ();
      else
        error ("intmin: argument must be a string or floating point variable");
    }

  if (cname == "double")
    return ovl (static_cast<double> (max_mantissa_value<double> () + 1));
  else if (cname == "single")
    return ovl (static_cast<float> (max_mantissa_value<float> () + 1));
  else
    error ("flintmax: not defined for class '%s'", cname.c_str ());
}

/*
%!assert (flintmax (), 2^53)
%!assert (flintmax ("double"), 2^53)
%!assert (flintmax ("single"), single (2^24))

%!test
%! x = single (1);
%! assert (flintmax (x), single (16777216));

%!error flintmax ("double", 0)
%!error <must be a string or floating point variable> flintmax (int8 (1))
%!error <not defined for class 'int8'> flintmax ("int8")
%!error <not defined for class 'char'> flintmax ("char")
*/

DEFUN (intmax, args, ,
       doc: /* -*- texinfo -*-
@deftypefn  {} {} intmax ()
@deftypefnx {} {} intmax ("@var{type}")
@deftypefnx {} {} intmax (@var{var})
Return the largest integer that can be represented by a specific integer type.

The input is either a string @qcode{"@var{type}"} specifying an integer type,
or it is an existing integer variable @var{var}.

Possible values for @var{type} are

@table @asis
@item @qcode{"int8"}
signed 8-bit integer.

@item @qcode{"int16"}
signed 16-bit integer.

@item @qcode{"int32"}
signed 32-bit integer.

@item @qcode{"int64"}
signed 64-bit integer.

@item @qcode{"uint8"}
unsigned 8-bit integer.

@item @qcode{"uint16"}
unsigned 16-bit integer.

@item @qcode{"uint32"}
unsigned 32-bit integer.

@item @qcode{"uint64"}
unsigned 64-bit integer.
@end table

The default for @var{type} is @qcode{"int32"}.

Example Code - query an existing variable

@example
@group
x = int8 (1);
intmax (x)
  @result{} 127
@end group
@end example

@seealso{intmin, flintmax}
@end deftypefn */)
{
  int nargin = args.length ();

  if (nargin > 1)
    print_usage ();

  std::string cname = "int32";
  if (nargin == 1)
    {
      if (args(0).is_string ())
        cname = args(0).string_value ();
      else if (args(0).isinteger ())
        cname = args(0).class_name ();
      else
        error ("intmax: argument must be a string or integer variable");
    }

  octave_value retval;

  if (cname == "uint8")
    retval = octave_uint8 (std::numeric_limits<uint8_t>::max ());
  else if (cname == "uint16")
    retval = octave_uint16 (std::numeric_limits<uint16_t>::max ());
  else if (cname == "uint32")
    retval = octave_uint32 (std::numeric_limits<uint32_t>::max ());
  else if (cname == "uint64")
    retval = octave_uint64 (std::numeric_limits<uint64_t>::max ());
  else if (cname == "int8")
    retval = octave_int8 (std::numeric_limits<int8_t>::max ());
  else if (cname == "int16")
    retval = octave_int16 (std::numeric_limits<int16_t>::max ());
  else if (cname == "int32")
    retval = octave_int32 (std::numeric_limits<int32_t>::max ());
  else if (cname == "int64")
    retval = octave_int64 (std::numeric_limits<int64_t>::max ());
  else
    error ("intmax: not defined for '%s' objects", cname.c_str ());

  return retval;
}

/*
%!assert (intmax (),          int32 (2^31 - 1))
%!assert (intmax ("int8"),     int8 (2^7 - 1))
%!assert (intmax ("uint8"),   uint8 (2^8 - 1))
%!assert (intmax ("int16"),   int16 (2^15 - 1))
%!assert (intmax ("uint16"), uint16 (2^16 - 1))
%!assert (intmax ("int32"),   int32 (2^31 - 1))
%!assert (intmax ("uint32"), uint32 (2^32 - 1))
%!assert (intmax ("int64"),   int64 (2^63 - 1))
%!assert (intmax ("uint64"), uint64 (2^64 - 1))

