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mirror of https://github.com/wader/fq.git synced 2024-12-26 15:02:28 +03:00
fq/pkg/decode/scalar.go
2021-11-28 17:29:56 +01:00

529 lines
12 KiB
Go

package decode
// TODO: d.Pos check err
// TODO: fn for actual?
// TODO: dsl import .? own scalar package?
// TODO: better IOError op names
import (
"bytes"
"encoding/binary"
"errors"
"fmt"
"math"
"strings"
"github.com/wader/fq/pkg/bitio"
"github.com/wader/fq/pkg/ranges"
"golang.org/x/text/encoding"
"golang.org/x/text/encoding/unicode"
)
//go:generate sh -c "cat scalar_gen.go.tmpl | go run ../../dev/tmpl.go scalar_gen.go.json | gofmt > scalar_gen.go"
type ScalarFn func(Scalar) (Scalar, error)
func (d *D) Bin(s Scalar) (Scalar, error) { s.DisplayFormat = NumberBinary; return s, nil }
func (d *D) Oct(s Scalar) (Scalar, error) { s.DisplayFormat = NumberOctal; return s, nil }
func (d *D) Dec(s Scalar) (Scalar, error) { s.DisplayFormat = NumberDecimal; return s, nil }
func (d *D) Hex(s Scalar) (Scalar, error) { s.DisplayFormat = NumberHex; return s, nil }
func (d *D) Actual(a interface{}) func(s Scalar) (Scalar, error) {
return func(s Scalar) (Scalar, error) { s.Actual = a; return s, nil }
}
func (d *D) Sym(sym interface{}) func(s Scalar) (Scalar, error) {
return func(s Scalar) (Scalar, error) { s.Sym = sym; return s, nil }
}
func (d *D) Description(desc string) func(s Scalar) (Scalar, error) {
return func(s Scalar) (Scalar, error) { s.Description = desc; return s, nil }
}
func (d *D) UAdd(n int) func(s Scalar) (Scalar, error) {
return func(s Scalar) (Scalar, error) {
// TODO: use math.Add/Sub?
s.Actual = uint64(int64(s.ActualU()) + int64(n))
return s, nil
}
}
func (d *D) SAdd(n int) func(s Scalar) (Scalar, error) {
return func(s Scalar) (Scalar, error) {
s.Actual = s.ActualS() + int64(n)
return s, nil
}
}
// TODO: nicer api?
func (d *D) Trim(cutset string) func(s Scalar) (Scalar, error) {
return func(s Scalar) (Scalar, error) {
s.Actual = strings.Trim(s.ActualStr(), cutset)
return s, nil
}
}
func (d *D) TrimSpace(s Scalar) (Scalar, error) {
s.Actual = strings.TrimSpace(s.ActualStr())
return s, nil
}
func (d *D) RawSym(s Scalar, nBytes int, fn func(b []byte) string) (Scalar, error) {
bb, ok := s.Actual.(*bitio.Buffer)
if !ok {
return s, nil
}
bbLen := bb.Len()
if nBytes < 0 {
nBytes = int(bbLen) / 8
if bbLen%8 != 0 {
nBytes++
}
}
if bbLen < int64(nBytes)*8 {
return s, nil
}
b := d.SharedReadBuf(nBytes)
if _, err := bb.ReadBitsAt(b, nBytes*8, 0); err != nil {
return s, err
}
s.Sym = fn(b[0:nBytes])
return s, nil
}
func (d *D) RawUUID(s Scalar) (Scalar, error) {
const uuidLen = 16
return d.RawSym(s, uuidLen, func(b []byte) string {
return fmt.Sprintf("%x-%x-%x-%x-%x", b[0:4], b[4:6], b[6:8], b[8:10], b[10:])
})
}
func (d *D) RawHex(s Scalar) (Scalar, error) {
return d.RawSym(s, -1, func(b []byte) string { return fmt.Sprintf("%x", b) })
}
func (d *D) RawHexReverse(s Scalar) (Scalar, error) {
return d.RawSym(s, -1, func(b []byte) string {
return fmt.Sprintf("%x", bitio.ReverseBytes(append([]byte{}, b...)))
