static _pd_interval
_find_entry(_pd_cmp cmp, const char *prefix, const char *start, const char *end)
{
_pd_interval res = {};
while (start < end) {
const char *middle = start + (end - start)/2;
/* looking for the start of line */
while (middle > start && middle[-1] != '\n') middle--;
const char *next = _nextline(middle);
int c = (*cmp)(prefix, middle);
if (c == 0) {
res.lower = _lower_bound(cmp, prefix, start, next);
res.upper = _upper_bound(cmp, prefix, next, end);
break;
}
if (c > 0) {
start = next;
} else {
end = middle;
}
}
return res;
}
static const char *
_lower_bound(_pd_cmp cmp, const char *prefix, const char *start, const char *end)
{
const char *middle = start + (end - start)/2;
/* looking for the start of line */
while (middle > start && middle[-1] != '\n') middle--;
const char *next = _nextline(middle);
/* If we've got a single line, then we've found it */
if (middle == start && next == end)
return middle;
int c = (*cmp)(prefix, middle);
if (c > 0)
return _lower_bound(cmp, prefix, next, end);
/* Check that middle is not last line. Without this check we'd go into
* infinite loop, as we'd call ourself with the same arguments. To avoid
* this situation, either terminate search or call itself again without last
* line.
*/
if (next == end) {
const char *prevline = middle - 1; /* skip \n on previous line */
while (prevline > start && prevline[-1] != '\n') prevline--;
/*
* Now check if prevline matches prefix. If it is, then drop last line,
* else we've found lower bound
*/
int c = (*cmp)(prefix, prevline);
if (c > 0)
return middle;
return _lower_bound(cmp, prefix, start, middle);
}
return _lower_bound(cmp, prefix, start, next);
}
BaseIndex::Iterator BaseIndex::lower_bound(const std::vector<AllTypeVariant>& values) const {
DebugAssert((_get_indexed_segments().size() >= values.size()),
"BaseIndex: The number of queried segments has to be less or equal to the number of indexed segments.");
return _lower_bound(values);
}
