From 922e9d6b0c7ae1acdae4986e8000ad9a693b7469 Mon Sep 17 00:00:00 2001
From: Erik Verbruggen <erik.verbruggen@theqtcompany.com>
Date: Thu, 3 Mar 2016 10:23:02 +0100
Subject: V4: Move BitVector to the util header, so it can be re-used.

Change-Id: I994ff9277fbbcebf2e45b3146859eb75264b83f4
Reviewed-by: Lars Knoll <lars.knoll@theqtcompany.com>
---
 src/qml/jsruntime/qv4util_p.h | 117 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 117 insertions(+)

(limited to 'src/qml/jsruntime')

diff --git a/src/qml/jsruntime/qv4util_p.h b/src/qml/jsruntime/qv4util_p.h
index 3ffcc8a846..132abd211e 100644
--- a/src/qml/jsruntime/qv4util_p.h
+++ b/src/qml/jsruntime/qv4util_p.h
@@ -51,6 +51,9 @@
 //
 
 #include "qv4global_p.h"
+#include <QtCore/QBitArray>
+#include <algorithm>
+#include <vector>
 
 QT_BEGIN_NAMESPACE
 
@@ -76,6 +79,120 @@ private:
     TemporaryAssignment operator=(const TemporaryAssignment<T>&);
 };
 
+#if !defined(BROKEN_STD_VECTOR_BOOL_OR_BROKEN_STD_FIND)
+// Sanity:
+class BitVector
+{
+    std::vector<bool> bits;
+
+public:
+    BitVector(int size = 0, bool value = false)
+        : bits(size, value)
+    {}
+
+    void reserve(int size)
+    { bits.reserve(size); }
+
+    int size() const
+    {
+        Q_ASSERT(bits.size() < INT_MAX);
+        return static_cast<int>(bits.size());
+    }
+
+    void resize(int newSize)
+    { bits.resize(newSize); }
+
+    void assign(int newSize, bool value)
+    { bits.assign(newSize, value); }
+
+    int findNext(int start, bool value, bool wrapAround) const
+    {
+        // The ++operator of std::vector<bool>::iterator in libc++ has a bug when using it on an
+        // iterator pointing to the last element. It will not be set to ::end(), but beyond
+        // that. (It will be set to the first multiple of the native word size that is bigger
+        // than size().)
+        //
+        // See http://llvm.org/bugs/show_bug.cgi?id=19663
+        //
+        // The work-around is to calculate the distance, and compare it to the size() to see if it's
+        // beyond the end, or take the minimum of the distance and the size.
+
+        size_t pos = std::distance(bits.begin(),
+                                   std::find(bits.begin() + start, bits.end(), value));
+        if (wrapAround && pos >= static_cast<size_t>(size()))
+            pos = std::distance(bits.begin(),
+                                std::find(bits.begin(), bits.begin() + start, value));
+
+        pos = qMin(pos, static_cast<size_t>(size()));
+
+        Q_ASSERT(pos <= static_cast<size_t>(size()));
+        Q_ASSERT(pos < INT_MAX);
+
+        return static_cast<int>(pos);
+    }
+
+    bool at(int idx) const
+    { return bits.at(idx); }
+
+    void setBit(int idx)
+    { bits[idx] = true; }
+
+    void clearBit(int idx)
+    { bits[idx] = false; }
+};
+#else // Insanity:
+class BitVector
+{
+    QBitArray bits;
+
+public:
+    BitVector(int size = 0, bool value = false)
+        : bits(size, value)
+    {}
+
+    void reserve(int size)
+    { Q_UNUSED(size); }
+
+    int size() const
+    { return bits.size(); }
+
+    void resize(int newSize)
+    { bits.resize(newSize); }
+
+    void assign(int newSize, bool value)
+    {
+        bits.resize(newSize);
+        bits.fill(value);
+    }
+
+    int findNext(int start, bool value, bool wrapAround) const
+    {
+        for (int i = start, ei = size(); i < ei; ++i) {
+            if (at(i) == value)
+                return i;
+        }
+
+        if (wrapAround) {
+            for (int i = 0, ei = start; i < ei; ++i) {
+                if (at(i) == value)
+                    return i;
+            }
+        }
+
+        return size();
+    }
+
+    bool at(int idx) const
+    { return bits.at(idx); }
+
+    void setBit(int idx)
+    { bits[idx] = true; }
+
+    void clearBit(int idx)
+    { bits[idx] = false; }
+};
+#endif
+
 }
 
 QT_END_NAMESPACE
-- 
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