kernel/util/ring_buffer.cpp

32 space_left_in_buffer(struct ring_buffer *buffer)
34 	return buffer->size - buffer->in;
39 read_from_buffer(struct ring_buffer *buffer, uint8 *data, ssize_t length,
42 	int32 available = buffer->in;
52 	if (buffer->first + length <= buffer->size) {
55 			if (user_memcpy(data, buffer->buffer + buffer->first, length) < B_OK)
58 			memcpy(data, buffer->buffer + buffer->first, length);
61 		size_t upper = buffer->size - buffer->first;
65 			if (user_memcpy(data, buffer->buffer + buffer->first, upper) < B_OK
66 				|| user_memcpy(data + upper, buffer->buffer, lower) < B_OK)
69 			memcpy(data, buffer->buffer + buffer->first, upper);
70 			memcpy(data + upper, buffer->buffer, lower);
74 	buffer->first = (buffer->first + bytesRead) % buffer->size;
75 	buffer->in -= bytesRead;
82 write_to_buffer(struct ring_buffer *buffer, const uint8 *data, ssize_t length,
85 	int32 left = space_left_in_buffer(buffer);
93 	int32 position = (buffer->first + buffer->in) % buffer->size;
95 	if (position + length <= buffer->size) {
98 			if (user_memcpy(buffer->buffer + position, data, length) < B_OK)
101 			memcpy(buffer->buffer + position, data, length);
104 		size_t upper = buffer->size - position;
108 			if (user_memcpy(buffer->buffer + position, data, upper) < B_OK
109 				|| user_memcpy(buffer->buffer, data + upper, lower) < B_OK)
112 			memcpy(buffer->buffer + position, data, upper);
113 			memcpy(buffer->buffer, data + upper, lower);
117 	buffer->in += bytesWritten;
137 		ring_buffer* buffer = (ring_buffer*)malloc(sizeof(ring_buffer) + size);
138 		if (buffer == NULL)
141 		buffer->size = size;
142 		ring_buffer_clear(buffer);
144 		return buffer;
148 	ring_buffer* buffer = (ring_buffer*)memory;
150 	buffer->size = size;
152 		&& (size_t)buffer->size == size
153 		&& buffer->in >= 0 && (size_t)buffer->in <= size
154 		&& buffer->first >= 0 && (size_t)buffer->first < size) {
157 		ring_buffer_clear(buffer);
159 	return buffer;
164 delete_ring_buffer(struct ring_buffer *buffer)
166 	free(buffer);
171 ring_buffer_clear(struct ring_buffer *buffer)
173 	buffer->in = 0;
174 	buffer->first = 0;
179 ring_buffer_readable(struct ring_buffer *buffer)
181 	return buffer->in;
186 ring_buffer_writable(struct ring_buffer *buffer)
188 	return buffer->size - buffer->in;
193 ring_buffer_flush(struct ring_buffer *buffer, size_t length)
196 	if (length > (size_t)buffer->in)
197 		length = buffer->in;
199 	buffer->in -= length;
200 	buffer->first = (buffer->first + length) % buffer->size;
205 ring_buffer_read(struct ring_buffer *buffer, uint8 *data, ssize_t length)
207 	return read_from_buffer(buffer, data, length, false);
212 ring_buffer_write(struct ring_buffer *buffer, const uint8 *data, ssize_t length)
214 	return write_to_buffer(buffer, data, length, false);
219 ring_buffer_user_read(struct ring_buffer *buffer, uint8 *data, ssize_t length)
221 	return read_from_buffer(buffer, data, length, true);
226 ring_buffer_user_write(struct ring_buffer *buffer, const uint8 *data, ssize_t length)
228 	return write_to_buffer(buffer, data, length, true);
232 /*!	Reads data from the ring buffer, but doesn't remove the data from it.
233 	\param buffer The ring buffer.
235 		buffer at which to start reading.
236 	\param data The buffer to which to copy the data.
238 	\return The number of bytes actually read from the buffer.
241 ring_buffer_peek(struct ring_buffer* buffer, size_t offset, void* data,
244 	size_t available = buffer->in;
252 	if ((offset += buffer->first) >= (size_t)buffer->size)
253 		offset -= buffer->size;
255 	if (offset + length <= (size_t)buffer->size) {
257 		memcpy(data, buffer->buffer + offset, length);
260 		size_t upper = buffer->size - offset;
263 		memcpy(data, buffer->buffer + offset, upper);
264 		memcpy((uint8*)data + upper, buffer->buffer, lower);
271 /*!	Returns iovecs describing the contents of the ring buffer.
273 	\param buffer The ring buffer.
277 		contents of the ring buffer. \c 0, if empty, \c 2 at maximum.
280 ring_buffer_get_vecs(struct ring_buffer* buffer, struct iovec* vecs)
282 	if (buffer->in == 0)
285 	if (buffer->first + buffer->in <= buffer->size) {
287 		vecs[0].iov_base = buffer->buffer + buffer->first;
288 		vecs[0].iov_len = buffer->in;
293 	size_t upper = buffer->size - buffer->first;
294 	size_t lower = buffer->in - upper;
296 	vecs[0].iov_base = buffer->buffer + buffer->first;
298 	vecs[1].iov_base = buffer->buffer;
305 /*! Moves data from one ring buffer to another.
307 	\param to The destination ring buffer.
309 	\param from The source ring buffer.
326 		bytesMoved = ring_buffer_write(to, from->buffer + from->first, length);
332 		bytesMoved = ring_buffer_write(to, from->buffer + from->first, upper);
335 			bytesMoved += ring_buffer_write(to, from->buffer, lower);
347 /**	Sends the contents of the ring buffer to a port.
348  *	The buffer will be empty afterwards only if sending the data actually works.
352 ring_buffer_write_to_port(struct ring_buffer *buffer, port_id port, int32 code,
355 	int32 length = buffer->in;
361 	if (buffer->first + length <= buffer->size) {
363 		status = write_port_etc(port, code, buffer->buffer + buffer->first, length,
367 		size_t upper = buffer->size - buffer->first;
371 		vecs[0].iov_base = buffer->buffer + buffer->first;
373 		vecs[1].iov_base = buffer->buffer;
382 	buffer->first = (buffer->first + length) % buffer->size;
383 	buffer->in -= length;