do
{
size_t head_ofs;
+ size_t space;
size_t n;
lex_source_expand__ (src);
head_ofs = src->head - src->tail;
+ space = src->allocated - head_ofs;
n = src->reader->class->read (src->reader, &src->buffer[head_ofs],
- src->allocated - head_ofs,
+ space,
segmenter_get_prompt (&src->segmenter));
+ assert (n <= space);
+
if (n == 0)
{
/* End of input.