// Package bao implements BLAKE3 verified streaming.
package bao

import (
	
	
	
	
	

	
)

func bytesToCV( []byte) ( [8]uint32) {
	_ = [31] // bounds check hint
	for  := range  {
		[] = binary.LittleEndian.Uint32([4*:])
	}
	return 
}

func cvToBytes( *[8]uint32) *[32]byte {
	var  [32]byte
	for ,  := range  {
		binary.LittleEndian.PutUint32([4*:], )
	}
	return &
}

func compressGroup( []byte,  uint64) guts.Node {
	var  [54 - guts.MaxSIMD][8]uint32
	var  uint64
	 := func( [8]uint32) {
		 := 0
		for &(1<<) != 0 {
			 = guts.ChainingValue(guts.ParentNode([], , &guts.IV, 0))
			++
		}
		[] = 
		++
	}

	var  [guts.MaxSIMD * guts.ChunkSize]byte
	var  int
	for len() > 0 {
		if  == len() {
			(guts.ChainingValue(guts.CompressBuffer(&, , &guts.IV, +(*guts.MaxSIMD), 0)))
			 = 0
		}
		 := copy([:], )
		 += 
		 = [:]
	}
	 := guts.CompressBuffer(&, , &guts.IV, +(*guts.MaxSIMD), 0)
	for  := bits.TrailingZeros64();  < bits.Len64(); ++ {
		if &(1<<) != 0 {
			 = guts.ParentNode([], guts.ChainingValue(), &guts.IV, 0)
		}
	}
	return 
}

// EncodedSize returns the size of a Bao encoding for the provided quantity
// of data.
func ( int,  int,  bool) int {
	 := guts.ChunkSize << 
	 := 8
	if  > 0 {
		 := ( +  - 1) / 
		 := 2* - 2 // no I will not elaborate
		 +=  * 32
	}
	if ! {
		 += 
	}
	return 
}

// Encode computes the intermediate BLAKE3 tree hashes of data and writes them
// to dst. If outboard is false, the contents of data are also written to dst,
// interleaved with the tree hashes. It also returns the tree root, i.e. the
// 256-bit BLAKE3 hash. The group parameter controls how many chunks are hashed
// per "group," as a power of 2; for standard Bao, use 0.
//
// Note that dst is not written sequentially, and therefore must be initialized
// with sufficient capacity to hold the encoding; see EncodedSize.
func ( io.WriterAt,  io.Reader,  int64,  int,  bool) ([32]byte, error) {
	 := uint64(guts.ChunkSize << )
	 := make([]byte, )
	var  error
	 := func( []byte) []byte {
		if  == nil {
			_,  = io.ReadFull(, )
		}
		return 
	}
	 := func( []byte,  uint64) {
		if  == nil {
			_,  = .WriteAt(, int64())
		}
	}
	var  uint64

	// NOTE: unlike the reference implementation, we write directly in
	// pre-order, rather than writing in post-order and then flipping. This cuts
	// the I/O required in half, at the cost of making it a lot trickier to hash
	// multiple groups in SIMD. However, you can still get the SIMD speedup if
	// group > 0, so maybe just do that.
	var  func( uint64,  uint32,  uint64) (uint64, [8]uint32)
	 = func( uint64,  uint32,  uint64) (uint64, [8]uint32) {
		if  != nil {
			return 0, [8]uint32{}
		} else if  <=  {
			 := ([:])
			if ! {
				(, )
			}
			 := compressGroup(, )
			 +=  / guts.ChunkSize
			.Flags |= 
			return 0, guts.ChainingValue()
		}
		 := uint64(1) << (bits.Len64(-1) - 1)
		,  := (, 0, +64)
		 :=  * 32
		if ! {
			 += ( / ) * 
		}
		,  := (-, 0, +64+)
		(cvToBytes(&)[:], )
		(cvToBytes(&)[:], +32)
		return 2 +  + , guts.ChainingValue(guts.ParentNode(, , &guts.IV, ))
	}

	binary.LittleEndian.PutUint64([:8], uint64())
	([:8], 0)
	,  := (uint64(), guts.FlagRoot, 8)
	return *cvToBytes(&), 
}

// Decode reads content and tree data from the provided reader(s), and
// streams the verified content to dst. It returns false if verification fails.
// If the content and tree data are interleaved, outboard should be nil.
func ( io.Writer, ,  io.Reader,  int,  [32]byte) (bool, error) {
	if  == nil {
		 = 
	}
	 := uint64(guts.ChunkSize << )
	 := make([]byte, )
	var  error
	 := func( io.Reader,  []byte) []byte {
		if  == nil {
			_,  = io.ReadFull(, )
		}
		return 
	}
	 := func( io.Writer,  []byte) {
		if  == nil {
			_,  = .Write()
		}
	}
	 := func() (,  [8]uint32) {
		(, [:64])
		return bytesToCV([:32]), bytesToCV([32:])
	}
	var  uint64
	var  func( [8]uint32,  uint64,  uint32) bool
	 = func( [8]uint32,  uint64,  uint32) bool {
		if  != nil {
			return false
		} else if  <=  {
			 := compressGroup((, [:]), )
			 +=  / guts.ChunkSize
			.Flags |= 
			 :=  == guts.ChainingValue()
			if  {
				(, [:])
			}
			return 
		}
		,  := ()
		 := guts.ParentNode(, , &guts.IV, )
		 := uint64(1) << (bits.Len64(-1) - 1)
		return guts.ChainingValue() ==  && (, , 0) && (, -, 0)
	}

