#define substdio_PEEK(s) ( (s)->x + (s)->n )
#define substdio_SEEK(s,len) ( ( (s)->p -= (len) ) , ( (s)->n += (len) ) )
+#define substdio_BPUTC(s,c) \
+ ( ((s)->n != (s)->p) \
+ ? ( (s)->x[(s)->p++] = (c), 0 ) \
+ : substdio_bput((s),&(c),1) \
+ )
+
extern int substdio_copy();
#endif