[J-u-boot.git] / lib / membuff.c

/*
 * Copyright (c) 2015 Google, Inc
 * Written by Simon Glass <[email protected]>
 *
 * Copyright (c) 1992 Simon Glass
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

#include <common.h>
#include <errno.h>
#include <malloc.h>
#include "membuff.h"

void membuff_purge(struct membuff *mb)
{
	/* set mb->head and mb->tail so the buffers look empty */
	mb->head = mb->start;
	mb->tail = mb->start;
}

static int membuff_putrawflex(struct membuff *mb, int maxlen, bool update,
			      char ***data, int *offsetp)
{
	int len;

	/* always write to 'mb->head' */
	assert(data && offsetp);
	*data = &mb->start;
	*offsetp = mb->head - mb->start;

	/* if there is no buffer, we can do nothing */
	if (!mb->start)
		return 0;

	/*
	 * if head is ahead of tail, we can write from head until the end of
	 * the buffer
	 */
	if (mb->head >= mb->tail) {
		/* work out how many bytes can fit here */
		len = mb->end - mb->head - 1;
		if (maxlen >= 0 && len > maxlen)
			len = maxlen;

		/* update the head pointer to mark these bytes as written */
		if (update)
			mb->head += len;

		/*
		 * if the tail isn't at start of the buffer, then we can
		 * write one more byte right at the end
		 */
		if ((maxlen < 0 || len < maxlen) && mb->tail != mb->start) {
			len++;
			if (update)
				mb->head = mb->start;
		}

	/* otherwise now we can write until head almost reaches tail */
	} else {
		/* work out how many bytes can fit here */
		len = mb->tail - mb->head - 1;
		if (maxlen >= 0 && len > maxlen)
			len = maxlen;

		/* update the head pointer to mark these bytes as written */
		if (update)
			mb->head += len;
	}

	/* return the number of bytes which can be/must be written */
	return len;
}

int membuff_putraw(struct membuff *mb, int maxlen, bool update, char **data)
{
	char **datap;
	int offset;
	int size;

	size = membuff_putrawflex(mb, maxlen, update, &datap, &offset);
	*data = *datap + offset;

	return size;
}

bool membuff_putbyte(struct membuff *mb, int ch)
{
	char *data;

	if (membuff_putraw(mb, 1, true, &data) != 1)
		return false;
	*data = ch;

	return true;
}

int membuff_getraw(struct membuff *mb, int maxlen, bool update, char **data)
{
	int len;

	/* assume for now there is no data to get */
	len = 0;

	/*
	 * in this case head is ahead of tail, so we must return data between
	 *'tail' and 'head'
	 */
	if (mb->head > mb->tail) {
		/* work out the amount of data */
		*data = mb->tail;
		len = mb->head - mb->tail;

		/* check it isn't too much */
		if (maxlen >= 0 && len > maxlen)
			len = maxlen;

		/* & mark it as read from the buffer */
		if (update)
			mb->tail += len;
	}

	/*
	 * if head is before tail, then we have data between 'tail' and 'end'
	 * and some more data between 'start' and 'head'(which we can't
	 * return this time
	 */
	else if (mb->head < mb->tail) {
		/* work out the amount of data */
		*data = mb->tail;
		len = mb->end - mb->tail;
		if (maxlen >= 0 && len > maxlen)
			len = maxlen;
		if (update) {
			mb->tail += len;
			if (mb->tail == mb->end)
				mb->tail = mb->start;
		}
	}

	debug("getraw: maxlen=%d, update=%d, head=%d, tail=%d, data=%d, len=%d",
	      maxlen, update, (int)(mb->head - mb->start),
	      (int)(mb->tail - mb->start), (int)(*data - mb->start), len);

	/* return the number of bytes we found */
	return len;
}

int membuff_getbyte(struct membuff *mb)
{
	char *data = 0;

	return membuff_getraw(mb, 1, true, &data) != 1 ? -1 : *(uint8_t *)data;
}

int membuff_peekbyte(struct membuff *mb)
{
	char *data = 0;

	return membuff_getraw(mb, 1, false, &data) != 1 ? -1 : *(uint8_t *)data;
}

int membuff_get(struct membuff *mb, char *buff, int maxlen)
{
	char *data = 0, *buffptr = buff;
	int len = 1, i;

