/
util.go
98 lines (79 loc) · 1.95 KB
/
util.go
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package util
import (
"errors"
"io"
internalio "github.com/ipld/go-car/v2/internal/io"
"github.com/multiformats/go-varint"
cid "github.com/ipfs/go-cid"
)
var ErrSectionTooLarge = errors.New("invalid section data, length of read beyond allowable maximum")
var ErrHeaderTooLarge = errors.New("invalid header data, length of read beyond allowable maximum")
type BytesReader interface {
io.Reader
io.ByteReader
}
func ReadNode(r io.Reader, zeroLenAsEOF bool, maxReadBytes uint64) (cid.Cid, []byte, error) {
data, err := LdRead(r, zeroLenAsEOF, maxReadBytes)
if err != nil {
return cid.Cid{}, nil, err
}
n, c, err := cid.CidFromBytes(data)
if err != nil {
return cid.Cid{}, nil, err
}
return c, data[n:], nil
}
func LdWrite(w io.Writer, d ...[]byte) error {
var sum uint64
for _, s := range d {
sum += uint64(len(s))
}
buf := make([]byte, 8)
n := varint.PutUvarint(buf, sum)
_, err := w.Write(buf[:n])
if err != nil {
return err
}
for _, s := range d {
_, err = w.Write(s)
if err != nil {
return err
}
}
return nil
}
func LdSize(d ...[]byte) uint64 {
var sum uint64
for _, s := range d {
sum += uint64(len(s))
}
s := varint.UvarintSize(sum)
return sum + uint64(s)
}
func LdReadSize(r io.Reader, zeroLenAsEOF bool, maxReadBytes uint64) (uint64, error) {
l, err := varint.ReadUvarint(internalio.ToByteReader(r))
if err != nil {
// If the length of bytes read is non-zero when the error is EOF then signal an unclean EOF.
if l > 0 && err == io.EOF {
return 0, io.ErrUnexpectedEOF
}
return 0, err
} else if l == 0 && zeroLenAsEOF {
return 0, io.EOF
}
if l > maxReadBytes { // Don't OOM
return 0, ErrSectionTooLarge
}
return l, nil
}
func LdRead(r io.Reader, zeroLenAsEOF bool, maxReadBytes uint64) ([]byte, error) {
l, err := LdReadSize(r, zeroLenAsEOF, maxReadBytes)
if err != nil {
return nil, err
}
buf := make([]byte, l)
if _, err := io.ReadFull(r, buf); err != nil {
return nil, err
}
return buf, nil
}