Annotation of libelwix/src/ring.c, revision 1.4.4.3
1.2 misho 1: /*************************************************************************
2: * (C) 2025 AITNET ltd - Sofia/Bulgaria - <misho@aitnet.org>
3: * by Michael Pounov <misho@elwix.org>
4: *
5: * $Author: misho $
1.4.4.3 ! misho 6: * $Id: ring.c,v 1.4.4.2 2026/02/10 17:24:39 misho Exp $
1.2 misho 7: *
8: **************************************************************************
9: The ELWIX and AITNET software is distributed under the following
10: terms:
11:
12: All of the documentation and software included in the ELWIX and AITNET
13: Releases is copyrighted by ELWIX - Sofia/Bulgaria <info@elwix.org>
14:
1.4.4.1 misho 15: Copyright 2004 - 2026
1.2 misho 16: by Michael Pounov <misho@elwix.org>. All rights reserved.
17:
18: Redistribution and use in source and binary forms, with or without
19: modification, are permitted provided that the following conditions
20: are met:
21: 1. Redistributions of source code must retain the above copyright
22: notice, this list of conditions and the following disclaimer.
23: 2. Redistributions in binary form must reproduce the above copyright
24: notice, this list of conditions and the following disclaimer in the
25: documentation and/or other materials provided with the distribution.
26: 3. All advertising materials mentioning features or use of this software
27: must display the following acknowledgement:
28: This product includes software developed by Michael Pounov <misho@elwix.org>
29: ELWIX - Embedded LightWeight unIX and its contributors.
30: 4. Neither the name of AITNET nor the names of its contributors
31: may be used to endorse or promote products derived from this software
32: without specific prior written permission.
33:
34: THIS SOFTWARE IS PROVIDED BY AITNET AND CONTRIBUTORS ``AS IS'' AND
35: ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
36: IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
37: ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
38: FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
39: DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
40: OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
41: HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
42: LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
43: OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
44: SUCH DAMAGE.
45: */
46: #include "global.h"
47:
48:
49: /*
50: * rbuf_init() - Init ring buffer
51: *
52: * @rbuf = Ring buffer
53: * @num = Number of elements in buffer
54: * return: -1 error or 0 ok
55: */
56: int
57: rbuf_init(ringbuf_t *rbuf, int num)
58: {
59: if (!rbuf)
60: return -1;
61:
1.3 misho 62: atomic_store_explicit((atomic_int*) &rbuf->rb_head, 0, memory_order_relaxed);
63: atomic_store_explicit((atomic_int*) &rbuf->rb_tail, 0, memory_order_relaxed);
1.2 misho 64:
65: rbuf->rb_buffer = e_calloc(num, sizeof(struct iovec));
66: if (!rbuf->rb_buffer)
67: return -1;
68: else
69: rbuf->rb_bufnum = num;
70: memset(rbuf->rb_buffer, 0, num * sizeof(struct iovec));
71:
72: return 0;
73: }
74:
75: /*
76: * rbuf_free() - Free ring buffer
77: *
78: * @rbuf = Ring buffer
79: * return: none
80: */
81: void
82: rbuf_free(ringbuf_t *rbuf)
83: {
84: if (!rbuf)
85: return;
86:
87: if (rbuf->rb_buffer) {
88: e_free(rbuf->rb_buffer);
