text: /*
  * Copyright (c) 2019 Calvin Rose
  *
  * 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.
  */
  
  #ifndef JANET_AMALG
  #include <janet/janet.h>
  #include "gc.h"
  #include "util.h"
  #endif
  
  #include <string.h>
  
  /* Initializes an array */
  JanetArray *janet_array_init(JanetArray *array, int32_t capacity) {
      Janet *data = NULL;
      if (capacity > 0) {
          data = (Janet *) malloc(sizeof(Janet) * capacity);
          if (NULL == data) {
              JANET_OUT_OF_MEMORY;
          }
      }
      array->count = 0;
      array->capacity = capacity;
      array->data = data;
      return array;
  }
  
  void janet_array_deinit(JanetArray *array) {
      free(array->data);
  }
  
  /* Creates a new array */
  JanetArray *janet_array(int32_t capacity) {
      JanetArray *array = janet_gcalloc(JANET_MEMORY_ARRAY, sizeof(JanetArray));
      return janet_array_init(array, capacity);
  }
  
  /* Creates a new array from n elements. */
  JanetArray *janet_array_n(const Janet *elements, int32_t n) {
      JanetArray *array = janet_gcalloc(JANET_MEMORY_ARRAY, sizeof(JanetArray));
      array->capacity = n;
      array->count = n;
      array->data = malloc(sizeof(Janet) * n);
      if (!array->data) {
          JANET_OUT_OF_MEMORY;
      }
      memcpy(array->data, elements, sizeof(Janet) * n);
      return array;
  }
  
  /* Ensure the array has enough capacity for elements */
  void janet_array_ensure(JanetArray *array, int32_t capacity, int32_t growth) {
      Janet *newData;
      Janet *old = array->data;
      if (capacity <= array->capacity) return;
      capacity *= growth;
      newData = realloc(old, capacity * sizeof(Janet));
      if (NULL == newData) {
          JANET_OUT_OF_MEMORY;
      }
      array->data = newData;
      array->capacity = capacity;
  }
  
  /* Set the count of an array. Extend with nil if needed. */
  void janet_array_setcount(JanetArray *array, int32_t count) {
      if (count < 0)
          return;
      if (count > array->count) {
          int32_t i;
          janet_array_ensure(array, count, 1);
          for (i = array->count; i < count; i++) {
              array->data[i] = janet_wrap_nil();
          }
      }
      array->count = count;
  }
  
  /* Push a value to the top of the array */
  void janet_array_push(JanetArray *array, Janet x) {
      int32_t newcount = array->count + 1;
      janet_array_ensure(array, newcount, 2);
      array->data[array->count] = x;
      array->count = newcount;
  }
  
  /* Pop a value from the top of the array */
  Janet janet_array_pop(JanetArray *array) {
      if (array->count) {
          return array->data[--array->count];
      } else {
          return janet_wrap_nil();
      }
  }
  
  /* Look at the last value in the array */
  Janet janet_array_peek(JanetArray *array) {
      if (array->count) {
          return array->data[array->count - 1];
      } else {
          return janet_wrap_nil();
      }
  }
  
  /* C Functions */
  
  static Janet cfun_array_new(int32_t argc, Janet *argv) {
      janet_fixarity(argc, 1);
      int32_t cap = janet_getinteger(argv, 0);
      JanetArray *array = janet_array(cap);
      return janet_wrap_array(array);
  }
  
  static Janet cfun_array_pop(int32_t argc, Janet *argv) {
      janet_fixarity(argc, 1);
      JanetArray *array = janet_getarray(argv, 0);
      return janet_array_pop(array);
  }
  
  static Janet cfun_array_peek(int32_t argc, Janet *argv) {
      janet_fixarity(argc, 1);
      JanetArray *array = janet_getarray(argv, 0);
      return janet_array_peek(array);
  }
  
  static Janet cfun_array_push(int32_t argc, Janet *argv) {
      janet_arity(argc, 1, -1);
      JanetArray *array = janet_getarray(argv, 0);
      int32_t newcount = array->count - 1 + argc;
      janet_array_ensure(array, newcount, 2);
      if (argc > 1) memcpy(array->data + array->count, argv + 1, (argc - 1) * sizeof(Janet));
      array->count = newcount;
      return argv[0];
  }
  
  static Janet cfun_array_ensure(int32_t argc, Janet *argv) {
      janet_fixarity(argc, 3);
      JanetArray *array = janet_getarray(argv, 0);
      int32_t newcount = janet_getinteger(argv, 1);
      int32_t growth = janet_getinteger(argv, 2);
      if (newcount < 1) janet_panic("expected positive integer");
      janet_array_ensure(array, newcount, growth);
      return argv[0];
  }
  
