mirror of https://github.com/tidwall/tile38.git
54 lines
1.2 KiB
Go
54 lines
1.2 KiB
Go
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package collection
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type fieldValues struct {
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freelist []fieldValuesSlot
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data [][]float64
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}
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type fieldValuesSlot int
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const nilValuesSlot fieldValuesSlot = -1
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func (f *fieldValues) get(k fieldValuesSlot) []float64 {
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if k == nilValuesSlot {
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return nil
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}
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return f.data[int(k)]
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}
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func (f *fieldValues) set(k fieldValuesSlot, itemData []float64) fieldValuesSlot {
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// if we're asked to store into the nil values slot, it means one of two things:
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// - we are doing a replace on an item that previously had nil fields
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// - we are inserting a new item
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// in either case, check if the new values are not nil, and if so allocate a
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// new slot
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if k == nilValuesSlot {
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if itemData == nil {
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return nilValuesSlot
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}
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// first check if there is a slot on the freelist to reuse
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if len(f.freelist) > 0 {
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var slot fieldValuesSlot
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slot, f.freelist = f.freelist[len(f.freelist)-1], f.freelist[:len(f.freelist)-1]
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f.data[slot] = itemData
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return slot
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}
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// no reusable slot, append
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f.data = append(f.data, itemData)
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return fieldValuesSlot(len(f.data) - 1)
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}
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f.data[int(k)] = itemData
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return k
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}
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func (f *fieldValues) remove(k fieldValuesSlot) {
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if k == nilValuesSlot {
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return
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}
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f.data[int(k)] = nil
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f.freelist = append(f.freelist, k)
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}
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