13481548301

Committed 23 Feb 2025 09:06AM UTC coverage: 4.031% (-54.8%) from 58.825%

Build # 13481548301

Build Type

Pull #9521

github

Committed by

web-flow

Commit Message

Merge 1ffbe99fe into 5fe900d18

Pull Request Pull Request #9521: unit: remove GOACC, use Go 1.20 native coverage functionality

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0.0

/zpay32/encode.go

package zpay32

import (
        "bytes"
        "encoding/binary"
        "fmt"

        "github.com/btcsuite/btcd/btcutil"
        "github.com/btcsuite/btcd/btcutil/bech32"
        "github.com/btcsuite/btcd/chaincfg"
        "github.com/btcsuite/btcd/chaincfg/chainhash"
        "github.com/lightningnetwork/lnd/fn/v2"
        "github.com/lightningnetwork/lnd/lnwire"
)

// Encode takes the given MessageSigner and returns a string encoding this
// invoice signed by the node key of the signer.
func (invoice *Invoice) Encode(signer MessageSigner) (string, error) {
        // First check that this invoice is valid before starting the encoding.
        if err := validateInvoice(invoice); err != nil {
                return "", err
        }

        // The buffer will encoded the invoice data using 5-bit groups (base32).
        var bufferBase32 bytes.Buffer

        // The timestamp will be encoded using 35 bits, in base32.
        timestampBase32 := uint64ToBase32(uint64(invoice.Timestamp.Unix()))

        // The timestamp must be exactly 35 bits, which means 7 groups. If it
        // can fit into fewer groups we add leading zero groups, if it is too
        // big we fail early, as there is not possible to encode it.
        if len(timestampBase32) > timestampBase32Len {
                return "", fmt.Errorf("timestamp too big: %d",
                        invoice.Timestamp.Unix())
        }

        // Add zero bytes to the first timestampBase32Len-len(timestampBase32)
        // groups, then add the non-zero groups.
        zeroes := make([]byte, timestampBase32Len-len(timestampBase32))
        _, err := bufferBase32.Write(zeroes)
        if err != nil {
                return "", fmt.Errorf("unable to write to buffer: %w", err)
        }
        _, err = bufferBase32.Write(timestampBase32)
        if err != nil {
                return "", fmt.Errorf("unable to write to buffer: %w", err)
        }

        // We now write the tagged fields to the buffer, which will fill the
        // rest of the data part before the signature.
        if err := writeTaggedFields(&bufferBase32, invoice); err != nil {
                return "", err
        }

        // The human-readable part (hrp) is "ln" + net hrp + optional amount,
        // except for signet where we add an additional "s" to differentiate it
        // from the older testnet3 (Core devs decided to use the same hrp for
        // signet as for testnet3 which is not optimal for LN). See
        // https://github.com/lightningnetwork/lightning-rfc/pull/844 for more
        // information.
        hrp := "ln" + invoice.Net.Bech32HRPSegwit
        if invoice.Net.Name == chaincfg.SigNetParams.Name {
                hrp = "lntbs"
        }
        if invoice.MilliSat != nil {
                // Encode the amount using the fewest possible characters.
                am, err := encodeAmount(*invoice.MilliSat)
                if err != nil {
                        return "", err
                }
                hrp += am
        }

        // The signature is over the single SHA-256 hash of the hrp + the
        // tagged fields encoded in base256.
        taggedFieldsBytes, err := bech32.ConvertBits(bufferBase32.Bytes(), 5, 8, true)
        if err != nil {
                return "", err
        }

        toSign := append([]byte(hrp), taggedFieldsBytes...)