89: rbuf->rb_buffer = NULL;
90: rbuf->rb_bufnum = 0;
91: }
92:
1.3 misho 93: atomic_store_explicit((atomic_int*) &rbuf->rb_head, 0, memory_order_relaxed);
94: atomic_store_explicit((atomic_int*) &rbuf->rb_tail, 0, memory_order_relaxed);
1.2 misho 95: }
96:
97: /*
98: * rbuf_purge() - Purge all buffer
99: *
100: * @rbuf = Ring buffer
101: * return: none
102: */
103: void
104: rbuf_purge(ringbuf_t *rbuf)
105: {
106: if (!rbuf)
107: return;
108:
109: if (rbuf->rb_buffer)
110: memset(rbuf->rb_buffer, 0, rbuf->rb_bufnum * sizeof(struct iovec));
111:
1.3 misho 112: atomic_store_explicit((atomic_int*) &rbuf->rb_head, 0, memory_order_relaxed);
113: atomic_store_explicit((atomic_int*) &rbuf->rb_tail, 0, memory_order_relaxed);
1.2 misho 114: }
115:
116: /*
117: * rbuf_isempty() - Check buffer is empty
118: *
119: * @rbuf = Ring buffer
120: * return: -1 error, 0 it isn't empty
121: */
122: int
123: rbuf_isempty(ringbuf_t *rbuf)
124: {
125: if (!rbuf)
126: return -1;
127:
1.3 misho 128: return (atomic_load_explicit((atomic_int*) &rbuf->rb_head, memory_order_acquire) ==
129: atomic_load_explicit((atomic_int*) &rbuf->rb_tail, memory_order_acquire));
1.2 misho 130: }
131:
132: /*
133: * rbuf_isfull() - Check buffer is full
134: *
135: * @rbuf = Ring buffer
136: * return: -1 error or 0 it isn't full
137: */
138: int
139: rbuf_isfull(ringbuf_t *rbuf)
140: {
1.4.4.1 misho 141: int h, t;
142:
1.2 misho 143: if (!rbuf)
144: return -1;
145: if (!rbuf->rb_bufnum)
146: return 1;
147:
1.4.4.1 misho 148: t = atomic_load_explicit((atomic_int*) &rbuf->rb_tail, memory_order_acquire);
149: h = atomic_load_explicit((atomic_int*) &rbuf->rb_head, memory_order_relaxed) + 1;
150: if (h >= rbuf->rb_bufnum)
151: h ^= h;
152:
153: return (h == t);
1.2 misho 154: }
155:
156: /*
157: * rbuf_enqueue() - Enqueue data to buffer
158: *
159: * @rbuf = Ring buffer
160: * @data = Data
161: * @len = Length
162: * return: -1 error, 1 buffer is full or 0 ok
163: */
164: int
165: rbuf_enqueue(ringbuf_t *rbuf, void *data, size_t len)
166: {
167: int h, t, n;
168: struct iovec *iov;
169:
170: if (!rbuf || !rbuf->rb_buffer)
171: return -1;
172: if (!rbuf->rb_bufnum)
173: return 1;
174:
1.3 misho 175: h = atomic_load_explicit((atomic_int*) &rbuf->rb_head, memory_order_relaxed);
176: t = atomic_load_explicit((atomic_int*) &rbuf->rb_tail, memory_order_acquire);
1.2 misho 177: n = (h + 1) % rbuf->rb_bufnum;
178:
179: if (n == t)
180: return 1;
181:
182: iov = rbuf->rb_buffer + h;
183: iov->iov_len = len;
184: iov->iov_base = data;
185:
1.3 misho 186: atomic_store_explicit((atomic_int*) &rbuf->rb_head, n, memory_order_release);
1.2 misho 187: return 0;
188: }
189:
190: /*
191: * rbuf_dequeue() - Dequeue data from buffer
192: *
193: * @rbuf = Ring buffer
194: * @out = Data, if =NULL, just dequeue data
195: * return: -1 error, 1 buffer is empty or 0 ok
196: */
197: int
1.4 misho 198: rbuf_dequeue(ringbuf_t *rbuf, struct iovec **out)
1.2 misho 199: {
200: int h, t, n;
201:
202: if (!rbuf || !rbuf->rb_buffer)
203: return -1;
204: if (!rbuf->rb_bufnum)
205: return 1;
206:
1.3 misho 207: h = atomic_load_explicit((atomic_int*) &rbuf->rb_head, memory_order_acquire);
208: t = atomic_load_explicit((atomic_int*) &rbuf->rb_tail, memory_order_relaxed);
1.2 misho 209: n = (t + 1) % rbuf->rb_bufnum;
