You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: encode_go.go
    path of file: ./repos/k6/vendor/github.com/klauspost/compress/s2
    
    the code of the file until where you have to start completion: //go:build !amd64 || appengine || !gc || noasm
// +build !amd64 appengine !gc noasm

package s2

import (
	"bytes"
	"math/bits"
)

const hasAmd64Asm = false

// encodeBlock encodes a non-empty src to a guaranteed-large-enough dst. It
// assumes that the varint-encoded length of the decompressed bytes has already
// been written.
//
// It also assumes that:
//
//	len(dst) >= MaxEncodedLen(len(src))
func encodeBlock(dst, src []byte) (d int) {
	if len(src) < minNonLiteralBlockSize {
		return 0
	}
	return encodeBlockGo(dst, src)
}

// encodeBlockBetter encodes a non-empty src to a guaranteed-large-enough dst. It
// assumes that the varint-encoded length of the decompressed bytes has already
// been written.
//
// It also assumes that:
//
//	len(dst) >= MaxEncodedLen(len(src))
func encodeBlockBetter(dst, src []byte) (d int) {
	return encodeBlockBetterGo(dst, src)
}

// encodeBlockBetter encodes a non-empty src to a guaranteed-large-enough dst. It
// assumes that the varint-encoded length of the decompressed bytes has already
// been written.
//
// It also assumes that:
//
//	len(dst) >= MaxEncodedLen(len(src))
func encodeBlockBetterSnappy(dst, src []byte) (d int) {
	return encodeBlockBetterSnappyGo(dst, src)
}

// encodeBlock encodes a non-empty src to a guaranteed-large-enough dst. It
// assumes that the varint-encoded length of the decompressed bytes has already
// been written.
//
// It also assumes that:
//
//	len(dst) >= MaxEncodedLen(len(src))
func encodeBlockSnappy(dst, src []byte) (d int) {
	if len(src) < minNonLiteralBlockSize {
		return 0
	}
	return encodeBlockSnappyGo(dst, src)
}

// emitLiteral writes a literal chunk and returns the number of bytes written.
//
// It assumes that:
//
//	dst is long enough to hold the encoded bytes
//	0 <= len(lit) && len(lit) <= math.MaxUint32
func emitLiteral(dst, lit []byte) int {
	if len(lit) == 0 {
		return 0
	}
	const num = 63<<2 | tagLiteral
	i, n := 0, uint(len(lit)-1)
	switch {
	case n < 60:
		dst[0] = uint8(n)<<2 | tagLiteral
		i = 1
	case n < 1<<8:
		dst[1] = uint8(n)
		dst[0] = 60<<2 | tagLiteral
		i = 2
	case n < 1<<16:
		dst[2] = uint8(n >> 8)
		dst[1] = uint8(n)
		dst[0] = 61<<2 | tagLiteral
		i = 3
	case n < 1<<24:
		dst[3] = uint8(n >> 16)
		dst[2] = uint8(n >> 8)
		dst[1] = uint8(n)
		dst[0] = 62<<2 | tagLiteral
		i = 4
	default:
		dst[4
    
func calcBlockSizeSmall(src []byte) (d int) {
	// Initialize the hash table.
	const (
		tableBits    = 9
		maxTableSize = 1 << tableBits
	)

	var table [maxTableSize]uint32

	// sLimit is when to stop looking for offset/length copies. The inputMargin
	// lets us use a fast path for emitLiteral in the main loop, while we are
	// looking for copies.
	sLimit := len(src) - inputMargin

	// Bail if we can't compress to at least this.
	dstLimit := len(src) - len(src)>>5 - 5

	// nextEmit is where in src the next emitLiteral should start from.
	nextEmit := 0

	// The encoded form must start with a literal, as there are no previous
	// bytes to copy, so we start looking for hash matches at s == 1.
	s := 1
	cv := load64(src, s)