        // We use compact signature format, and also encoded the recovery ID
        // such that a reader of the invoice can recover our pubkey from the
        // signature.
        sign, err := signer.SignCompact(toSign)
        if err != nil {
                return "", err
        }

        // From the header byte we can extract the recovery ID, and the last 64
        // bytes encode the signature.
        recoveryID := sign[0] - 27 - 4
        sig, err := lnwire.NewSigFromWireECDSA(sign[1:])
        if err != nil {
                return "", err
        }

        // If the pubkey field was explicitly set, it must be set to the pubkey
        // used to create the signature.
        if invoice.Destination != nil {
                signature, err := sig.ToSignature()
                if err != nil {
                        return "", fmt.Errorf("unable to deserialize "+
                                "signature: %v", err)
                }

                hash := chainhash.HashB(toSign)
                valid := signature.Verify(hash, invoice.Destination)
                if !valid {
                        return "", fmt.Errorf("signature does not match " +
                                "provided pubkey")
                }
        }

        // Convert the signature to base32 before writing it to the buffer.
        signBase32, err := bech32.ConvertBits(
                append(sig.RawBytes(), recoveryID),
                8, 5, true,
        )
        if err != nil {
                return "", err
        }
        bufferBase32.Write(signBase32)

        // Now we can create the bech32 encoded string from the base32 buffer.
        b32, err := bech32.Encode(hrp, bufferBase32.Bytes())
        if err != nil {
                return "", err
        }

        // Before returning, check that the bech32 encoded string is not greater
        // than our largest supported invoice size.
        if len(b32) > maxInvoiceLength {
                return "", ErrInvoiceTooLarge
        }

        return b32, nil
}

// writeTaggedFields writes the non-nil tagged fields of the Invoice to the
// base32 buffer.
func writeTaggedFields(bufferBase32 *bytes.Buffer, invoice *Invoice) error {
        if invoice.PaymentHash != nil {
                err := writeBytes32(bufferBase32, fieldTypeP, *invoice.PaymentHash)
                if err != nil {
                        return err
                }
        }

        if invoice.Description != nil {
                base32, err := bech32.ConvertBits([]byte(*invoice.Description),
                        8, 5, true)
                if err != nil {
                        return err
                }
                err = writeTaggedField(bufferBase32, fieldTypeD, base32)
                if err != nil {
                        return err
                }
        }

        if invoice.DescriptionHash != nil {
                err := writeBytes32(
                        bufferBase32, fieldTypeH, *invoice.DescriptionHash,
                )
                if err != nil {
                        return err
                }
        }

        if invoice.Metadata != nil {
                base32, err := bech32.ConvertBits(invoice.Metadata, 8, 5, true)
                if err != nil {
                        return err
                }
                err = writeTaggedField(bufferBase32, fieldTypeM, base32)
                if err != nil {
                        return err
                }
        }

        if invoice.minFinalCLTVExpiry != nil {
                finalDelta := uint64ToBase32(*invoice.minFinalCLTVExpiry)
                err := writeTaggedField(bufferBase32, fieldTypeC, finalDelta)
                if err != nil {
                        return err
                }
        }

        if invoice.expiry != nil {
                seconds := invoice.expiry.Seconds()
                expiry := uint64ToBase32(uint64(seconds))
                err := writeTaggedField(bufferBase32, fieldTypeX, expiry)
                if err != nil {
                        return err
                }
        }

        if invoice.FallbackAddr != nil {
                var version byte
                switch addr := invoice.FallbackAddr.(type) {
                case *btcutil.AddressPubKeyHash:
                        version = 17
                case *btcutil.AddressScriptHash:
                        version = 18
                case *btcutil.AddressWitnessPubKeyHash:
                        version = addr.WitnessVersion()
                case *btcutil.AddressWitnessScriptHash:
                        version = addr.WitnessVersion()
                default:
                        return fmt.Errorf("unknown fallback address type")
                }
                base32Addr, err := bech32.ConvertBits(
                        invoice.FallbackAddr.ScriptAddress(), 8, 5, true)
                if err != nil {
                        return err
                }

                err = writeTaggedField(bufferBase32, fieldTypeF,
                        append([]byte{version}, base32Addr...))
                if err != nil {
                        return err
                }
        }

        for _, routeHint := range invoice.RouteHints {
                // Each hop hint is encoded using 51 bytes, so we'll make to
                // sure to allocate enough space for the whole route hint.
                routeHintBase256 := make([]byte, 0, hopHintLen*len(routeHint))

