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package patricia
var _leftMasks32 []uint32
var _leftMasks64 []uint64
func initBuildLeftMasks() {
_leftMasks32 = make([]uint32, 33)
for i := uint(1); i < 33; i++ {
_leftMasks32[i] = uint32(_leftMasks32[i-1] | 1<<(32-i))
}
_leftMasks64 = make([]uint64, 65)
for i := uint(1); i < 65; i++ {
_leftMasks64[i] = uint64(_leftMasks64[i-1] | 1<<(64-i))
}
}
// MergePrefixes32 merges two 32-bit prefixes, returning new prefix, new length
func MergePrefixes32(left uint32, leftLength uint, right uint32, rightLength uint) (uint32, uint) {
return (left & _leftMasks32[leftLength]) | ((right & _leftMasks32[rightLength]) >> leftLength), (leftLength + rightLength)
}
// MergePrefixes64 merges two pairs of uint64s, returning a new prefix, new length
func MergePrefixes64(leftLeft uint64, leftRight uint64, leftLength uint, rightLeft uint64, rightRight uint64, rightLength uint) (uint64, uint64, uint) {
// mask the left 128 bits
if leftLength <= 64 {
leftLeft &= _leftMasks64[leftLength]
leftRight = 0
} else {
leftRight &= _leftMasks64[leftLength-64]
}
// mask the right 128 bits
if rightLength <= 64 {
rightLeft &= _leftMasks64[rightLength]
rightRight = 0
} else {
rightRight &= _leftMasks64[rightLength-64]
}
// shift the right 128 bits to the right
rightLeft, rightRight = ShiftRightIPv6(rightLeft, rightRight, leftLength)
// now merge the two
return leftLeft | rightLeft, leftRight | rightRight, leftLength + rightLength
}
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