encode.gno

 1package rlp
 2
 3// EncodeBytes returns the RLP string encoding of b.
 4func EncodeBytes(b []byte) []byte {
 5	out := make([]byte, 0, bytesSize(b))
 6	return appendBytes(out, b)
 7}
 8
 9// EncodeList returns the RLP list encoding of already-encoded items.
10func EncodeList(items ...[]byte) []byte {
11	size := 0
12	for _, item := range items {
13		size += len(item)
14	}
15
16	out := make([]byte, 0, listSize(size))
17
18	out = appendHeader(out, 0xC0, uint64(size))
19	for _, item := range items {
20		out = append(out, item...)
21	}
22
23	return out
24}
25
26func appendBytes(out []byte, b []byte) []byte {
27	if len(b) == 1 && b[0] <= 0x7f {
28		return append(out, b[0])
29	}
30
31	out = appendHeader(out, 0x80, uint64(len(b)))
32
33	return append(out, b...)
34}
35
36func bytesSize(b []byte) int {
37	n := len(b)
38	if n == 1 && b[0] <= 0x7f {
39		return 1
40	}
41
42	return headerSize(n) + n
43}
44
45func listSize(contentSize int) int {
46	return headerSize(contentSize) + contentSize
47}
48
49func appendHeader(out []byte, baseTag byte, size uint64) []byte {
50	if size < 56 {
51		return append(out, baseTag+byte(size))
52	}
53
54	n := intSize(size)
55	out = append(out, baseTag+55+byte(n))
56
57	return appendBigEndianUint(out, size, n)
58}
59
60// appendBigEndianUint appends the n low-order bytes of x to out, big-endian.
61func appendBigEndianUint(out []byte, x uint64, n int) []byte {
62	for i := n - 1; i >= 0; i-- {
63		out = append(out, byte(x>>uint(i*8)))
64	}
65
66	return out
67}
68
69func headerSize(payloadSize int) int {
70	if payloadSize < 56 {
71		return 1
72	}
73
74	return 1 + intSize(uint64(payloadSize))
75}
76
77func intSize(x uint64) int {
78	switch {
79	case x < 1<<8:
80		return 1
81	case x < 1<<16:
82		return 2
83	case x < 1<<24:
84		return 3
85	case x < 1<<32:
86		return 4
87	case x < 1<<40:
88		return 5
89	case x < 1<<48:
90		return 6
91	case x < 1<<56:
92		return 7
93	default:
94		return 8
95	}
96}