35 lines
857 B
JavaScript
35 lines
857 B
JavaScript
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var tick = 1
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var maxTick = 65535
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var resolution = 4
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var inc = function() {
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tick = (tick + 1) & maxTick
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}
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var timer = setInterval(inc, (1000 / resolution) | 0)
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if (timer.unref) timer.unref()
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module.exports = function(seconds) {
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var size = resolution * (seconds || 5)
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var buffer = [0]
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var pointer = 1
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var last = (tick-1) & maxTick
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return function(delta) {
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var dist = (tick - last) & maxTick
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if (dist > size) dist = size
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last = tick
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while (dist--) {
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if (pointer === size) pointer = 0
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buffer[pointer] = buffer[pointer === 0 ? size-1 : pointer-1]
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pointer++
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}
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if (delta) buffer[pointer-1] += delta
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var top = buffer[pointer-1]
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var btm = buffer.length < size ? 0 : buffer[pointer === size ? 0 : pointer]
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return buffer.length < resolution ? top : (top - btm) * resolution / buffer.length
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}
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}
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