util/StringUtil: move comparison functions to StringCompare.cxx

src/util/StringCompare.cxx

@@ -0,0 +1,82 @@
+/*
+ * 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.
+ */
+
+#include "StringCompare.hxx"
+#include "StringAPI.hxx"
+
+#include <assert.h>
+#include <string.h>
+
+bool
+StringStartsWith(const char *haystack, const char *needle)
+{
+	const size_t length = strlen(needle);
+	return memcmp(haystack, needle, length) == 0;
+}
+
+bool
+StringEndsWith(const char *haystack, const char *needle)
+{
+	const size_t haystack_length = strlen(haystack);
+	const size_t needle_length = strlen(needle);
+
+	return haystack_length >= needle_length &&
+		memcmp(haystack + haystack_length - needle_length,
+		       needle, needle_length) == 0;
+}
+
+const char *
+StringAfterPrefix(const char *string, const char *prefix)
+{
+#if !CLANG_CHECK_VERSION(3,6)
+	/* disabled on clang due to -Wtautological-pointer-compare */
+	assert(string != nullptr);
+	assert(prefix != nullptr);
+#endif
+
+	size_t prefix_length = strlen(prefix);
+	return StringIsEqual(string, prefix, prefix_length)
+		? string + prefix_length
+		: nullptr;
+}
+
+const char *
+FindStringSuffix(const char *p, const char *suffix)
+{
+	const size_t p_length = strlen(p);
+	const size_t suffix_length = strlen(suffix);
+
+	if (p_length < suffix_length)
+		return nullptr;
+
+	const char *q = p + p_length - suffix_length;
+	return memcmp(q, suffix, suffix_length) == 0
+		? q
+		: nullptr;
+}