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mirror of https://github.com/wader/fq.git synced 2024-12-01 02:30:32 +03:00
fq/format/ar/ar.go
2022-07-19 18:33:50 +02:00

51 lines
1.5 KiB
Go

package ar
import (
"github.com/wader/fq/format"
"github.com/wader/fq/pkg/decode"
"github.com/wader/fq/pkg/interp"
"github.com/wader/fq/pkg/scalar"
)
var probeFormat decode.Group
func init() {
interp.RegisterFormat(decode.Format{
Name: format.AR,
Description: "Unix archive",
Groups: []string{format.PROBE},
DecodeFn: decodeAr,
Dependencies: []decode.Dependency{
{Names: []string{format.PROBE}, Group: &probeFormat},
},
})
}
func decodeAr(d *decode.D, _ any) any {
d.FieldUTF8("signature", 8, d.AssertStr("!<arch>\n"))
d.FieldArray("files", func(d *decode.D) {
for !d.End() {
d.FieldStruct("file", func(d *decode.D) {
d.FieldUTF8("identifier", 16, scalar.ActualTrimSpace)
d.FieldUTF8("modification_timestamp", 12, scalar.ActualTrimSpace, scalar.SymUParseUint(10))
d.FieldUTF8("owner_id", 6, scalar.ActualTrimSpace, scalar.SymUParseUint(10))
d.FieldUTF8("group_id", 6, scalar.ActualTrimSpace, scalar.SymUParseUint(10))
d.FieldUTF8("file_mode", 8, scalar.ActualTrimSpace, scalar.SymUParseUint(8)) // Octal
sizeS := d.FieldScalarUTF8("file_size", 10, scalar.ActualTrimSpace, scalar.SymUParseUint(10))
if sizeS.Sym == nil {
d.Fatalf("could not decode file_size")
}
size := int64(sizeS.SymU()) * 8
d.FieldUTF8("ending_characters", 2)
d.FieldFormatOrRawLen("data", size, probeFormat, nil)
padding := d.AlignBits(16)
if padding > 0 {
d.FieldRawLen("padding", int64(padding))
}
})
}
})
return nil
}