// Thus, a backwards copy is performed here; that is, the exact bytes in
	// the source prior to the copy is placed in the destination.
	if srcPos < 0 {
		srcPos += len(dd.hist)
		dstPos += copy(dd.hist[dstPos:endPos], dd.hist[srcPos:])
		srcPos = 0
	}

	// Copy possibly overlapping section before destination position.
	//
	// This section can overlap if the copy length for this section is larger

     */
    public void find(char c) {
        int cpos = pos;
        while (cpos < input.length()) {
            if (input.charAt(cpos) == c) {
                break;
            }
            cpos++;
        }
        pos = cpos;
    }

    /**

		return false
	}
	return prev.(*ImportSpec).Comment == nil
}

type posSpan struct {
	Start token.Pos
	End   token.Pos
}

type cgPos struct {
	left bool // true if comment is to the left of the spec, false otherwise.
	cg   *CommentGroup
}

func sortSpecs(fset *token.FileSet, f *File, specs []Spec) []Spec {