Datum pg_quantiles_double_sketch_get_cdf()

in src/quantiles_double_sketch_pg_functions.c [301:349]

• 37 lines of code
• 2 McCabe index (conditional complexity)

Datum pg_quantiles_double_sketch_get_cdf(PG_FUNCTION_ARGS) {
  const bytea* bytes_in;
  void* sketchptr;

  // input array of split points
  ArrayType* arr_in;
  Oid elmtype_in;
  int16 elmlen_in;
  bool elmbyval_in;
  char elmalign_in;
  Datum* data_in;
  bool* nulls_in;
  int arr_len_in;
  double* split_points;

  // output array of fractions
  Datum* result;
  ArrayType* arr_out;
  int16 elmlen_out;
  bool elmbyval_out;
  char elmalign_out;
  int arr_len_out;

  int i;

  bytes_in = PG_GETARG_BYTEA_P(0);
  sketchptr = quantiles_double_sketch_deserialize(VARDATA(bytes_in), VARSIZE(bytes_in) - VARHDRSZ);

  arr_in = PG_GETARG_ARRAYTYPE_P(1);
  elmtype_in = ARR_ELEMTYPE(arr_in);
  get_typlenbyvalalign(elmtype_in, &elmlen_in, &elmbyval_in, &elmalign_in);
  deconstruct_array(arr_in, elmtype_in, elmlen_in, elmbyval_in, elmalign_in, &data_in, &nulls_in, &arr_len_in);

  split_points = palloc(sizeof(double) * arr_len_in);
  for (i = 0; i < arr_len_in; i++) {
    split_points[i] = DatumGetFloat8(data_in[i]);
  }
  result = (Datum*) quantiles_double_sketch_get_pmf_or_cdf(sketchptr, split_points, arr_len_in, true, false);
  pfree(split_points);

  // construct output array of fractions
  arr_len_out = arr_len_in + 1; // N split points divide the number line into N+1 intervals
  get_typlenbyvalalign(FLOAT8OID, &elmlen_out, &elmbyval_out, &elmalign_out);
  arr_out = construct_array(result, arr_len_out, FLOAT8OID, elmlen_out, elmbyval_out, elmalign_out);

  quantiles_double_sketch_delete(sketchptr);

  PG_RETURN_ARRAYTYPE_P(arr_out);
}