* Add statistical analysis to the testsuite to check our random number

generator.

.gitignore

@@ -20,3 +20,4 @@ stamp-*
 *-stamp
 src/zzuf
 test/zzcat
+test/zzero

test/Makefile.am

@@ -1,6 +1,9 @@
 
 EXTRA_DIST = testsuite.sh file-00 file-ff file-random file-text
 
-noinst_PROGRAMS = zzcat
+noinst_PROGRAMS = zzcat zzero
+
 zzcat_SOURCES = zzcat.c
 
+zzero_SOURCES = zzero.c
+

test/testsuite.sh

@@ -2,52 +2,43 @@
 
 set -e
 
-check()
+checkflip()
 {
-    ZZOPTS="$1"
-    CMD="$2"
-    ALIAS="$3"
-    CHECK="$4"
-    echo -n " $(echo "$ALIAS .............." | cut -b1-18) "
-    MD5="$(eval "$ZZUF -m $ZZOPTS $CMD" 2>/dev/null | cut -f2 -d' ')"
-    if [ -n "$CHECK" ]; then
-        REFMD5="$CHECK"
-    fi
-    if [ -z "$REFMD5" ]; then
-        REFMD5="$MD5"
-        echo "$MD5"
+    r=$1
+    expect=$2
+    s2=$seed
+    mib=20
+    echo "*** $mib MiB of zeroes, ratio $r ***"
+    echo " expected ....... $expect"
+    rmax=-1
+    rmin=-1
+    rtot=0
+    for x in 0 1 2 3 4 5 6 7 8 9; do
+        ret=`dd if=/dev/zero bs=1048576 count=$mib 2>/dev/null | "$ZZUF" -s $s2 -r $r | "$ZZERO"`
+        if [ "$rmax" = -1 -o "$ret" -gt "$rmax" ]; then rmax=$ret; fi
+        if [ "$rmin" = -1 -o "$ret" -lt "$rmin" ]; then rmin=$ret; fi
+        rtot=`expr $rtot + $ret || true`
+        echo " try $x .......... $ret"
+        s2=`expr $s2 + 1`
+    done
+    rmean=`expr '(' $rtot + 5 ')' / 10 || true`
+    delta=`expr $rmean - $expect || true`
+    if [ "$delta" -gt -5 -a "$delta" -lt 5 ]; then
+        result="ok"
+    elif [ $(($rmean * 8)) -lt $(($expect * 7)) \
+               -o $(($rmean * 7)) -gt $(($expect * 8)) ]; then
+        result="FAILED"
+        FAILED=$(($FAILED + 1))
     else
-        TESTED=$(($TESTED + 1))
-        if [ "$MD5" != "$REFMD5" ]; then
-            FAILED=$(($FAILED + 1))
-            echo "$MD5 FAILED"
-        else
-            echo 'ok'
-        fi
+        result="ok"
     fi
+    TESTED=$(($TESTED + 1))
+    echo " min/avg/max $rmin/$rmean/$rmax .......... $result"
 }
 
-seed=$((0+0$1))
-DIR="$(dirname "$0")"
-ZZUF="$DIR/../src/zzuf"
-ZZCAT="$DIR/zzcat"
-if [ ! -f "$ZZCAT" ]; then
-  echo "error: test/zzcat is missing"
-  exit 1
-fi
-if file /bin/cat | grep -q 'statically linked'; then
-  STATIC_CAT=1
-fi
-if file /bin/dd | grep -q 'statically linked'; then
-  STATIC_DD=1
-fi
-FAILED=0
-TESTED=0
-
-echo "*** running zzuf test suite ***"
-echo "*** using seed $seed ***"
-
-for r in 0.0 0.00001 0.001 0.1 10.0; do
+checkutils()
+{
+    r=$1
     for type in 00 ff text random; do
         file="$DIR/file-$type"
         ZZOPTS="-s $seed -r $r"
@@ -96,8 +87,87 @@ for r in 0.0 0.00001 0.001 0.1 10.0; do
             ;;
         esac
     done
-done
+}
 
