mirror of
https://gitlab.com/pulsechaincom/erigon-pulse.git
synced 2024-12-22 19:50:36 +00:00
2aab8f496c
rlp2 is a package that aims to replace the existing erigon-lib/rlp package and the erigon/common/rlp it is called rlp2 for now because it requires breaking changes to erigon-lib/rlp and i do not have the time right now to test all current uses of such functions however, the encoder/decoder characteristics of rlp2 might be desirable for caplin, and also for execution layer parsing blob txns, so im putting it in a folder called rlp2 (note that it exports package rlp for easier switching later) importantly, rlp2 is designed for single-pass decoding with the ability to skip elements one does not care about. it also is zero alloc.
299 lines
6.9 KiB
Go
299 lines
6.9 KiB
Go
/*
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Copyright 2021 The Erigon contributors
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package rlp
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import (
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"encoding/binary"
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"math/bits"
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"github.com/ledgerwatch/erigon-lib/common"
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)
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// General design:
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// - rlp package doesn't manage memory - and Caller must ensure buffers are big enough.
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// - no io.Writer, because it's incompatible with binary.BigEndian functions and Writer can't be used as temporary buffer
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//
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// Composition:
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// - each Encode method does write to given buffer and return written len
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// - each Parse accept position in payload and return new position
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//
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// General rules:
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// - functions to calculate prefix len are fast (and pure). it's ok to call them multiple times during encoding of large object for readability.
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// - rlp has 2 data types: List and String (bytes array), and low-level funcs are operate with this types.
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// - but for convenience and performance - provided higher-level functions (for example for EncodeHash - for []byte of len 32)
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// - functions to Parse (Decode) data - using data type as name (without any prefix): rlp.String(), rlp.List, rlp.U64(), rlp.U256()
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//
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func ListPrefixLen(dataLen int) int {
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if dataLen >= 56 {
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return 1 + common.BitLenToByteLen(bits.Len64(uint64(dataLen)))
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}
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return 1
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}
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func EncodeListPrefix(dataLen int, to []byte) int {
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if dataLen >= 56 {
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_ = to[9]
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beLen := common.BitLenToByteLen(bits.Len64(uint64(dataLen)))
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binary.BigEndian.PutUint64(to[1:], uint64(dataLen))
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to[8-beLen] = 247 + byte(beLen)
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copy(to, to[8-beLen:9])
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return 1 + beLen
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}
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to[0] = 192 + byte(dataLen)
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return 1
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}
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func U32Len(i uint32) int {
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if i < 128 {
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return 1
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}
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return 1 + common.BitLenToByteLen(bits.Len32(i))
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}
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func U64Len(i uint64) int {
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if i < 128 {
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return 1
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}
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return 1 + common.BitLenToByteLen(bits.Len64(i))
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}
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func EncodeU32(i uint32, to []byte) int {
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if i == 0 {
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to[0] = 128
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return 1
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}
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if i < 128 {
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to[0] = byte(i) // fits single byte
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return 1
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}
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b := to[1:]
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var l int
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// writes i to b in big endian byte order, using the least number of bytes needed to represent i.
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switch {
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case i < (1 << 8):
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b[0] = byte(i)
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l = 1
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case i < (1 << 16):
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b[0] = byte(i >> 8)
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b[1] = byte(i)
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l = 2
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case i < (1 << 24):
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b[0] = byte(i >> 16)
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b[1] = byte(i >> 8)
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b[2] = byte(i)
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l = 3
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default:
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b[0] = byte(i >> 24)
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b[1] = byte(i >> 16)
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b[2] = byte(i >> 8)
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b[3] = byte(i)
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l = 4
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}
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to[0] = 128 + byte(l)
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return 1 + l
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}
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func EncodeU64(i uint64, to []byte) int {
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if i == 0 {
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to[0] = 128
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return 1
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}
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if i < 128 {
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to[0] = byte(i) // fits single byte
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return 1
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}
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b := to[1:]
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var l int
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// writes i to b in big endian byte order, using the least number of bytes needed to represent i.
