3 * Copyright 2006 Free Software Foundation, Inc.
5 * This file is part of GNU Radio.
7 * GNU Radio is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 3, or (at your option)
12 * GNU Radio is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with GNU Radio; see the file COPYING. If not, write to
19 * the Free Software Foundation, Inc., 51 Franklin Street,
20 * Boston, MA 02110-1301, USA.
23 #ifndef _CIRCULAR_BUFFER_H_
24 #define _CIRCULAR_BUFFER_H_
26 #include "mld_threads.h"
32 #define DEBUG(X) do{X} while(0);
34 #define DEBUG(X) do{} while(0);
37 template <class T> class circular_buffer
43 // the following are in Items (type T)
44 UInt32 d_bufLen_I, d_readNdx_I, d_writeNdx_I;
45 UInt32 d_n_avail_write_I, d_n_avail_read_I;
47 // stuff to control access to class internals
48 mld_mutex_ptr d_internal;
49 mld_condition_ptr d_readBlock, d_writeBlock;
51 // booleans to decide how to control reading, writing, and aborting
52 bool d_doWriteBlock, d_doFullRead, d_doAbort;
54 void delete_mutex_cond () {
70 circular_buffer (UInt32 bufLen_I,
71 bool doWriteBlock = true, bool doFullRead = false) {
73 throw std::runtime_error ("circular_buffer(): "
74 "Number of items to buffer must be > 0.\n");
75 d_bufLen_I = bufLen_I;
76 d_buffer = (T*) new T[d_bufLen_I];
77 d_doWriteBlock = doWriteBlock;
78 d_doFullRead = doFullRead;
80 d_readBlock = d_writeBlock = NULL;
82 DEBUG (fprintf (stderr, "c_b(): buf len (items) = %ld, "
83 "doWriteBlock = %s, doFullRead = %s\n", d_bufLen_I,
84 (d_doWriteBlock ? "true" : "false"),
85 (d_doFullRead ? "true" : "false")));
93 inline UInt32 n_avail_write_items () {
95 UInt32 retVal = d_n_avail_write_I;
96 d_internal->unlock ();
100 inline UInt32 n_avail_read_items () {
102 UInt32 retVal = d_n_avail_read_I;
103 d_internal->unlock ();
107 inline UInt32 buffer_length_items () {return (d_bufLen_I);};
108 inline bool do_write_block () {return (d_doWriteBlock);};
109 inline bool do_full_read () {return (d_doFullRead);};
113 bzero (d_buffer, d_bufLen_I * sizeof (T));
114 d_readNdx_I = d_writeNdx_I = d_n_avail_read_I = 0;
115 d_n_avail_write_I = d_bufLen_I;
116 delete_mutex_cond ();
117 // create a mutex to handle contention of shared resources;
118 // any routine needed access to shared resources uses lock()
119 // before doing anything, then unlock() when finished.
120 d_internal = new mld_mutex ();
121 // link the internal mutex to the read and write conditions;
122 // when wait() is called, the internal mutex will automatically
123 // be unlock()'ed. Upon return (from a signal() to the condition),
124 // the internal mutex will be lock()'ed.
125 d_readBlock = new mld_condition (d_internal);
126 d_writeBlock = new mld_condition (d_internal);
130 * enqueue: add the given buffer of item-length to the queue,
131 * first-in-first-out (FIFO).
134 * buf: a pointer to the buffer holding the data
136 * bufLen_I: the buffer length in items (of the instantiated type)
139 * -1: on overflow (write is not blocking, and data is being
140 * written faster than it is being read)
141 * 0: if nothing to do (0 length buffer)
143 * 2: in the process of aborting, do doing nothing
145 * will throw runtime errors if inputs are improper:
146 * buffer pointer is NULL
147 * buffer length is larger than the instantiated buffer length
150 int enqueue (T* buf, UInt32 bufLen_I) {
151 DEBUG (fprintf (stderr, "enqueue: buf = %X, bufLen = %ld, #av_wr = %ld, "
152 "#av_rd = %ld.\n", (unsigned int)buf, bufLen_I,
153 d_n_avail_write_I, d_n_avail_read_I));
154 if (bufLen_I > d_bufLen_I) {
155 fprintf (stderr, "cannot add buffer longer (%ld"
156 ") than instantiated length (%ld"
157 ").\n", bufLen_I, d_bufLen_I);
158 throw std::runtime_error ("circular_buffer::enqueue()");
164 throw std::runtime_error ("circular_buffer::enqueue(): "
165 "input buffer is NULL.\n");
168 d_internal->unlock ();
171 // set the return value to 1: success; change if needed
173 if (bufLen_I > d_n_avail_write_I) {
174 if (d_doWriteBlock) {
175 while (bufLen_I > d_n_avail_write_I) {
176 DEBUG (fprintf (stderr, "enqueue: #len > #a, waiting.\n"));
177 // wait will automatically unlock() the internal mutex
178 d_writeBlock->wait ();
179 // and lock() it here.
