From 787af8de1808e286bc0ea2d8dcc5d7208d237209 Mon Sep 17 00:00:00 2001
From: Michael Davidsaver <mdavidsaver@gmail.com>
Date: Thu, 7 Sep 2017 11:49:07 -0500
Subject: [PATCH] BitSet building convenience

Allow set()/clear()/flip() to be chained.
Support c++11 initializer lists.
---
 src/misc/bitSet.cpp         | 31 +++++++++++++++++++++++--------
 src/misc/pv/bitSet.h        | 20 +++++++++++++++++---
 testApp/misc/testBitSet.cpp | 20 +++++++++++++++++++-
 3 files changed, 59 insertions(+), 12 deletions(-)

diff --git a/src/misc/bitSet.cpp b/src/misc/bitSet.cpp
index 930b470..e58e778 100644
--- a/src/misc/bitSet.cpp
+++ b/src/misc/bitSet.cpp
@@ -55,6 +55,19 @@ namespace epics { namespace pvData {
         words.reserve((nbits == 0) ? 1 : WORD_INDEX(nbits-1) + 1);
     }
 
+#if __cplusplus>=201103L
+    BitSet::BitSet(std::initializer_list<uint32> I)
+    {
+        // optimistically guess that highest bit is last (not required)
+        words.reserve((I.size() == 0) ? 1 : WORD_INDEX(*(I.end()-1)) + 1);
+
+        for(uint32 idx : I)
+        {
+            set(idx);
+        }
+    }
+#endif
+
     BitSet::~BitSet() {}
 
     void BitSet::recalculateWordsInUse() {
@@ -76,7 +89,7 @@ namespace epics { namespace pvData {
         ensureCapacity(wordIndex+1);
     }
 
-    void BitSet::flip(uint32 bitIndex) {
+    BitSet& BitSet::flip(uint32 bitIndex) {
 
         uint32 wordIdx = WORD_INDEX(bitIndex);
         expandTo(wordIdx);
@@ -84,25 +97,27 @@ namespace epics { namespace pvData {
         words[wordIdx] ^= (((uint64)1) << WORD_OFFSET(bitIndex));
 
         recalculateWordsInUse();
+        return *this;
     }
 
-    void BitSet::set(uint32 bitIndex) {
+    BitSet& BitSet::set(uint32 bitIndex) {
 
         uint32 wordIdx = WORD_INDEX(bitIndex);
         expandTo(wordIdx);
 
         words[wordIdx] |= (((uint64)1) << WORD_OFFSET(bitIndex));
+        return *this;
     }
 
-    void BitSet::clear(uint32 bitIndex) {
+    BitSet& BitSet::clear(uint32 bitIndex) {
 
         uint32 wordIdx = WORD_INDEX(bitIndex);
-        if (wordIdx >= words.size())
-            return;
+        if (wordIdx < words.size()) {
+            words[wordIdx] &= ~(((uint64)1) << WORD_OFFSET(bitIndex));
 
-        words[wordIdx] &= ~(((uint64)1) << WORD_OFFSET(bitIndex));
-
-        recalculateWordsInUse();
+            recalculateWordsInUse();
+        }
+        return *this;
     }
 
     void BitSet::set(uint32 bitIndex, bool value) {
diff --git a/src/misc/pv/bitSet.h b/src/misc/pv/bitSet.h
index ac78c16..aac6ea9 100644
--- a/src/misc/pv/bitSet.h
+++ b/src/misc/pv/bitSet.h
@@ -9,6 +9,10 @@
 #ifndef BITSET_H
 #define BITSET_H
 
+#if __cplusplus>=201103L
+#  include <initializer_list>
+#endif
+
 #include <vector>
 
 #include <pv/pvType.h>
@@ -65,6 +69,16 @@ namespace epics { namespace pvData {
          */
         BitSet(uint32 nbits);
 
+#if __cplusplus>=201103L
+        /** Initialize from a list of indicies
+         @code
+         BitSet X({1, 5});
+         assert(X.get(1) && X.get(5));
+         @endcode
+         */
+        BitSet(std::initializer_list<uint32> I);
+#endif
+
         /**
          * Destructor.
          */
@@ -76,21 +90,21 @@ namespace epics { namespace pvData {
          *
          * @param  bitIndex the index of the bit to flip
          */
-        void flip(uint32 bitIndex);
+        BitSet& flip(uint32 bitIndex);
 
         /**
          * Sets the bit at the specified index to @c true.
          *
          * @param  bitIndex a bit index
          */
-        void set(uint32 bitIndex);
+        BitSet& set(uint32 bitIndex);
 
         /**
          * Sets the bit specified by the index to @c false.
          *
          * @param  bitIndex the index of the bit to be cleared
          */
-        void clear(uint32 bitIndex);
+        BitSet& clear(uint32 bitIndex);
 
         /**
          * Sets the bit at the specified index to the specified value.
diff --git a/testApp/misc/testBitSet.cpp b/testApp/misc/testBitSet.cpp
index 5370699..1fd55d0 100644
--- a/testApp/misc/testBitSet.cpp
+++ b/testApp/misc/testBitSet.cpp
@@ -23,10 +23,13 @@
 
 #include <pv/bitSet.h>
 #include <pv/serializeHelper.h>
+#include <pv/pvUnitTest.h>
 
 #include <epicsUnitTest.h>
 #include <testMain.h>
 
+namespace {
+
 using namespace epics::pvData;
 using std::string;
 
@@ -37,6 +40,18 @@ static string toString(BitSet& bitSet)
     return oss.str();
 }
 
+void testInitialize()
+{
+    testDiag("testInitialize()");
+#if __cplusplus>=201103L
+    testOk1(BitSet().size()==0);
+    testOk1(BitSet({}).size()==0);
+    testEqual(BitSet().set(1).set(5).set(500), BitSet({1, 5, 500}));
+#else
+    testSkip(3, "Not c++11");
+#endif
+}
+
 static void testGetSetClearFlip()
 {
     testDiag("testGetSetClearFlip... ");
@@ -292,9 +307,12 @@ static void testSerialize()
 #undef TOFRO
 }
 
+} // namespace
+
 MAIN(testBitSet)
 {
-    testPlan(87);
+    testPlan(90);
+    testInitialize();
     testGetSetClearFlip();
     testOperators();
     testLogical();