	/*
	 * do this in up to two lots(see GetRaw for why) stopping when there
	 * is no more data
	 */
	for (i = 0; len && i < 2; i++) {
		/* get a pointer to the data available */
		len = membuff_getraw(mb, maxlen, true, &data);

		/* copy it into the buffer */
		memcpy(buffptr, data, len);
		buffptr += len;
		maxlen -= len;
	}

	/* return the number of bytes read */
	return buffptr - buff;
}

int membuff_put(struct membuff *mb, const char *buff, int length)
{
	char *data;
	int towrite, i, written;

	for (i = written = 0; i < 2; i++) {
		/* ask where some data can be written */
		towrite = membuff_putraw(mb, length, true, &data);

		/* and write it, updating the bytes length */
		memcpy(data, buff, towrite);
		written += towrite;
		buff += towrite;
		length -= towrite;
	}

	/* return the number of bytes written */
	return written;
}

bool membuff_isempty(struct membuff *mb)
{
	return mb->head == mb->tail;
}

int membuff_avail(struct membuff *mb)
{
	struct membuff copy;
	int i, avail;
	char *data = 0;

	/* make a copy of this buffer's control data */
	copy = *mb;

	/* now read everything out of the copied buffer */
	for (i = avail = 0; i < 2; i++)
		avail += membuff_getraw(&copy, -1, true, &data);

	/* and return how much we read */
	return avail;
}

int membuff_size(struct membuff *mb)
{
	return mb->end - mb->start;
}

bool membuff_makecontig(struct membuff *mb)
{
	int topsize, botsize;

	debug("makecontig: head=%d, tail=%d, size=%d",
	      (int)(mb->head - mb->start), (int)(mb->tail - mb->start),
	      (int)(mb->end - mb->start));

	/*
	 * first we move anything at the start of the buffer into the correct
	 * place some way along
	 */
	if (mb->tail > mb->head) {
		/*
		 * the data is split into two parts, from 0 to ->head and
		 * from ->tail to ->end. We move the stuff from 0 to ->head
		 * up to make space for the other data before it
		 */
		topsize = mb->end - mb->tail;
		botsize = mb->head - mb->start;

		/*
		 * must move data at bottom up by 'topsize' bytes - check if
		 * there's room
		 */
		if (mb->head + topsize >= mb->tail)
			return false;
		memmove(mb->start + topsize, mb->start, botsize);
		debug("	- memmove(%d, %d, %d)", topsize, 0, botsize);

	/* nothing at the start, so skip that step */
	} else {
		topsize = mb->head - mb->tail;
		botsize = 0;
	}

	/* now move data at top down to the bottom */
	memcpy(mb->start, mb->tail, topsize);
	debug("	- memcpy(%d, %d, %d)", 0, (int)(mb->tail - mb->start), topsize);

	/* adjust pointers */
	mb->tail = mb->start;
	mb->head = mb->start + topsize + botsize;

	debug("	- head=%d, tail=%d", (int)(mb->head - mb->start),
	      (int)(mb->tail - mb->start));

	/* all ok */
	return true;
}

int membuff_free(struct membuff *mb)
{
	return mb->end == mb->start ? 0 :
			(mb->end - mb->start) - 1 - membuff_avail(mb);
}

int membuff_readline(struct membuff *mb, char *str, int maxlen, int minch)
{
	int len;  /* number of bytes read (!= string length) */
	char *s, *end;
	bool ok = false;
	char *orig = str;

	end = mb->head >= mb->tail ? mb->head : mb->end;
	for (len = 0, s = mb->tail; s < end && len < maxlen - 1; str++) {
		*str = *s++;
		len++;
		if (*str == '\n' || *str < minch) {
			ok = true;
			break;
		}
		if (s == end && mb->tail > mb->head) {
			s = mb->start;
			end = mb->head;
		}
	}

	/* couldn't get the whole string */
	if (!ok) {
		if (maxlen)
			*orig = '\0';
		return 0;
	}

	/* terminate the string, update the membuff and return success */
	*str = '\0';
	mb->tail = s == mb->end ? mb->start : s;

	return len;
}

int membuff_extend_by(struct membuff *mb, int by, int max)
{
	int oldhead, oldtail;
	int size, orig;
	char *ptr;

