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/******************************************************************************/
#ifdef JEMALLOC_H_TYPES
/*
* Simple linear congruential pseudo-random number generator:
*
* prng(y) = (a*x + c) % m
*
* where the following constants ensure maximal period:
*
* a == Odd number (relatively prime to 2^n), and (a-1) is a multiple of 4.
* c == Odd number (relatively prime to 2^n).
* m == 2^32
*
* See Knuth's TAOCP 3rd Ed., Vol. 2, pg. 17 for details on these constraints.
*
* This choice of m has the disadvantage that the quality of the bits is
* proportional to bit position. For example. the lowest bit has a cycle of 2,
* the next has a cycle of 4, etc. For this reason, we prefer to use the upper
* bits.
*
* Macro parameters:
* uint32_t r : Result.
* unsigned lg_range : (0..32], number of least significant bits to return.
* uint32_t state : Seed value.
* const uint32_t a, c : See above discussion.
*/
#define prng32(r, lg_range, state, a, c) do { \
assert(lg_range > 0); \
assert(lg_range <= 32); \
\
r = (state * (a)) + (c); \
state = r; \
r >>= (32 - lg_range); \
} while (false)
/* Same as prng32(), but 64 bits of pseudo-randomness, using uint64_t. */
#define prng64(r, lg_range, state, a, c) do { \
assert(lg_range > 0); \
assert(lg_range <= 64); \
\
r = (state * (a)) + (c); \
state = r; \
r >>= (64 - lg_range); \
} while (false)
#endif /* JEMALLOC_H_TYPES */
/******************************************************************************/
#ifdef JEMALLOC_H_STRUCTS
#endif /* JEMALLOC_H_STRUCTS */
/******************************************************************************/
#ifdef JEMALLOC_H_EXTERNS
#endif /* JEMALLOC_H_EXTERNS */
/******************************************************************************/
#ifdef JEMALLOC_H_INLINES
#endif /* JEMALLOC_H_INLINES */
/******************************************************************************/
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