func()

in insertablebuffer.go [148:178]

• 27 lines of code
• 7 McCabe index (conditional complexity)

func (b *Builder) ReadFrom(r io.Reader) (n int64, err error) {
	b.lastRead = opInvalid
	// If buffer is empty, reset to recover space.
	if b.off >= len(b.buf) {
		b.Truncate(0)
	}
	for {
		if free := cap(b.buf) - len(b.buf); free < bytes.MinRead {
			// not enough space at end
			newBuf := b.buf
			if b.off+free < bytes.MinRead {
				// not enough space using beginning of buffer;
				// double buffer capacity
				newBuf = makeSlice(2*cap(b.buf) + bytes.MinRead)
			}
			copy(newBuf, b.buf[b.off:])
			b.buf = newBuf[:len(b.buf)-b.off]
			b.off = 0
		}
		m, e := r.Read(b.buf[len(b.buf):cap(b.buf)])
		b.buf = b.buf[0 : len(b.buf)+m]
		n += int64(m)
		if e == io.EOF {
			break
		}
		if e != nil {
			return n, e
		}
	}
	return n, nil // err is EOF, so return nil explicitly
}