git.squeep.com Git - reservoir_sample/blob - reservoir.h

   1 #ifndef RESERVOIR_H_MZSA8WJ3
   2 #define RESERVOIR_H_MZSA8WJ3
   3
   4 #include <stdlib.h>
   5
   6 #include "buf.h"
   7
   8 #ifndef NDEBUG
   9 #include "notify.h"
  10 #endif /* NDEBUG */
  11
  12 /*
  13         A size-limited pool of buf_t entries.  When the reservoir is filled with
  14         more entries than there is room for, some spill away and are lost.
  15 */
  16
  17 typedef struct reservoir_ {
  18         size_t reservoir_sz; /* allocated slots */
  19         size_t reservoir_used; /* slots filled */
  20         unsigned long reservoir_tally; /* total number of items remembered */
  21         buf_t reservoir[];
  22 } *reservoir_t;
  23
  24 #ifndef NDEBUG
  25 /*      For debugging, dump an entire reservoir's contents. */
  26 #define D_RESERVOIR(__r__) do {\
  27         size_t i;\
  28                 NOTIFY_DEBUG("reservoir:%p sz: %zu used:%zu tally:%zu", (__r__), (__r__)->reservoir_sz, (__r__)->reservoir_used, (__r__)->reservoir_tally);\
  29                 for (i = 0; i < (__r__)->reservoir_sz; i++) {\
  30                         D_BUF("reservoir[%zu] ", (__r__)->reservoir[i], i);\
  31                 }\
  32 } while (0)
  33 #else /* NDEBUG */
  34 #define D_RESERVOIR(...)
  35 #endif /* NDEBUG */
  36
  37 /*      reservoir_new
  38                 Allocate and return a new reservoir capable of holding #sz buf_t
  39         entries.
  40 */
  41 reservoir_t reservoir_new(size_t sz);
  42
  43 /*      reservoir_del
  44                 Deallocate the reservoir pointed to by #preservoir.
  45 */
  46 void reservoir_del(reservoir_t *preservoir);
  47
  48 /*      reservoir_grow
  49                 Increase the storage capacity of the reservoir pointed to by
  50         #preservoir by #growby entries.
  51 */
  52 int reservoir_grow(reservoir_t *preservoir, size_t growby);
  53
  54 /*      reservoir_remember
  55                 Remember #buf, forgetting (and freeing) another buf_t chosen at random
  56         if the reservoir pointed to by #preservoir is already full to capacity.
  57 */
  58 void reservoir_remember(reservoir_t reservoir, buf_t buf);
  59
  60 /*      reservoir_write
  61                 Write the contents of the buf_t entries within #reservoir to #fd, each
  62         with a trailing #delim character.
  63 */
  64 int reservoir_write(int fd, reservoir_t reservoir, char delim);
  65
  66 /*      reservoir_write_meta
  67                 Write metadata about #reservoir and #samples to fd.
  68 */
  69 int reservoir_write_meta(int fd, reservoir_t reservoir, unsigned long samples, char delim);
  70
  71 #endif /* RESERVOIR_H_MZSA8WJ3 */