func()

in cpc/cpc_sketch.go [435:482]

• 48 lines of code
• 12 McCabe index (conditional complexity)

func (c *CpcSketch) modifyOffset(newOffset int) error {
	if newOffset < 0 || newOffset > 56 {
		return fmt.Errorf("newOffset < 0 || newOffset > 56")
	}
	if newOffset != (c.windowOffset + 1) {
		return fmt.Errorf("newOffset != (c.windowOffset + 1)")
	}
	if c.slidingWindow == nil || c.pairTable == nil {
		return fmt.Errorf("slidingWindow == nil || pairTable == nil")
	}
	k := 1 << c.lgK
	bitMatrix, err := c.bitMatrixOfSketch()
	if err != nil {
		return err
	}
	if (newOffset & 0x7) == 0 {
		c.refreshKXP(bitMatrix)
	}
	c.pairTable.clear()
	maskForClearingWindow := (0xFF << newOffset) ^ -1
	maskForFlippingEarlyZone := (1 << newOffset) - 1
	allSurprisesORed := uint64(0)
	for i := 0; i < k; i++ {
		pattern := bitMatrix[i]
		c.slidingWindow[i] = byte((pattern >> newOffset) & 0xFF)
		pattern &= uint64(maskForClearingWindow)
		pattern ^= uint64(maskForFlippingEarlyZone)
		allSurprisesORed |= pattern
		for pattern != 0 {
			col := bits.TrailingZeros64(pattern)
			pattern ^= 1 << col
			rowCol := (i << 6) | col
			isNovel, err := c.pairTable.maybeInsert(rowCol)
			if err != nil {
				return err
			}
			if !isNovel {
				return nil
			}
		}
	}
	c.windowOffset = newOffset
	c.fiCol = bits.TrailingZeros64(allSurprisesORed)
	if c.fiCol > newOffset {
		c.fiCol = newOffset
	}
	return nil
}