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switch {
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case i < (1 << 8):
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b[0] = byte(i)
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l = 1
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case i < (1 << 16):
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b[0] = byte(i >> 8)
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b[1] = byte(i)
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l = 2
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case i < (1 << 24):
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b[0] = byte(i >> 16)
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b[1] = byte(i >> 8)
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b[2] = byte(i)
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l = 3
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case i < (1 << 32):
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b[0] = byte(i >> 24)
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b[1] = byte(i >> 16)
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b[2] = byte(i >> 8)
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b[3] = byte(i)
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l = 4
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case i < (1 << 40):
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b[0] = byte(i >> 32)
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b[1] = byte(i >> 24)
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b[2] = byte(i >> 16)
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b[3] = byte(i >> 8)
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b[4] = byte(i)
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l = 5
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case i < (1 << 48):
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b[0] = byte(i >> 40)
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b[1] = byte(i >> 32)
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b[2] = byte(i >> 24)
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b[3] = byte(i >> 16)
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b[4] = byte(i >> 8)
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b[5] = byte(i)
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l = 6
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case i < (1 << 56):
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b[0] = byte(i >> 48)
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b[1] = byte(i >> 40)
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b[2] = byte(i >> 32)
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b[3] = byte(i >> 24)
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b[4] = byte(i >> 16)
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b[5] = byte(i >> 8)
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b[6] = byte(i)
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l = 7
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default:
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b[0] = byte(i >> 56)
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b[1] = byte(i >> 48)
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b[2] = byte(i >> 40)
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b[3] = byte(i >> 32)
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b[4] = byte(i >> 24)
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b[5] = byte(i >> 16)
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b[6] = byte(i >> 8)
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b[7] = byte(i)
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l = 8
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}
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to[0] = 128 + byte(l)
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return 1 + l
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}
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func StringLen(s []byte) int {
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sLen := len(s)
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switch {
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case sLen > 56:
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beLen := common.BitLenToByteLen(bits.Len(uint(sLen)))
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return 1 + beLen + sLen
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case sLen == 0:
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return 1
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case sLen == 1:
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if s[0] < 128 {
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return 1
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}
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return 1 + sLen
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default: // 1<s<56
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return 1 + sLen
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}
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}
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func EncodeString(s []byte, to []byte) int {
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switch {
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case len(s) > 56:
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beLen := common.BitLenToByteLen(bits.Len(uint(len(s))))
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binary.BigEndian.PutUint64(to[1:], uint64(len(s)))
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_ = to[beLen+len(s)]
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to[8-beLen] = byte(beLen) + 183
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copy(to, to[8-beLen:9])
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copy(to[1+beLen:], s)
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return 1 + beLen + len(s)
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case len(s) == 0:
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to[0] = 128
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return 1
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case len(s) == 1:
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if s[0] < 128 {
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to[0] = s[0]
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return 1
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}
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to[0] = 129
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to[1] = s[0]
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return 2
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default: // 1<s<56
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_ = to[len(s)]
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to[0] = byte(len(s)) + 128
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copy(to[1:], s)
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return 1 + len(s)
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}
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}
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// EncodeHash assumes that `to` buffer is already 32bytes long
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func EncodeHash(h, to []byte) int {
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_ = to[32] // early bounds check to guarantee safety of writes below
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to[0] = 128 + 32
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copy(to[1:33], h[:32])
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return 33
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}
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func HashesLen(hashes []byte) int {
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hashesLen := len(hashes) / 32 * 33
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return ListPrefixLen(hashesLen) + hashesLen
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}
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func EncodeHashes(hashes []byte, encodeBuf []byte) int {
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pos := 0
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hashesLen := len(hashes) / 32 * 33
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pos += EncodeListPrefix(hashesLen, encodeBuf)
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for i := 0; i < len(hashes); i += 32 {
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pos += EncodeHash(hashes[i:], encodeBuf[pos:])
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}
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return pos
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}
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func AnnouncementsLen(types []byte, sizes []uint32, hashes []byte) int {
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if len(types) == 0 {
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return 4
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}
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typesLen := StringLen(types)
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var sizesLen int
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for _, size := range sizes {
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sizesLen += U32Len(size)
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}
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hashesLen := len(hashes) / 32 * 33
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totalLen := typesLen + sizesLen + ListPrefixLen(sizesLen) + hashesLen + ListPrefixLen(hashesLen)
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return ListPrefixLen(totalLen) + totalLen
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}
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// EIP-5793: eth/68 - Add tx type to tx announcement
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func EncodeAnnouncements(types []byte, sizes []uint32, hashes []byte, encodeBuf []byte) int {
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if len(types) == 0 {
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encodeBuf[0] = 0xc3
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encodeBuf[1] = 0x80
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encodeBuf[2] = 0xc0
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encodeBuf[3] = 0xc0
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return 4
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}
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pos := 0
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typesLen := StringLen(types)
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var sizesLen int
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for _, size := range sizes {
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sizesLen += U32Len(size)
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}
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hashesLen := len(hashes) / 32 * 33
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totalLen := typesLen + sizesLen + ListPrefixLen(sizesLen) + hashesLen + ListPrefixLen(hashesLen)
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pos += EncodeListPrefix(totalLen, encodeBuf)
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pos += EncodeString(types, encodeBuf[pos:])
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pos += EncodeListPrefix(sizesLen, encodeBuf[pos:])
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for _, size := range sizes {
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pos += EncodeU32(size, encodeBuf[pos:])
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}
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pos += EncodeListPrefix(hashesLen, encodeBuf[pos:])
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for i := 0; i < len(hashes); i += 32 {
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pos += EncodeHash(hashes[i:], encodeBuf[pos:])
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}
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return pos
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}
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