	(, [:8])
	 := binary.LittleEndian.Uint64([:8])
	 := (bytesToCV([:]), , guts.FlagRoot)
	return , 
}

type bufferAt struct {
	buf []byte
}

func ( *bufferAt) ( []byte,  int64) (int, error) {
	if copy(.buf[:], ) != len() {
		panic("bad buffer size")
	}
	return len(), nil
}

// EncodeBuf returns the Bao encoding and root (i.e. BLAKE3 hash) for data.
func ( []byte,  int,  bool) ([]byte, [32]byte) {
	 := bufferAt{buf: make([]byte, EncodedSize(len(), , ))}
	,  := Encode(&, bytes.NewReader(), int64(len()), , )
	return .buf, 
}

// VerifyBuf verifies the Bao encoding and root (i.e. BLAKE3 hash) for data.
// If the content and tree data are interleaved, outboard should be nil.
func (,  []byte,  int,  [32]byte) bool {
	,  := bytes.NewBuffer(), bytes.NewBuffer()
	var  io.Reader = 
	if  == nil {
		 = nil
	}
	,  := Decode(io.Discard, , , , )
	return  && .Len() == 0 && .Len() == 0 // check for trailing data
}

// ExtractSlice returns the slice encoding for the given offset and length. When
// extracting from an outboard encoding, data should contain only the chunk
// groups that will be present in the slice.
func ( io.Writer, ,  io.Reader,  int,  uint64,  uint64) error {
	 :=  == nil
	if  {
		 = 
	}
	 := uint64(guts.ChunkSize << )
	 := make([]byte, )
	var  error
	 := func( io.Reader,  uint64,  bool) {
		if  == nil {
			_,  = io.ReadFull(, [:])
			if  == nil &&  {
				_,  = .Write([:])
			}
		}
	}
	var  func(,  uint64)
	 = func(,  uint64) {
		 :=  < (+) &&  < (+)
		if  != nil {
			return
		} else if  <=  {
			if  ||  {
				(, , )
			}
			return
		}
		(, 64, )
		 := uint64(1) << (bits.Len64(-1) - 1)
		(, )
		(+, -)
	}
	(, 8, true)
	 := binary.LittleEndian.Uint64([:8])
	if  < + {
		return errors.New("invalid slice length")
	}
	(0, )
	return 
}

// DecodeSlice reads from data, which must contain a slice encoding for the
// given offset and length, and streams verified content to dst. It returns
// false if verification fails.
func ( io.Writer,  io.Reader,  int, ,  uint64,  [32]byte) (bool, error) {
	 := uint64(guts.ChunkSize << )
	 := make([]byte, )
	var  error
	 := func( uint64) []byte {
		if  == nil {
			_,  = io.ReadFull(, [:])
		}
		return [:]
	}
	 := func() (,  [8]uint32) {
		(64)
		return bytesToCV([:32]), bytesToCV([32:])
	}
	 := func( []byte) {
		if  == nil {
			_,  = .Write()
		}
	}
	var  func( [8]uint32, ,  uint64,  uint32) bool
	 = func( [8]uint32, ,  uint64,  uint32) bool {
		 :=  < (+) &&  < (+)
		if  != nil {
			return false
		} else if  <=  {
			if ! {
				return true
			}
			 := compressGroup((), /guts.ChunkSize)
			.Flags |= 
			 :=  == guts.ChainingValue()
			if  {
				// only write within range
				 := [:]
				if + > + {
					 = [:+-]
				}
				if  <  {
					 = [-:]
				}
				()
			}
			return 
		}
		if ! {
			return true
		}
		,  := ()
		 := guts.ParentNode(, , &guts.IV, )
		 := uint64(1) << (bits.Len64(-1) - 1)
		return guts.ChainingValue() ==  && (, , , 0) && (, +, -, 0)
	}

	 := binary.LittleEndian.Uint64((8))
	if  < + {
		return false, errors.New("invalid slice length")
	}
	 := (bytesToCV([:]), 0, , guts.FlagRoot)
	return , 
}

// VerifySlice verifies the Bao slice encoding in data, returning the
// verified bytes.
func ( []byte,  int,  uint64,  uint64,  [32]byte) ([]byte, bool) {
	 := bytes.NewBuffer()
	var  bytes.Buffer
	if ,  := DecodeSlice(&, , , , , ); ! || .Len() > 0 {
		return nil, false
	}
	return .Bytes(), true
}

// VerifyChunks verifies the provided chunks with a full outboard encoding.
func (,  []byte,  int,  uint64,  [32]byte) bool {
	 := bytes.NewBuffer()
	 := bytes.NewBuffer()
	 := uint64(guts.ChunkSize << )
	 := uint64(len())
	 := func( uint64) int {
		 := int( / )
		if % == 0 {
			--
		}
		return 
	}

	var  func( [8]uint32, ,  uint64,  uint32) bool
	 = func( [8]uint32, ,  uint64,  uint32) bool {
		 :=  < (+) &&  < (+)
		if  <=  {
			if ! {
				return true
			}
			 := compressGroup(.Next(int()), /guts.ChunkSize)
			.Flags |= 
			return  == guts.ChainingValue()
		}
		if ! {
			_ = .Next(64 * ()) // skip
			return true
		}
		,  := bytesToCV(.Next(32)), bytesToCV(.Next(32))
		 := guts.ParentNode(, , &guts.IV, )
		 := uint64(1) << (bits.Len64(-1) - 1)
		return guts.ChainingValue() ==  && (, , , 0) && (, +, -, 0)
	}

	if .Len() < 8 {
		return false
	}
	 := binary.LittleEndian.Uint64(.Next(8))
	if  < + || .Len() != 64*() {
		return false
	}
	return (bytesToCV([:]), 0, , guts.FlagRoot)
}