                for _, hopHint := range routeHint {
                        hopHintBase256 := make([]byte, hopHintLen)
                        copy(hopHintBase256[:33], hopHint.NodeID.SerializeCompressed())
                        binary.BigEndian.PutUint64(
                                hopHintBase256[33:41], hopHint.ChannelID,
                        )
                        binary.BigEndian.PutUint32(
                                hopHintBase256[41:45], hopHint.FeeBaseMSat,
                        )
                        binary.BigEndian.PutUint32(
                                hopHintBase256[45:49], hopHint.FeeProportionalMillionths,
                        )
                        binary.BigEndian.PutUint16(
                                hopHintBase256[49:51], hopHint.CLTVExpiryDelta,
                        )
                        routeHintBase256 = append(routeHintBase256, hopHintBase256...)
                }

                routeHintBase32, err := bech32.ConvertBits(
                        routeHintBase256, 8, 5, true,
                )
                if err != nil {
                        return err
                }

                err = writeTaggedField(bufferBase32, fieldTypeR, routeHintBase32)
                if err != nil {
                        return err
                }
        }

        for _, path := range invoice.BlindedPaymentPaths {
                var buf bytes.Buffer

                err := path.Encode(&buf)
                if err != nil {
                        return err
                }

                blindedPathBase32, err := bech32.ConvertBits(
                        buf.Bytes(), 8, 5, true,
                )
                if err != nil {
                        return err
                }

                err = writeTaggedField(
                        bufferBase32, fieldTypeB, blindedPathBase32,
                )
                if err != nil {
                        return err
                }
        }

        if invoice.Destination != nil {
                // Convert 33 byte pubkey to 53 5-bit groups.
                pubKeyBase32, err := bech32.ConvertBits(
                        invoice.Destination.SerializeCompressed(), 8, 5, true)
                if err != nil {
                        return err
                }

                if len(pubKeyBase32) != pubKeyBase32Len {
                        return fmt.Errorf("invalid pubkey length: %d",
                                len(invoice.Destination.SerializeCompressed()))
                }

                err = writeTaggedField(bufferBase32, fieldTypeN, pubKeyBase32)
                if err != nil {
                        return err
                }
        }

        err := fn.MapOptionZ(invoice.PaymentAddr, func(addr [32]byte) error {
                return writeBytes32(bufferBase32, fieldTypeS, addr)
        })
        if err != nil {
                return err
        }

        if invoice.Features.SerializeSize32() > 0 {
                var b bytes.Buffer
                err := invoice.Features.RawFeatureVector.EncodeBase32(&b)
                if err != nil {
                        return err
                }

                err = writeTaggedField(bufferBase32, fieldType9, b.Bytes())
                if err != nil {
                        return err
                }
        }

        return nil
}

// writeBytes32 encodes a 32-byte array as base32 and writes it to bufferBase32
// under the passed fieldType.
func writeBytes32(bufferBase32 *bytes.Buffer, fieldType byte, b [32]byte) error {
        // Convert 32 byte hash to 52 5-bit groups.
        base32, err := bech32.ConvertBits(b[:], 8, 5, true)
        if err != nil {
                return err
        }

        return writeTaggedField(bufferBase32, fieldType, base32)
}

// writeTaggedField takes the type of a tagged data field, and the data of
// the tagged field (encoded in base32), and writes the type, length and data
// to the buffer.
func writeTaggedField(bufferBase32 *bytes.Buffer, dataType byte, data []byte) error {
        // Length must be exactly 10 bits, so add leading zero groups if
        // needed.
        lenBase32 := uint64ToBase32(uint64(len(data)))
        for len(lenBase32) < 2 {
                lenBase32 = append([]byte{0}, lenBase32...)
        }

        if len(lenBase32) != 2 {
                return fmt.Errorf("data length too big to fit within 10 bits: %d",
                        len(data))
        }

