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