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mirror of https://github.com/wader/fq.git synced 2024-12-23 13:22:58 +03:00
fq/format/bitcoin/bitcoin_block.go
Mattias Wadman 9b81d4d3ab decode: More type safe API and split scalar into multiple types
Preparation to make decoder use less memory and API more type safe.
Now each scalar type has it's own struct type so it can store different
things and enables to have a scalar interface.
Also own types will enable experimenting with decode DLS designs like
using chained methods that are type aware.
2022-12-14 16:23:58 +01:00

86 lines
2.0 KiB
Go

package bitcoin
// https://learnmeabitcoin.com/technical/blkdat
import (
"fmt"
"time"
"github.com/wader/fq/format"
"github.com/wader/fq/pkg/decode"
"github.com/wader/fq/pkg/interp"
"github.com/wader/fq/pkg/scalar"
)
var bitcoinTranscationFormat decode.Group
func init() {
interp.RegisterFormat(decode.Format{
Name: format.BITCOIN_BLOCK,
Description: "Bitcoin block",
Dependencies: []decode.Dependency{
{Names: []string{format.BITCOIN_TRANSACTION}, Group: &bitcoinTranscationFormat},
},
DecodeFn: decodeBitcoinBlock,
DecodeInArg: format.BitCoinBlockIn{
HasHeader: false,
},
})
}
var rawHexReverse = scalar.BitBufFn(func(s scalar.BitBuf) (scalar.BitBuf, error) {
return scalar.RawSym(s, -1, func(b []byte) string {
decode.ReverseBytes(b)
return fmt.Sprintf("%x", b)
})
})
func decodeBitcoinBlock(d *decode.D, in interface{}) interface{} {
bbi, _ := in.(format.BitCoinBlockIn)
size := d.BitsLeft()
if bbi.HasHeader {
magic := d.PeekBits(32)
switch magic {
case 0xf9beb4d9,
0x0b110907,
0xfabfb5da:
d.FieldU32("magic", scalar.UintMapSymStr{
0xf9beb4d9: "mainnet",
0x0b110907: "testnet3",
0xfabfb5da: "regtest",
}, scalar.UintHex)
size = int64(d.FieldU32LE("size")) * 8
default:
d.Fatalf("unknown magic %x", magic)
}
}
d.Endian = decode.LittleEndian
d.FramedFn(size, func(d *decode.D) {
d.FieldStruct("header", func(d *decode.D) {
d.FieldU32("version", scalar.UintHex)
d.FieldRawLen("previous_block_hash", 32*8, rawHexReverse)
d.FieldRawLen("merkle_root", 32*8, rawHexReverse)
d.FieldU32("time", scalar.UintActualUnixTime(time.RFC3339))
d.FieldU32("bits", scalar.UintHex)
d.FieldU32("nonce", scalar.UintHex)
})
// TODO: remove? support header only decode this way?
if d.BitsLeft() == 0 {
return
}
txCount := d.FieldUintFn("tx_count", decodeVarInt)
d.FieldArray("transactions", func(d *decode.D) {
for i := uint64(0); i < txCount; i++ {
d.FieldFormat("transaction", bitcoinTranscationFormat, nil)
}
})
})
return nil
}