From 7774e759a0799d7e4cb9c6f5e1087157ea3e662b Mon Sep 17 00:00:00 2001
From: ache <ache@FreeBSD.org>
Date: Sun, 29 May 2016 13:57:06 +0000
Subject: [PATCH] 1) Unifdef USE_WEAK_SEEDING since it is too obsolete to
 support and makes reading hard.

2) Instead of doing range transformation in each and every function here,
do it single time directly in do_rand(). One "mod" operation overhead is not
a big deal, but the code looks nicer and possible future functions additions
or PRNG change do not miss range transformations neither have unneeded ones.

3) Use POSIX argument types for visible functions (cosmetic).

MFC after:      1 week
---
 lib/libc/stdlib/rand.c | 52 +++++++++---------------------------------
 1 file changed, 11 insertions(+), 41 deletions(-)

diff --git a/lib/libc/stdlib/rand.c b/lib/libc/stdlib/rand.c
index eb3c10a2894d..2e0456a9edc3 100644
--- a/lib/libc/stdlib/rand.c
+++ b/lib/libc/stdlib/rand.c
@@ -48,14 +48,6 @@ __FBSDID("$FreeBSD$");
 static int
 do_rand(unsigned long *ctx)
 {
-#ifdef  USE_WEAK_SEEDING
-/*
- * Historic implementation compatibility.
- * The random sequences do not vary much with the seed,
- * even with overflowing.
- */
-	return ((*ctx = *ctx * 1103515245 + 12345) % ((u_long)RAND_MAX + 1));
-#else   /* !USE_WEAK_SEEDING */
 /*
  * Compute x = (7^5 * x) mod (2^31 - 1)
  * without overflowing 31 bits:
@@ -66,48 +58,34 @@ do_rand(unsigned long *ctx)
  */
 	long hi, lo, x;
 
-	/* Must be in [1, 0x7ffffffe] range at this point. */
-	hi = *ctx / 127773;
-	lo = *ctx % 127773;
+	/* Transform to [1, 0x7ffffffe] range. */
+	x = (*ctx % 0x7ffffffe) + 1;
+	hi = x / 127773;
+	lo = x % 127773;
 	x = 16807 * lo - 2836 * hi;
 	if (x < 0)
 		x += 0x7fffffff;
-	*ctx = x;
 	/* Transform to [0, 0x7ffffffd] range. */
-	return (x - 1);
-#endif  /* !USE_WEAK_SEEDING */
+	x--;
+	*ctx = x;
+	return (x);
 }
 
 
 int
-rand_r(unsigned int *ctx)
+rand_r(unsigned *ctx)
 {
 	u_long val;
 	int r;
 
-#ifdef  USE_WEAK_SEEDING
 	val = *ctx;
-#else
-	/* Transform to [1, 0x7ffffffe] range. */
-	val = (*ctx % 0x7ffffffe) + 1;
-#endif
 	r = do_rand(&val);
-
-#ifdef  USE_WEAK_SEEDING
-	*ctx = (unsigned int)val;
-#else
-	*ctx = (unsigned int)(val - 1);
-#endif
+	*ctx = (unsigned)val;
 	return (r);
 }
 
 
-static u_long next =
-#ifdef  USE_WEAK_SEEDING
-    1;
-#else
-    2;
-#endif
+static u_long next = 1;
 
 int
 rand(void)
@@ -116,13 +94,9 @@ rand(void)
 }
 
 void
-srand(u_int seed)
+srand(unsigned seed)
 {
 	next = seed;
-#ifndef USE_WEAK_SEEDING
-	/* Transform to [1, 0x7ffffffe] range. */
-	next = (next % 0x7ffffffe) + 1;
-#endif
 }
 
 
@@ -144,10 +118,6 @@ sranddev(void)
 	mib[0] = CTL_KERN;
 	mib[1] = KERN_ARND;
 	sysctl(mib, 2, (void *)&next, &len, NULL, 0);
-#ifndef USE_WEAK_SEEDING
-	/* Transform to [1, 0x7ffffffe] range. */
-	next = (next % 0x7ffffffe) + 1;
-#endif
 }