From 5f0b04eedc5bbdb9319c9f1f1a6c599337f5bbe3 Mon Sep 17 00:00:00 2001
From: Pieter Wuille <pieter.wuille@gmail.com>
Date: Wed, 7 Jun 2017 11:34:58 -0700
Subject: [PATCH] Replace rand() & ((1 << N) - 1) with randbits(N)

---
 src/test/coins_tests.cpp       |  4 ++--
 src/test/pmt_tests.cpp         |  2 +-
 src/test/versionbits_tests.cpp | 12 ++++++------
 3 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/src/test/coins_tests.cpp b/src/test/coins_tests.cpp
index c923f8df28..27d8db8b9e 100644
--- a/src/test/coins_tests.cpp
+++ b/src/test/coins_tests.cpp
@@ -155,11 +155,11 @@ BOOST_AUTO_TEST_CASE(coins_cache_simulation_test)
                 newcoin.out.nValue = insecure_rand();
                 newcoin.nHeight = 1;
                 if (insecure_randrange(16) == 0 && coin.IsSpent()) {
-                    newcoin.out.scriptPubKey.assign(1 + (insecure_rand() & 0x3F), OP_RETURN);
+                    newcoin.out.scriptPubKey.assign(1 + insecure_randbits(6), OP_RETURN);
                     BOOST_CHECK(newcoin.out.scriptPubKey.IsUnspendable());
                     added_an_unspendable_entry = true;
                 } else {
-                    newcoin.out.scriptPubKey.assign(insecure_rand() & 0x3F, 0); // Random sizes so we can test memory usage accounting
+                    newcoin.out.scriptPubKey.assign(insecure_randbits(6), 0); // Random sizes so we can test memory usage accounting
                     (coin.IsSpent() ? added_an_entry : updated_an_entry) = true;
                     coin = newcoin;
                 }
diff --git a/src/test/pmt_tests.cpp b/src/test/pmt_tests.cpp
index d07a9f3959..32086ead5e 100644
--- a/src/test/pmt_tests.cpp
+++ b/src/test/pmt_tests.cpp
@@ -62,7 +62,7 @@ BOOST_AUTO_TEST_CASE(pmt_test1)
             std::vector<bool> vMatch(nTx, false);
             std::vector<uint256> vMatchTxid1;
             for (unsigned int j=0; j<nTx; j++) {
-                bool fInclude = (insecure_rand() & ((1 << (att/2)) - 1)) == 0;
+                bool fInclude = insecure_randbits(att / 2) == 0;
                 vMatch[j] = fInclude;
                 if (fInclude)
                     vMatchTxid1.push_back(vTxid[j]);
diff --git a/src/test/versionbits_tests.cpp b/src/test/versionbits_tests.cpp
index 5302af9464..7af29f2aa6 100644
--- a/src/test/versionbits_tests.cpp
+++ b/src/test/versionbits_tests.cpp
@@ -80,7 +80,7 @@ public:
 
     VersionBitsTester& TestStateSinceHeight(int height) {
         for (int i = 0; i < CHECKERS; i++) {
-            if ((insecure_rand() & ((1 << i) - 1)) == 0) {
+            if (insecure_randbits(i) == 0) {
                 BOOST_CHECK_MESSAGE(checker[i].GetStateSinceHeightFor(vpblock.empty() ? NULL : vpblock.back()) == height, strprintf("Test %i for StateSinceHeight", num));
             }
         }
@@ -90,7 +90,7 @@ public:
 
     VersionBitsTester& TestDefined() {
         for (int i = 0; i < CHECKERS; i++) {
-            if ((insecure_rand() & ((1 << i) - 1)) == 0) {
+            if (insecure_randbits(i) == 0) {
                 BOOST_CHECK_MESSAGE(checker[i].GetStateFor(vpblock.empty() ? NULL : vpblock.back()) == THRESHOLD_DEFINED, strprintf("Test %i for DEFINED", num));
             }
         }
@@ -100,7 +100,7 @@ public:
 
     VersionBitsTester& TestStarted() {
         for (int i = 0; i < CHECKERS; i++) {
-            if ((insecure_rand() & ((1 << i) - 1)) == 0) {
+            if (insecure_randbits(i) == 0) {
                 BOOST_CHECK_MESSAGE(checker[i].GetStateFor(vpblock.empty() ? NULL : vpblock.back()) == THRESHOLD_STARTED, strprintf("Test %i for STARTED", num));
             }
         }
@@ -110,7 +110,7 @@ public:
 
     VersionBitsTester& TestLockedIn() {
         for (int i = 0; i < CHECKERS; i++) {
-            if ((insecure_rand() & ((1 << i) - 1)) == 0) {
+            if (insecure_randbits(i) == 0) {
                 BOOST_CHECK_MESSAGE(checker[i].GetStateFor(vpblock.empty() ? NULL : vpblock.back()) == THRESHOLD_LOCKED_IN, strprintf("Test %i for LOCKED_IN", num));
             }
         }
@@ -120,7 +120,7 @@ public:
 
     VersionBitsTester& TestActive() {
         for (int i = 0; i < CHECKERS; i++) {
-            if ((insecure_rand() & ((1 << i) - 1)) == 0) {
+            if (insecure_randbits(i) == 0) {
                 BOOST_CHECK_MESSAGE(checker[i].GetStateFor(vpblock.empty() ? NULL : vpblock.back()) == THRESHOLD_ACTIVE, strprintf("Test %i for ACTIVE", num));
             }
         }
@@ -130,7 +130,7 @@ public:
 
     VersionBitsTester& TestFailed() {
         for (int i = 0; i < CHECKERS; i++) {
-            if ((insecure_rand() & ((1 << i) - 1)) == 0) {
+            if (insecure_randbits(i) == 0) {
                 BOOST_CHECK_MESSAGE(checker[i].GetStateFor(vpblock.empty() ? NULL : vpblock.back()) == THRESHOLD_FAILED, strprintf("Test %i for FAILED", num));
             }
         }