        err := bufferBase32.WriteByte(dataType)
        if err != nil {
                return fmt.Errorf("unable to write to buffer: %w", err)
        }
        _, err = bufferBase32.Write(lenBase32)
        if err != nil {
                return fmt.Errorf("unable to write to buffer: %w", err)
        }
        _, err = bufferBase32.Write(data)
        if err != nil {
                return fmt.Errorf("unable to write to buffer: %w", err)
        }

        return nil
}

// uint64ToBase32 converts a uint64 to a base32 encoded integer encoded using
// as few 5-bit groups as possible.
func uint64ToBase32(num uint64) []byte {
        // Return at least one group.
        if num == 0 {
                return []byte{0}
        }

        // To fit an uint64, we need at most is ceil(64 / 5) = 13 groups.
        arr := make([]byte, 13)
        i := 13
        for num > 0 {
                i--
                arr[i] = byte(num & uint64(31)) // 0b11111 in binary
                num >>= 5
        }

        // We only return non-zero leading groups.
        return arr[i:]
}

1	package zpay32
2
3	import (
4	"bytes"
5	"encoding/binary"
6	"fmt"
7
8	"github.com/btcsuite/btcd/btcutil"
9	"github.com/btcsuite/btcd/btcutil/bech32"
10	"github.com/btcsuite/btcd/chaincfg"
11	"github.com/btcsuite/btcd/chaincfg/chainhash"
12	"github.com/lightningnetwork/lnd/fn/v2"
13	"github.com/lightningnetwork/lnd/lnwire"
14	)
15
16	// Encode takes the given MessageSigner and returns a string encoding this
17	// invoice signed by the node key of the signer.
18	func (invoice *Invoice) Encode(signer MessageSigner) (string, error) {	×
19	// First check that this invoice is valid before starting the encoding.	×
20	if err := validateInvoice(invoice); err != nil {	×
21	return "", err	×
22	}	×
23
24	// The buffer will encoded the invoice data using 5-bit groups (base32).
25	var bufferBase32 bytes.Buffer	×
26		×
27	// The timestamp will be encoded using 35 bits, in base32.	×
28	timestampBase32 := uint64ToBase32(uint64(invoice.Timestamp.Unix()))	×
29		×
30	// The timestamp must be exactly 35 bits, which means 7 groups. If it	×
31	// can fit into fewer groups we add leading zero groups, if it is too	×
32	// big we fail early, as there is not possible to encode it.	×
33	if len(timestampBase32) > timestampBase32Len {	×
34	return "", fmt.Errorf("timestamp too big: %d",	×
35	invoice.Timestamp.Unix())	×
36	}	×
37
38	// Add zero bytes to the first timestampBase32Len-len(timestampBase32)
39	// groups, then add the non-zero groups.
40	zeroes := make([]byte, timestampBase32Len-len(timestampBase32))	×
41	_, err := bufferBase32.Write(zeroes)	×
42	if err != nil {	×
43	return "", fmt.Errorf("unable to write to buffer: %w", err)	×
44	}	×
45	_, err = bufferBase32.Write(timestampBase32)	×
46	if err != nil {	×
47	return "", fmt.Errorf("unable to write to buffer: %w", err)	×
48	}	×
49
50	// We now write the tagged fields to the buffer, which will fill the
51	// rest of the data part before the signature.
52	if err := writeTaggedFields(&bufferBase32, invoice); err != nil {	×
53	return "", err	×
54	}	×
55
56	// The human-readable part (hrp) is "ln" + net hrp + optional amount,
57	// except for signet where we add an additional "s" to differentiate it
58	// from the older testnet3 (Core devs decided to use the same hrp for
