[utf8] Add UTF-8 accumulation self-tests

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/tests/tests.c

diff --git a/src/tests/tests.c b/src/tests/tests.c
index 1cc4c81..4dd4adf 100644
--- a/src/tests/tests.c
+++ b/src/tests/tests.c
@@ -75,3 +75,4 @@
 REQUIRE_OBJECT ( ntlm_test );
 REQUIRE_OBJECT ( zlib_test );
 REQUIRE_OBJECT ( gzip_test );
+REQUIRE_OBJECT ( utf8_test );

src/tests/utf8_test.c

diff --git a/src/tests/utf8_test.c b/src/tests/utf8_test.c
new file mode 100644
index 0000000..1996915
--- /dev/null
+++ b/src/tests/utf8_test.c
@@ -0,0 +1,164 @@
+/*
+ * Copyright (C) 2022 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+/** @file
+ *
+ * UTF-8 Unicode encoding tests
+ *
+ */
+
+/* Forcibly enable assertions */
+#undef NDEBUG
+
+#include <string.h>
+#include <ipxe/utf8.h>
+#include <ipxe/test.h>
+
+/** A UTF-8 accumulation test */
+struct utf8_accumulate_test {
+	/** UTF-8 byte string */
+	const char *bytes;
+	/** Expected character sequence */
+	const unsigned int *expected;
+	/** Length */
+	size_t len;
+};
+
+/** Define inline data */
+#define DATA(...) { __VA_ARGS__ }
+
+/** Define a UTF-8 accumulation test */
+#define UTF8_ACCUMULATE( name, BYTES, EXPECTED )			\
+	static const char name ## _bytes[] = BYTES;			\
+	static const unsigned int name ## _expected[] = EXPECTED;	\
+	static struct utf8_accumulate_test name = {			\
+		.bytes = name ## _bytes,				\
+		.expected = name ## _expected,				\
+		.len = ( sizeof ( name ## _expected ) /			\
+			 sizeof ( name ## _expected[0] ) ),		\
+	};
+
+/** Basic ASCII test */
+UTF8_ACCUMULATE ( ascii, "Hello world!",
+		  DATA ( 'H', 'e', 'l', 'l', 'o', ' ',
+			 'w', 'o', 'r', 'l', 'd', '!' ) );
+
+/** Multi-byte character test */
+UTF8_ACCUMULATE ( multibyte, "Héllô wörld 🥳",
+		  DATA ( 'H', 0, L'é', 'l', 'l', 0, L'ô', ' ',
+			 'w', 0, L'ö', 'r', 'l', 'd', ' ',
+			 0, 0, 0, 0x1f973 ) );
+
+/** Stray continuation byte test */
+UTF8_ACCUMULATE ( stray_continuation,
+		  DATA ( 'a', 0x81, 'b', 0xc3, 0x82, 0x83, 'c' ),
+		  DATA ( 'a', 0xfffd, 'b', 0, 0xc2, 0xfffd, 'c' ) );
+
+/** Missing continuation byte test */
+UTF8_ACCUMULATE ( missing_continuation,
+		  DATA ( 'a', 0xc3, 'b', 0xe1, 0x86, 0xc3, 0x89, 'c' ),
+		  DATA ( 'a', 0, 'b', 0, 0, 0, 0xc9, 'c' ) );
+
+/** Illegal two-byte sequence test */
+UTF8_ACCUMULATE ( illegal_two,
+		  DATA ( 'a', 0xc2, 0x80, 'b', 0xc1, 0xbf, 'c', 0xc0, 0x80,
+			 'd' ),
+		  DATA ( 'a', 0, 0x80, 'b', 0, 0xfffd, 'c', 0, 0xfffd, 'd' ) );
+
+/** Illegal three-byte sequence test */
+UTF8_ACCUMULATE ( illegal_three,
+		  DATA ( 'a', 0xe0, 0xa0, 0x80, 'b', 0xe0, 0x9f, 0xbf, 'c',
+			 0xe0, 0x80, 0x80, 'd' ),
+		  DATA ( 'a', 0, 0, 0x800, 'b', 0, 0, 0xfffd, 'c',
+			 0, 0, 0xfffd, 'd' ) );
+
+/** Illegal four-byte sequence test */
+UTF8_ACCUMULATE ( illegal_four,
+		  DATA ( 'a', 0xf0, 0x90, 0x80, 0x80, 'b', 0xf0, 0x8f, 0xbf,
+			 0xbf, 'c', 0xf0, 0x80, 0x80, 0x80, 'd' ),
+		  DATA ( 'a', 0, 0, 0, 0x10000, 'b', 0, 0, 0, 0xfffd, 'c',
+			 0, 0, 0, 0xfffd, 'd' ) );
+
+/** Illegal overlength sequence test */
+UTF8_ACCUMULATE ( illegal_length,
+		  DATA ( 'a', 0xf8, 0xbf, 0xbf, 0xbf, 0xbf, 'b', 0xfc, 0xbf,
+			 0xbf, 0xbf, 0xbf, 0xbf, 'c', 0xfe, 0xbf, 0xbf, 0xbf,
+			 0xbf, 0xbf, 0xbf, 'd', 0xff, 0xbf, 0xbf, 0xbf, 0xbf,
+			 0xbf, 0xbf, 0xbf, 'e' ),
+		  DATA ( 'a', 0xfffd, 0xfffd, 0xfffd, 0xfffd, 0xfffd, 'b',
+			 0xfffd, 0xfffd, 0xfffd, 0xfffd, 0xfffd, 0xfffd, 'c',
+			 0xfffd, 0xfffd, 0xfffd, 0xfffd, 0xfffd, 0xfffd,
+			 0xfffd, 'd', 0xfffd, 0xfffd, 0xfffd, 0xfffd, 0xfffd,
+			 0xfffd, 0xfffd, 0xfffd, 'e' ) );
+
+/**
+ * Report UTF-8 accumulation test result
+ *
+ * @v test		UTF-8 accumulation test
+ * @v file		Test code file
+ * @v line		Test code line
+ */
+static void utf8_accumulate_okx ( struct utf8_accumulate_test *test,
+				  const char *file, unsigned int line ) {
+	struct utf8_accumulator utf8;
+	unsigned int character;
+	unsigned int i;
+
+	/* Initialise accumulator */
+	memset ( &utf8, 0, sizeof ( utf8 ) );
+
+	/* Test each byte in turn */
+	for ( i = 0 ; i < test->len ; i++ ) {
+		character = utf8_accumulate ( &utf8, test->bytes[i] );
+		DBGC ( test, "UTF8 byte %02x character %02x\n",
+		       test->bytes[i], character );
+		okx ( character == test->expected[i], file, line );
+	}
+}
+#define utf8_accumulate_ok( test ) \
+	utf8_accumulate_okx ( test, __FILE__, __LINE__ )
+
+/**
+ * Perform UTF-8 self-test
+ *
+ */
+static void utf8_test_exec ( void ) {
+
+	/* Accumulation tests */
+	utf8_accumulate_ok ( &ascii );
+	utf8_accumulate_ok ( &multibyte );
+	utf8_accumulate_ok ( &stray_continuation );
+	utf8_accumulate_ok ( &missing_continuation );
+	utf8_accumulate_ok ( &illegal_two );
+	utf8_accumulate_ok ( &illegal_three );
+	utf8_accumulate_ok ( &illegal_four );
+	utf8_accumulate_ok ( &illegal_length );
+}
+
+/** UTF-8 self-test */
+struct self_test utf8_test __self_test = {
+	.name = "utf8",
+	.exec = utf8_test_exec,
+};