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111 lines
3.0 KiB
111 lines
3.0 KiB
// Copyright (c) 2014 Couchbase, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package analysis
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// TokenLocation represents one occurrence of a term at a particular location in
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// a field. Start, End and Position have the same meaning as in analysis.Token.
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// Field and ArrayPositions identify the field value in the source document.
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// See document.Field for details.
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type TokenLocation struct {
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Field string
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ArrayPositions []uint64
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Start int
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End int
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Position int
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}
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// TokenFreq represents all the occurrences of a term in all fields of a
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// document.
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type TokenFreq struct {
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Term []byte
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Locations []*TokenLocation
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frequency int
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}
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func (tf *TokenFreq) Frequency() int {
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return tf.frequency
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}
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// TokenFrequencies maps document terms to their combined frequencies from all
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// fields.
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type TokenFrequencies map[string]*TokenFreq
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func (tfs TokenFrequencies) MergeAll(remoteField string, other TokenFrequencies) {
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// walk the new token frequencies
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for tfk, tf := range other {
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// set the remoteField value in incoming token freqs
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for _, l := range tf.Locations {
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l.Field = remoteField
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}
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existingTf, exists := tfs[tfk]
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if exists {
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existingTf.Locations = append(existingTf.Locations, tf.Locations...)
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existingTf.frequency = existingTf.frequency + tf.frequency
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} else {
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tfs[tfk] = &TokenFreq{
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Term: tf.Term,
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frequency: tf.frequency,
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Locations: make([]*TokenLocation, len(tf.Locations)),
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}
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copy(tfs[tfk].Locations, tf.Locations)
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}
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}
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}
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func TokenFrequency(tokens TokenStream, arrayPositions []uint64, includeTermVectors bool) TokenFrequencies {
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rv := make(map[string]*TokenFreq, len(tokens))
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if includeTermVectors {
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tls := make([]TokenLocation, len(tokens))
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tlNext := 0
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for _, token := range tokens {
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tls[tlNext] = TokenLocation{
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ArrayPositions: arrayPositions,
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Start: token.Start,
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End: token.End,
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Position: token.Position,
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}
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curr, ok := rv[string(token.Term)]
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if ok {
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curr.Locations = append(curr.Locations, &tls[tlNext])
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curr.frequency++
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} else {
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rv[string(token.Term)] = &TokenFreq{
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Term: token.Term,
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Locations: []*TokenLocation{&tls[tlNext]},
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frequency: 1,
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}
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}
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tlNext++
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}
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} else {
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for _, token := range tokens {
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curr, exists := rv[string(token.Term)]
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if exists {
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curr.frequency++
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} else {
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rv[string(token.Term)] = &TokenFreq{
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Term: token.Term,
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frequency: 1,
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}
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}
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}
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}
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return rv
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}
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