Long live Qt 4.5!

1 files changed, 111 insertions, 0 deletions

diff --git a/util/qlalr/examples/qparser/qparser.h b/util/qlalr/examples/qparser/qparser.h
new file mode 100644
index 0000000000..e3ff61d7c8
--- /dev/null
+++ b/util/qlalr/examples/qparser/qparser.h
@@ -0,0 +1,111 @@
+#ifndef QPARSER_H
+#define QPARSER_H
+
+#include <QtCore/QSharedDataPointer>
+#include <QtCore/QVarLengthArray>
+
+template <typename _Parser, typename _Table, typename _Value = int>
+class QParser: protected _Table
+{
+public:
+    QParser();
+    ~QParser();
+
+    bool parse();
+
+    inline _Value &sym(int index);
+
+private:
+    inline int nextToken()
+    {
+        return static_cast<_Parser*> (this)->nextToken();
+    }
+
+    inline void consumeRule(int rule)
+    {
+        static_cast<_Parser*> (this)->consumeRule(rule);
+    }
+
+    enum { DefaultStackSize = 128 };
+
+    struct Data: public QSharedData
+    {
+        Data(): stackSize (DefaultStackSize), tos (0) {}
+
+        QVarLengthArray<int, DefaultStackSize> stateStack;
+        QVarLengthArray<_Value, DefaultStackSize> parseStack;
+        int stackSize;
+        int tos;
+
+        void reallocateStack() {
+            stackSize <<= 1;
+            stateStack.resize(stackSize);
+            parseStack.resize(stackSize);
+        }
+    };
+
+    QSharedDataPointer<Data> d;
+};
+
+template <typename _Parser, typename _Table, typename _Value>
+inline _Value &QParser<_Parser, _Table, _Value>::sym(int n)
+{
+    return d->parseStack [d->tos + n - 1];
+}
+
+template <typename _Parser, typename _Table, typename _Value>
+QParser<_Parser, _Table, _Value>::QParser():
+    d(new Data())
+{
+}
+
+template <typename _Parser, typename _Table, typename _Value>
+QParser<_Parser, _Table, _Value>::~QParser()
+{
+}
+
+template <typename _Parser, typename _Table, typename _Value>
+bool QParser<_Parser, _Table, _Value>::parse()
+{
+    const int INITIAL_STATE = 0;
+
+    d->tos = 0;
+    d->reallocateStack();
+
+    int act = d->stateStack[++d->tos] = INITIAL_STATE;
+    int token = -1;
+
+    forever {
+        if (token == -1 && - _Table::TERMINAL_COUNT != _Table::action_index[act])
+            token = nextToken();
+
+        act = _Table::t_action(act, token);
+
+        if (d->stateStack[d->tos] == _Table::ACCEPT_STATE)
+            return true;
+
+        else if (act > 0) {
+            if (++d->tos == d->stackSize)
+                d->reallocateStack();
+
+            d->parseStack[d->tos] = d->parseStack[d->tos - 1];
+            d->stateStack[d->tos] = act;
+            token = -1;
+        }
+
+        else if (act < 0) {
+            int r = - act - 1;
+            d->tos -= _Table::rhs[r];
+            act = d->stateStack[d->tos++];
+            consumeRule(r);
+            act = d->stateStack[d->tos] = _Table::nt_action(act, _Table::lhs[r] - _Table::TERMINAL_COUNT);
+        }
+
+        else break;
+    }
+
+    return false;
+}
+
+
+#endif // QPARSER_H