16 	/* set mb->head and mb->tail so the buffers look empty */  in membuff_purge()
17 	mb->head = mb->start;  in membuff_purge()
26 	/* always write to 'mb->head' */  in membuff_putrawflex()
29 	*offsetp = mb->head - mb->start;  in membuff_putrawflex()
36 	 * if head is ahead of tail, we can write from head until the end of  in membuff_putrawflex()
39 	if (mb->head >= mb->tail) {  in membuff_putrawflex()
41 		len = mb->end - mb->head - 1;  in membuff_putrawflex()
45 		/* update the head pointer to mark these bytes as written */  in membuff_putrawflex()
47 			mb->head += len;  in membuff_putrawflex()
56 				mb->head = mb->start;  in membuff_putrawflex()
59 	/* otherwise now we can write until head almost reaches tail */  in membuff_putrawflex()
62 		len = mb->tail - mb->head - 1;  in membuff_putrawflex()
66 		/* update the head pointer to mark these bytes as written */  in membuff_putrawflex()
68 			mb->head += len;  in membuff_putrawflex()
106 	 * in this case head is ahead of tail, so we must return data between  in membuff_getraw()
107 	 *'tail' and 'head'  in membuff_getraw()
109 	if (mb->head > mb->tail) {  in membuff_getraw()
112 		len = mb->head - mb->tail;  in membuff_getraw()
124 	 * if head is before tail, then we have data between 'tail' and 'end'  in membuff_getraw()
125 	 * and some more data between 'start' and 'head'(which we can't  in membuff_getraw()
128 	else if (mb->head < mb->tail) {  in membuff_getraw()
141 	debug("getraw: maxlen=%d, update=%d, head=%d, tail=%d, data=%d, len=%d",  in membuff_getraw()
142 	      maxlen, update, (int)(mb->head - mb->start),  in membuff_getraw()
208 	return mb->head == mb->tail;  in membuff_isempty()
237 	debug("makecontig: head=%d, tail=%d, size=%d",  in membuff_makecontig()
238 	      (int)(mb->head - mb->start), (int)(mb->tail - mb->start),  in membuff_makecontig()
245 	if (mb->tail > mb->head) {  in membuff_makecontig()
247 		 * the data is split into two parts, from 0 to ->head and  in membuff_makecontig()
248 		 * from ->tail to ->end. We move the stuff from 0 to ->head  in membuff_makecontig()
252 		botsize = mb->head - mb->start;  in membuff_makecontig()
258 		if (mb->head + topsize >= mb->tail)  in membuff_makecontig()
265 		topsize = mb->head - mb->tail;  in membuff_makecontig()
275 	mb->head = mb->start + topsize + botsize;  in membuff_makecontig()
277 	debug("	- head=%d, tail=%d", (int)(mb->head - mb->start),  in membuff_makecontig()
297 	end = mb->head >= mb->tail ? mb->head : mb->end;  in membuff_readline()
305 		if (s == end && mb->tail > mb->head) {  in membuff_readline()
307 			end = mb->head;  in membuff_readline()
343 	oldhead = mb->head - mb->start;  in membuff_extend_by()
349 	mb->head = mb->start + oldhead;  in membuff_extend_by()
352 	if (mb->head < mb->tail) {  in membuff_extend_by()