+check()
+{
+    ZZOPTS="$1"
+    CMD="$2"
+    ALIAS="$3"
+    CHECK="$4"
+    echo -n " $(echo "$ALIAS .............." | cut -b1-18) "
+    MD5="$(eval "$ZZUF -m $ZZOPTS $CMD" 2>/dev/null | cut -f2 -d' ')"
+    if [ -n "$CHECK" ]; then
+        REFMD5="$CHECK"
+    fi
+    if [ -z "$REFMD5" ]; then
+        REFMD5="$MD5"
+        echo "$MD5"
+    else
+        TESTED=$(($TESTED + 1))
+        if [ "$MD5" != "$REFMD5" ]; then
+            FAILED=$(($FAILED + 1))
+            echo "$MD5 FAILED"
+        else
+            echo 'ok'
+        fi
+    fi
+}
+
+DIR="$(dirname "$0")"
+ZZUF="$DIR/../src/zzuf"
+ZZCAT="$DIR/zzcat"
+if [ ! -f "$ZZCAT" ]; then
+  echo "error: test/zzcat is missing"
+  exit 1
+fi
+ZZERO="$DIR/zzero"
+if [ ! -f "$ZZERO" ]; then
+  echo "error: test/zzero is missing"
+  exit 1
+fi
+if file /bin/cat | grep -q 'statically linked'; then
+  STATIC_CAT=1
+fi
+if file /bin/dd | grep -q 'statically linked'; then
+  STATIC_DD=1
+fi
+FAILED=0
+TESTED=0
+
+if [ -z "$1" ]; then
+  seed=$(date | $ZZUF -m 2>/dev/null | cut -f2 -d' ' | tr -d abcdef | cut -b1-8)
+else
+  seed="$1"
+fi
+
+echo "*** running zzuf test suite with seed $seed ***"
+
+echo ""
+echo "*** check #1: random number generator ***"
+# if X flips are performed on N bits set to 0, the average number of bits
+# set to 1 is: N / 2 * (1 - pow(1 - 2 / N, X)
+checkflip 0.000000001 0
+checkflip 0.00000001  1
+checkflip 0.0000001  16
+checkflip 0.000001  167
+checkflip 0.00001  1677
+checkflip 0.0001  16775
+checkflip 0.001  167604
+checkflip 0.01  1661055
+checkflip 0.1  15205967
+
+echo ""
+echo "*** check #2: libc functions coverage ***"
+checkutils 0.0
+checkutils 0.000000001
+checkutils 0.0000001
+checkutils 0.00001
+checkutils 0.001
+checkutils 0.1
+checkutils 10.0
+
+echo ""
 if [ "$FAILED" != 0 ]; then
     echo "*** $FAILED tests failed out of $TESTED ***"
     exit 1

test/zzero.c

@@ -0,0 +1,36 @@
+/*
+ *  zzero - check how many bits zzuf changes in a stream of zeroes
+ *  Copyright (c) 2008 Sam Hocevar <sam@zoy.org>
+ *                All Rights Reserved
+ *
+ *  $Id$
+ *
+ *  This program is free software. It comes without any warranty, to
+ *  the extent permitted by applicable law. You can redistribute it
+ *  and/or modify it under the terms of the Do What The Fuck You Want
+ *  To Public License, Version 2, as published by Sam Hocevar. See
+ *  http://sam.zoy.org/wtfpl/COPYING for more details.
+ */
+
+#include "config.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+    static const int lut[16] =
+    {
+        0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4
+    };
+
+    int ones = 0, ch;
+
+    while((ch = getc(stdin)) != EOF)
+        ones += lut[ch & 0xf] + lut[(ch >> 4) & 0xf];
+
+    printf("%i\n", ones);
+
+    return EXIT_SUCCESS;
+}
+