libzahl

commit c5f0bedd07467c089b0eca567828508abfcc9b6d
parent 8dc182ff87cafe3337490bc8db90a67449b9c837
Author: Mattias Andrée <maandree@kth.se>
Date:   Fri, 25 Mar 2016 13:33:41 +0100

zrand: add DEFAULT_RANDOM and FASTEST_RANDOM

Signed-off-by: Mattias Andrée <maandree@kth.se>

Diffstat:
M
man/zrand.3
 | 
23
+++++++++++++++++++++++
M
src/zrand.c
 | 
2
++
M
test.c
 | 
14
+++++++-------
M
zahl.h
 | 
4
+++-

4 files changed, 35 insertions(+), 8 deletions(-)
diff --git a/man/zrand.3 b/man/zrand.3
@@ -18,6 +18,29 @@ selects the device
 uses to generate random bits.
 This value may be either of:
 .TP
+.B DEFAULT_RANDOM
+This is a version-dependent alias for the
+default random number generator. That is,
+using this option will cause
+.B zrand
+to select the default random number generator.
+Which random number generator is actually
+selected may change between versions of
+.B zrand.
+
+The selection will be a balance between randomness
+and performance.
+.TP
+.B FASTEST_RANDOM
+This is a version-dependent alias for the
+fastest random number generator. That is,
+using this option will cause
+.B zrand
+to select the fastest random number generator.
+Which random number generator is actually
+selected may change between versions of
+.B zrand.
+.TP
 .B FAST_RANDOM
 The fast, non-blocking random number generator.
 This is /dev/urandom on Linux.
diff --git a/src/zrand.c b/src/zrand.c
@@ -55,6 +55,8 @@ zrand(z_t r, enum zranddev dev, enum zranddist dist, z_t n)
 	int fd;
 
         switch (dev) {
+	case DEFAULT_RANDOM:
+	case FASTEST_RANDOM:
 	case FAST_RANDOM:
 		pathname = FAST_RANDOM_PATHNAME;
 		break;
diff --git a/test.c b/test.c
@@ -731,7 +731,7 @@ main(void)
 	zrand(b, SECURE_RANDOM, UNIFORM, d);
 	assert(zcmp(b, _0), >= 0);
 	assert(zcmp(b, d), <= 0);
-	zrand(c, FAST_RANDOM, UNIFORM, d);
+	zrand(c, FASTEST_RANDOM, UNIFORM, d);
 	assert(zcmp(c, _0), >= 0);
 	assert(zcmp(c, d), <= 0);
 	assert(zcmp(a, b), != 0);
@@ -739,13 +739,13 @@ main(void)
 	assert(zcmp(b, c), != 0);
 
 	zsetu(d, 100000UL);
-	zrand(a, FAST_RANDOM, QUASIUNIFORM, d);
+	zrand(a, DEFAULT_RANDOM, QUASIUNIFORM, d);
 	assert(zcmp(a, _0), >= 0);
 	assert(zcmp(a, d), <= 0);
-	zrand(b, FAST_RANDOM, QUASIUNIFORM, d);
+	zrand(b, DEFAULT_RANDOM, QUASIUNIFORM, d);
 	assert(zcmp(b, _0), >= 0);
 	assert(zcmp(b, d), <= 0);
-	zrand(c, FAST_RANDOM, QUASIUNIFORM, d);
+	zrand(c, DEFAULT_RANDOM, QUASIUNIFORM, d);
 	assert(zcmp(c, _0), >= 0);
 	assert(zcmp(c, d), <= 0);
 	assert(zcmp(a, b), != 0);
@@ -753,13 +753,13 @@ main(void)
 	assert(zcmp(b, c), != 0);
 
 	zsetu(d, 100000UL);
-	zrand(a, FAST_RANDOM, MODUNIFORM, d);
+	zrand(a, DEFAULT_RANDOM, MODUNIFORM, d);
 	assert(zcmp(a, _0), >= 0);
 	assert(zcmp(a, d), <= 0);
-	zrand(b, FAST_RANDOM, MODUNIFORM, d);
+	zrand(b, DEFAULT_RANDOM, MODUNIFORM, d);
 	assert(zcmp(b, _0), >= 0);
 	assert(zcmp(b, d), <= 0);
-	zrand(c, FAST_RANDOM, MODUNIFORM, d);
+	zrand(c, DEFAULT_RANDOM, MODUNIFORM, d);
 	assert(zcmp(c, _0), >= 0);
 	assert(zcmp(c, d), <= 0);
 	assert(zcmp(a, b), != 0);
diff --git a/zahl.h b/zahl.h
@@ -48,7 +48,9 @@ enum zprimality {
 
 enum zranddev {
 	FAST_RANDOM = 0,                /* Random numbers are generated directly from /dev/urandom. */
-	SECURE_RANDOM                   /* Random numbers are generated directly from /dev/random. */
+	SECURE_RANDOM,                  /* Random numbers are generated directly from /dev/random. */
+	DEFAULT_RANDOM,                 /* Select the default random number generator. */
+	FASTEST_RANDOM                  /* Select the fastest random number generator. */
 };
 
 enum zranddist {