mirror of
https://github.com/wader/fq.git
synced 2024-11-24 11:16:09 +03:00
e9d9f8aef9
Rename s/interface{}/any/g
Preparation for using generics in decode API and native jq funcations etc
Remove some unused linter ignores as linter has been fixed
101 lines
3.1 KiB
Go
101 lines
3.1 KiB
Go
package tar
|
|
|
|
// https://www.gnu.org/software/tar/manual/html_node/Standard.html
|
|
// TODO: extensions?
|
|
|
|
import (
|
|
"bytes"
|
|
|
|
"github.com/wader/fq/format"
|
|
"github.com/wader/fq/format/registry"
|
|
"github.com/wader/fq/pkg/decode"
|
|
"github.com/wader/fq/pkg/scalar"
|
|
)
|
|
|
|
var probeFormat decode.Group
|
|
|
|
func init() {
|
|
registry.MustRegister(decode.Format{
|
|
Name: format.TAR,
|
|
Description: "Tar archive",
|
|
Groups: []string{format.PROBE},
|
|
DecodeFn: tarDecode,
|
|
Dependencies: []decode.Dependency{
|
|
{Names: []string{format.PROBE}, Group: &probeFormat},
|
|
},
|
|
})
|
|
}
|
|
|
|
func tarDecode(d *decode.D, in any) any {
|
|
const blockBytes = 512
|
|
const blockBits = blockBytes * 8
|
|
|
|
mapTrimSpaceNull := scalar.ActualTrim(" \x00")
|
|
blockPadding := func(d *decode.D) int64 {
|
|
return (blockBits - (d.Pos() % blockBits)) % blockBits
|
|
}
|
|
|
|
// end marker is 512*2 zero bytes
|
|
endMarker := [blockBytes * 2]byte{}
|
|
var endMarkerStart int64
|
|
var endMarkerEnd int64
|
|
filesCount := 0
|
|
|
|
d.FieldArray("files", func(d *decode.D) {
|
|
for !d.End() {
|
|
d.FieldStruct("file", func(d *decode.D) {
|
|
d.FieldUTF8("name", 100, mapTrimSpaceNull)
|
|
d.FieldUTF8NullFixedLen("mode", 8, scalar.SymUParseUint(8))
|
|
d.FieldUTF8NullFixedLen("uid", 8, scalar.SymUParseUint(8))
|
|
d.FieldUTF8NullFixedLen("gid", 8, scalar.SymUParseUint(8))
|
|
sizeS := d.FieldScalarUTF8NullFixedLen("size", 12, scalar.SymUParseUint(8))
|
|
if sizeS.Sym == nil {
|
|
d.Fatalf("could not decode size")
|
|
}
|
|
size := int64(sizeS.SymU()) * 8
|
|
d.FieldUTF8NullFixedLen("mtime", 12, scalar.SymUParseUint(8), scalar.DescriptionSymUUnixTime)
|
|
d.FieldUTF8NullFixedLen("chksum", 8, scalar.SymUParseUint(8))
|
|
d.FieldUTF8("typeflag", 1, mapTrimSpaceNull)
|
|
d.FieldUTF8("linkname", 100, mapTrimSpaceNull)
|
|
d.FieldUTF8("magic", 6, mapTrimSpaceNull, d.AssertStr("ustar"))
|
|
d.FieldUTF8NullFixedLen("version", 2, scalar.SymUParseUint(8))
|
|
d.FieldUTF8("uname", 32, mapTrimSpaceNull)
|
|
d.FieldUTF8("gname", 32, mapTrimSpaceNull)
|
|
d.FieldUTF8NullFixedLen("devmajor", 8, scalar.SymUParseUint(8))
|
|
d.FieldUTF8NullFixedLen("devminor", 8, scalar.SymUParseUint(8))
|
|
d.FieldUTF8("prefix", 155, mapTrimSpaceNull)
|
|
d.FieldRawLen("header_block_padding", blockPadding(d), d.BitBufIsZero())
|
|
|
|
d.FieldFormatOrRawLen("data", size, probeFormat, nil)
|
|
|
|
d.FieldRawLen("data_block_padding", blockPadding(d), d.BitBufIsZero())
|
|
})
|
|
filesCount++
|
|
|
|
if d.BitsLeft() >= int64(len(endMarker))*8 && bytes.Equal(d.PeekBytes(len(endMarker)), endMarker[:]) {
|
|
endMarkerStart = d.Pos()
|
|
// consensus seems to be to allow more than 2 zero blocks at end
|
|
d.SeekRel(int64(len(endMarker)) * 8)
|
|
zeroBlock := [blockBytes]byte{}
|
|
for d.BitsLeft() >= blockBytes*8 && bytes.Equal(d.PeekBytes(blockBytes), zeroBlock[:]) {
|
|
d.SeekRel(int64(len(zeroBlock)) * 8)
|
|
}
|
|
endMarkerEnd = d.Pos()
|
|
break
|
|
}
|
|
}
|
|
})
|
|
endMarkerSize := endMarkerEnd - endMarkerStart
|
|
if endMarkerSize > 0 {
|
|
d.RangeFn(endMarkerStart, endMarkerSize, func(d *decode.D) {
|
|
d.FieldRawLen("end_marker", d.BitsLeft())
|
|
})
|
|
}
|
|
|
|
if filesCount == 0 {
|
|
d.Errorf("no files found")
|
|
}
|
|
|
|
return nil
|
|
}
|