codekingpro/portable-devtools

1/*-------------------------------------------------------------------------2 *3 * Pseudo-Random Number Generator4 *5 * Copyright (c) 2021-2023, PostgreSQL Global Development Group6 *7 * src/include/common/pg_prng.h8 *9 *-------------------------------------------------------------------------10 */11#ifndef PG_PRNG_H12#define PG_PRNG_H13 14/*15 * State vector for PRNG generation.  Callers should treat this as an16 * opaque typedef, but we expose its definition to allow it to be17 * embedded in other structs.18 */19typedef struct pg_prng_state20{21	uint64		s0,22				s1;23} pg_prng_state;24 25/*26 * Callers not needing local PRNG series may use this global state vector,27 * after initializing it with one of the pg_prng_...seed functions.28 */29extern PGDLLIMPORT pg_prng_state pg_global_prng_state;30 31extern void pg_prng_seed(pg_prng_state *state, uint64 seed);32extern void pg_prng_fseed(pg_prng_state *state, double fseed);33extern bool pg_prng_seed_check(pg_prng_state *state);34 35/*36 * Initialize the PRNG state from the pg_strong_random source,37 * taking care that we don't produce all-zeroes.  If this returns false,38 * caller should initialize the PRNG state from some other random seed,39 * using pg_prng_[f]seed.40 *41 * We implement this as a macro, so that the pg_strong_random() call is42 * in the caller.  If it were in pg_prng.c, programs using pg_prng.c43 * but not needing strong seeding would nonetheless be forced to pull in44 * pg_strong_random.c and thence OpenSSL.45 */46#define pg_prng_strong_seed(state) \47	(pg_strong_random((void *) (state), sizeof(pg_prng_state)) ? \48	 pg_prng_seed_check(state) : false)49 50extern uint64 pg_prng_uint64(pg_prng_state *state);51extern uint64 pg_prng_uint64_range(pg_prng_state *state, uint64 rmin, uint64 rmax);52extern int64 pg_prng_int64(pg_prng_state *state);53extern int64 pg_prng_int64p(pg_prng_state *state);54extern uint32 pg_prng_uint32(pg_prng_state *state);55extern int32 pg_prng_int32(pg_prng_state *state);56extern int32 pg_prng_int32p(pg_prng_state *state);57extern double pg_prng_double(pg_prng_state *state);58extern double pg_prng_double_normal(pg_prng_state *state);59extern bool pg_prng_bool(pg_prng_state *state);60 61#endif							/* PG_PRNG_H */62