	/* double the buffer size until it is big enough */
	assert(by >= 0);
	for (orig = mb->end - mb->start, size = orig; size < orig + by;)
		size *= 2;
	if (max != -1)
		size = min(size, max);
	by = size - orig;

	/* if we're already at maximum, give up */
	if (by <= 0)
		return -E2BIG;

	oldhead = mb->head - mb->start;
	oldtail = mb->tail - mb->start;
	ptr = realloc(mb->start, size);
	if (!ptr)
		return -ENOMEM;
	mb->start = ptr;
	mb->head = mb->start + oldhead;
	mb->tail = mb->start + oldtail;

	if (mb->head < mb->tail) {
		memmove(mb->tail + by, mb->tail, orig - oldtail);
		mb->tail += by;
	}
	mb->end = mb->start + size;

	return 0;
}

void membuff_init(struct membuff *mb, char *buff, int size)
{
	mb->start = buff;
	mb->end = mb->start + size;
	membuff_purge(mb);
}

int membuff_new(struct membuff *mb, int size)
{
	mb->start = malloc(size);
	if (!mb->start)
		return -ENOMEM;

	membuff_init(mb, mb->start, size);
	return 0;
}

void membuff_uninit(struct membuff *mb)
{
	mb->end = NULL;
	mb->start = NULL;
	membuff_purge(mb);
}

