forgejo/vendor/github.com/minio/md5-simd/md5-util_amd64.go

//+build !noasm,!appengine,gc

// Copyright (c) 2020 MinIO Inc. All rights reserved.
// Use of this source code is governed by a license that can be
// found in the LICENSE file.

package md5simd

// Helper struct for sorting blocks based on length
type lane struct {
	len uint
	pos uint
}

type digest struct {
	s [4]uint32
}

// Helper struct for generating number of rounds in combination with mask for valid lanes
type maskRounds struct {
	mask   uint64
	rounds uint64
}

func generateMaskAndRounds8(input [8][]byte, mr *[8]maskRounds) (rounds int) {
	// Sort on blocks length small to large
	var sorted [8]lane
	for c, inpt := range input[:] {
		sorted[c] = lane{uint(len(inpt)), uint(c)}
		for i := c - 1; i >= 0; i-- {
			// swap so largest is at the end...
			if sorted[i].len > sorted[i+1].len {
				sorted[i], sorted[i+1] = sorted[i+1], sorted[i]
				continue
			}
			break
		}
	}

	// Create mask array including 'rounds' (of processing blocks of 64 bytes) between masks
	m, round := uint64(0xff), uint64(0)

	for _, s := range sorted[:] {
		if s.len > 0 {
			if uint64(s.len)>>6 > round {
				mr[rounds] = maskRounds{m, (uint64(s.len) >> 6) - round}
				rounds++
			}
			round = uint64(s.len) >> 6
		}
		m = m & ^(1 << uint(s.pos))
	}
	return
}

func generateMaskAndRounds16(input [16][]byte, mr *[16]maskRounds) (rounds int) {
	// Sort on blocks length small to large
	var sorted [16]lane
	for c, inpt := range input[:] {
		sorted[c] = lane{uint(len(inpt)), uint(c)}
		for i := c - 1; i >= 0; i-- {
			// swap so largest is at the end...
			if sorted[i].len > sorted[i+1].len {
				sorted[i], sorted[i+1] = sorted[i+1], sorted[i]
				continue
			}
			break
		}
	}

	// Create mask array including 'rounds' (of processing blocks of 64 bytes) between masks
	m, round := uint64(0xffff), uint64(0)

	for _, s := range sorted[:] {
		if s.len > 0 {
			if uint64(s.len)>>6 > round {
				mr[rounds] = maskRounds{m, (uint64(s.len) >> 6) - round}
				rounds++
			}
			round = uint64(s.len) >> 6
		}
		m = m & ^(1 << uint(s.pos))
	}
	return
}