/* Negation across a range of the container.
* Compute the negation of src and write the result
* to *dst. Returns true if the result is a bitset container
* and false for an array container. *dst is not preallocated.
*/
bool array_container_negation_range(const array_container_t *src,
const int range_start, const int range_end,
void **dst) {
/* close port of the Java implementation */
if (range_start >= range_end) {
*dst = array_container_clone(src);
return false;
}
int32_t start_index =
binarySearch(src->array, src->cardinality, (uint16_t)range_start);
if (start_index < 0) start_index = -start_index - 1;
int32_t last_index =
binarySearch(src->array, src->cardinality, (uint16_t)(range_end - 1));
if (last_index < 0) last_index = -last_index - 2;
const int32_t current_values_in_range = last_index - start_index + 1;
const int32_t span_to_be_flipped = range_end - range_start;
const int32_t new_values_in_range =
span_to_be_flipped - current_values_in_range;
const int32_t cardinality_change =
new_values_in_range - current_values_in_range;
const int32_t new_cardinality = src->cardinality + cardinality_change;
if (new_cardinality > DEFAULT_MAX_SIZE) {
bitset_container_t *temp = bitset_container_from_array(src);
bitset_flip_range(temp->array, (uint32_t)range_start,
(uint32_t)range_end);
temp->cardinality = new_cardinality;
*dst = temp;
return true;
}
array_container_t *arr =
array_container_create_given_capacity(new_cardinality);
*dst = (void *)arr;
// copy stuff before the active area
memcpy(arr->array, src->array, start_index * sizeof(uint16_t));
// work on the range
int32_t out_pos = start_index, in_pos = start_index;
int32_t val_in_range = range_start;
for (; val_in_range < range_end && in_pos <= last_index; ++val_in_range) {
if ((uint16_t)val_in_range != src->array[in_pos]) {
arr->array[out_pos++] = (uint16_t)val_in_range;
} else {
++in_pos;
}
}
for (; val_in_range < range_end; ++val_in_range)
arr->array[out_pos++] = (uint16_t)val_in_range;
// content after the active range
memcpy(arr->array + out_pos, src->array + (last_index + 1),
(src->cardinality - (last_index + 1)) * sizeof(uint16_t));
arr->cardinality = new_cardinality;
return false;
}
/*
* Same as bitset_container_negation except that if the output is to
* be a
* bitset_container_t, then src is modified and no allocation is made.
* If the output is to be an array_container_t, then caller is responsible
* to free the container.
* In all cases, the result is in *dst.
*/
bool bitset_container_negation_range_inplace(bitset_container_t *src,
const int range_start,
const int range_end, void **dst) {
bitset_flip_range(src->array, (uint32_t)range_start, (uint32_t)range_end);
src->cardinality = bitset_container_compute_cardinality(src);
if (src->cardinality > DEFAULT_MAX_SIZE) {
*dst = src;
return true;
}
*dst = array_container_from_bitset(src);
bitset_container_free(src);
return false;
}
bool run_bitset_container_andnot(const run_container_t *src_1,
const bitset_container_t *src_2, void **dst) {
// follows the Java implementation as of June 2016
int card = run_container_cardinality(src_1);
if (card <= DEFAULT_MAX_SIZE) {
// must be an array
array_container_t *answer = array_container_create_given_capacity(card);
answer->cardinality = 0;
for (int32_t rlepos = 0; rlepos < src_1->n_runs; ++rlepos) {
rle16_t rle = src_1->runs[rlepos];
for (int run_value = rle.value; run_value <= rle.value + rle.length;
++run_value) {
if (!bitset_container_get(src_2, (uint16_t)run_value)) {
answer->array[answer->cardinality++] = (uint16_t)run_value;
}
}
}
*dst = answer;
return false;
} else { // we guess it will be a bitset, though have to check guess when
// done
bitset_container_t *answer = bitset_container_clone(src_2);
uint32_t last_pos = 0;
for (int32_t rlepos = 0; rlepos < src_1->n_runs; ++rlepos) {
rle16_t rle = src_1->runs[rlepos];
uint32_t start = rle.value;
uint32_t end = start + rle.length + 1;
bitset_reset_range(answer->array, last_pos, start);
bitset_flip_range(answer->array, start, end);
last_pos = end;
}
bitset_reset_range(answer->array, last_pos, (uint32_t)(1 << 16));
answer->cardinality = bitset_container_compute_cardinality(answer);
if (answer->cardinality <= DEFAULT_MAX_SIZE) {
*dst = array_container_from_bitset(answer);
bitset_container_free(answer);
return false; // not bitset
}
*dst = answer;
return true; // bitset
}
}
/* Negation across a range of the container
* Compute the negation of src and write the result
* to *dst. A true return value indicates a bitset result,
* otherwise the result is an array container.
* We assume that dst is not pre-allocated. In
* case of failure, *dst will be NULL.
*/
bool bitset_container_negation_range(const bitset_container_t *src,
const int range_start, const int range_end,
void **dst) {
// TODO maybe consider density-based estimate
// and sometimes build result directly as array, with
// conversion back to bitset if wrong. Or determine
// actual result cardinality, then go directly for the known final cont.
// keep computation using bitsets as long as possible.
bitset_container_t *t = bitset_container_clone(src);
bitset_flip_range(t->array, (uint32_t)range_start, (uint32_t)range_end);
t->cardinality = bitset_container_compute_cardinality(t);
if (t->cardinality > DEFAULT_MAX_SIZE) {
*dst = t;
return true;
} else {
*dst = array_container_from_bitset(t);
bitset_container_free(t);
return false;
}
}