Alc/ringbuffer.h

   1 #ifndef RINGBUFFER_H
   2 #define RINGBUFFER_H
   3
   4 #include <stddef.h>
   5
   6
   7 #ifdef __cplusplus
   8 extern "C" {
   9 #endif
  10
  11 typedef struct ll_ringbuffer ll_ringbuffer_t;
  12 typedef struct ll_ringbuffer_data {
  13     char *buf;
  14     size_t len;
  15 } ll_ringbuffer_data_t;
  16
  17
  18 /**
  19  * Create a new ringbuffer to hold at least `sz' elements of `elem_sz' bytes.
  20  * The number of elements is rounded up to the next power of two (even if it is
  21  * already a power of two, to ensure the requested amount can be written).
  22  */
  23 ll_ringbuffer_t *ll_ringbuffer_create(size_t sz, size_t elem_sz, int limit_writes);
  24 /** Free all data associated with the ringbuffer `rb'. */
  25 void ll_ringbuffer_free(ll_ringbuffer_t *rb);
  26 /** Reset the read and write pointers to zero. This is not thread safe. */
  27 void ll_ringbuffer_reset(ll_ringbuffer_t *rb);
  28
  29 /**
  30  * The non-copying data reader. `vec' is an array of two places. Set the values
  31  * at `vec' to hold the current readable data at `rb'. If the readable data is
  32  * in one segment the second segment has zero length.
  33  */
  34 void ll_ringbuffer_get_read_vector(const ll_ringbuffer_t *rb, ll_ringbuffer_data_t vec[2]);
  35 /**
  36  * The non-copying data writer. `vec' is an array of two places. Set the values
  37  * at `vec' to hold the current writeable data at `rb'. If the writeable data
  38  * is in one segment the second segment has zero length.
  39  */
  40 void ll_ringbuffer_get_write_vector(const ll_ringbuffer_t *rb, ll_ringbuffer_data_t vec[2]);
  41
  42 /**
  43  * Return the number of elements available for reading. This is the number of
  44  * elements in front of the read pointer and behind the write pointer.
  45  */
  46 size_t ll_ringbuffer_read_space(const ll_ringbuffer_t *rb);
  47 /**
  48  * The copying data reader. Copy at most `cnt' elements from `rb' to `dest'.
  49  * Returns the actual number of elements copied.
  50  */
  51 size_t ll_ringbuffer_read(ll_ringbuffer_t *rb, char *dest, size_t cnt);
  52 /**
  53  * The copying data reader w/o read pointer advance. Copy at most `cnt'
  54  * elements from `rb' to `dest'. Returns the actual number of elements copied.
  55  */
  56 size_t ll_ringbuffer_peek(ll_ringbuffer_t *rb, char *dest, size_t cnt);
  57 /** Advance the read pointer `cnt' places. */
  58 void ll_ringbuffer_read_advance(ll_ringbuffer_t *rb, size_t cnt);
  59
  60 /**
  61  * Return the number of elements available for writing. This is the number of
  62  * elements in front of the write pointer and behind the read pointer.
  63  */
  64 size_t ll_ringbuffer_write_space(const ll_ringbuffer_t *rb);
  65 /**
  66  * The copying data writer. Copy at most `cnt' elements to `rb' from `src'.
  67  * Returns the actual number of elements copied.
  68  */
  69 size_t ll_ringbuffer_write(ll_ringbuffer_t *rb, const char *src, size_t cnt);
  70 /** Advance the write pointer `cnt' places. */
  71 void ll_ringbuffer_write_advance(ll_ringbuffer_t *rb, size_t cnt);
  72
  73 #ifdef __cplusplus
  74 } /* extern "C" */
  75 #endif
  76
  77 #endif /* RINGBUFFER_H */