/
value.go
293 lines (260 loc) · 5.68 KB
/
value.go
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package decode
import (
"cmp"
"errors"
"fmt"
"github.com/wader/fq/pkg/bitio"
"github.com/wader/fq/pkg/ranges"
"github.com/wader/fq/pkg/scalar"
"golang.org/x/exp/slices"
)
type Compound struct {
ByName map[string]*Value
Description string
Children []*Value
IsArray bool
}
// TODO: Encoding, u16le, varint etc, encode?
// TODO: Value/Compound interface? can have per type and save memory
// TODO: Make some fields optional somehow? map/slice?
type Value struct {
V any // scalar.S or Compound (array/struct)
RootReader bitio.ReaderAtSeeker
Err error
Parent *Value
Format *Format // TODO: rework
Name string
Description string
Range ranges.Range
Index int // index in parent array/struct
IsRoot bool // TODO: rework?
}
type WalkFn func(v *Value, rootV *Value, depth int, rootDepth int) error
var ErrWalkSkipChildren = errors.New("skip children")
var ErrWalkBreak = errors.New("break")
var ErrWalkStop = errors.New("stop")
type WalkOpts struct {
PreOrder bool
OneRoot bool
Fn WalkFn
}
func (v *Value) Walk(opts WalkOpts) error {
var walkFn WalkFn
walkFn = func(wv *Value, rootV *Value, depth int, rootDepth int) error {
if opts.OneRoot && wv != v && wv.IsRoot {
return nil
}
rootDepthDelta := 0
// only count switching to a new root
if wv.IsRoot && wv != rootV {
rootV = wv
rootDepthDelta = 1
}
if opts.PreOrder {
err := opts.Fn(wv, rootV, depth, rootDepth+rootDepthDelta)
switch {
case errors.Is(err, ErrWalkSkipChildren):
return nil
case errors.Is(err, ErrWalkStop):
fallthrough
default:
if err != nil {
return err
}
}
}
switch wvv := wv.V.(type) {
case *Compound:
for _, wv := range wvv.Children {
if err := walkFn(wv, rootV, depth+1, rootDepth+rootDepthDelta); err != nil {
if errors.Is(err, ErrWalkBreak) {
break
}
return err
}
}
}
if !opts.PreOrder {
err := opts.Fn(wv, rootV, depth, rootDepth+rootDepthDelta)
switch {
case errors.Is(err, ErrWalkSkipChildren):
return errors.New("can't skip children in post-order")
case errors.Is(err, ErrWalkStop):
fallthrough
default:
if err != nil {
return err
}
}
}
return nil
}
// figure out root value for v as it might not be a root itself
rootV := v.BufferRoot()
err := walkFn(v, rootV, 0, 0)
if errors.Is(err, ErrWalkStop) {
err = nil
}
return err
}
func (v *Value) WalkPreOrder(fn WalkFn) error {
return v.Walk(WalkOpts{
PreOrder: true,
Fn: fn,
})
}
func (v *Value) WalkPostOrder(fn WalkFn) error {
return v.Walk(WalkOpts{
PreOrder: false,
Fn: fn,
})
}
func (v *Value) WalkRootPreOrder(fn WalkFn) error {
return v.Walk(WalkOpts{
PreOrder: true,
OneRoot: true,
Fn: fn,
})
}
func (v *Value) WalkRootPostOrder(fn WalkFn) error {
return v.Walk(WalkOpts{
PreOrder: false,
OneRoot: true,
Fn: fn,
})
}
func (v *Value) root(findSubRoot bool, findFormatRoot bool) *Value {
rootV := v
for rootV.Parent != nil {
if findSubRoot && rootV.IsRoot {
break
}
if findFormatRoot && rootV.Format != nil {
break
}
rootV = rootV.Parent
}
return rootV
}
func (v *Value) Root() *Value { return v.root(false, false) }
func (v *Value) BufferRoot() *Value { return v.root(true, false) }
func (v *Value) FormatRoot() *Value { return v.root(true, true) }
func (v *Value) Errors() []error {
var errs []error
_ = v.WalkPreOrder(func(v *Value, _ *Value, _ int, _ int) error {
if v.Err != nil {
errs = append(errs, v.Err)
}
return nil
})
return errs
}
func (v *Value) InnerRange() ranges.Range {
if v.IsRoot {
return ranges.Range{Start: 0, Len: v.Range.Len}
}
return v.Range
}
func (v *Value) postProcess() {
if err := v.WalkRootPostOrder(func(v *Value, _ *Value, _ int, _ int) error {
switch vv := v.V.(type) {
case *Compound:
first := true
for _, f := range vv.Children {
if f.IsRoot {
continue
}
if s, ok := f.V.(scalar.Scalarable); ok && s.ScalarFlags().IsSynthetic() {
continue
}
if first {
v.Range = f.Range
first = false
} else {
v.Range = ranges.MinMax(v.Range, f.Range)
}
}
// sort struct fields and make sure to keep order if range is the same
if !vv.IsArray {
slices.SortStableFunc(vv.Children, func(a, b *Value) int {
return cmp.Compare(a.Range.Start, b.Range.Start)
})
}
v.Index = -1
if vv.IsArray {
for i, f := range vv.Children {
f.Index = i
}
} else {
for _, f := range vv.Children {
f.Index = -1
}
}
}
return nil
}); err != nil {
panic(err)
}
}
// TODO: rethink this
func (v *Value) TryUintScalarFn(sms ...scalar.UintMapper) error {
var err error
sr, ok := v.V.(*scalar.Uint)
if !ok {
panic("not a scalar value")
}
s := *sr
for _, sm := range sms {
s, err = sm.MapUint(s)
if err != nil {
break
}
}
v.V = &s
return err
}
func (v *Value) TryBitBufScalarFn(sms ...scalar.BitBufMapper) error {
var err error
sr, ok := v.V.(*scalar.BitBuf)
if !ok {
panic("not a scalar value")
}
s := *sr
for _, sm := range sms {
s, err = sm.MapBitBuf(s)
if err != nil {
break
}
}
v.V = &s
return err
}
func (v *Value) Remove() error {
p := v.Parent
if p == nil {
return fmt.Errorf("d has no parent")
}
switch fv := p.V.(type) {
case *Compound:
if !fv.IsArray {
if _, ok := fv.ByName[v.Name]; !ok {
return fmt.Errorf("d not in parent ByName")
}
delete(fv.ByName, p.Name)
}
found := false
var cs []*Value
for _, c := range fv.Children {
if c == v {
found = true
continue
}
cs = append(cs, c)
}
if !found {
return fmt.Errorf("d not in parent children")
}
fv.Children = cs
}
return nil
}