210:
211: if (h == t)
212: return 1;
213:
214: if (out)
1.4 misho 215: *out = rbuf->rb_buffer + t;
1.2 misho 216:
1.3 misho 217: atomic_store_explicit((atomic_int*) &rbuf->rb_tail, n, memory_order_release);
1.2 misho 218: return 0;
219: }
1.4.4.1 misho 220:
221:
222: /*
223: * lrb_init() - Init linear ring buffer
224: *
225: * @lrb = Linear ring buffer
226: * @size = Size of ring buffer
227: * return: -1 error or 0 ok
228: */
229: int
230: lrb_init(lrbuf_t *lrb, u_int size)
231: {
232: if (!lrb)
233: return -1;
234:
235: atomic_store_explicit((atomic_int*) &lrb->lrb_head, 0, memory_order_relaxed);
236: atomic_store_explicit((atomic_int*) &lrb->lrb_tail, 0, memory_order_relaxed);
237:
238: lrb->lrb_data = e_malloc(size);
239: if (!lrb->lrb_data)
240: return -1;
241: else
242: lrb->lrb_size = size;
243: memset(lrb->lrb_data, 0, lrb->lrb_size);
244:
245: return 0;
246: }
247:
248: /*
249: * lrb_free() - Free linear ring buffer
250: *
251: * @lrb = Linear ring buffer
252: * return: none
253: */
254: void
255: lrb_free(lrbuf_t *lrb)
256: {
257: if (!lrb)
258: return;
259:
260: if (lrb->lrb_data) {
261: e_free(lrb->lrb_data);
262: lrb->lrb_data = NULL;
263: lrb->lrb_size = 0;
264: }
265:
266: atomic_store_explicit((atomic_int*) &lrb->lrb_head, 0, memory_order_relaxed);
267: atomic_store_explicit((atomic_int*) &lrb->lrb_tail, 0, memory_order_relaxed);
268: }
269:
270: /*
271: * lrb_purge() - Purge all buffer
272: *
273: * @lrb = Linear ring buffer
274: * return: none
275: */
276: void
277: lrb_purge(lrbuf_t *lrb)
278: {
279: if (!lrb)
280: return;
281:
282: if (lrb->lrb_data)
283: memset(lrb->lrb_data, 0, lrb->lrb_size);
284:
285: atomic_store_explicit((atomic_int*) &lrb->lrb_head, 0, memory_order_relaxed);
286: atomic_store_explicit((atomic_int*) &lrb->lrb_tail, 0, memory_order_relaxed);
1.4.4.3 ! misho 287: atomic_store_explicit((atomic_int*) &lrb->lrb_full, 0, memory_order_relaxed);
1.4.4.1 misho 288: }
289:
290: /*
291: * lrb_isempty() - Check buffer is empty
292: *
293: * @lrb = Linear ring buffer
294: * return: -1 error, 0 it isn't empty
295: */
296: int
297: lrb_isempty(lrbuf_t *lrb)
298: {
299: if (!lrb)
300: return -1;
301:
1.4.4.2 misho 302: return (!atomic_load_explicit((atomic_int*) &lrb->lrb_full, memory_order_acquire) &&
303: (atomic_load_explicit((atomic_int*) &lrb->lrb_head, memory_order_acquire) ==
304: atomic_load_explicit((atomic_int*) &lrb->lrb_tail, memory_order_acquire)));
1.4.4.1 misho 305: }
306:
307: /*
308: * lrb_isfull() - Check buffer is full
309: *
310: * @lrb = Linear ring buffer
311: * return: -1 error or 0 it isn't full
312: */
313: int
314: lrb_isfull(lrbuf_t *lrb)
315: {
316: int h, t;
317:
318: if (!lrb)
319: return -1;
320: if (!lrb->lrb_size)
321: return 1;
322:
1.4.4.2 misho 323: if (!atomic_load_explicit((atomic_int*) &lrb->lrb_full, memory_order_acquire))
324: return 0;
325:
1.4.4.1 misho 326: t = atomic_load_explicit((atomic_int*) &lrb->lrb_tail, memory_order_acquire);
1.4.4.3 ! misho 327: h = atomic_load_explicit((atomic_int*) &lrb->lrb_head, memory_order_acquire);
1.4.4.1 misho 328: return (h == t);
329: }
330:
331: /*
332: * lrb_enqueue() - Enqueue data to buffer
333: *
334: * @lrb = Linear ring buffer
335: * @data = Data
336: * @len = Length
337: * @lost = Permit to lost data