void membuff_dispose(struct membuff *mb)
{
	free(&mb->start);
	membuff_uninit(mb);
}
Commit	Line	Data
b7b65090 SG	1	/*
	2	* Copyright (c) 2015 Google, Inc
	3	* Written by Simon Glass <[email protected]>
	4	*
	5	* Copyright (c) 1992 Simon Glass
	6	*
	7	* SPDX-License-Identifier: GPL-2.0+
	8	*/
	9
	10	#include <common.h>
	11	#include <errno.h>
	12	#include <malloc.h>
	13	#include "membuff.h"
	14
	15	void membuff_purge(struct membuff *mb)
	16	{
	17	/* set mb->head and mb->tail so the buffers look empty */
	18	mb->head = mb->start;
	19	mb->tail = mb->start;
	20	}
	21
	22	static int membuff_putrawflex(struct membuff *mb, int maxlen, bool update,
	23	char **data, int offsetp)
	24	{
	25	int len;
	26
	27	/* always write to 'mb->head' */
	28	assert(data && offsetp);
	29	*data = &mb->start;
	30	*offsetp = mb->head - mb->start;
	31
	32	/* if there is no buffer, we can do nothing */
	33	if (!mb->start)
	34	return 0;
	35
	36	/*
	37	* if head is ahead of tail, we can write from head until the end of
	38	* the buffer
	39	*/
	40	if (mb->head >= mb->tail) {
	41	/* work out how many bytes can fit here */
	42	len = mb->end - mb->head - 1;
	43	if (maxlen >= 0 && len > maxlen)
	44	len = maxlen;
	45
	46	/* update the head pointer to mark these bytes as written */
	47	if (update)
	48	mb->head += len;
	49
	50	/*
	51	* if the tail isn't at start of the buffer, then we can
	52	* write one more byte right at the end
	53	*/
	54	if ((maxlen < 0 \|\| len < maxlen) && mb->tail != mb->start) {
	55	len++;
	56	if (update)
	57	mb->head = mb->start;
	58	}
	59
	60	/* otherwise now we can write until head almost reaches tail */
	61	} else {
	62	/* work out how many bytes can fit here */
	63	len = mb->tail - mb->head - 1;
	64	if (maxlen >= 0 && len > maxlen)
65	len = maxlen;
66
67	/* update the head pointer to mark these bytes as written */
68	if (update)
69	mb->head += len;
70	}
71
72	/* return the number of bytes which can be/must be written */
73	return len;
74	}
75
76	int membuff_putraw(struct membuff mb, int maxlen, bool update, char *data)
77	{
78	char **datap;
79	int offset;
80	int size;
81
82	size = membuff_putrawflex(mb, maxlen, update, &datap, &offset);
83	data = datap + offset;
84
85	return size;
86	}
87
88	bool membuff_putbyte(struct membuff *mb, int ch)
89	{
90	char *data;
91
92	if (membuff_putraw(mb, 1, true, &data) != 1)
93	return false;
94	*data = ch;
95
96	return true;
97	}
98
99	int membuff_getraw(struct membuff mb, int maxlen, bool update, char *data)
100	{
101	int len;
102
103	/* assume for now there is no data to get */
104	len = 0;
105
106	/*
107	* in this case head is ahead of tail, so we must return data between
108	*'tail' and 'head'
109	*/
110	if (mb->head > mb->tail) {
111	/* work out the amount of data */
112	*data = mb->tail;
113	len = mb->head - mb->tail;
114
115	/* check it isn't too much */
116	if (maxlen >= 0 && len > maxlen)
117	len = maxlen;
118
119	/* & mark it as read from the buffer */
120	if (update)
121	mb->tail += len;
122	}
123
124	/*
125	* if head is before tail, then we have data between 'tail' and 'end'
126	* and some more data between 'start' and 'head'(which we can't
127	* return this time
128	*/
129	else if (mb->head < mb->tail) {
130	/* work out the amount of data */
131	*data = mb->tail;
132	len = mb->end - mb->tail;
133	if (maxlen >= 0 && len > maxlen)
134	len = maxlen;
135	if (update) {
136	mb->tail += len;
137	if (mb->tail == mb->end)
138	mb->tail = mb->start;
139	}
140	}
141
142	debug("getraw: maxlen=%d, update=%d, head=%d, tail=%d, data=%d, len=%d",
143	maxlen, update, (int)(mb->head - mb->start),
144	(int)(mb->tail - mb->start), (int)(*data - mb->start), len);
145
146	/* return the number of bytes we found */
147	return len;
148	}
149
150	int membuff_getbyte(struct membuff *mb)
151	{
152	char *data = 0;
153
154	return membuff_getraw(mb, 1, true, &data) != 1 ? -1 : (uint8_t )data;
155	}
156
157	int membuff_peekbyte(struct membuff *mb)
158	{
159	char *data = 0;
160
161	return membuff_getraw(mb, 1, false, &data) != 1 ? -1 : (uint8_t )data;
162	}
163
164	int membuff_get(struct membuff mb, char buff, int maxlen)
165	{
166	char data = 0, buffptr = buff;
167	int len = 1, i;
168
169	/*
170	* do this in up to two lots(see GetRaw for why) stopping when there
171	* is no more data
172	*/
173	for (i = 0; len && i < 2; i++) {
174	/* get a pointer to the data available */
175	len = membuff_getraw(mb, maxlen, true, &data);
176
177	/* copy it into the buffer */
178	memcpy(buffptr, data, len);
179	buffptr += len;
180	maxlen -= len;
181	}
182
183	/* return the number of bytes read */
184	return buffptr - buff;
185	}
186
187	int membuff_put(struct membuff mb, const char buff, int length)
188	{
189	char *data;
190	int towrite, i, written;
191
192	for (i = written = 0; i < 2; i++) {
