func (b *Buffer) ReadFrom(r io.Reader) (n int64, err error) {
b.lastRead = opInvalid
for {
i := b.grow(MinRead)
b.buf = b.buf[:i]
m, e := r.Read(b.buf[i:cap(b.buf)])
if m < 0 {
panic(errNegativeRead)
}
b.buf = b.buf[:i+m]
n += int64(m)
if e == io.EOF {
return n, nil // e is EOF, so return nil explicitly
}
if e != nil {
return n, e
}
}
}
@gyr666 @msyyyy 可以仿照这个，这是go库的实现