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mirror of https://github.com/wader/fq.git synced 2024-11-22 15:45:45 +03:00
fq/format/ar/ar.go
Mattias Wadman e2eb667091 html: Add to probe group
As decoder now can know they are decoding as part of probing we can now
use some heuristics to see if we should decode as html.
The reason heuristics is needed is that x/html parser will alwaus succeed.

Add lazyre package to help delay compile of RE and make it concurrency safe.
2023-05-11 19:07:18 +02:00

52 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 probeGroup decode.Group
func init() {
interp.RegisterFormat(
format.AR,
&decode.Format{
Description: "Unix archive",
Groups: []*decode.Group{format.Probe},
DecodeFn: decodeAr,
Dependencies: []decode.Dependency{
{Groups: []*decode.Group{format.Probe}, Out: &probeGroup},
},
})
}
func decodeAr(d *decode.D) any {
d.FieldUTF8("signature", 8, d.StrAssert("!<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.TryStrSymParseUint(10))
d.FieldUTF8("owner_id", 6, scalar.ActualTrimSpace, scalar.TryStrSymParseUint(10))
d.FieldUTF8("group_id", 6, scalar.ActualTrimSpace, scalar.TryStrSymParseUint(10))
d.FieldUTF8("file_mode", 8, scalar.ActualTrimSpace, scalar.TryStrSymParseUint(8)) // Octal
sizeStr := d.FieldScalarUTF8("file_size", 10, scalar.ActualTrimSpace, scalar.TryStrSymParseUint(10))
if sizeStr.Sym == nil {
d.Fatalf("could not decode file_size")
}
size := int64(sizeStr.SymUint()) * 8
d.FieldUTF8("ending_characters", 2)
d.FieldFormatOrRawLen("data", size, &probeGroup, format.Probe_In{})
padding := d.AlignBits(16)
if padding > 0 {
d.FieldRawLen("padding", int64(padding))
}
})
}
})
return nil
}