})
}
func (d *D) MapURangeToScalar(rm map[[2]uint64]Scalar) func(s Scalar) (Scalar, error) {
return func(s Scalar) (Scalar, error) {
n, ok := s.Actual.(uint64)
if !ok {
return s, nil
}
for r, rs := range rm {
if n >= r[0] && n <= r[1] {
ns := rs
ns.Actual = s.Actual
s = ns
break
}
}
return s, nil
}
}
func (d *D) MapSRangeToScalar(rm map[[2]int64]Scalar) func(s Scalar) (Scalar, error) {
return func(s Scalar) (Scalar, error) {
n := s.ActualS()
for r, rs := range rm {
if n >= r[0] && n <= r[1] {
ns := rs
ns.Actual = s.Actual
s = ns
break
}
}
return s, nil
}
}
type BytesToScalar []struct {
Bytes []byte
Scalar Scalar
}
func (d *D) MapRawToScalar(btss BytesToScalar) func(s Scalar) (Scalar, error) {
return func(s Scalar) (Scalar, error) {
ab, err := s.ActualBitBuf().Bytes()
if err != nil {
return s, err
}
for _, bs := range btss {
if bytes.Equal(ab, bs.Bytes) {
ns := bs.Scalar
ns.Actual = s.Actual
s = ns
break
}
}
return s, nil
}
}
func (d *D) bitBufIsZero(s Scalar, err bool) (Scalar, error) {
bb, ok := s.Actual.(*bitio.Buffer)
if !ok {
return s, nil
}
isZero := true
b := d.SharedReadBuf(32 * 1024)
bLen := len(b) * 8
bbLeft := int(bb.Len())
bbPos := int64(0)
for bbLeft > 0 {
rl := bbLeft
if bbLeft > bLen {
rl = bLen
}
// zero last byte if uneven read
if rl%8 != 0 {
b[rl/8] = 0
}
n, err := bitio.ReadAtFull(bb, b, rl, bbPos)
if err != nil {
return s, err
}
nb := int(bitio.BitsByteCount(int64(n)))
for i := 0; i < nb; i++ {
if b[i] != 0 {
isZero = false
break
}
}
bbLeft -= n
}
if isZero {
s.Description = "all zero"
} else {
s.Description = "all not zero"
if err {
return s, errors.New("validate is zero failed")
}
}
return s, nil
}
func (d *D) BitBufIsZero(s Scalar) (Scalar, error) {
return d.bitBufIsZero(s, false)
}
func (d *D) BitBufValidateIsZero(s Scalar) (Scalar, error) {
return d.bitBufIsZero(s, true)
}
// TODO: generate?
func (d *D) assertBitBuf(assert bool, bss ...[]byte) func(s Scalar) (Scalar, error) {
return func(s Scalar) (Scalar, error) {
ab, err := s.ActualBitBuf().Bytes()
if err != nil {
return s, err
}
for _, bs := range bss {
if bytes.Equal(ab, bs) {
s.Description = "valid"
return s, nil
}
}
s.Description = "invalid"
if assert && !d.Options.Force {
return s, errors.New("failed to validate raw")
}
return s, nil
}
}
func (d *D) AssertBitBuf(bss ...[]byte) func(s Scalar) (Scalar, error) {
return d.assertBitBuf(true, bss...)
}
func (d *D) ValidateBitBuf(bss ...[]byte) func(s Scalar) (Scalar, error) {
return d.assertBitBuf(false, bss...)
}
func (d *D) assertUBytes(assert bool, endian Endian, bss ...[]byte) func(s Scalar) (Scalar, error) {
var bo binary.ByteOrder
switch endian {
case LittleEndian:
bo = binary.BigEndian
case BigEndian:
bo = binary.BigEndian
default:
panic("invalid endian")
}
return func(s Scalar) (Scalar, error) {
au := s.ActualU()
for _, bs := range bss {
var bu uint64
switch len(bs) {
case 1:
bu = uint64(bs[0])
case 2:
bu = uint64(bo.Uint16(bs))
case 4:
bu = uint64(bo.Uint32(bs))
case 8:
bu = bo.Uint64(bs)
default:
panic("invalid bs length")
}
if au == bu {
s.Description = "valid"
return s, nil
}
}
s.Description = "invalid"
if assert && !d.Options.Force {
return s, errors.New("failed to validate raw")
}
return s, nil
}
}
func (d *D) AssertUBytes(bss ...[]byte) func(s Scalar) (Scalar, error) {
return d.assertUBytes(true, d.Endian, bss...)
}
func (d *D) ValidateUBytes(bss ...[]byte) func(s Scalar) (Scalar, error) {
return d.assertUBytes(false, d.Endian, bss...)
}
func (d *D) AssertULEBytes(bss ...[]byte) func(s Scalar) (Scalar, error) {
return d.assertUBytes(true, LittleEndian, bss...)
}
func (d *D) ValidateULEBytes(bss ...[]byte) func(s Scalar) (Scalar, error) {
return d.assertUBytes(false, LittleEndian, bss...)
}
func (d *D) AssertUBEBytes(bss ...[]byte) func(s Scalar) (Scalar, error) {
return d.assertUBytes(true, BigEndian, bss...)
}
func (d *D) ValidateUBEBytes(bss ...[]byte) func(s Scalar) (Scalar, error) {
return d.assertUBytes(false, BigEndian, bss...)
