rlpgen: step 1

go.mod

@@ -277,7 +277,7 @@ require (
 	go.uber.org/multierr v1.11.0 // indirect
 	golang.org/x/mod v0.19.0 // indirect
 	golang.org/x/text v0.16.0 // indirect
-	golang.org/x/tools v0.23.0 // indirect
+	golang.org/x/tools v0.23.0
 	gopkg.in/cenkalti/backoff.v1 v1.1.0 // indirect
 	gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7 // indirect
 	gotest.tools/v3 v3.5.1 // indirect

rlp/encbuffer.go

@@ -0,0 +1,224 @@
+// Copyright 2022 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package rlp
+
+import (
+	"io"
+	"reflect"
+	"sync"
+)
+
+type encBuffer struct {
+	str      []byte        // string data, contains everything except list headers
+	lheads   []listhead    // all list headers
+	lhsize   int           // sum of sizes of all encoded list headers
+	sizebuf  [9]byte       // auxiliary buffer for uint encoding
+	bufvalue reflect.Value // used in writeByteArrayCopy
+}
+
+// encbufs are pooled.
+var encBufferPool = sync.Pool{
+	New: func() interface{} {
+		var bytes []byte
+		return &encBuffer{bufvalue: reflect.ValueOf(&bytes).Elem()}
+	},
+}
+
+func (w *encBuffer) reset() {
+	w.lhsize = 0
+	w.str = w.str[:0]
+	w.lheads = w.lheads[:0]
+}
+
+// encBuffer implements io.Writer so it can be passed it into EncodeRLP.
+func (w *encBuffer) Write(b []byte) (int, error) {
+	w.str = append(w.str, b...)
+	return len(b), nil
+}
+
+func (w *encBuffer) encode(val interface{}) error {
+	rval := reflect.ValueOf(val)
+	writer, err := cachedWriter(rval.Type())
+	if err != nil {
+		return err
+	}
+	return writer(rval, w)
+}
+
+func (w *encBuffer) encodeStringHeader(size int) {
+	if size < 56 {
+		w.str = append(w.str, EmptyStringCode+byte(size))
+	} else {
+		sizesize := putint(w.sizebuf[1:], uint64(size))
+		w.sizebuf[0] = 0xB7 + byte(sizesize)
+		w.str = append(w.str, w.sizebuf[:sizesize+1]...)
+	}
+}
+
+func (w *encBuffer) encodeString(b []byte) {
+	if len(b) == 1 && b[0] <= 0x7F {
+		// fits single byte, no string header
+		w.str = append(w.str, b[0])
+	} else {
+		w.encodeStringHeader(len(b))
+		w.str = append(w.str, b...)
+	}
+}
+
+func (w *encBuffer) encodeUint(i uint64) {
+	if i == 0 {
+		w.str = append(w.str, 0x80)
+	} else if i < 128 {
+		// fits single byte
+		w.str = append(w.str, byte(i))
+	} else {
+		s := putint(w.sizebuf[1:], i)
+		w.sizebuf[0] = 0x80 + byte(s)
+		w.str = append(w.str, w.sizebuf[:s+1]...)
+	}
+}
+
+// list adds a new list header to the header stack. It returns the index
+// of the header. The caller must call listEnd with this index after encoding
+// the content of the list.
+func (w *encBuffer) list() int {
+	w.lheads = append(w.lheads, listhead{offset: len(w.str), size: w.lhsize})
+	return len(w.lheads) - 1
+}
+
+func (w *encBuffer) listEnd(index int) {
+	lh := &w.lheads[index]
+	lh.size = w.size() - lh.offset - lh.size
+	if lh.size < 56 {
+		w.lhsize++ // length encoded into kind tag
+	} else {
+		w.lhsize += 1 + intsize(uint64(lh.size))
+	}
+}
+
+func (w *encBuffer) size() int {
+	return len(w.str) + w.lhsize
+}
+
+func (w *encBuffer) toBytes() []byte {
+	out := make([]byte, w.size())
+	strpos := 0
+	pos := 0
+	for _, head := range w.lheads {
+		// write string data before header
+		n := copy(out[pos:], w.str[strpos:head.offset])
+		pos += n
+		strpos += n
+		// write the header
+		enc := head.encode(out[pos:])
+		pos += len(enc)
+	}
+	// copy string data after the last list header
+	copy(out[pos:], w.str[strpos:])
+	return out
+}
+
+func (w *encBuffer) toWriter(out io.Writer) (err error) {
+	strpos := 0
+	for _, head := range w.lheads {
+		// write string data before header
+		if head.offset-strpos > 0 {
+			n, nErr := out.Write(w.str[strpos:head.offset])
+			strpos += n
+			if nErr != nil {
+				return nErr
+			}
+		}
+		// write the header
+		enc := head.encode(w.sizebuf[:])
+		if _, wErr := out.Write(enc); wErr != nil {
+			return wErr
+		}
+	}
+	if strpos < len(w.str) {
+		// write string data after the last list header
+		_, err = out.Write(w.str[strpos:])
+	}
+	return err
+}
+
+// encReader is the io.Reader returned by EncodeToReader.
+// It releases its encbuf at EOF.
+type encReader struct {
+	buf    *encBuffer // the buffer we're reading from. this is nil when we're at EOF.
+	lhpos  int        // index of list header that we're reading
+	strpos int        // current position in string buffer
+	piece  []byte     // next piece to be read
+}
+
+func (r *encReader) Read(b []byte) (n int, err error) {
+	for {
+		if r.piece = r.next(); r.piece == nil {
+			// Put the encode buffer back into the pool at EOF when it
+			// is first encountered. Subsequent calls still return EOF
+			// as the error but the buffer is no longer valid.
+			if r.buf != nil {
+				encBufferPool.Put(r.buf)
+				r.buf = nil
+			}
+			return n, io.EOF
+		}
+		nn := copy(b[n:], r.piece)
+		n += nn
+		if nn < len(r.piece) {
+			// piece didn't fit, see you next time.
+			r.piece = r.piece[nn:]
+			return n, nil
+		}
+		r.piece = nil
+	}
+}
+
+// next returns the next piece of data to be read.
+// it returns nil at EOF.
+func (r *encReader) next() []byte {
+	switch {
+	case r.buf == nil:
+		return nil
+
+	case r.piece != nil:
+		// There is still data available for reading.
+		return r.piece
+
+	case r.lhpos < len(r.buf.lheads):
+		// We're before the last list header.
+		head := r.buf.lheads[r.lhpos]
+		sizebefore := head.offset - r.strpos
+		if sizebefore > 0 {
+			// String data before header.
+			p := r.buf.str[r.strpos:head.offset]
+			r.strpos += sizebefore
+			return p
+		}
+		r.lhpos++
+		return head.encode(r.buf.sizebuf[:])
+
+	case r.strpos < len(r.buf.str):
+		// String data at the end, after all list headers.
+		p := r.buf.str[r.strpos:]
+		r.strpos = len(r.buf.str)
+		return p
+
+	default:
+		return nil
+	}
+}