util/StringView: new utility class

src/util/StringView.hxx

@@ -0,0 +1,108 @@
+/*
+ * Copyright (C) 2013-2015 Max Kellermann <max@duempel.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+ * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef STRING_VIEW_HXX
+#define STRING_VIEW_HXX
+
+#include "ConstBuffer.hxx"
+
+#include <string.h>
+
+struct StringView : ConstBuffer<char> {
+	StringView() = default;
+
+	constexpr StringView(pointer_type _data, size_type _size)
+		:ConstBuffer<char>(_data, _size) {}
+
+	constexpr StringView(pointer_type _begin, pointer_type _end)
+		:ConstBuffer<char>(_begin, _end - _begin) {}
+
+	StringView(pointer_type _data)
+		:ConstBuffer<char>(_data,
+				   _data != nullptr ? strlen(_data) : 0) {}
+
+	StringView(std::nullptr_t n)
+		:ConstBuffer<char>(n) {}
+
+	static constexpr StringView Empty() {
+		return StringView("", size_t(0));
+	}
+
+	void SetEmpty() {
+		data = "";
+		size = 0;
+	}
+
+	gcc_pure
+	pointer_type Find(char ch) const {
+		return (pointer_type)memchr(data, ch, size);
+	}
+
+	StringView &operator=(std::nullptr_t) {
+		data = nullptr;
+		size = 0;
+		return *this;
+	}
+
+	StringView &operator=(pointer_type _data) {
+		data = _data;
+		size = _data != nullptr ? strlen(_data) : 0;
+		return *this;
+	}
+
+	gcc_pure
+	bool StartsWith(StringView needle) const {
+		return size >= needle.size &&
+			memcmp(data, needle.data, needle.size) == 0;
+	}
+
+	gcc_pure
+	bool Equals(StringView other) const {
+		return size == other.size &&
+			memcmp(data, other.data, size) == 0;
+	}
+
+	template<size_t n>
+	bool EqualsLiteral(const char (&other)[n]) const {
+		return Equals({other, n - 1});
+	}
+
+	gcc_pure
+	bool EqualsIgnoreCase(StringView other) const {
+		return size == other.size &&
+			strncasecmp(data, other.data, size) == 0;
+	}
+
+	template<size_t n>
+	bool EqualsLiteralIgnoreCase(const char (&other)[n]) const {
+		return EqualsIgnoreCase({other, n - 1});
+	}
+};
+
+#endif