	// We search for a repeat at -1, but don't output repeats when nextEmit == 0
	repeat := 1

	for {
		candidate := 0
		for {
			// Next src position to check
			nextS := s + (s-nextEmit)>>6 + 4
			if nextS > sLimit {
				goto emitRemainder
			}
			hash0 := hash6(cv, tableBits)
			hash1 := hash6(cv>>8, tableBits)
			candidate = int(table[hash0])
			candidate2 := int(table[hash1])
			table[hash0] = uint32(s)
			table[hash1] = uint32(s + 1)
			hash2 := hash6(cv>>16, tableBits)

			// Check repeat at offset checkRep.
			const checkRep = 1
			if uint32(cv>>(checkRep*8)) == load32(src, s-repeat+checkRep) {
				base := s + checkRep
				// Extend back
				for i := base - repeat; base > nextEmit && i > 0 && src[i-1] == src[base-1]; {
					i--
					base--
				}
				d += emitLiteralSize(src[nextEmit:base])

				// Extend forward
				candidate := s - repeat + 4 + checkRep
				s += 4 + checkRep
				for s <= sLimit {
					if diff := load64(src, s) ^ load64(src, candidate); diff != 0 {
						s += bits.TrailingZeros64(diff) >> 3
						break
					}
					s += 8
					candidate += 8
				}

				d += emitCopyNoRepeatSize(repeat, s-base)
				nextEmit = s
				if s >= sLimit {
					goto emitRemainder
				}

				cv = load64(src, s)
				continue
			}

			if uint32(cv) == load32(src, candidate) {
				break
			}
			candidate = int(table[hash2])
			if uint32(cv>>8) == load32(src, candidate2) {
				table[hash2] = uint32(s + 2)
				candidate = candidate2
				s++
				break
			}
			table[hash2] = uint32(s + 2)
			if uint32(cv>>16) == load32(src, candidate) {
				s += 2
				break
			}

			cv = load64(src, nextS)
			s = nextS
		}

		// Extend backwards
		for candidate > 0 && s > nextEmit && src[candidate-1] == src[s-1] {
			candidate--
			s--
		}

		// Bail if we exceed the maximum size.
		if d+(s-nextEmit) > dstLimit {
			return 0
		}

		// A 4-byte match has been found. We'll later see if more than 4 bytes
		// match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
		// them as literal bytes.

		d += emitLiteralSize(src[nextEmit:s])

		// Call emitCopy, and then see if another emitCopy could be our next
		// move. Repeat until we find no match for the input immediately after
		// what was consumed by the last emitCopy call.
		//
		// If we exit this loop normally then we need to call emitLiteral next,
		// though we don't yet know how big the literal will be. We handle that
		// by proceeding to the next iteration of the main loop. We also can
		// exit this loop via goto if we get close to exhausting the input.
		for {
			// Invariant: we have a 4-byte match at s, and no need to emit any
			// literal bytes prior to s.
			base := s
			repeat = base - candidate

			// Extend the 4-byte match as long as possible.
			s += 4
			candidate += 4
			for s <= len(src)-8 {
				if diff := load64(src, s) ^ load64(src, candidate); diff != 0 {
					s += bits.TrailingZeros64(diff) >> 3
					break
				}
				s += 8
				candidate += 8
			}

			d += emitCopyNoRepeatSize(repeat, s-base)
			if false {
				// Validate match.
				a := src[base:s]
				b := src[base-repeat : base-repeat+(s-base)]
				if !bytes.Equal(a, b) {
					panic("mismatch")
				}
			}

			nextEmit = s
			if s >= sLimit {
				goto emitRemainder
			}

			if d > dstLimit {
				// Do we have space for more, if not bail.
				return 0
			}
			// Check for an immediate match, otherwise start search at s+1
			x := load64(src, s-2)
			m2Hash := hash6(x, tableBits)
			currHash := hash6(x>>16, tableBits)
			candidate = int(table[currHash])
			table[m2Hash] = uint32(s - 2)
			table[currHash] = uint32(s)
			if uint32(x>>16) != load32(src, candidate) {
				cv = load64(src, s+1)
				s++
				break
			}
		}
	}

emitRemainder:
	if nextEmit < len(src) {
		// Bail if we exceed the maximum size.
		if d+len(src)-nextEmit > dstLimit {
			return 0
		}
		d += emitLiteralSize(src[nextEmit:])
	}
	return d
}