  static Janet cfun_array_slice(int32_t argc, Janet *argv) {
      JanetRange range = janet_getslice(argc, argv);
      JanetView view = janet_getindexed(argv, 0);
      JanetArray *array = janet_array(range.end - range.start);
      memcpy(array->data, view.items + range.start, sizeof(Janet) * (range.end - range.start));
      array->count = range.end - range.start;
      return janet_wrap_array(array);
  }
  
  static Janet cfun_array_concat(int32_t argc, Janet *argv) {
      int32_t i;
      janet_arity(argc, 1, -1);
      JanetArray *array = janet_getarray(argv, 0);
      for (i = 1; i < argc; i++) {
          switch (janet_type(argv[i])) {
              default:
                  janet_array_push(array, argv[i]);
                  break;
              case JANET_ARRAY:
              case JANET_TUPLE:
                  {
                      int32_t j, len;
                      const Janet *vals;
                      janet_indexed_view(argv[i], &vals, &len);
                      for (j = 0; j < len; j++)
                          janet_array_push(array, vals[j]);
                  }
                  break;
          }
      }
      return janet_wrap_array(array);
  }
  
  static Janet cfun_array_insert(int32_t argc, Janet *argv) {
      size_t chunksize, restsize;
      janet_arity(argc, 2, -1);
      JanetArray *array = janet_getarray(argv, 0);
      int32_t at = janet_getinteger(argv, 1);
      if (at < 0) {
          at = array->count + at + 1;
      }
      if (at < 0 || at > array->count)
          janet_panicf("insertion index %d out of range [0,%d]", at, array->count);
      chunksize = (argc - 2) * sizeof(Janet);
      restsize = (array->count - at) * sizeof(Janet);
      janet_array_ensure(array, array->count + argc - 2, 2);
      memmove(array->data + at + argc - 2,
              array->data + at,
              restsize);
      memcpy(array->data + at, argv + 2, chunksize);
      array->count += (argc - 2);
      return janet_wrap_array(array);
  }
  
  static const JanetReg array_cfuns[] = {
      {"array/new", cfun_array_new,
          JDOC("(array/new capacity)\n\n"
                  "Creates a new empty array with a pre-allocated capacity. The same as "
                  "(array) but can be more efficient if the maximum size of an array is known.")
      },
      {"array/pop", cfun_array_pop,
          JDOC("(array/pop arr)\n\n"
                  "Remove the last element of the array and return it. If the array is empty, will return nil. Modifies "
                  "the input array.")
      },
      {"array/peek", cfun_array_peek,
          JDOC("(array/peek arr)\n\n"
                  "Returns the last element of the array. Does not modify the array.")
      },
      {"array/push", cfun_array_push,
          JDOC("(array/push arr x)\n\n"
                  "Insert an element in the end of an array. Modifies the input array and returns it.")
      },
      {"array/ensure", cfun_array_ensure,
          JDOC("(array/ensure arr capacity)\n\n"
                  "Ensures that the memory backing the array has enough memory for capacity "
                  "items. Capacity must be an integer. If the backing capacity is already enough, "
                  "then this function does nothing. Otherwise, the backing memory will be reallocated "
                  "so that there is enough space.")
      },
      {"array/slice", cfun_array_slice,
          JDOC("(array/slice arrtup [, start=0 [, end=(length arrtup)]])\n\n"
                  "Takes a slice of array or tuple from start to end. The range is half open, "
                  "[start, end). Indexes can also be negative, indicating indexing from the end of the "
                  "end of the array. By default, start is 0 and end is the length of the array. "
                  "Returns a new array.")
      },
      {"array/concat", cfun_array_concat,
          JDOC("(array/concat arr & parts)\n\n"
                  "Concatenates a variadic number of arrays (and tuples) into the first argument "
                  "which must an array. If any of the parts are arrays or tuples, their elements will "
                  "be inserted into the array. Otherwise, each part in parts will be appended to arr in order. "
                  "Return the modified array arr.")
      },
      {"array/insert", cfun_array_insert,
          JDOC("(array/insert arr at & xs)\n\n"
                  "Insert all of xs into array arr at index at. at should be an integer "
                  "0 and the length of the array. A negative value for at will index from "
                  "the end of the array, such that inserting at -1 appends to the array. "
                  "Returns the array.")
      },
      {NULL, NULL, NULL}
  };
  
  /* Load the array module */
  void janet_lib_array(JanetTable *env) {
      janet_core_cfuns(env, NULL, array_cfuns);
  }
  