%!test
%! x = int8 (1);
%! assert (intmax (x), int8 (127));

%!error intmax ("int32", 0)
%!error <must be a string or integer variable> intmax (1.0)
%!error <not defined for 'double' objects> intmax ("double")
%!error <not defined for 'char' objects> intmax ("char")
*/

DEFUN (intmin, args, ,
       doc: /* -*- texinfo -*-
@deftypefn  {} {} intmin ()
@deftypefnx {} {} intmin ("@var{type}")
@deftypefnx {} {} intmin (@var{var})
Return the smallest integer that can be represented by a specific integer type.

The input is either a string @qcode{"@var{type}"} specifying an integer type,
or it is an existing integer variable @var{var}.

Possible values for @var{type} are

@table @asis
@item @qcode{"int8"}
signed 8-bit integer.

@item @qcode{"int16"}
signed 16-bit integer.

@item @qcode{"int32"}
signed 32-bit integer.

@item @qcode{"int64"}
signed 64-bit integer.

@item @qcode{"uint8"}
unsigned 8-bit integer.

@item @qcode{"uint16"}
unsigned 16-bit integer.

@item @qcode{"uint32"}
unsigned 32-bit integer.

@item @qcode{"uint64"}
unsigned 64-bit integer.
@end table

The default for @var{type} is @qcode{"int32"}.

Example Code - query an existing variable

@example
@group
x = int8 (1);
intmin (x)
  @result{} -128
@end group
@end example

@seealso{intmax, flintmax}
@end deftypefn */)
{
  int nargin = args.length ();

  if (nargin > 1)
    print_usage ();

  std::string cname = "int32";
  if (nargin == 1)
    {
      if (args(0).is_string ())
        cname = args(0).string_value ();
      else if (args(0).isinteger ())
        cname = args(0).class_name ();
      else
        error ("intmin: argument must be a string or integer variable");
    }

  octave_value retval;

  if (cname == "uint8")
    retval = octave_uint8 (std::numeric_limits<uint8_t>::min ());
  else if (cname == "uint16")
    retval = octave_uint16 (std::numeric_limits<uint16_t>::min ());
  else if (cname == "uint32")
    retval = octave_uint32 (std::numeric_limits<uint32_t>::min ());
  else if (cname == "uint64")
    retval = octave_uint64 (std::numeric_limits<uint64_t>::min ());
  else if (cname == "int8")
    retval = octave_int8 (std::numeric_limits<int8_t>::min ());
  else if (cname == "int16")
    retval = octave_int16 (std::numeric_limits<int16_t>::min ());
  else if (cname == "int32")
    retval = octave_int32 (std::numeric_limits<int32_t>::min ());
  else if (cname == "int64")
    retval = octave_int64 (std::numeric_limits<int64_t>::min ());
  else
    error ("intmin: not defined for '%s' objects", cname.c_str ());

  return retval;
}

/*
%!assert (intmin (),          int32 (-2^31))
%!assert (intmin ("int8"),     int8 (-2^7))
%!assert (intmin ("uint8"),   uint8 (-2^8))
%!assert (intmin ("int16"),   int16 (-2^15))
%!assert (intmin ("uint16"), uint16 (-2^16))
%!assert (intmin ("int32"),   int32 (-2^31))
%!assert (intmin ("uint32"), uint32 (-2^32))
%!assert (intmin ("int64"),   int64 (-2^63))
%!assert (intmin ("uint64"), uint64 (-2^64))

%!test
%! x = int8 (1);
%! assert (intmin (x), int8 (-128));

%!error intmin ("int32", 0)
%!error <must be a string or integer variable> intmin (1.0)
%!error <not defined for 'double' objects> intmin ("double")
%!error <not defined for 'char' objects> intmin ("char")
*/