16 	/* set mb->head and mb->tail so the buffers look empty */  in membuff_purge()
18 	mb->tail = mb->start;  in membuff_purge()
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()
50 		 * if the tail isn't at start of the buffer, then we can  in membuff_putrawflex()
53 		if ((maxlen < 0 || len < maxlen) && mb->tail != 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()
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()
111 		*data = mb->tail;  in membuff_getraw()
112 		len = mb->head - mb->tail;  in membuff_getraw()
120 			mb->tail += len;  in membuff_getraw()
124 	 * if head is before tail, then we have data between 'tail' and 'end'  in membuff_getraw()
128 	else if (mb->head < mb->tail) {  in membuff_getraw()
130 		*data = mb->tail;  in membuff_getraw()
131 		len = mb->end - mb->tail;  in membuff_getraw()
135 			mb->tail += len;  in membuff_getraw()
136 			if (mb->tail == mb->end)  in membuff_getraw()
137 				mb->tail = mb->start;  in membuff_getraw()
141 	debug("getraw: maxlen=%d, update=%d, head=%d, tail=%d, data=%d, len=%d",  in membuff_getraw()
143 	      (int)(mb->tail - mb->start), (int)(*data - mb->start), len);  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()
248 		 * from ->tail to ->end. We move the stuff from 0 to ->head  in membuff_makecontig()
251 		topsize = mb->end - mb->tail;  in membuff_makecontig()
258 		if (mb->head + topsize >= mb->tail)  in membuff_makecontig()
265 		topsize = mb->head - mb->tail;  in membuff_makecontig()
270 	memcpy(mb->start, mb->tail, topsize);  in membuff_makecontig()
271 	debug("	- memcpy(%d, %d, %d)", 0, (int)(mb->tail - mb->start), topsize);  in membuff_makecontig()
274 	mb->tail = mb->start;  in membuff_makecontig()
277 	debug("	- head=%d, tail=%d", (int)(mb->head - mb->start),  in membuff_makecontig()
278 	      (int)(mb->tail - mb->start));  in membuff_makecontig()
297 	end = mb->head >= mb->tail ? mb->head : mb->end;  in membuff_readline()
298 	for (len = 0, s = mb->tail; s < end && len < maxlen - 1; str++) {  in membuff_readline()
305 		if (s == end && mb->tail > mb->head) {  in membuff_readline()
320 	mb->tail = s == mb->end ? mb->start : s;  in membuff_readline()
344 	oldtail = mb->tail - mb->start;  in membuff_extend_by()
350 	mb->tail = mb->start + oldtail;  in membuff_extend_by()
352 	if (mb->head < mb->tail) {  in membuff_extend_by()
353 		memmove(mb->tail + by, mb->tail, orig - oldtail);  in membuff_extend_by()
354 		mb->tail += by;  in membuff_extend_by()