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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#pragma once
#include <vespa/vespalib/stllike/string.h>
#include <vespa/vespalib/util/issue.h>
#include <climits>
#include <cinttypes>
namespace search::predicate {
/**
* Helper class for expanding a point in a predicate range query to
* the hashed labels. Used by PredicateBlueprint.
*/
class PredicateRangeTermExpander {
int _arity;
uint16_t _max_positive_levels;
uint16_t _max_negative_levels;
int64_t _lower_bound;
int64_t _upper_bound;
public:
PredicateRangeTermExpander(int arity,
int64_t lower_bound = LLONG_MIN,
int64_t upper_bound = LLONG_MAX)
: _arity(arity),
_max_positive_levels(1),
_max_negative_levels(1),
_lower_bound(lower_bound),
_upper_bound(upper_bound) {
uint64_t t = _upper_bound;
while ((t /= _arity) > 0) ++_max_positive_levels;
t = uint64_t(0)-_lower_bound;
while ((t /= _arity) > 0) ++_max_negative_levels;
}
template <typename Handler>
void expand(const vespalib::string &key, int64_t value, Handler &handler);
};
/**
* Handler must implement handleRange(string) and handleEdge(string, uint64_t).
*/
template <typename Handler>
void PredicateRangeTermExpander::expand(const vespalib::string &key, int64_t signed_value, Handler &handler) {
if (signed_value < _lower_bound || signed_value > _upper_bound) {
vespalib::Issue::report("predicate_range_term_expander: Search outside bounds should have been rejected by ValidatePredicateSearcher.");
return;
}
size_t buffer_size = 21 * 2 + 3 + key.size(); // 2 numbers + punctuation + key
char buffer[buffer_size];
int size;
int prefix_size = snprintf(buffer, buffer_size, "%s=", key.c_str());
bool negative = signed_value < 0;
uint64_t value;
int max_levels;
if (negative) {
value = uint64_t(0)-signed_value;
buffer[prefix_size++] = '-';
max_levels = _max_negative_levels;
} else {
value = signed_value;
max_levels = _max_positive_levels;
}
int64_t edge_interval = (value / _arity) * _arity;
size = snprintf(buffer + prefix_size, buffer_size - prefix_size, "%" PRIu64, edge_interval);
handler.handleEdge(vespalib::stringref(buffer, prefix_size + size),
value - edge_interval);
uint64_t level_size = _arity;
for (int i = 0; i < max_levels; ++i) {
uint64_t start = (value / level_size) * level_size;
if (negative) {
if (start + level_size - 1 > (uint64_t(0)-LLONG_MIN)) {
break;
}
size = snprintf(buffer + prefix_size, buffer_size - prefix_size,
"%" PRIu64 "-%" PRIu64,
start + level_size - 1, start);
} else {
if (start + level_size - 1 > LLONG_MAX) {
break;
}
size = snprintf(buffer + prefix_size, buffer_size - prefix_size,
"%" PRIu64 "-%" PRIu64,
start, start + level_size - 1);
}
handler.handleRange(vespalib::stringref(buffer, prefix_size + size));
level_size *= _arity;
if (!level_size) { // overflow
break;
}
}
}
}
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