btcd/invvect.go
Dave Collins 9ee6a8aeb6 Optimize writeElement.
This commit modifies the writeElement function to have a "fast path" which uses type
assertions for all of the types which btcwire write so the more expensive
reflection-based binary.Write can be avoided.

Also, this changes all cases that were writing raw ShaHash (32-byte) arrays (which
requires a stack copy) instead simply passing the pointer.

The following benchmark results show the results for serializing a block header
after these changes:

Before: BenchmarkWriteBlockHeader         500000              5566 ns/op
After:  BenchmarkWriteBlockHeader        1000000               991 ns/op

This is part of the ongoing effort to optimize serialization as noted in
conformal/btcd#27.
2013-11-07 00:56:20 -06:00

81 lines
1.9 KiB
Go

// Copyright (c) 2013 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package btcwire
import (
"fmt"
"io"
)
const (
// MaxInvPerMsg is the maximum number of inventory vectors that can be in a
// single bitcoin inv message.
MaxInvPerMsg = 50000
// Maximum payload size for an inventory vector.
maxInvVectPayload = 4 + HashSize
)
// InvType represents the allowed types of inventory vectors. See InvVect.
type InvType uint32
// These constants define the various supported inventory vector types.
const (
InvTypeError InvType = 0
InvTypeTx InvType = 1
InvTypeBlock InvType = 2
)
// Map of service flags back to their constant names for pretty printing.
var ivStrings = map[InvType]string{
InvTypeError: "ERROR",
InvTypeTx: "MSG_TX",
InvTypeBlock: "MSG_BLOCK",
}
// String returns the InvType in human-readable form.
func (invtype InvType) String() string {
if s, ok := ivStrings[invtype]; ok {
return s
}
return fmt.Sprintf("Unknown InvType (%d)", uint32(invtype))
}
// InvVect defines a bitcoin inventory vector which is used to describe data,
// as specified by the Type field, that a peer wants, has, or does not have to
// another peer.
type InvVect struct {
Type InvType // Type of data
Hash ShaHash // Hash of the data
}
// NewInvVect returns a new InvVect using the provided type and hash.
func NewInvVect(typ InvType, hash *ShaHash) *InvVect {
return &InvVect{
Type: typ,
Hash: *hash,
}
}
// readInvVect reads an encoded InvVect from r depending on the protocol
// version.
func readInvVect(r io.Reader, pver uint32, iv *InvVect) error {
err := readElements(r, &iv.Type, &iv.Hash)
if err != nil {
return err
}
return nil
}
// writeInvVect serializes an InvVect to w depending on the protocol version.
func writeInvVect(w io.Writer, pver uint32, iv *InvVect) error {
err := writeElements(w, iv.Type, &iv.Hash)
if err != nil {
return err
}
return nil
}