mirror of https://github.com/tidwall/tile38.git
90 lines
1.8 KiB
Go
90 lines
1.8 KiB
Go
package collection
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import (
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"sync"
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"github.com/tidwall/tile38/internal/collection/item"
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)
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// Fields ...
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type Fields struct {
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mu sync.Mutex
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unpacked bool // fields have been unpacked
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values []float64 // unpacked values
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item *item.Item // base item
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}
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func (fields *Fields) unpack() {
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if fields.unpacked {
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return
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}
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fields.values = nil
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fields.item.ForEachField(-1, func(value float64) bool {
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fields.values = append(fields.values, value)
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return true
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})
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fields.unpacked = true
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}
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// ForEach iterates over each field. The count param is the number of
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// iterations. When count is less than zero, then all fields are returns.
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func (fields *Fields) ForEach(count int, iter func(value float64) bool) {
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if fields == nil || fields.item == nil {
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return
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}
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if !item.PackedFields {
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fields.item.ForEachField(count, iter)
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return
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}
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// packed values
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fields.mu.Lock()
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defer fields.mu.Unlock()
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if !fields.unpacked {
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fields.unpack()
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}
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var n int
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if count < 0 {
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n = len(fields.values)
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} else {
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n = count
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}
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for i := 0; i < n; i++ {
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var field float64
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if i < len(fields.values) {
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field = fields.values[i]
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}
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if !iter(field) {
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return
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}
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}
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}
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// Get returns the value for a field at index. If there is no field at index,
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// then zero is returned.
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func (fields *Fields) Get(index int) float64 {
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if fields == nil || fields.item == nil {
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return 0
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}
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if !item.PackedFields {
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return fields.item.GetField(index)
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}
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// packed values
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fields.mu.Lock()
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if !fields.unpacked {
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fields.unpack()
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}
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var value float64
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if index < len(fields.values) {
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value = fields.values[index]
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}
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fields.mu.Unlock()
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return value
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}
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func itemFields(item *item.Item) *Fields {
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if item == nil || !item.HasFields() {
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return nil
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}
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return &Fields{item: item}
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}
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