338: * return: -1 error, 1 buffer is full or 0 ok
339: */
340: int
341: lrb_enqueue(lrbuf_t *lrb, void *data, size_t len, int lost)
342: {
343: int h, t, n, t2, unused, drop = 0;
344:
345: if (!lrb || !lrb->lrb_data)
346: return -1;
347: if (!lrb->lrb_size || lrb->lrb_size <= len)
348: return 1;
349:
350: lrb_unused(lrb, unused);
351: if (!lost) {
352: if (len > unused)
353: return 1;
354: } else {
355: drop = len - unused;
356: if(drop < 0)
357: drop ^= drop;
358: }
359:
360: if (drop > 0) {
361: t = atomic_load_explicit((atomic_int*) &lrb->lrb_tail, memory_order_acquire);
362: t2 = (t + drop) % lrb->lrb_size;
363: }
364: h = atomic_load_explicit((atomic_int*) &lrb->lrb_head, memory_order_relaxed);
365: n = lrb->lrb_size - h;
366: if (len < n) {
367: memcpy(lrb->lrb_data + h, data, len);
368: n = h + len;
369: } else {
370: memcpy(lrb->lrb_data + h, data, n);
371: memcpy(lrb->lrb_data, data + n, len - n);
372: n = len - n;
373: }
374:
1.4.4.2 misho 375: h = n;
376: atomic_store_explicit((atomic_int*) &lrb->lrb_head, h, memory_order_release);
1.4.4.1 misho 377: if (drop > 0)
378: while (42) {
379: n = t;
380: if (atomic_compare_exchange_weak_explicit((atomic_int*) &lrb->lrb_tail,
381: &n, t2, memory_order_release, memory_order_relaxed))
382: break;
383: t = n;
384: t2 = (t + drop) % lrb->lrb_size;
385: }
1.4.4.2 misho 386: else
387: t2 = atomic_load_explicit((atomic_int*) &lrb->lrb_tail, memory_order_acquire);
388: atomic_store_explicit((atomic_int*) &lrb->lrb_full, (h == t2), memory_order_release);
1.4.4.1 misho 389: return 0;
390: }
391:
392: /*
393: * lrb_dequeue() - Dequeue data from buffer
394: *
395: * @lrb = Linear ring buffer
396: * @data = Data, if =NULL, just dequeue data
397: * @len = Length of data
398: * return: -1 error, 0 buffer is empty or >0 stored data bytes
399: */
400: int
401: lrb_dequeue(lrbuf_t *lrb, void *data, size_t len)
402: {
1.4.4.3 ! misho 403: int h, t, t2, n, l, f;
1.4.4.1 misho 404:
405: if (!lrb)
406: return -1;
407: if (!lrb->lrb_size || !len || lrb_isempty(lrb))
408: return 0;
409: if (lrb->lrb_size <= len)
410: len = lrb->lrb_size - 1;
411:
412: while (42) {
413: t = atomic_load_explicit((atomic_int*) &lrb->lrb_tail, memory_order_acquire);
414: h = atomic_load_explicit((atomic_int*) &lrb->lrb_head, memory_order_acquire);
1.4.4.3 ! misho 415: f = atomic_load_explicit((atomic_int*) &lrb->lrb_full, memory_order_acquire);
1.4.4.1 misho 416:
417: l = h - t;
418: if (l < 0)
419: l += lrb->lrb_size;
1.4.4.3 ! misho 420: if (!l) {
! 421: if (!f)
! 422: return 0;
! 423: l = lrb->lrb_size;
! 424: }
1.4.4.1 misho 425: if (l > len)
426: l = len;
427:
428: n = lrb->lrb_size - t;
429: if (l < n) {
430: if (data)
431: memcpy(data, lrb->lrb_data + t, l);
432: t2 = t + l;
433: } else {
434: if (data) {
435: memcpy(data, lrb->lrb_data + t, n);
436: memcpy(data + n, lrb->lrb_data, l - n);
437: }
438: t2 = l - n;
439: }
440:
441: n = t;
442: if (atomic_compare_exchange_weak_explicit((atomic_int*) &lrb->lrb_tail,
1.4.4.2 misho 443: &n, t2, memory_order_release, memory_order_relaxed)) {
444: atomic_store_explicit((atomic_int*) &lrb->lrb_full, 0, memory_order_release);
1.4.4.1 misho 445: return l;
1.4.4.2 misho 446: }
1.4.4.1 misho 447: }
448:
449: return 0;
450: }
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