forked from Shiloh/githaven
162 lines
3.2 KiB
Go
162 lines
3.2 KiB
Go
package roaring
|
|
|
|
import (
|
|
"encoding/binary"
|
|
"io"
|
|
)
|
|
|
|
type byteInput interface {
|
|
// next returns a slice containing the next n bytes from the buffer,
|
|
// advancing the buffer as if the bytes had been returned by Read.
|
|
next(n int) ([]byte, error)
|
|
// readUInt32 reads uint32 with LittleEndian order
|
|
readUInt32() (uint32, error)
|
|
// readUInt16 reads uint16 with LittleEndian order
|
|
readUInt16() (uint16, error)
|
|
// getReadBytes returns read bytes
|
|
getReadBytes() int64
|
|
// skipBytes skips exactly n bytes
|
|
skipBytes(n int) error
|
|
}
|
|
|
|
func newByteInputFromReader(reader io.Reader) byteInput {
|
|
return &byteInputAdapter{
|
|
r: reader,
|
|
readBytes: 0,
|
|
}
|
|
}
|
|
|
|
func newByteInput(buf []byte) byteInput {
|
|
return &byteBuffer{
|
|
buf: buf,
|
|
off: 0,
|
|
}
|
|
}
|
|
|
|
type byteBuffer struct {
|
|
buf []byte
|
|
off int
|
|
}
|
|
|
|
// next returns a slice containing the next n bytes from the reader
|
|
// If there are fewer bytes than the given n, io.ErrUnexpectedEOF will be returned
|
|
func (b *byteBuffer) next(n int) ([]byte, error) {
|
|
m := len(b.buf) - b.off
|
|
|
|
if n > m {
|
|
return nil, io.ErrUnexpectedEOF
|
|
}
|
|
|
|
data := b.buf[b.off : b.off+n]
|
|
b.off += n
|
|
|
|
return data, nil
|
|
}
|
|
|
|
// readUInt32 reads uint32 with LittleEndian order
|
|
func (b *byteBuffer) readUInt32() (uint32, error) {
|
|
if len(b.buf)-b.off < 4 {
|
|
return 0, io.ErrUnexpectedEOF
|
|
}
|
|
|
|
v := binary.LittleEndian.Uint32(b.buf[b.off:])
|
|
b.off += 4
|
|
|
|
return v, nil
|
|
}
|
|
|
|
// readUInt16 reads uint16 with LittleEndian order
|
|
func (b *byteBuffer) readUInt16() (uint16, error) {
|
|
if len(b.buf)-b.off < 2 {
|
|
return 0, io.ErrUnexpectedEOF
|
|
}
|
|
|
|
v := binary.LittleEndian.Uint16(b.buf[b.off:])
|
|
b.off += 2
|
|
|
|
return v, nil
|
|
}
|
|
|
|
// getReadBytes returns read bytes
|
|
func (b *byteBuffer) getReadBytes() int64 {
|
|
return int64(b.off)
|
|
}
|
|
|
|
// skipBytes skips exactly n bytes
|
|
func (b *byteBuffer) skipBytes(n int) error {
|
|
m := len(b.buf) - b.off
|
|
|
|
if n > m {
|
|
return io.ErrUnexpectedEOF
|
|
}
|
|
|
|
b.off += n
|
|
|
|
return nil
|
|
}
|
|
|
|
// reset resets the given buffer with a new byte slice
|
|
func (b *byteBuffer) reset(buf []byte) {
|
|
b.buf = buf
|
|
b.off = 0
|
|
}
|
|
|
|
type byteInputAdapter struct {
|
|
r io.Reader
|
|
readBytes int
|
|
}
|
|
|
|
// next returns a slice containing the next n bytes from the buffer,
|
|
// advancing the buffer as if the bytes had been returned by Read.
|
|
func (b *byteInputAdapter) next(n int) ([]byte, error) {
|
|
buf := make([]byte, n)
|
|
m, err := io.ReadAtLeast(b.r, buf, n)
|
|
b.readBytes += m
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
return buf, nil
|
|
}
|
|
|
|
// readUInt32 reads uint32 with LittleEndian order
|
|
func (b *byteInputAdapter) readUInt32() (uint32, error) {
|
|
buf, err := b.next(4)
|
|
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
|
|
return binary.LittleEndian.Uint32(buf), nil
|
|
}
|
|
|
|
// readUInt16 reads uint16 with LittleEndian order
|
|
func (b *byteInputAdapter) readUInt16() (uint16, error) {
|
|
buf, err := b.next(2)
|
|
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
|
|
return binary.LittleEndian.Uint16(buf), nil
|
|
}
|
|
|
|
// getReadBytes returns read bytes
|
|
func (b *byteInputAdapter) getReadBytes() int64 {
|
|
return int64(b.readBytes)
|
|
}
|
|
|
|
// skipBytes skips exactly n bytes
|
|
func (b *byteInputAdapter) skipBytes(n int) error {
|
|
_, err := b.next(n)
|
|
|
|
return err
|
|
}
|
|
|
|
// reset resets the given buffer with a new stream
|
|
func (b *byteInputAdapter) reset(stream io.Reader) {
|
|
b.r = stream
|
|
b.readBytes = 0
|
|
}
|