164 lines
2.8 KiB
Go
164 lines
2.8 KiB
Go
// Copyright (C) 2014 Jakob Borg and Contributors (see the CONTRIBUTORS file).
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// All rights reserved. Use of this source code is governed by an MIT-style
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// license that can be found in the LICENSE file.
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package xdr
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import (
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"errors"
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"io"
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)
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var ErrElementSizeExceeded = errors.New("element size exceeded")
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type Reader struct {
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r io.Reader
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err error
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b [8]byte
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sb []byte
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}
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func NewReader(r io.Reader) *Reader {
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return &Reader{
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r: r,
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}
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}
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func (r *Reader) ReadString() string {
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if r.sb == nil {
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r.sb = make([]byte, 64)
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} else {
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r.sb = r.sb[:cap(r.sb)]
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}
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r.sb = r.ReadBytesInto(r.sb)
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return string(r.sb)
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}
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func (r *Reader) ReadStringMax(max int) string {
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if r.sb == nil {
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r.sb = make([]byte, 64)
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} else {
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r.sb = r.sb[:cap(r.sb)]
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}
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r.sb = r.ReadBytesMaxInto(max, r.sb)
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return string(r.sb)
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}
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func (r *Reader) ReadBytes() []byte {
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return r.ReadBytesInto(nil)
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}
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func (r *Reader) ReadBytesMax(max int) []byte {
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return r.ReadBytesMaxInto(max, nil)
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}
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func (r *Reader) ReadBytesInto(dst []byte) []byte {
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return r.ReadBytesMaxInto(0, dst)
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}
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func (r *Reader) ReadBytesMaxInto(max int, dst []byte) []byte {
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if r.err != nil {
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return nil
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}
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l := int(r.ReadUint32())
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if r.err != nil {
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return nil
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}
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if max > 0 && l > max {
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r.err = ErrElementSizeExceeded
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return nil
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}
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if l+pad(l) > len(dst) {
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dst = make([]byte, l+pad(l))
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} else {
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dst = dst[:l+pad(l)]
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}
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var n int
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n, r.err = io.ReadFull(r.r, dst)
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if r.err != nil {
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if debug {
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dl.Debugf("rd bytes (%d): %v", len(dst), r.err)
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}
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return nil
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}
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if debug {
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if n > maxDebugBytes {
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dl.Debugf("rd bytes (%d): %x...", len(dst), dst[:maxDebugBytes])
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} else {
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dl.Debugf("rd bytes (%d): %x", len(dst), dst)
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}
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}
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return dst[:l]
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}
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func (r *Reader) ReadBool() bool {
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return r.ReadUint32() != 0
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}
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func (r *Reader) ReadUint16() uint16 {
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return uint16(r.ReadUint32())
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}
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func (r *Reader) ReadUint32() uint32 {
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if r.err != nil {
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return 0
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}
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_, r.err = io.ReadFull(r.r, r.b[:4])
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if r.err != nil {
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if debug {
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dl.Debugf("rd uint32: %v", r.err)
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}
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return 0
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}
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v := uint32(r.b[3]) | uint32(r.b[2])<<8 | uint32(r.b[1])<<16 | uint32(r.b[0])<<24
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if debug {
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dl.Debugf("rd uint32=%d (0x%08x)", v, v)
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}
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return v
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}
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func (r *Reader) ReadUint64() uint64 {
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if r.err != nil {
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return 0
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}
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_, r.err = io.ReadFull(r.r, r.b[:8])
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if r.err != nil {
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if debug {
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dl.Debugf("rd uint64: %v", r.err)
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}
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return 0
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}
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v := uint64(r.b[7]) | uint64(r.b[6])<<8 | uint64(r.b[5])<<16 | uint64(r.b[4])<<24 |
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uint64(r.b[3])<<32 | uint64(r.b[2])<<40 | uint64(r.b[1])<<48 | uint64(r.b[0])<<56
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if debug {
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dl.Debugf("rd uint64=%d (0x%016x)", v, v)
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}
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return v
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}
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type XDRError struct {
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op string
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err error
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}
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func (e XDRError) Error() string {
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return "xdr " + e.op + ": " + e.err.Error()
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}
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func (r *Reader) Error() error {
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if r.err == nil {
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return nil
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}
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return XDRError{"read", r.err}
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}
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