1 files changed, 89 insertions, 0 deletions
diff --git a/src/include/string_view.hpp b/src/include/string_view.hpp
new file mode 100644
index 00000000..7d049e9e
--- /dev/null
+++ b/src/include/string_view.hpp
@@ -0,0 +1,89 @@
+/*
+ * MRustC - Rust Compiler
+ * - By John Hodge (Mutabah/thePowersGang)
+ *
+ * include/string_view.hpp
+ * - Clone of the `string_view` class (introduced in C++17)
+ */
+#pragma once
+#include <string>
+#include <cstddef>  // size_t
+#include <iostream> // ostream
+
+namespace std {
+
+class string_view
+{
+    const char* m_start;
+    const char* m_end;
+
+public:
+    string_view():
+        m_start(nullptr), m_end(nullptr)
+    {
+    }
+    string_view(const char* s, const char* e):
+        m_start(s), m_end(e)
+    {
+        if(!(s <= e))
+            throw ::std::invalid_argument("start must be before end for string_view");
+    }
+    string_view(const char* s):
+        m_start(s), m_end(s)
+    {
+        while(*m_end)
+            m_end ++;
+    }
+    string_view(const string& s):
+        m_start(s.data()), m_end(m_start + s.size())
+    {
+    }
+
+    size_t size() const {
+        return m_end - m_start;
+    }
+
+    bool operator==(const string_view& x) const { return cmp(x) == 0; }
+    bool operator!=(const string_view& x) const { return cmp(x) != 0; }
+    bool operator< (const string_view& x) const { return cmp(x) <  0; }
+    bool operator> (const string_view& x) const { return cmp(x) >  0; }
+    bool operator<=(const string_view& x) const { return cmp(x) <= 0; }
+    bool operator>=(const string_view& x) const { return cmp(x) >= 0; }
+    bool operator==(const char* x) const { return cmp(string_view(x)) == 0; }
+    bool operator!=(const char* x) const { return cmp(string_view(x)) != 0; }
+    bool operator< (const char* x) const { return cmp(string_view(x)) <  0; }
+    bool operator> (const char* x) const { return cmp(string_view(x)) >  0; }
+    bool operator<=(const char* x) const { return cmp(string_view(x)) <= 0; }
+    bool operator>=(const char* x) const { return cmp(string_view(x)) >= 0; }
+    bool operator==(const string& x) const { return cmp(string_view(x)) == 0; }
+    bool operator!=(const string& x) const { return cmp(string_view(x)) != 0; }
+    bool operator< (const string& x) const { return cmp(string_view(x)) <  0; }
+    bool operator> (const string& x) const { return cmp(string_view(x)) >  0; }
+    bool operator<=(const string& x) const { return cmp(string_view(x)) <= 0; }
+    bool operator>=(const string& x) const { return cmp(string_view(x)) >= 0; }
+
+    friend ::std::ostream& operator<<(::std::ostream& os, const string_view& x) {
+        for(const char* s = x.m_start; s != x.m_end; s++)
+            os << *s;
+        return os;
+    }
+
+private:
+    int cmp(const string_view& x) const {
+        const char *a, *b;
+        for( a = m_start, b = x.m_start; a != m_end && b != x.m_end; a++, b++)
+        {
+            if( *a != *b ) {
+                return *a < *b ? -1 : 1;
+            }
+        }
+        if( a == m_end && b == m_end )
+            return 0;
+        if( a == m_end )
+            return -1;
+        else
+            return 1;
+    }
+};
+
+}