Refactor and improve CTL and other code

ctl/string_view.h

@@ -0,0 +1,159 @@
+// -*-mode:c++;indent-tabs-mode:nil;c-basic-offset:4;tab-width:8;coding:utf-8-*-
+// vi: set et ft=c++ ts=4 sts=4 sw=4 fenc=utf-8 :vi
+#ifndef COSMOPOLITAN_CTL_STRINGVIEW_H_
+#define COSMOPOLITAN_CTL_STRINGVIEW_H_
+
+namespace ctl {
+
+struct string_view;
+
+int
+strcmp(const string_view, const string_view) noexcept;
+
+struct string_view
+{
+    const char* p;
+    size_t n;
+
+    using iterator = const char*;
+    using const_iterator = const char*;
+    static constexpr size_t npos = -1;
+
+    constexpr string_view() noexcept : p(nullptr), n(0)
+    {
+    }
+
+    constexpr string_view(const char* s) noexcept
+      : p(s), n(s ? __builtin_strlen(s) : 0)
+    {
+    }
+
+    constexpr string_view(const char* s, size_t n) noexcept : p(s), n(n)
+    {
+    }
+
+    inline constexpr ~string_view() noexcept
+    {
+    }
+
+    bool operator==(const string_view) const noexcept;
+    bool operator!=(const string_view) const noexcept;
+    bool contains(const string_view) const noexcept;
+    bool ends_with(const string_view) const noexcept;
+    bool starts_with(const string_view) const noexcept;
+    string_view substr(size_t = 0, size_t = npos) const noexcept;
+    size_t find(char, size_t = 0) const noexcept;
+    size_t find(const string_view, size_t = 0) const noexcept;
+
+    constexpr string_view& operator=(const string_view& s) noexcept
+    {
+        p = s.p;
+        n = s.n;
+        return *this;
+    }
+
+    constexpr bool empty() const noexcept
+    {
+        return !n;
+    }
+
+    constexpr const char* data() const noexcept
+    {
+        return p;
+    }
+
+    constexpr size_t size() const noexcept
+    {
+        return n;
+    }
+
+    constexpr size_t length() const noexcept
+    {
+        return n;
+    }
+
+    constexpr const char& operator[](size_t i) const noexcept
+    {
+        if (i >= n)
+            __builtin_trap();
+        return p[i];
+    }
+
+    constexpr void remove_prefix(size_t count)
+    {
+        if (count > n)
+            __builtin_trap();
+        p += count;
+        n -= count;
+    }
+
+    constexpr void remove_suffix(size_t count)
+    {
+        if (count > n)
+            __builtin_trap();
+        n -= count;
+    }
+
+    constexpr const char& front() const
+    {
+        if (!n)
+            __builtin_trap();
+        return p[0];
+    }
+
+    constexpr const char& back() const
+    {
+        if (!n)
+            __builtin_trap();
+        return p[n - 1];
+    }
+
+    constexpr const_iterator begin() noexcept
+    {
+        return p;
+    }
+
+    constexpr const_iterator end() noexcept
+    {
+        return p + n;
+    }
+
+    constexpr const_iterator cbegin() const noexcept
+    {
+        return p;
+    }
+
+    constexpr const_iterator cend() const noexcept
+    {
+        return p + n;
+    }
+
+    int compare(const string_view s) const noexcept
+    {
+        return strcmp(*this, s);
+    }
+
+    bool operator<(const string_view& s) const noexcept
+    {
+        return compare(s) < 0;
+    }
+
+    bool operator<=(const string_view& s) const noexcept
+    {
+        return compare(s) <= 0;
+    }
+
+    bool operator>(const string_view& s) const noexcept
+    {
+        return compare(s) > 0;
+    }
+
+    bool operator>=(const string_view& s) const noexcept
+    {
+        return compare(s) >= 0;
+    }
+};
+
+} // namespace ctl
+
+#endif // COSMOPOLITAN_CTL_STRINGVIEW_H_