ceph/src/zstd/tests/seqgen.h

   1 /*
   2  * Copyright (c) 2017-present, Facebook, Inc.
   3  * All rights reserved.
   4  *
   5  * This source code is licensed under both the BSD-style license (found in the
   6  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
   7  * in the COPYING file in the root directory of this source tree).
   8  * You may select, at your option, one of the above-listed licenses.
   9  */
  10
  11 #ifndef SEQGEN_H
  12 #define SEQGEN_H
  13
  14 #define XXH_STATIC_LINKING_ONLY
  15
  16 #include "xxhash.h"
  17 #include <stddef.h>   /* size_t */
  18
  19 typedef enum {
  20     SEQ_gen_ml = 0,
  21     SEQ_gen_ll,
  22     SEQ_gen_of,
  23     SEQ_gen_max /* Must be the last value */
  24 } SEQ_gen_type;
  25
  26 /* Internal state, do not use */
  27 typedef struct {
  28     XXH64_state_t xxh; /* xxh state for all the data produced so far (seed=0) */
  29     unsigned seed;
  30     int state; /* enum to control state machine (clean=0) */
  31     unsigned saved;
  32     size_t bytesLeft;
  33 } SEQ_stream;
  34
  35 SEQ_stream SEQ_initStream(unsigned seed);
  36
  37 typedef struct {
  38     void* dst;
  39     size_t size;
  40     size_t pos;
  41 } SEQ_outBuffer;
  42
  43 /* Returns non-zero until the current type/value has been generated.
  44  * Must pass the same type/value until it returns 0.
  45  *
  46  * Recommended to pick a value in the middle of the range you want, since there
  47  * may be some noise that causes actual results to be slightly different.
  48  * We try to be more accurate for smaller values.
  49  *
  50  * NOTE: Very small values don't work well (< 6).
  51  */
  52 size_t SEQ_gen(SEQ_stream* stream, SEQ_gen_type type, unsigned value,
  53                SEQ_outBuffer* out);
  54
  55 /* Returns the xxhash of the data produced so far */
  56 XXH64_hash_t SEQ_digest(SEQ_stream const* stream);
  57
  58 #endif /* SEQGEN_H */