}
func (d *D) TryFieldValue(name string, fn func() (*Value, error)) (*Value, error) {
start := d.Pos()
v, err := fn()
stop := d.Pos()
v.Name = name
v.RootBitBuf = d.bitBuf
v.Range = ranges.Range{Start: start, Len: stop - start}
if err != nil {
return nil, err
}
d.AddChild(v)
return v, err
}
func (d *D) FieldValue(name string, fn func() *Value) *Value {
v, err := d.TryFieldValue(name, func() (*Value, error) { return fn(), nil })
if err != nil {
panic(err)
}
return v
}
// looks a bit weird to force at least one ScalarFn arg
func (d *D) TryFieldScalar(name string, sfn ScalarFn, sfns ...ScalarFn) (Scalar, error) {
v, err := d.TryFieldValue(name, func() (*Value, error) {
s, err := sfn(Scalar{})
if err != nil {
return &Value{V: s}, err
}
for _, sfn := range sfns {
s, err = sfn(s)
if err != nil {
return &Value{V: s}, err
}
}
return &Value{V: s}, nil
})
if err != nil {
return Scalar{}, err
}
return v.V.(Scalar), nil
}
func (d *D) FieldScalar(name string, sfn ScalarFn, sfns ...ScalarFn) Scalar {
v, err := d.TryFieldScalar(name, sfn, sfns...)
if err != nil {
panic(err)
}
return v
}
func (d *D) tryUE(nBits int, endian Endian) (uint64, error) {
n, err := d.bits(nBits)
if err != nil {
return 0, err
}
if endian == LittleEndian {
n = bitio.Uint64ReverseBytes(nBits, n)
}
return n, nil
}
func (d *D) tryBitBuf(nBits int64) (*bitio.Buffer, error) {
return d.bitBuf.BitBufLen(nBits)
}
func (d *D) trySE(nBits int, endian Endian) (int64, error) {
n, err := d.bits(nBits)
if err != nil {
return 0, err
}
if nBits == 0 {
return 0, nil
}
if endian == LittleEndian {
n = bitio.Uint64ReverseBytes(nBits, n)
}
var s int64
if n&(1<<(nBits-1)) > 0 {
// two's complement
s = -int64((^n & ((1 << nBits) - 1)) + 1)
} else {
s = int64(n)
}
return s, nil
}
func (d *D) tryFE(nBits int, endian Endian) (float64, error) {
n, err := d.bits(nBits)
if err != nil {
return 0, err
}
if endian == LittleEndian {
n = bitio.Uint64ReverseBytes(nBits, n)
}
switch nBits {
case 32:
return float64(math.Float32frombits(uint32(n))), nil
case 64:
return math.Float64frombits(n), nil
default:
return 0, fmt.Errorf("unsupported float size %d", nBits)
}
}
func (d *D) tryFPE(nBits int, fBits int, endian Endian) (float64, error) {
n, err := d.bits(nBits)
if err != nil {
return 0, err
}
if endian == LittleEndian {
n = bitio.Uint64ReverseBytes(nBits, n)
}
return float64(n) / float64(uint64(1<<fBits)), nil
}
var UTF8BOM = unicode.UTF8BOM
var UTF16BOM = unicode.UTF16(unicode.LittleEndian, unicode.UseBOM)
var UTF16BE = unicode.UTF16(unicode.BigEndian, unicode.IgnoreBOM)
var UTF16LE = unicode.UTF16(unicode.LittleEndian, unicode.IgnoreBOM)
func (d *D) tryText(nBytes int, e encoding.Encoding) (string, error) {
bs, err := d.bitBuf.BytesLen(nBytes)
if err != nil {
return "", err
}
return e.NewDecoder().String(string(bs))
}
// read length prefixed text (ex pascal short string)
// lBits length prefix
// fixedBytes if != -1 read nBytes but trim to length
//nolint:unparam
func (d *D) tryTextLenPrefixed(lenBits int, fixedBytes int, e encoding.Encoding) (string, error) {
p := d.Pos()
l, err := d.bits(lenBits)
if err != nil {
return "", err
}
n := int(l)
if fixedBytes != -1 {
n = fixedBytes - 1
// TODO: error?
if l > uint64(n) {
l = uint64(n)
}
}
bs, err := d.bitBuf.BytesLen(n)
if err != nil {
d.SeekAbs(p)
return "", err
}
return e.NewDecoder().String(string(bs[0:l]))
}
func (d *D) tryTextNull(nullBytes int, e encoding.Encoding) (string, error) {
p := d.Pos()
peekBits, _, err := d.TryPeekFind(nullBytes*8, 8, -1, func(v uint64) bool { return v == 0 })
if err != nil {
return "", err
}
n := (int(peekBits) / 8) + nullBytes
bs, err := d.bitBuf.BytesLen(n)
if err != nil {
d.SeekAbs(p)
return "", err
}
return e.NewDecoder().String(string(bs[0 : n-nullBytes]))
}
func (d *D) tryTextNullLen(fixedBytes int, e encoding.Encoding) (string, error) {
bs, err := d.bitBuf.BytesLen(fixedBytes)
if err != nil {
return "", err
}
nullIndex := bytes.IndexByte(bs, 0)
if nullIndex != -1 {
bs = bs[:nullIndex]
}
return e.NewDecoder().String(string(bs))
}
// ov is what to treat as 1
func (d *D) tryUnary(ov uint64) (uint64, error) {
p := d.Pos()
var n uint64
for {
b, err := d.bits(1)
if err != nil {
d.SeekAbs(p)
return 0, err
}
if b != ov {
break
}
n++
}
return n, nil
}
func (d *D) tryBool() (bool, error) {
n, err := d.bits(1)
if err != nil {
return false, err
}
return n == 1, nil
}