Add a StringLexer utility class that can be used when you have string data that needs to be parsed - I don't think such a general purpose facility is part of LLVM, and I am going to need this, so just add it to lldb_utility

llvm-svn: 215133

1 files changed, 93 insertions, 0 deletions

diff --git a/lldb/source/Utility/StringLexer.cpp b/lldb/source/Utility/StringLexer.cpp
new file mode 100644
index 00000000000..69880d21e96
--- /dev/null
+++ b/lldb/source/Utility/StringLexer.cpp
@@ -0,0 +1,93 @@
+//===--------------------- StringLexer.cpp -----------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/Utility/StringLexer.h"
+
+using namespace lldb_utility;
+
+StringLexer::StringLexer (std::string s) :
+m_data(s),
+m_position(0),
+m_putback_data()
+{ }
+
+StringLexer::StringLexer (const StringLexer& rhs) :
+m_data(rhs.m_data),
+m_position(rhs.m_position),
+m_putback_data(rhs.m_putback_data)
+{ }
+
+StringLexer::Character
+StringLexer::Peek ()
+{
+    if (m_putback_data.empty())
+        return m_data[m_position];
+    else
+        return m_putback_data.front();
+}
+
+bool
+StringLexer::NextIf (Character c)
+{
+    auto val = Peek();
+    if (val == c)
+    {
+        Next();
+        return true;
+    }
+    return false;
+}
+
+StringLexer::Character
+StringLexer::Next ()
+{
+    auto val = Peek();
+    Consume();
+    return val;
+}
+
+bool
+StringLexer::HasAtLeast (Size s)
+{
+    return m_data.size()-m_position >= s;
+}
+
+
+void
+StringLexer::PutBack (Character c)
+{
+    m_putback_data.push_back(c);
+}
+
+bool
+StringLexer::HasAny (Character c)
+{
+    return m_data.find(c, m_position) != std::string::npos;
+}
+
+void
+StringLexer::Consume()
+{
+    if (m_putback_data.empty())
+        m_position++;
+    else
+        m_putback_data.pop_front();
+}
+
+StringLexer&
+StringLexer::operator = (const StringLexer& rhs)
+{
+    if (this != &rhs)
+    {
+        m_data = rhs.m_data;
+        m_position = rhs.m_position;
+        m_putback_data = rhs.m_putback_data;
+    }
+    return *this;
+}