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diff --git a/gfx/angle/checkout/src/compiler/preprocessor/numeric_lex.h b/gfx/angle/checkout/src/compiler/preprocessor/numeric_lex.h
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+++ b/gfx/angle/checkout/src/compiler/preprocessor/numeric_lex.h
@@ -0,0 +1,54 @@
+//
+// Copyright 2012 The ANGLE Project Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+
+// numeric_lex.h: Functions to extract numeric values from string.
+
+#ifndef COMPILER_PREPROCESSOR_NUMERICLEX_H_
+#define COMPILER_PREPROCESSOR_NUMERICLEX_H_
+
+#include <sstream>
+
+namespace angle
+{
+
+namespace pp
+{
+
+inline std::ios::fmtflags numeric_base_int(const std::string &str)
+{
+    if ((str.size() >= 2) && (str[0] == '0') && (str[1] == 'x' || str[1] == 'X'))
+    {
+        return std::ios::hex;
+    }
+    if ((str.size() >= 1) && (str[0] == '0'))
+    {
+        return std::ios::oct;
+    }
+    return std::ios::dec;
+}
+
+// The following functions parse the given string to extract a numerical
+// value of the given type. These functions assume that the string is
+// of the correct form. They can only fail if the parsed value is too big,
+// in which case false is returned.
+
+template <typename IntType>
+bool numeric_lex_int(const std::string &str, IntType *value)
+{
+    std::istringstream stream(str);
+    // This should not be necessary, but MSVS has a buggy implementation.
+    // It returns incorrect results if the base is not specified.
+    stream.setf(numeric_base_int(str), std::ios::basefield);
+
+    stream >> (*value);
+    return !stream.fail();
+}
+
+}  // namespace pp
+
+}  // namespace angle
+
+#endif  // COMPILER_PREPROCESSOR_NUMERICLEX_H_