diff options
Diffstat (limited to 'vppinfra/vppinfra/random.h')
| -rw-r--r-- | vppinfra/vppinfra/random.h | 61 |
1 files changed, 43 insertions, 18 deletions
diff --git a/vppinfra/vppinfra/random.h b/vppinfra/vppinfra/random.h index 1347c47c6f7..fad05898350 100644 --- a/vppinfra/vppinfra/random.h +++ b/vppinfra/vppinfra/random.h @@ -39,7 +39,7 @@ #define included_random_h #include <vppinfra/clib.h> -#include <vppinfra/vec.h> /* for vec_resize */ +#include <vppinfra/vec.h> /* for vec_resize */ #include <vppinfra/format.h> /* for unformat_input_t */ /** \file @@ -48,12 +48,12 @@ This specific random number generator is described in "Numerical Recipes in C", 2nd edition, page 284. If you need random numbers with really excellent statistics, take a look - at Chapter 7... - + at Chapter 7... + By definition, a linear congruential random number generator is of the form: rand[i+1] = a*rand[i] + c (mod m) for specific - values of (a,c,m). - + values of (a,c,m). + In this case, choose m = 2**32 and use the low-order 32-bits of the 64-bit product a*N[i]. Knuth suggests the use of a=1664525, H.W. Lewis has tested C=1013904223 extensively. This routine is @@ -65,25 +65,33 @@ */ /** \brief 32-bit random number generator */ -always_inline u32 random_u32 (u32 * seed) +always_inline u32 +random_u32 (u32 * seed) { *seed = (1664525 * *seed) + 1013904223; return *seed; } + /* External test routine. */ int test_random_main (unformat_input_t * input); /** \brief Maximum value returned by random_u32() */ -always_inline u32 random_u32_max (void) -{ return 0xffffffff; } +always_inline u32 +random_u32_max (void) +{ + return 0xffffffff; +} #ifdef CLIB_UNIX #include <unistd.h> /* for getpid */ /** \brief Default random seed (unix/linux user-mode) */ -always_inline uword random_default_seed (void) -{ return getpid (); } +always_inline uword +random_default_seed (void) +{ + return getpid (); +} #endif @@ -92,16 +100,22 @@ always_inline uword random_default_seed (void) #include <linux/sched.h> /* for jiffies */ /** \brief Default random seed (Linux kernel) */ -always_inline uword random_default_seed (void) -{ return jiffies; } +always_inline uword +random_default_seed (void) +{ + return jiffies; +} #endif #ifdef CLIB_STANDALONE extern u32 standalone_random_default_seed; -always_inline u32 random_default_seed (void) -{ return standalone_random_default_seed; } +always_inline u32 +random_default_seed (void) +{ + return standalone_random_default_seed; +} #endif /** \brief 64-bit random number generator @@ -130,8 +144,11 @@ random_uword (u32 * seed) } /** \brief Generate f64 random number in the interval [0,1] */ -always_inline f64 random_f64 (u32 * seed) -{ return (f64) random_u32 (seed) / (f64) random_u32_max (); } +always_inline f64 +random_f64 (u32 * seed) +{ + return (f64) random_u32 (seed) / (f64) random_u32_max (); +} /** \brief Generate random character vector @@ -142,8 +159,8 @@ always_inline f64 random_f64 (u32 * seed) always_inline u8 * random_string (u32 * seed, uword len) { - u8 * alphabet = (u8 *) "abcdefghijklmnopqrstuvwxyz"; - u8 * s = 0; + u8 *alphabet = (u8 *) "abcdefghijklmnopqrstuvwxyz"; + u8 *s = 0; word i; vec_resize (s, len); @@ -154,3 +171,11 @@ random_string (u32 * seed, uword len) } #endif /* included_random_h */ + +/* + * fd.io coding-style-patch-verification: ON + * + * Local Variables: + * eval: (c-set-style "gnu") + * End: + */ |