influxdb/tsdb/cursors/arrayvalues.gen.go.tmpl

package cursors

{{range .}}

{{ $typename := print .Name "Array" }}

type {{ $typename }} struct {
	Timestamps []int64
	Values     []{{.Type}}
}

func New{{$typename}}Len(sz int) *{{$typename}} {
	return &{{$typename}}{
		Timestamps: make([]int64, sz),
		Values: make([]{{.Type}}, sz),
	}
}

func (a *{{ $typename }}) MinTime() int64 {
	return a.Timestamps[0]
}

func (a *{{ $typename }}) MaxTime() int64 {
	return a.Timestamps[len(a.Timestamps)-1]
}

func (a *{{ $typename }}) Size() int {
	panic("not implemented")
}

func (a *{{ $typename}}) Len() int {
	return len(a.Timestamps)
}

// Exclude removes the subset of values in [min, max]. The values must
// be deduplicated and sorted before calling Exclude or the results are undefined.
func (a *{{ $typename }}) Exclude(min, max int64) {
	rmin, rmax := a.FindRange(min, max)
	if rmin == -1 && rmax == -1 {
		return
	}

	// a.Timestamps[rmin] ≥ min
	// a.Timestamps[rmax] ≥ max

	if rmax < a.Len() {
		if a.Timestamps[rmax] == max {
			rmax++
		}
		rest := a.Len()-rmax
		if rest > 0 {
			ts := a.Timestamps[:rmin+rest]
			copy(ts[rmin:], a.Timestamps[rmax:])
			a.Timestamps = ts

			vs := a.Values[:rmin+rest]
			copy(vs[rmin:], a.Values[rmax:])
			a.Values = vs
			return
		}
	}

	a.Timestamps = a.Timestamps[:rmin]
	a.Values = a.Values[:rmin]
}

// Include returns the subset values between min and max inclusive. The values must
// be deduplicated and sorted before calling Include or the results are undefined.
func (a *{{ $typename }}) Include(min, max int64) {
	rmin, rmax := a.FindRange(min, max)
	if rmin == -1 && rmax == -1 {
		a.Timestamps = a.Timestamps[:0]
		a.Values = a.Values[:0]
		return
	}

	// a.Timestamps[rmin] ≥ min
	// a.Timestamps[rmax] ≥ max

	if rmax < a.Len() && a.Timestamps[rmax] == max {
		rmax++
	}

	if rmin > -1 {
		ts := a.Timestamps[:rmax-rmin]
		copy(ts, a.Timestamps[rmin:rmax])
		a.Timestamps = ts
		vs := a.Values[:rmax-rmin]
		copy(vs, a.Values[rmin:rmax])
		a.Values = vs
	} else {
		a.Timestamps = a.Timestamps[:rmax]
		a.Values = a.Values[:rmax]
	}
}

// search performs a binary search for UnixNano() v in a
// and returns the position, i, where v would be inserted.
// An additional check of a.Timestamps[i] == v is necessary
// to determine if the value v exists.
func (a *{{ $typename }}) search(v int64) int {
	// Define: f(x) → a.Timestamps[x] < v
	// Define: f(-1) == true, f(n) == false
	// Invariant: f(lo-1) == true, f(hi) == false
	lo := 0
	hi := a.Len()
	for lo < hi {
		mid := int(uint(lo+hi) >> 1)
		if a.Timestamps[mid] < v {
			lo = mid + 1 // preserves f(lo-1) == true
		} else {
			hi = mid // preserves f(hi) == false
		}
	}

	// lo == hi
	return lo
}

// FindRange returns the positions where min and max would be
// inserted into the array. If a[0].UnixNano() > max or
// a[len-1].UnixNano() < min then FindRange returns (-1, -1)
// indicating the array is outside the [min, max]. The values must
// be deduplicated and sorted before calling Exclude or the results
// are undefined.
func (a *{{ $typename }}) FindRange(min, max int64) (int, int) {
	if a.Len() == 0 || min > max {
		return -1, -1
	}

	minVal := a.MinTime()
	maxVal := a.MaxTime()

	if maxVal < min || minVal > max {
		return -1, -1
	}

	return a.search(min), a.search(max)
}

// Merge overlays b to top of a.  If two values conflict with
// the same timestamp, b is used.  Both a and b must be sorted
// in ascending order.
func (a *{{ $typename }}) Merge(b *{{ $typename }}) {
	if a.Len() == 0 {
		*a = *b
		return
	}

	if b.Len() == 0 {
		return
	}

	// Normally, both a and b should not contain duplicates.  Due to a bug in older versions, it's
	// possible stored blocks might contain duplicate values.  Remove them if they exists before
	// merging.
	// a = a.Deduplicate()
	// b = b.Deduplicate()

	if a.MaxTime() < b.MinTime() {
		a.Timestamps = append(a.Timestamps, b.Timestamps...)
		a.Values = append(a.Values, b.Values...)
		return
	}

	if b.MaxTime() < a.MinTime() {
		var tmp {{$typename}}
		tmp.Timestamps = append(b.Timestamps, a.Timestamps...)
		tmp.Values = append(b.Values, a.Values...)
		*a = tmp
		return
	}

	out := New{{$typename}}Len(a.Len()+b.Len())
	i, j, k := 0, 0, 0
	for i < len(a.Timestamps) && j < len(b.Timestamps) {
		if a.Timestamps[i] < b.Timestamps[j] {
			out.Timestamps[k] = a.Timestamps[i]
			out.Values[k] = a.Values[i]
			i++
		} else if a.Timestamps[i] == b.Timestamps[j] {
			out.Timestamps[k] = b.Timestamps[j]
			out.Values[k] = b.Values[j]
			i++
			j++
		} else {
			out.Timestamps[k] = b.Timestamps[j]
			out.Values[k] = b.Values[j]
			j++
		}
		k++
	}

	if i < len(a.Timestamps) {
		n := copy(out.Timestamps[k:], a.Timestamps[i:])
		copy(out.Values[k:], a.Values[i:])
		k += n
	} else if j < len(b.Timestamps) {
		n := copy(out.Timestamps[k:], b.Timestamps[j:])
		copy(out.Values[k:], b.Values[j:])
		k += n
	}

	a.Timestamps = out.Timestamps[:k]
	a.Values = out.Values[:k]
}

{{ end }}