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https://github.com/kopia/kopia.git
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948162dce5
Cleanups: - use non-format variants of Log/Print with no additional args; - fold in Fprintf call with no args into the following one; - add missing arg placeholder in format strings; - use require.Positive instead of Greater(..., 0); - rename function to fillWithZeros to avoid collision with builtin clear; - define type for context key to avoid collisions.
70 lines
1.2 KiB
Go
70 lines
1.2 KiB
Go
package ecc
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import "math"
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func computeShards(spaceOverhead float32) (data, parity int) {
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// It's recommended to have at least 2 parity shards.
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// So the approach here is: we start with 128 data shards and compute
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// how many shards parity shards are needed for the selected space overhead.
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// If it turns out it is only 1, we invert the logic and compute how many
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// data shards are needed for 2 parity shards.
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data = 128
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parity = between(applyPercent(data, spaceOverhead/100), 1, 128) //nolint:mnd
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if parity == 1 {
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parity = 2
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data = between(applyPercent(parity, 100/spaceOverhead), 128, 254) //nolint:mnd
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}
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return
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}
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func between(val, minValue, maxValue int) int {
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switch {
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case val < minValue:
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return minValue
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case val > maxValue:
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return maxValue
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default:
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return val
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}
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}
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func applyPercent(val int, percent float32) int {
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return int(math.Floor(float64(val) * float64(percent)))
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}
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func fillWithZeros(b []byte) {
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for i := range b {
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b[i] = 0
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}
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}
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func minInt(a, b int) int {
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if a <= b {
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return a
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}
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return b
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}
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func maxInt(a, b int) int {
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if a >= b {
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return a
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}
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return b
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}
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func maxFloat32(a, b float32) float32 {
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if a >= b {
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return a
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}
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return b
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}
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func ceilInt(a, b int) int {
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return int(math.Ceil(float64(a) / float64(b)))
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}
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