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bleve/analysis/freq.go
2014-07-21 17:05:55 -04:00

90 lines
2.2 KiB
Go

// Copyright (c) 2014 Couchbase, Inc.
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
// except in compliance with the License. You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software distributed under the
// License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
// either express or implied. See the License for the specific language governing permissions
// and limitations under the License.
package analysis
import ()
type TokenLocation struct {
Field string
Start int
End int
Position int
}
type TokenFreq struct {
Term []byte
Locations []*TokenLocation
}
type TokenFrequencies []*TokenFreq
func (tfs TokenFrequencies) MergeAll(remoteField string, other TokenFrequencies) TokenFrequencies {
// put existing tokens into a map
index := make(map[string]*TokenFreq)
for _, tf := range tfs {
index[string(tf.Term)] = tf
}
// walk the new token frequencies
for _, tf := range other {
// set the remoteField value in incoming token freqs
for _, l := range tf.Locations {
l.Field = remoteField
}
existingTf, exists := index[string(tf.Term)]
if exists {
existingTf.Locations = append(existingTf.Locations, tf.Locations...)
} else {
index[string(tf.Term)] = tf
}
}
// flatten map back to array
rv := make(TokenFrequencies, len(index))
i := 0
for _, tf := range index {
rv[i] = tf
i += 1
}
return rv
}
func TokenFrequency(tokens TokenStream) TokenFrequencies {
index := make(map[string]*TokenFreq)
for _, token := range tokens {
curr, ok := index[string(token.Term)]
if ok {
curr.Locations = append(curr.Locations, &TokenLocation{
Start: token.Start,
End: token.End,
Position: token.Position,
})
} else {
index[string(token.Term)] = &TokenFreq{
Term: token.Term,
Locations: []*TokenLocation{
&TokenLocation{
Start: token.Start,
End: token.End,
Position: token.Position,
},
},
}
}
}
rv := make(TokenFrequencies, len(index))
i := 0
for _, tf := range index {
rv[i] = tf
i += 1
}
return rv
}