/* Negation across a range of container
* Compute the negation of src and write the result
* to *dst. Return values are the *_TYPECODES as defined * in containers.h
* We assume that dst is not pre-allocated. In
* case of failure, *dst will be NULL.
*/
int run_container_negation_range(const run_container_t *src,
const int range_start, const int range_end,
void **dst) {
uint8_t return_typecode;
// follows the Java implementation
if (range_end <= range_start) {
*dst = run_container_clone(src);
return RUN_CONTAINER_TYPE_CODE;
}
run_container_t *ans = run_container_create_given_capacity(
src->n_runs + 1); // src->n_runs + 1);
int k = 0;
for (; k < src->n_runs && src->runs[k].value < range_start; ++k) {
ans->runs[k] = src->runs[k];
ans->n_runs++;
}
run_container_smart_append_exclusive(
ans, (uint16_t)range_start, (uint16_t)(range_end - range_start - 1));
for (; k < src->n_runs; ++k) {
run_container_smart_append_exclusive(ans, src->runs[k].value,
src->runs[k].length);
}
*dst = convert_run_to_efficient_container(ans, &return_typecode);
if (return_typecode != RUN_CONTAINER_TYPE_CODE) run_container_free(ans);
return return_typecode;
}
int run_array_container_andnot(const run_container_t *src_1,
const array_container_t *src_2, void **dst) {
// follows the Java impl as of June 2016
int card = run_container_cardinality(src_1);
const int arbitrary_threshold = 32;
if (card <= arbitrary_threshold) {
if (src_2->cardinality == 0) {
*dst = run_container_clone(src_1);
return RUN_CONTAINER_TYPE_CODE;
}
// Java's "lazyandNot.toEfficientContainer" thing
run_container_t *answer = run_container_create_given_capacity(
card + array_container_cardinality(src_2));
int rlepos = 0;
int xrlepos = 0; // "x" is src_2
rle16_t rle = src_1->runs[rlepos];
int32_t start = rle.value;
int32_t end = start + rle.length + 1;
int32_t xstart = src_2->array[xrlepos];
while ((rlepos < src_1->n_runs) && (xrlepos < src_2->cardinality)) {
if (end <= xstart) {
// output the first run
answer->runs[answer->n_runs++] =
(rle16_t){.value = (uint16_t)start,
.length = (uint16_t)(end - start - 1)};
rlepos++;
if (rlepos < src_1->n_runs) {
start = src_1->runs[rlepos].value;
end = start + src_1->runs[rlepos].length + 1;
}
} else if (xstart + 1 <= start) {
// exit the second run
xrlepos++;
if (xrlepos < src_2->cardinality) {
xstart = src_2->array[xrlepos];
}
} else {
if (start < xstart) {
answer->runs[answer->n_runs++] =
(rle16_t){.value = (uint16_t)start,
.length = (uint16_t)(xstart - start - 1)};
}
if (xstart + 1 < end) {
start = xstart + 1;
} else {
rlepos++;
if (rlepos < src_1->n_runs) {
start = src_1->runs[rlepos].value;
end = start + src_1->runs[rlepos].length + 1;
}
}
}
}
if (rlepos < src_1->n_runs) {
answer->runs[answer->n_runs++] =
(rle16_t){.value = (uint16_t)start,
.length = (uint16_t)(end - start - 1)};
rlepos++;
if (rlepos < src_1->n_runs) {
memcpy(answer->runs + answer->n_runs, src_1->runs + rlepos,
(src_1->n_runs - rlepos) * sizeof(rle16_t));
answer->n_runs += (src_1->n_runs - rlepos);
}
}
uint8_t return_type;
*dst = convert_run_to_efficient_container(answer, &return_type);
if (answer != *dst) run_container_free(answer);
return return_type;
}
/*
* Same as run_container_negation except that if the output is to
* be a
* run_container_t, and has the capacity to hold the result,
* then src is modified and no allocation is made.
* In all cases, the result is in *dst.
*/
int run_container_negation_range_inplace(run_container_t *src,
const int range_start,
const int range_end, void **dst) {
uint8_t return_typecode;
if (range_end <= range_start) {
*dst = src;
return RUN_CONTAINER_TYPE_CODE;
}
// TODO: efficient special case when range is 0 to 65535 inclusive
if (src->capacity == src->n_runs) {
// no excess room. More checking to see if result can fit
bool last_val_before_range = false;
bool first_val_in_range = false;
bool last_val_in_range = false;
bool first_val_past_range = false;
if (range_start > 0)
last_val_before_range =
run_container_contains(src, (uint16_t)(range_start - 1));
first_val_in_range = run_container_contains(src, (uint16_t)range_start);
if (last_val_before_range == first_val_in_range) {
last_val_in_range =
run_container_contains(src, (uint16_t)(range_end - 1));
if (range_end != 0x10000)
first_val_past_range =
run_container_contains(src, (uint16_t)range_end);
if (last_val_in_range ==
first_val_past_range) { // no space for inplace
int ans = run_container_negation_range(src, range_start,
range_end, dst);
run_container_free(src);
return ans;
}
}
}
// all other cases: result will fit
run_container_t *ans = src;
int my_nbr_runs = src->n_runs;
ans->n_runs = 0;
int k = 0;
for (; (k < my_nbr_runs) && (src->runs[k].value < range_start); ++k) {
// ans->runs[k] = src->runs[k]; (would be self-copy)
ans->n_runs++;
}
// as with Java implementation, use locals to give self a buffer of depth 1
rle16_t buffered = (rle16_t){.value = (uint16_t)0, .length = (uint16_t)0};
rle16_t next = buffered;
if (k < my_nbr_runs) buffered = src->runs[k];
run_container_smart_append_exclusive(
ans, (uint16_t)range_start, (uint16_t)(range_end - range_start - 1));
for (; k < my_nbr_runs; ++k) {
if (k + 1 < my_nbr_runs) next = src->runs[k + 1];
run_container_smart_append_exclusive(ans, buffered.value,
buffered.length);
buffered = next;
}
*dst = convert_run_to_efficient_container(ans, &return_typecode);
if (return_typecode != RUN_CONTAINER_TYPE_CODE) run_container_free(ans);
return return_typecode;
}
