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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/searchlib/fef/iqueryenvironment.h>
#include <vespa/searchlib/fef/table.h>
#include <vespa/searchlib/fef/termfieldmatchdata.h>
#include <vespa/searchlib/fef/itermdata.h>
#include <vespa/searchlib/fef/itermfielddata.h>
#include <vespa/searchlib/common/feature.h>
#include <vespa/vespalib/util/string_hash.h>
#include <limits>
namespace search::features::util {
/**
* Maximum feature value
*/
const feature_t FEATURE_MAX = std::numeric_limits<feature_t>::max();
/**
* Minimum feature value
*/
const feature_t FEATURE_MIN = -std::numeric_limits<feature_t>::max();
using ConstCharPtr = const char *;
/**
* Converts the given string to a numeric value.
*
* @param str The string to convert.
* @return The numeric value.
*/
template <typename T>
T strToNum(vespalib::stringref str);
template <typename T>
feature_t getAsFeature(T value) __attribute__((__always_inline__));
/**
* Converts the given value to a feature value.
*
* @param value The value to convert.
* @return The feature value.
*/
template <typename T>
inline feature_t getAsFeature(T value)
{
return static_cast<feature_t>(value);
}
/**
* Specialization for const char *.
*
* @param value The string to convert.
* @return The feature value.
*/
template <>
inline feature_t getAsFeature<ConstCharPtr>(ConstCharPtr value) {
return vespalib::hash2d(value, strlen(value));
}
/**
* Specialization for a string value.
*
* @param value The string to convert.
* @return The feature value.
*/
template <>
inline feature_t getAsFeature<vespalib::stringref>(vespalib::stringref value) {
return vespalib::hash2d(value);
}
/**
* This method inputs a value to cap to the range [capFloor, capCeil] and then normalize this
* value to the unit range [0, 1].
*
* @param val The value to unit normalize.
* @param capFloor The minimum value of the cap range.
* @param capCeil The maximum value of the cap range.
* @return The unit normalized value.
*/
template <typename T>
T unitNormalize(const T &val, const T &capFloor, const T &capCeil)
{
return (std::max(capFloor, std::min(capCeil, val)) - capFloor) / (capCeil - capFloor);
}
/**
* Returns the normalized strength with which the given term is connected to the previous term in the query.
* Uses the property map of the query environment to lookup this data.
*
* @param env The query environment.
* @param termId The term id.
* @param fallback The value to return if the connectedness was not found in the property map.
* @return The connectedness.
*/
feature_t lookupConnectedness(const search::fef::IQueryEnvironment & env, uint32_t termId, feature_t fallback = 0.1f);
/**
* Returns the normalized strength with which the given current term is connected to the given previous term.
* Uses the property map of the query environment to lookup this data.
*
* @param env The query environment.
* @param currUniqueId Unique id of the current term.
* @param prevUniqueId Unique id of the previous term.
* @param fallback The value to return if the connectedness was not found in the property map.
* @return The connectedness between the current term and previous term.
*/
feature_t lookupConnectedness(const search::fef::IQueryEnvironment & env,
uint32_t currUniqueId, uint32_t prevUniqueId, feature_t fallback = 0.1f);
/**
* Returns the significance of the given term.
* Uses the property map of the query environment to lookup this data.
*
* @param env The query environment.
* @param term The term data.
* @param fallback The value to return if the significance was not found in the property map.
* @return The significance.
*/
feature_t lookupSignificance(const search::fef::IQueryEnvironment& env, const search::fef::ITermData& term, feature_t fallback);
/**
* Returns the significance of the given term.
* Uses the property map of the query environment to lookup this data.
*
* @param env The query environment.
* @param termId The term id.
* @param fallback The value to return if the significance was not found in the property map.
* @return The significance.
*/
feature_t lookupSignificance(const search::fef::IQueryEnvironment & env, uint32_t termId, feature_t fallback = 0.0f);
/**
* Returns the Robertson-Sparck-Jones weight based on the given document count
* (number of documents containing the term) and the number of documents in the corpus.
* This weight is a variant of inverse document frequency.
*/
double getRobertsonSparckJonesWeight(double docCount, double docsInCorpus);
/**
* Returns the significance based on the given scaled number of documents containing the term.
*
* @param docFreq The scaled number of documents containing the term.
* @return The significance.
*/
feature_t getSignificance(double docFreq);
/**
* Returns the significance based on max known frequency of the term
*
* @param termData Data for the term
* @return The significance.
*/
feature_t getSignificance(const search::fef::ITermData &termData);
/**
* Lookups a table by using the properties and the table manager in the given index environment.
* The table name is found by looking up the following properties and using the first found:
* 'featureName.table.fieldName', 'featureName.table'.
* The table name 'fallback' is used if no properties are found.
*
* @param env the index environment.
* @param featureName the name of the feature.
* @param table the table to be used by the feature.
* @param fieldName the name of the field we want to lookup a table for.
* @param fallback the actual name of the table to use if we do not find any properties.
* @return the table pointer or NULL if not found.
**/
const search::fef::Table *
lookupTable(const search::fef::IIndexEnvironment & env, const vespalib::string & featureName,
const vespalib::string & table, const vespalib::string & fieldName, const vespalib::string & fallback);
/**
* Obtain query information for a term/field combination.
*
* @return query information for a term/field combination, or 0 if not found
* @param env query environment
* @param termId the term id
* @param fieldId the field id
**/
inline const search::fef::ITermFieldData *
getTermFieldData(const search::fef::IQueryEnvironment &env, uint32_t termId, uint32_t fieldId) {
const search::fef::ITermData *td = env.getTerm(termId);
return (td == nullptr) ? nullptr : td->lookupField(fieldId);
}
/**
* Obtain the match handle for the given term within the given field.
*
* @return match handle, or IllegalHandle if not found
* @param env query environment
* @param termId the term id
* @param fieldId the field id
**/
inline search::fef::TermFieldHandle
getTermFieldHandle(const search::fef::IQueryEnvironment &env, uint32_t termId, uint32_t fieldId) {
const search::fef::ITermFieldData *tfd = getTermFieldData(env, termId, fieldId);
return (tfd == nullptr) ? search::fef::IllegalHandle : tfd->getHandle();
}
/**
* Obtain the term annotated with the given label. This function will
* reverse map label to unique id and then traverse the query
* environment trying to locate the term with the appropriate unique
* id. If no such term can be found, 0 will be returned.
*
* @return term with given label, or 0 if not found
* @param env query environment
* @param label query item label
**/
const search::fef::ITermData *
getTermByLabel(const search::fef::IQueryEnvironment &env, const vespalib::string &label);
}
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