181 d_internal->unlock ();
182 DEBUG (fprintf (stderr, "enqueue: #len > #a, aborting.\n"));
185 DEBUG (fprintf (stderr, "enqueue: #len > #a, done waiting.\n"));
188 d_n_avail_read_I = d_bufLen_I - bufLen_I;
189 d_n_avail_write_I = bufLen_I;
190 DEBUG (fprintf (stderr, "circular_buffer::enqueue: overflow\n"));
194 UInt32 n_now_I = d_bufLen_I - d_writeNdx_I, n_start_I = 0;
195 if (n_now_I > bufLen_I)
197 else if (n_now_I < bufLen_I)
198 n_start_I = bufLen_I - n_now_I;
199 bcopy (buf, &(d_buffer[d_writeNdx_I]), n_now_I * sizeof (T));
201 bcopy (&(buf[n_now_I]), d_buffer, n_start_I * sizeof (T));
202 d_writeNdx_I = n_start_I;
204 d_writeNdx_I += n_now_I;
205 d_n_avail_read_I += bufLen_I;
206 d_n_avail_write_I -= bufLen_I;
207 d_readBlock->signal ();
208 d_internal->unlock ();
213 * dequeue: removes from the queue the number of items requested, or
214 * available, into the given buffer on a FIFO basis.
217 * buf: a pointer to the buffer into which to copy the data
219 * bufLen_I: pointer to the number of items to remove in items
220 * (of the instantiated type)
223 * 0: if nothing to do (0 length buffer)
225 * 2: in the process of aborting, do doing nothing
227 * will throw runtime errors if inputs are improper:
228 * buffer pointer is NULL
229 * buffer length pointer is NULL
230 * buffer length is larger than the instantiated buffer length
233 int dequeue (T* buf, UInt32* bufLen_I) {
234 DEBUG (fprintf (stderr, "dequeue: buf = %X, *bufLen = %ld, #av_wr = %ld, "
235 "#av_rd = %ld.\n", (unsigned int)buf, *bufLen_I,
236 d_n_avail_write_I, d_n_avail_read_I));
238 throw std::runtime_error ("circular_buffer::dequeue(): "
239 "input bufLen pointer is NULL.\n");
241 throw std::runtime_error ("circular_buffer::dequeue(): "
242 "input buffer pointer is NULL.\n");
243 UInt32 l_bufLen_I = *bufLen_I;
246 if (l_bufLen_I > d_bufLen_I) {
247 fprintf (stderr, "cannot remove buffer longer (%ld"
248 ") than instantiated length (%ld"
249 ").\n", l_bufLen_I, d_bufLen_I);
250 throw std::runtime_error ("circular_buffer::dequeue()");
255 d_internal->unlock ();
259 while (d_n_avail_read_I < l_bufLen_I) {
260 DEBUG (fprintf (stderr, "dequeue: #a < #len, waiting.\n"));
261 // wait will automatically unlock() the internal mutex
262 d_readBlock->wait ();
263 // and lock() it here.
265 d_internal->unlock ();
266 DEBUG (fprintf (stderr, "dequeue: #a < #len, aborting.\n"));
269 DEBUG (fprintf (stderr, "dequeue: #a < #len, done waiting.\n"));
272 while (d_n_avail_read_I == 0) {
273 DEBUG (fprintf (stderr, "dequeue: #a == 0, waiting.\n"));
274 // wait will automatically unlock() the internal mutex
275 d_readBlock->wait ();
276 // and lock() it here.
278 d_internal->unlock ();
279 DEBUG (fprintf (stderr, "dequeue: #a == 0, aborting.\n"));
282 DEBUG (fprintf (stderr, "dequeue: #a == 0, done waiting.\n"));
285 if (l_bufLen_I > d_n_avail_read_I)
286 l_bufLen_I = d_n_avail_read_I;
287 UInt32 n_now_I = d_bufLen_I - d_readNdx_I, n_start_I = 0;
288 if (n_now_I > l_bufLen_I)
289 n_now_I = l_bufLen_I;
290 else if (n_now_I < l_bufLen_I)
291 n_start_I = l_bufLen_I - n_now_I;
292 bcopy (&(d_buffer[d_readNdx_I]), buf, n_now_I * sizeof (T));
294 bcopy (d_buffer, &(buf[n_now_I]), n_start_I * sizeof (T));
295 d_readNdx_I = n_start_I;
297 d_readNdx_I += n_now_I;
298 *bufLen_I = l_bufLen_I;
299 d_n_avail_read_I -= l_bufLen_I;
300 d_n_avail_write_I += l_bufLen_I;
301 d_writeBlock->signal ();
302 d_internal->unlock ();
309 d_writeBlock->signal ();
310 d_readBlock->signal ();
311 d_internal->unlock ();
315 #endif /* _CIRCULAR_BUFFER_H_ */