Alc/ringbuffer.h

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