59	// signet as for testnet3 which is not optimal for LN). See
60	// https://github.com/lightningnetwork/lightning-rfc/pull/844 for more
61	// information.
62	hrp := "ln" + invoice.Net.Bech32HRPSegwit	×
63	if invoice.Net.Name == chaincfg.SigNetParams.Name {	×
64	hrp = "lntbs"	×
65	}	×
66	if invoice.MilliSat != nil {	×
67	// Encode the amount using the fewest possible characters.	×
68	am, err := encodeAmount(*invoice.MilliSat)	×
69	if err != nil {	×
70	return "", err	×
71	}	×
72	hrp += am	×
73	}
74
75	// The signature is over the single SHA-256 hash of the hrp + the
76	// tagged fields encoded in base256.
77	taggedFieldsBytes, err := bech32.ConvertBits(bufferBase32.Bytes(), 5, 8, true)	×
78	if err != nil {	×
79	return "", err	×
80	}	×
81
82	toSign := append([]byte(hrp), taggedFieldsBytes...)	×
83		×
84	// We use compact signature format, and also encoded the recovery ID	×
85	// such that a reader of the invoice can recover our pubkey from the	×
86	// signature.	×
87	sign, err := signer.SignCompact(toSign)	×
88	if err != nil {	×
89	return "", err	×
90	}	×
91
92	// From the header byte we can extract the recovery ID, and the last 64
93	// bytes encode the signature.
94	recoveryID := sign[0] - 27 - 4	×
95	sig, err := lnwire.NewSigFromWireECDSA(sign[1:])	×
96	if err != nil {	×
97	return "", err	×
98	}	×
99
100	// If the pubkey field was explicitly set, it must be set to the pubkey
101	// used to create the signature.
102	if invoice.Destination != nil {	×
103	signature, err := sig.ToSignature()	×
104	if err != nil {	×
105	return "", fmt.Errorf("unable to deserialize "+	×
106	"signature: %v", err)	×
107	}	×
108
109	hash := chainhash.HashB(toSign)	×
110	valid := signature.Verify(hash, invoice.Destination)	×
111	if !valid {	×
112	return "", fmt.Errorf("signature does not match " +	×
113	"provided pubkey")	×
114	}	×
115	}
116
117	// Convert the signature to base32 before writing it to the buffer.
118	signBase32, err := bech32.ConvertBits(	×
119	append(sig.RawBytes(), recoveryID),	×
120	8, 5, true,	×
121	)	×
122	if err != nil {	×
123	return "", err	×
124	}	×
125	bufferBase32.Write(signBase32)	×
126		×
127	// Now we can create the bech32 encoded string from the base32 buffer.	×
128	b32, err := bech32.Encode(hrp, bufferBase32.Bytes())	×
129	if err != nil {	×
130	return "", err	×
131	}	×
132
133	// Before returning, check that the bech32 encoded string is not greater
134	// than our largest supported invoice size.
135	if len(b32) > maxInvoiceLength {	×
136	return "", ErrInvoiceTooLarge	×
137	}	×
138
139	return b32, nil	×
140	}
141
142	// writeTaggedFields writes the non-nil tagged fields of the Invoice to the
143	// base32 buffer.
144	func writeTaggedFields(bufferBase32 bytes.Buffer, invoice Invoice) error {	×
145	if invoice.PaymentHash != nil {	×
146	err := writeBytes32(bufferBase32, fieldTypeP, *invoice.PaymentHash)	×
147	if err != nil {	×
148	return err	×
149	}	×
150	}
151
152	if invoice.Description != nil {	×
153	base32, err := bech32.ConvertBits([]byte(*invoice.Description),	×
154	8, 5, true)	×
155	if err != nil {	×
156	return err	×
157	}	×
158	err = writeTaggedField(bufferBase32, fieldTypeD, base32)	×
159	if err != nil {	×
160	return err	×
161	}	×
162	}
163
164	if invoice.DescriptionHash != nil {	×
