text: /*
   * This file is part of the MicroPython project, http://micropython.org/
   *
   * The MIT License (MIT)
   *
   * Copyright (c) 2013, 2014 Damien P. George
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   * THE SOFTWARE.
   */
  
  #include <stdlib.h>
  #include <assert.h>
  
  #include "py/runtime.h"
  
  /******************************************************************************/
  /* slice object                                                               */
  
  #if MICROPY_PY_BUILTINS_SLICE
  
  STATIC void slice_print(const mp_print_t *print, mp_obj_t o_in, mp_print_kind_t kind) {
      (void)kind;
      mp_obj_slice_t *o = MP_OBJ_TO_PTR(o_in);
      mp_print_str(print, "slice(");
      mp_obj_print_helper(print, o->start, PRINT_REPR);
      mp_print_str(print, ", ");
      mp_obj_print_helper(print, o->stop, PRINT_REPR);
      mp_print_str(print, ", ");
      mp_obj_print_helper(print, o->step, PRINT_REPR);
      mp_print_str(print, ")");
  }
  
  #if MICROPY_PY_BUILTINS_SLICE_INDICES
  STATIC mp_obj_t slice_indices(mp_obj_t self_in, mp_obj_t length_obj) {
      mp_int_t length = mp_obj_int_get_checked(length_obj);
      mp_bound_slice_t bound_indices;
      mp_obj_slice_indices(self_in, length, &bound_indices);
  
      mp_obj_t results[3] = {
          MP_OBJ_NEW_SMALL_INT(bound_indices.start),
          MP_OBJ_NEW_SMALL_INT(bound_indices.stop),
          MP_OBJ_NEW_SMALL_INT(bound_indices.step),
      };
      return mp_obj_new_tuple(3, results);
  }
  STATIC MP_DEFINE_CONST_FUN_OBJ_2(slice_indices_obj, slice_indices);
  #endif
  
  #if MICROPY_PY_BUILTINS_SLICE_ATTRS
  STATIC void slice_attr(mp_obj_t self_in, qstr attr, mp_obj_t *dest) {
      if (dest[0] != MP_OBJ_NULL) {
          // not load attribute
          return;
      }
      mp_obj_slice_t *self = MP_OBJ_TO_PTR(self_in);
  
      if (attr == MP_QSTR_start) {
          dest[0] = self->start;
      } else if (attr == MP_QSTR_stop) {
          dest[0] = self->stop;
      } else if (attr == MP_QSTR_step) {
          dest[0] = self->step;
      #if MICROPY_PY_BUILTINS_SLICE_INDICES
      } else if (attr == MP_QSTR_indices) {
          dest[0] = MP_OBJ_FROM_PTR(&slice_indices_obj);
          dest[1] = self_in;
      #endif
      }
  }
  #endif
  
  #if MICROPY_PY_BUILTINS_SLICE_INDICES && !MICROPY_PY_BUILTINS_SLICE_ATTRS
  STATIC const mp_rom_map_elem_t slice_locals_dict_table[] = {
      { MP_ROM_QSTR(MP_QSTR_indices), MP_ROM_PTR(&slice_indices_obj) },
  };
  STATIC MP_DEFINE_CONST_DICT(slice_locals_dict, slice_locals_dict_table);
  #endif
  
  const mp_obj_type_t mp_type_slice = {
      { &mp_type_type },
      .name = MP_QSTR_slice,
      .print = slice_print,
      #if MICROPY_PY_BUILTINS_SLICE_ATTRS
      .attr = slice_attr,
      #elif MICROPY_PY_BUILTINS_SLICE_INDICES
      .locals_dict = (mp_obj_dict_t *)&slice_locals_dict,
      #endif
  };
  
  mp_obj_t mp_obj_new_slice(mp_obj_t ostart, mp_obj_t ostop, mp_obj_t ostep) {
      mp_obj_slice_t *o = m_new_obj(mp_obj_slice_t);
      o->base.type = &mp_type_slice;
      o->start = ostart;
      o->stop = ostop;
      o->step = ostep;
      return MP_OBJ_FROM_PTR(o);
  }
  
  // Return the real index and step values for a slice when applied to a sequence of
  // the given length, resolving missing components, negative values and values off
  // the end of the sequence.
  void mp_obj_slice_indices(mp_obj_t self_in, mp_int_t length, mp_bound_slice_t *result) {
      mp_obj_slice_t *self = MP_OBJ_TO_PTR(self_in);
      mp_int_t start, stop, step;
  
      if (self->step == mp_const_none) {
          step = 1;
      } else {
          step = mp_obj_get_int(self->step);
          if (step == 0) {
              mp_raise_ValueError("slice step cannot be zero");
          }
      }
  
      if (step > 0) {
          // Positive step
          if (self->start == mp_const_none) {
              start = 0;
          } else {
              start = mp_obj_get_int(self->start);
              if (start < 0) {
                  start += length;
              }
              start = MIN(length, MAX(start, 0));
          }
  
          if (self->stop == mp_const_none) {
              stop = length;
          } else {
              stop = mp_obj_get_int(self->stop);
              if (stop < 0) {
                  stop += length;
              }
              stop = MIN(length, MAX(stop, 0));
          }
      } else {
          // Negative step
          if (self->start == mp_const_none) {
              start = length - 1;
          } else {
              start = mp_obj_get_int(self->start);
              if (start < 0) {
                  start += length;
              }
              start = MIN(length - 1, MAX(start, -1));
          }
  
          if (self->stop == mp_const_none) {
              stop = -1;
          } else {
              stop = mp_obj_get_int(self->stop);
              if (stop < 0) {
                  stop += length;
              }
              stop = MIN(length - 1, MAX(stop, -1));
          }
      }
  
      result->start = start;
      result->stop = stop;
      result->step = step;
  }
  
  #endif
  