Rocket - diplomacy - TransferSizes

https://mp.weixin.qq.com/s/Sf0owQxWzxacVvykJZ5oTQ

 

介绍TransferSizes的实现。

 

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1. 基本定义

 

从min到max的闭合区间：[min, max]

 

判断条件：

a. min和max为2的幂；

b. min <= max;

c. min和max为非负整数；

d. min和max必须同时为0；

 

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2. none

 

因为min和max必须同时为0，所以只需要判断min是否为0即可：

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3. contains

 

判断this是否包含x，即x落在this的范围内：

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4. containsLg

 

判断this是否包含2^x。

 

5. intersect

 

计算this和x的交集。

 

6. 伴生对象

 

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a. 构造方法：min = max = x;

b. none对象：min = max = 0;

c. asBool：x是否为空；

 

7. 附录

 

TransferSizes：

// An potentially empty inclusive range of 2-powers [min, max] (in bytes)

case class TransferSizes(min: Int, max: Int)

{

def this(x: Int) = this(x, x)

 

require (min <= max, s"Min transfer $min > max transfer $max")

require (min >= 0 && max >= 0, s"TransferSizes must be positive, got: ($min, $max)")

require (max == 0 || isPow2(max), s"TransferSizes must be a power of 2, got: $max")

require (min == 0 || isPow2(min), s"TransferSizes must be a power of 2, got: $min")

require (max == 0 || min != 0, s"TransferSize 0 is forbidden unless (0,0), got: ($min, $max)")

 

def none = min == 0

def contains(x: Int) = isPow2(x) && min <= x && x <= max

def containsLg(x: Int) = contains(1 << x)

def containsLg(x: UInt) =

if (none) Bool(false)

else if (min == max) { UInt(log2Ceil(min)) === x }

else { UInt(log2Ceil(min)) <= x && x <= UInt(log2Ceil(max)) }

 

def contains(x: TransferSizes) = x.none || (min <= x.min && x.max <= max)

 

def intersect(x: TransferSizes) =

if (x.max < min || max < x.min) TransferSizes.none

else TransferSizes(scala.math.max(min, x.min), scala.math.min(max, x.max))

 

override def toString() = "TransferSizes[%d, %d]".format(min, max)

 

}

 

object TransferSizes {

def apply(x: Int) = new TransferSizes(x)

val none = new TransferSizes(0)

 

implicit def asBool(x: TransferSizes) = !x.none

}