165	err := writeBytes32(	×
166	bufferBase32, fieldTypeH, *invoice.DescriptionHash,	×
167	)	×
168	if err != nil {	×
169	return err	×
170	}	×
171	}
172
173	if invoice.Metadata != nil {	×
174	base32, err := bech32.ConvertBits(invoice.Metadata, 8, 5, true)	×
175	if err != nil {	×
176	return err	×
177	}	×
178	err = writeTaggedField(bufferBase32, fieldTypeM, base32)	×
179	if err != nil {	×
180	return err	×
181	}	×
182	}
183
184	if invoice.minFinalCLTVExpiry != nil {	×
185	finalDelta := uint64ToBase32(*invoice.minFinalCLTVExpiry)	×
186	err := writeTaggedField(bufferBase32, fieldTypeC, finalDelta)	×
187	if err != nil {	×
188	return err	×
189	}	×
190	}
191
192	if invoice.expiry != nil {	×
193	seconds := invoice.expiry.Seconds()	×
194	expiry := uint64ToBase32(uint64(seconds))	×
195	err := writeTaggedField(bufferBase32, fieldTypeX, expiry)	×
196	if err != nil {	×
197	return err	×
198	}	×
199	}
200
201	if invoice.FallbackAddr != nil {	×
202	var version byte	×
203	switch addr := invoice.FallbackAddr.(type) {	×
204	case *btcutil.AddressPubKeyHash:	×
205	version = 17	×
206	case *btcutil.AddressScriptHash:	×
207	version = 18	×
208	case *btcutil.AddressWitnessPubKeyHash:	×
209	version = addr.WitnessVersion()	×
210	case *btcutil.AddressWitnessScriptHash:	×
211	version = addr.WitnessVersion()	×
212	default:	×
213	return fmt.Errorf("unknown fallback address type")	×
214	}
215	base32Addr, err := bech32.ConvertBits(	×
216	invoice.FallbackAddr.ScriptAddress(), 8, 5, true)	×
217	if err != nil {	×
218	return err	×
219	}	×
220
221	err = writeTaggedField(bufferBase32, fieldTypeF,	×
222	append([]byte{version}, base32Addr...))	×
223	if err != nil {	×
224	return err	×
225	}	×
226	}
227
228	for _, routeHint := range invoice.RouteHints {	×
229	// Each hop hint is encoded using 51 bytes, so we'll make to	×
230	// sure to allocate enough space for the whole route hint.	×
231	routeHintBase256 := make([]byte, 0, hopHintLen*len(routeHint))	×
232		×
233	for _, hopHint := range routeHint {	×
234	hopHintBase256 := make([]byte, hopHintLen)	×
235	copy(hopHintBase256[:33], hopHint.NodeID.SerializeCompressed())	×
236	binary.BigEndian.PutUint64(	×
237	hopHintBase256[33:41], hopHint.ChannelID,	×
238	)	×
239	binary.BigEndian.PutUint32(	×
240	hopHintBase256[41:45], hopHint.FeeBaseMSat,	×
241	)	×
242	binary.BigEndian.PutUint32(	×
243	hopHintBase256[45:49], hopHint.FeeProportionalMillionths,	×
244	)	×
245	binary.BigEndian.PutUint16(	×
246	hopHintBase256[49:51], hopHint.CLTVExpiryDelta,	×
247	)	×
248	routeHintBase256 = append(routeHintBase256, hopHintBase256...)	×
249	}	×
250
251	routeHintBase32, err := bech32.ConvertBits(	×
252	routeHintBase256, 8, 5, true,	×
253	)	×
254	if err != nil {	×
255	return err	×
256	}	×
257
258	err = writeTaggedField(bufferBase32, fieldTypeR, routeHintBase32)	×
259	if err != nil {	×
260	return err	×
261	}	×
262	}
263
264	for _, path := range invoice.BlindedPaymentPaths {	×
265	var buf bytes.Buffer	×
266		×
267	err := path.Encode(&buf)	×
268	if err != nil {	×
269	return err	×
270	}	×
271
272	blindedPathBase32, err := bech32.ConvertBits(	×
273	buf.Bytes(), 8, 5, true,	×
274	)	×
275	if err != nil {	×
276	return err	×
277	}	×
278
279	err = writeTaggedField(	×
280	bufferBase32, fieldTypeB, blindedPathBase32,	×
281	)	×
282	if err != nil {	×
