PipeWire  1.4.6
ringbuffer.h
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1 /* Simple Plugin API */
2 /* SPDX-FileCopyrightText: Copyright © 2018 Wim Taymans */
3 /* SPDX-License-Identifier: MIT */
4 
5 #ifndef SPA_RINGBUFFER_H
6 #define SPA_RINGBUFFER_H
7 
8 #ifdef __cplusplus
9 extern "C" {
10 #endif
11 
22 struct spa_ringbuffer;
23 
24 #include <string.h>
25 
26 #include <spa/utils/defs.h>
27 
28 #ifndef SPA_API_RINGBUFFER
29  #ifdef SPA_API_IMPL
30  #define SPA_API_RINGBUFFER SPA_API_IMPL
31  #else
32  #define SPA_API_RINGBUFFER static inline
33  #endif
34 #endif
35 
39 struct spa_ringbuffer {
40  uint32_t readindex; /*< the current read index */
41  uint32_t writeindex; /*< the current write index */
42 };
43 
44 #define SPA_RINGBUFFER_INIT() ((struct spa_ringbuffer) { 0, 0 })
45 
52 {
54 }
55 
62 SPA_API_RINGBUFFER void spa_ringbuffer_set_avail(struct spa_ringbuffer *rbuf, uint32_t size)
63 {
64  rbuf->readindex = 0;
65  rbuf->writeindex = size;
66 }
67 
78 SPA_API_RINGBUFFER int32_t spa_ringbuffer_get_read_index(struct spa_ringbuffer *rbuf, uint32_t *index)
79 {
80  *index = __atomic_load_n(&rbuf->readindex, __ATOMIC_RELAXED);
81  return (int32_t) (__atomic_load_n(&rbuf->writeindex, __ATOMIC_ACQUIRE) - *index);
82 }
83 
97  const void *buffer, uint32_t size,
98  uint32_t offset, void *data, uint32_t len)
99 {
100  uint32_t l0 = SPA_MIN(len, size - offset), l1 = len - l0;
101  spa_memcpy(data, SPA_PTROFF(buffer, offset, void), l0);
102  if (SPA_UNLIKELY(l1 > 0))
103  spa_memcpy(SPA_PTROFF(data, l0, void), buffer, l1);
104 }
105 
112 SPA_API_RINGBUFFER void spa_ringbuffer_read_update(struct spa_ringbuffer *rbuf, int32_t index)
113 {
114  __atomic_store_n(&rbuf->readindex, index, __ATOMIC_RELEASE);
115 }
116 
128 SPA_API_RINGBUFFER int32_t spa_ringbuffer_get_write_index(struct spa_ringbuffer *rbuf, uint32_t *index)
129 {
130  *index = __atomic_load_n(&rbuf->writeindex, __ATOMIC_RELAXED);
131  return (int32_t) (*index - __atomic_load_n(&rbuf->readindex, __ATOMIC_ACQUIRE));
132 }
133 
147  void *buffer, uint32_t size,
148  uint32_t offset, const void *data, uint32_t len)
149 {
150  uint32_t l0 = SPA_MIN(len, size - offset), l1 = len - l0;
151  spa_memcpy(SPA_PTROFF(buffer, offset, void), data, l0);
152  if (SPA_UNLIKELY(l1 > 0))
153  spa_memcpy(buffer, SPA_PTROFF(data, l0, void), l1);
154 }
155 
162 SPA_API_RINGBUFFER void spa_ringbuffer_write_update(struct spa_ringbuffer *rbuf, int32_t index)
163 {
164  __atomic_store_n(&rbuf->writeindex, index, __ATOMIC_RELEASE);
165 }
166 
172 #ifdef __cplusplus
173 } /* extern "C" */
174 #endif
175 
176 #endif /* SPA_RINGBUFFER_H */
spa/utils/defs.h
buffer[1023]
Definition: core.h:437
SPA_API_RINGBUFFER void spa_ringbuffer_set_avail(struct spa_ringbuffer *rbuf, uint32_t size)
Sets the pointers so that the ringbuffer contains size bytes.
Definition: ringbuffer.h:71
#define SPA_API_RINGBUFFER
Definition: ringbuffer.h:40
#define SPA_RINGBUFFER_INIT()
Definition: ringbuffer.h:53
SPA_API_RINGBUFFER int32_t spa_ringbuffer_get_read_index(struct spa_ringbuffer *rbuf, uint32_t *index)
Get the read index and available bytes for reading.
Definition: ringbuffer.h:87
SPA_API_RINGBUFFER void spa_ringbuffer_write_update(struct spa_ringbuffer *rbuf, int32_t index)
Update the write pointer to index.
Definition: ringbuffer.h:171
SPA_API_RINGBUFFER void spa_ringbuffer_read_update(struct spa_ringbuffer *rbuf, int32_t index)
Update the read pointer to index.
Definition: ringbuffer.h:121
SPA_API_RINGBUFFER int32_t spa_ringbuffer_get_write_index(struct spa_ringbuffer *rbuf, uint32_t *index)
Get the write index and the number of bytes inside the ringbuffer.
Definition: ringbuffer.h:137
SPA_API_RINGBUFFER void spa_ringbuffer_write_data(struct spa_ringbuffer *rbuf, void *buffer, uint32_t size, uint32_t offset, const void *data, uint32_t len)
Write len bytes to buffer starting offset.
Definition: ringbuffer.h:155
SPA_API_RINGBUFFER void spa_ringbuffer_init(struct spa_ringbuffer *rbuf)
Initialize a spa_ringbuffer with size.
Definition: ringbuffer.h:60
SPA_API_RINGBUFFER void spa_ringbuffer_read_data(struct spa_ringbuffer *rbuf, const void *buffer, uint32_t size, uint32_t offset, void *data, uint32_t len)
Read len bytes from rbuf starting offset.
Definition: ringbuffer.h:105
#define SPA_MIN(a, b)
Definition: defs.h:165
#define SPA_UNUSED
Definition: defs.h:307
#define SPA_UNLIKELY(x)
Definition: defs.h:394
#define spa_memcpy(d, s, n)
Definition: defs.h:524
#define SPA_PTROFF(ptr_, offset_, type_)
Return the address (buffer + offset) as pointer of type.
Definition: defs.h:222
spa/utils/string.h
A ringbuffer type.
Definition: ringbuffer.h:47
uint32_t readindex
Definition: ringbuffer.h:48
uint32_t writeindex
Definition: ringbuffer.h:49