}

// backup steps back to the last byte we used.
func (br *bitReader) backup() {
	for br.cnt >= 8 {
		br.off--
		br.cnt -= 8
	}
}

// makeError returns an error at the current offset wrapping a string.
func (br *bitReader) makeError(msg string) error {
	return br.r.makeError(int(br.off), msg)
}

// reverseBitReader reads a bit stream in reverse.
type reverseBitReader struct {
	r     *Reader // for error reporting

		if w > 12 {
			return 0, 0, r.makeError(off, "Huffman weight overflow")
		}
		weightMark[w]++
		if w > 0 {
			weightMask += 1 << (w - 1)
		}
	}
	if weightMask == 0 {
		return 0, 0, r.makeError(off, "bad Huffman weights")
	}

	tableBits = 32 - bits.LeadingZeros32(weightMask)
	if tableBits > maxHuffmanBits {
		return 0, 0, r.makeError(off, "bad Huffman weights")
	}

		} else {
			remaining--
		}
		if sym >= 256 {
			return 0, 0, br.makeError("FSE sym overflow")
		}
		norm[uint8(sym)] = int16(count)
		sym++

		prev0 = count == 0

		for remaining < threshold {
			bitsNeeded--
			threshold >>= 1
		}
	}

	if remaining != 1 {
		return 0, 0, br.makeError("too many symbols in FSE table")
	}

	for ; sym <= maxSym; sym++ {

	r.buffer = append(r.buffer, litbuf...)

	if rbr.cnt != 0 {
		return r.makeError(off, "extraneous data after sequences")
	}

	return nil
}

// Copy match bytes from the decoded output, or the window, at offset.
func (r *Reader) copyFromWindow(rbr *reverseBitReader, offset, match uint32) error {
	if offset == 0 {
		return rbr.makeError("invalid zero offset")
	}

	// The maximum size of one decompressed block is 128K,
	// so we can't have more literals than that.
	if regeneratedSize > 128<<10 {
		return 0, nil, r.makeError(off, "literal size too large")
	}

	if raw {
		// RFC 3.1.1.3.1.2.
		if off+regeneratedSize > len(data) {
			return 0, nil, r.makeError(off, "raw literal size too large")
		}
		outbuf = append(outbuf, data[off:off+regeneratedSize]...)
		off += regeneratedSize
	} else {

			return r.makeError(relativeOffset, "windowSize too large")
		}
	}

	// Dictionary_ID. RFC 3.1.1.1.3.
	if dictionaryIdSize != 0 {
		dictionaryId := r.scratch[windowDescriptorSize : windowDescriptorSize+dictionaryIdSize]
		// Allow only zero Dictionary ID.
		for _, b := range dictionaryId {
			if b != 0 {
				return r.makeError(relativeOffset, "dictionaries are not supported")
			}

`,
		},
		{
			desc: "BadTag",
			yamlStr: `
hub: ?illegal-tag!
`,
			wantErrs: makeErrors([]string{`invalid value Hub: ?illegal-tag!`}),
		},
		{
			desc: "BadHub",
			yamlStr: `
hub: docker.io:tag/istio
`,
			wantErrs: makeErrors([]string{`invalid value Hub: docker.io:tag/istio`}),
		},
		{
			desc: "GoodURL",
			yamlStr: `
installPackagePath: /local/file/path
`,

			yamlStr: `
global:
  proxy:
    includeIPRanges: "*,1.1.0.0/16,2.2.0.0/16"
`,
			wantErrs: makeErrors([]string{`global.proxy.includeIPRanges netip.ParsePrefix("*"): no '/'`}),
		},
		{
			desc: "BadPortRange",
			yamlStr: `
global:
  proxy:
    excludeInboundPorts: "-1,444"
`,
			wantErrs: makeErrors([]string{`value global.proxy.excludeInboundPorts:-1 falls outside range [0, 65535]`}),
		},
		{

	{new(mapError), new(error), true},
	{new(*mapError), new(error), true},
}

type notAnExpr struct{}

func (notAnExpr) Pos() token.Pos { return token.NoPos }
func (notAnExpr) End() token.Pos { return token.NoPos }
func (notAnExpr) exprNode()      {}

type notASTExpr interface {
	Pos() token.Pos
	End() token.Pos
	exprNode()
}

type mapError map[string]string

	mean        float64
	stddev      float64
	closeEnough float64
	maxError    float64
}

func nearEqual(a, b, closeEnough, maxError float64) bool {
	absDiff := math.Abs(a - b)
	if absDiff < closeEnough { // Necessary when one value is zero and one value is close to zero.
		return true
	}
	return absDiff/max(math.Abs(a), math.Abs(b)) < maxError
}

var testSeeds = []int64{1, 1754801282, 1698661970, 1550503961}