283	return err	×
284	}	×
285	}
286
287	if invoice.Destination != nil {	×
288	// Convert 33 byte pubkey to 53 5-bit groups.	×
289	pubKeyBase32, err := bech32.ConvertBits(	×
290	invoice.Destination.SerializeCompressed(), 8, 5, true)	×
291	if err != nil {	×
292	return err	×
293	}	×
294
295	if len(pubKeyBase32) != pubKeyBase32Len {	×
296	return fmt.Errorf("invalid pubkey length: %d",	×
297	len(invoice.Destination.SerializeCompressed()))	×
298	}	×
299
300	err = writeTaggedField(bufferBase32, fieldTypeN, pubKeyBase32)	×
301	if err != nil {	×
302	return err	×
303	}	×
304	}
305
306	err := fn.MapOptionZ(invoice.PaymentAddr, func(addr [32]byte) error {	×
307	return writeBytes32(bufferBase32, fieldTypeS, addr)	×
308	})	×
309	if err != nil {	×
310	return err	×
311	}	×
312
313	if invoice.Features.SerializeSize32() > 0 {	×
314	var b bytes.Buffer	×
315	err := invoice.Features.RawFeatureVector.EncodeBase32(&b)	×
316	if err != nil {	×
317	return err	×
318	}	×
319
320	err = writeTaggedField(bufferBase32, fieldType9, b.Bytes())	×
321	if err != nil {	×
322	return err	×
323	}	×
324	}
325
326	return nil	×
327	}
328
329	// writeBytes32 encodes a 32-byte array as base32 and writes it to bufferBase32
330	// under the passed fieldType.
331	func writeBytes32(bufferBase32 *bytes.Buffer, fieldType byte, b [32]byte) error {	×
332	// Convert 32 byte hash to 52 5-bit groups.	×
333	base32, err := bech32.ConvertBits(b[:], 8, 5, true)	×
334	if err != nil {	×
335	return err	×
336	}	×
337
338	return writeTaggedField(bufferBase32, fieldType, base32)	×
339	}
340
341	// writeTaggedField takes the type of a tagged data field, and the data of
342	// the tagged field (encoded in base32), and writes the type, length and data
343	// to the buffer.
344	func writeTaggedField(bufferBase32 *bytes.Buffer, dataType byte, data []byte) error {	×
345	// Length must be exactly 10 bits, so add leading zero groups if	×
346	// needed.	×
347	lenBase32 := uint64ToBase32(uint64(len(data)))	×
348	for len(lenBase32) < 2 {	×
349	lenBase32 = append([]byte{0}, lenBase32...)	×
350	}	×
351
352	if len(lenBase32) != 2 {	×
353	return fmt.Errorf("data length too big to fit within 10 bits: %d",	×
354	len(data))	×
355	}	×
356
357	err := bufferBase32.WriteByte(dataType)	×
358	if err != nil {	×
359	return fmt.Errorf("unable to write to buffer: %w", err)	×
360	}	×
361	_, err = bufferBase32.Write(lenBase32)	×
362	if err != nil {	×
363	return fmt.Errorf("unable to write to buffer: %w", err)	×
364	}	×
365	_, err = bufferBase32.Write(data)	×
366	if err != nil {	×
367	return fmt.Errorf("unable to write to buffer: %w", err)	×
368	}	×
369
370	return nil	×
371	}
372
373	// uint64ToBase32 converts a uint64 to a base32 encoded integer encoded using
374	// as few 5-bit groups as possible.
375	func uint64ToBase32(num uint64) []byte {	×
376	// Return at least one group.	×
377	if num == 0 {	×
378	return []byte{0}	×
379	}	×
380
381	// To fit an uint64, we need at most is ceil(64 / 5) = 13 groups.
382	arr := make([]byte, 13)	×
383	i := 13	×
384	for num > 0 {	×
385	i--	×
386	arr[i] = byte(num & uint64(31)) // 0b11111 in binary	×
387	num >>= 5	×
388	}	×
389
390	// We only return non-zero leading groups.
391	return arr[i:]	×
392	}

lightningnetwork / lnd / 13481548301

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