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9b93564e21
This change adds a code generator tool for creating EncodeRLP method implementations. The generated methods will behave identically to the reflect-based encoder, but run faster because there is no reflection overhead. Package rlp now provides the EncoderBuffer type for incremental encoding. This is used by generated code, but the new methods can also be useful for hand-written encoders. There is also experimental support for generating DecodeRLP, and some new methods have been added to the existing Stream type to support this. Creating decoders with rlpgen is not recommended at this time because the generated methods create very poor error reporting. More detail about package rlp changes: * rlp: externalize struct field processing / validation This adds a new package, rlp/internal/rlpstruct, in preparation for the RLP encoder generator. I think the struct field rules are subtle enough to warrant extracting this into their own package, even though it means that a bunch of adapter code is needed for converting to/from rlpstruct.Type. * rlp: add more decoder methods (for rlpgen) This adds new methods on rlp.Stream: - Uint64, Uint32, Uint16, Uint8, BigInt - ReadBytes for decoding into []byte - MoreDataInList - useful for optional list elements * rlp: expose encoder buffer (for rlpgen) This exposes the internal encoder buffer type for use in EncodeRLP implementations. The new EncoderBuffer type is a sort-of 'opaque handle' for a pointer to encBuffer. It is implemented this way to ensure the global encBuffer pool is handled correctly.
49 lines
1.4 KiB
Go
49 lines
1.4 KiB
Go
// Copyright 2014 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package rlp_test
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import (
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"fmt"
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"io"
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"github.com/ethereum/go-ethereum/rlp"
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)
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type MyCoolType struct {
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Name string
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a, b uint
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}
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// EncodeRLP writes x as RLP list [a, b] that omits the Name field.
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func (x *MyCoolType) EncodeRLP(w io.Writer) (err error) {
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return rlp.Encode(w, []uint{x.a, x.b})
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}
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func ExampleEncoder() {
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var t *MyCoolType // t is nil pointer to MyCoolType
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bytes, _ := rlp.EncodeToBytes(t)
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fmt.Printf("%v → %X\n", t, bytes)
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t = &MyCoolType{Name: "foobar", a: 5, b: 6}
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bytes, _ = rlp.EncodeToBytes(t)
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fmt.Printf("%v → %X\n", t, bytes)
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// Output:
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// <nil> → C0
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// &{foobar 5 6} → C20506
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}
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