193	/* ask where some data can be written */
194	towrite = membuff_putraw(mb, length, true, &data);
195
196	/* and write it, updating the bytes length */
197	memcpy(data, buff, towrite);
198	written += towrite;
199	buff += towrite;
200	length -= towrite;
201	}
202
203	/* return the number of bytes written */
204	return written;
205	}
206
207	bool membuff_isempty(struct membuff *mb)
208	{
209	return mb->head == mb->tail;
210	}
211
212	int membuff_avail(struct membuff *mb)
213	{
214	struct membuff copy;
215	int i, avail;
216	char *data = 0;
217
218	/* make a copy of this buffer's control data */
219	copy = *mb;
220
221	/* now read everything out of the copied buffer */
222	for (i = avail = 0; i < 2; i++)
223	avail += membuff_getraw(&copy, -1, true, &data);
224
225	/* and return how much we read */
226	return avail;
227	}
228
229	int membuff_size(struct membuff *mb)
230	{
231	return mb->end - mb->start;
232	}
233
234	bool membuff_makecontig(struct membuff *mb)
235	{
236	int topsize, botsize;
237
238	debug("makecontig: head=%d, tail=%d, size=%d",
239	(int)(mb->head - mb->start), (int)(mb->tail - mb->start),
240	(int)(mb->end - mb->start));
241
242	/*
243	* first we move anything at the start of the buffer into the correct
244	* place some way along
245	*/
246	if (mb->tail > mb->head) {
247	/*
248	* the data is split into two parts, from 0 to ->head and
249	* from ->tail to ->end. We move the stuff from 0 to ->head
250	* up to make space for the other data before it
251	*/
252	topsize = mb->end - mb->tail;
253	botsize = mb->head - mb->start;
254
255	/*
256	* must move data at bottom up by 'topsize' bytes - check if
257	* there's room
258	*/
259	if (mb->head + topsize >= mb->tail)
260	return false;
261	memmove(mb->start + topsize, mb->start, botsize);
262	debug(" - memmove(%d, %d, %d)", topsize, 0, botsize);
263
264	/* nothing at the start, so skip that step */
265	} else {
266	topsize = mb->head - mb->tail;
267	botsize = 0;
268	}
269
270	/* now move data at top down to the bottom */
271	memcpy(mb->start, mb->tail, topsize);
272	debug(" - memcpy(%d, %d, %d)", 0, (int)(mb->tail - mb->start), topsize);
273
274	/* adjust pointers */
275	mb->tail = mb->start;
276	mb->head = mb->start + topsize + botsize;
277
278	debug(" - head=%d, tail=%d", (int)(mb->head - mb->start),
279	(int)(mb->tail - mb->start));
280
281	/* all ok */
282	return true;
283	}
284
285	int membuff_free(struct membuff *mb)
286	{
287	return mb->end == mb->start ? 0 :
288	(mb->end - mb->start) - 1 - membuff_avail(mb);
289	}
290
291	int membuff_readline(struct membuff mb, char str, int maxlen, int minch)
292	{
293	int len; /* number of bytes read (!= string length) */
294	char s, end;
295	bool ok = false;
296	char *orig = str;
297
298	end = mb->head >= mb->tail ? mb->head : mb->end;
299	for (len = 0, s = mb->tail; s < end && len < maxlen - 1; str++) {
300	str = s++;
301	len++;
302	if (str == '\n' \|\| str < minch) {
303	ok = true;
304	break;
305	}
306	if (s == end && mb->tail > mb->head) {
307	s = mb->start;
308	end = mb->head;
309	}
310	}
311
312	/* couldn't get the whole string */
313	if (!ok) {
314	if (maxlen)
315	*orig = '\0';
316	return 0;
317	}
318
319	/* terminate the string, update the membuff and return success */
320	*str = '\0';
321	mb->tail = s == mb->end ? mb->start : s;
322
323	return len;
324	}
325
326	int membuff_extend_by(struct membuff *mb, int by, int max)
327	{
328	int oldhead, oldtail;
329	int size, orig;
330	char *ptr;
331
332	/* double the buffer size until it is big enough */
333	assert(by >= 0);
334	for (orig = mb->end - mb->start, size = orig; size < orig + by;)
335	size *= 2;
336	if (max != -1)
337	size = min(size, max);
338	by = size - orig;
339
340	/* if we're already at maximum, give up */
341	if (by <= 0)
342	return -E2BIG;
343
344	oldhead = mb->head - mb->start;
345	oldtail = mb->tail - mb->start;
346	ptr = realloc(mb->start, size);
347	if (!ptr)
348	return -ENOMEM;
349	mb->start = ptr;
350	mb->head = mb->start + oldhead;
351	mb->tail = mb->start + oldtail;
352
353	if (mb->head < mb->tail) {
354	memmove(mb->tail + by, mb->tail, orig - oldtail);
355	mb->tail += by;
356	}
357	mb->end = mb->start + size;
358
359	return 0;
360	}
361
362	void membuff_init(struct membuff mb, char buff, int size)
363	{
364	mb->start = buff;
365	mb->end = mb->start + size;
366	membuff_purge(mb);
367	}
368
369	int membuff_new(struct membuff *mb, int size)
370	{
371	mb->start = malloc(size);
372	if (!mb->start)
373	return -ENOMEM;
374
375	membuff_init(mb, mb->start, size);
376	return 0;
377	}
378
379	void membuff_uninit(struct membuff *mb)
380	{
381	mb->end = NULL;
382	mb->start = NULL;
383	membuff_purge(mb);
384	}
385
386	void membuff_dispose(struct membuff *mb)
387	{
388	free(&mb->start);
389	membuff_uninit(mb);
390	}