From f73e64b4ea7e888d1827dee2017155b538ea9093 Mon Sep 17 00:00:00 2001
From: Amos Jeffries <squid3@treenet.co.nz>
Date: Sun, 8 Feb 2015 08:17:29 -0800
Subject: [PATCH] Convert testSBuf to C++11 random engine

Also remove SBufTest::randomSeed as it would now only be used in a
static function.
---
 src/tests/SBufFindTest.cc | 25 ++++++++++++-------------
 src/tests/SBufFindTest.h  |  1 -
 2 files changed, 12 insertions(+), 14 deletions(-)

diff --git a/src/tests/SBufFindTest.cc b/src/tests/SBufFindTest.cc
index a9db2ed75d..a5245e5d82 100644
--- a/src/tests/SBufFindTest.cc
+++ b/src/tests/SBufFindTest.cc
@@ -9,9 +9,11 @@
 #include "squid.h"
 #include "base/CharacterSet.h"
 #include "SBufFindTest.h"
+
 #include <cppunit/extensions/HelperMacros.h>
 #include <cppunit/Message.h>
 #include <limits>
+#include <random>
 
 /* TODO: The whole SBufFindTest class is currently implemented as a single
    CppUnit test case (because we do not want to register and report every one
@@ -22,7 +24,6 @@
 SBufFindTest::SBufFindTest():
     caseLimit(std::numeric_limits<int>::max()),
     errorLimit(std::numeric_limits<int>::max()),
-    randomSeed(1),
     hushSimilar(true),
     maxHayLength(40),
     thePos(0),
@@ -44,8 +45,6 @@ SBufFindTest::SBufFindTest():
 void
 SBufFindTest::run()
 {
-    srandom(randomSeed);
-
     for (SBuf::size_type hayLen = 0U; hayLen <= maxHayLength; nextLen(hayLen, maxHayLength)) {
         const SBuf cleanHay = RandomSBuf(hayLen);
 
@@ -380,19 +379,19 @@ SBufFindTest::RandomSBuf(const int length)
         "0123456789"
         "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
         "abcdefghijklomnpqrstuvwxyz";
+
+    static std::mt19937 mt(time(0));
+
     // sizeof() counts the terminating zero at the end of characters
+    // and the distribution is an 'inclusive' value range, so -2
     // TODO: add \0 character (needs reporting adjustments to print it as \0)
-    static const size_t charCount = sizeof(characters)-1;
-
-    char buf[length];
-    for (int i = 0; i < length; ++i) {
-        const unsigned int pos = random() % charCount;
-        assert(pos < sizeof(characters));
-        assert(characters[pos] > 32);
-        buf[i] = characters[random() % charCount];
-    }
+    static std::uniform_int_distribution<uint8_t> dist(0, sizeof(characters)-2);
 
-    return SBuf(buf, length);
+    SBuf buf;
+    buf.reserveCapacity(length);
+    for (int i = 0; i < length; ++i)
+        buf.append(characters[dist(mt)]);
+    return buf;
 }
 
 /// increments len to quickly cover [0, max] range, slowing down in risky areas
diff --git a/src/tests/SBufFindTest.h b/src/tests/SBufFindTest.h
index 920a407425..5ed88709a0 100644
--- a/src/tests/SBufFindTest.h
+++ b/src/tests/SBufFindTest.h
@@ -26,7 +26,6 @@ public:
     /* test configuration parameters; can be optionally set before run() */
     int caseLimit; ///< approximate caseCount limit
     int errorLimit; ///< errorCount limit
-    unsigned int randomSeed; ///< pseudo-random sequence choice
     /// whether to report only one failed test case per "category"
     bool hushSimilar;
     /// approximate maximum generated hay string length
-- 
2.47.2