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fq/format/bencode/bencode.go
Mattias Wadman 149cb3f45a interp: Add torepr/0 that converts decode value into what it reptresents
Ex: fq -d msgpack torepr file.msgpack
Willoutput the JSON representation of the msgpack

Make per format *_torepr functions internal
2022-01-12 17:33:58 +01:00

95 lines
2.1 KiB
Go

package bencode
import (
"embed"
"strconv"
"github.com/wader/fq/format"
"github.com/wader/fq/format/registry"
"github.com/wader/fq/pkg/decode"
"github.com/wader/fq/pkg/scalar"
)
//go:embed *.jq
var bencodeFS embed.FS
func init() {
registry.MustRegister(decode.Format{
Name: format.BENCODE,
Description: "BitTorrent bencoding",
DecodeFn: decodeBencode,
Files: bencodeFS,
ToRepr: "_bencode_torepr",
})
}
var typeToNames = scalar.StrToSymStr{
"d": "dictionary",
"i": "integer",
"l": "list",
"0": "string",
"1": "string",
"2": "string",
"3": "string",
"4": "string",
"5": "string",
"6": "string",
"7": "string",
"8": "string",
"9": "string",
}
func decodeStrIntUntil(b byte) func(d *decode.D) int64 {
return func(d *decode.D) int64 {
// 21 is sign + longest 64 bit in base 10
i := d.PeekFindByte(b, 21)
if i == -1 {
d.Fatalf("decodeStrIntUntil: failed to find %v", b)
}
s := d.UTF8(int(i))
n, err := strconv.ParseInt(s, 10, 64)
if err != nil {
d.Fatalf("decodeStrIntUntil: %q: %s", s, err)
}
return n
}
}
func decodeBencodeValue(d *decode.D) {
typ := d.FieldUTF8("type", 1, typeToNames)
switch typ {
case "0", "1", "2", "3", "4", "5", "6", "7", "8", "9":
d.SeekRel(-8)
length := d.FieldSFn("length", decodeStrIntUntil(':'))
d.FieldUTF8("separator", 1, d.AssertStr(":"))
d.FieldUTF8("value", int(length))
case "i":
d.FieldSFn("value", decodeStrIntUntil('e'))
d.FieldUTF8("end", 1, d.AssertStr("e"))
case "l":
d.FieldArray("values", func(d *decode.D) {
for d.PeekBits(8) != 'e' {
d.FieldStruct("value", decodeBencodeValue)
}
})
d.FieldUTF8("end", 1, d.AssertStr("e"))
case "d":
d.FieldArray("pairs", func(d *decode.D) {
for d.PeekBits(8) != 'e' {
d.FieldStruct("pair", func(d *decode.D) {
d.FieldStruct("key", decodeBencodeValue)
d.FieldStruct("value", decodeBencodeValue)
})
}
})
d.FieldUTF8("end", 1, d.AssertStr("e"))
default:
d.Fatalf("unknown type %v", typ)
}
}
func decodeBencode(d *decode.D, in interface{}) interface{} {
decodeBencodeValue(d)
return nil
}