From efc4e3141fea4df7c0f568451815c38563c6d7c8 Mon Sep 17 00:00:00 2001
From: Frank Tang <ftang@chromium.org>
Date: Sat, 18 Nov 2023 06:40:08 +0000
Subject: [PATCH] ICU-22549 Add DateTimePatternGenerator fuzzer

See #2708
---
 icu4c/source/test/fuzzer/Makefile.in          |  2 +-
 .../date_time_pattern_generator_fuzzer.cpp    | 56 +++++++++++++++++++
 2 files changed, 57 insertions(+), 1 deletion(-)
 create mode 100644 icu4c/source/test/fuzzer/date_time_pattern_generator_fuzzer.cpp

diff --git a/icu4c/source/test/fuzzer/Makefile.in b/icu4c/source/test/fuzzer/Makefile.in
index 5f895a73950d..9ee25d703ca7 100644
--- a/icu4c/source/test/fuzzer/Makefile.in
+++ b/icu4c/source/test/fuzzer/Makefile.in
@@ -33,7 +33,7 @@ CPPFLAGS += -I$(srcdir) -I$(top_srcdir)/common -I$(top_srcdir)/i18n -I$(top_srcd
 DEFS += -D'U_TOPSRCDIR="$(top_srcdir)/"' -D'U_TOPBUILDDIR="$(BUILDDIR)"'
 LIBS = $(LIBCTESTFW) $(LIBICUTOOLUTIL) $(LIBICUIO) $(LIBICUI18N) $(LIBICUUC) $(DEFAULT_LIBS) $(LIB_M)
 
-FUZZER_TARGETS = break_iterator_fuzzer calendar_fuzzer collator_compare_fuzzer collator_rulebased_fuzzer converter_fuzzer date_format_fuzzer list_format_fuzzer locale_fuzzer locale_morph_fuzzer number_format_fuzzer relative_date_time_formatter_fuzzer rule_based_break_iterator_fuzzer ucasemap_fuzzer uloc_canonicalize_fuzzer uloc_for_language_tag_fuzzer uloc_get_name_fuzzer uloc_is_right_to_left_fuzzer uloc_open_keywords_fuzzer unicode_string_codepage_create_fuzzer uregex_open_fuzzer
+FUZZER_TARGETS = break_iterator_fuzzer calendar_fuzzer collator_compare_fuzzer collator_rulebased_fuzzer converter_fuzzer date_format_fuzzer date_time_pattern_generator_fuzzer list_format_fuzzer locale_fuzzer locale_morph_fuzzer number_format_fuzzer relative_date_time_formatter_fuzzer rule_based_break_iterator_fuzzer ucasemap_fuzzer uloc_canonicalize_fuzzer uloc_for_language_tag_fuzzer uloc_get_name_fuzzer uloc_is_right_to_left_fuzzer uloc_open_keywords_fuzzer unicode_string_codepage_create_fuzzer uregex_open_fuzzer
 
 OBJECTS = $(FUZZER_TARGETS:%=%.o)
 OBJECTS += fuzzer_driver.o locale_util.o
diff --git a/icu4c/source/test/fuzzer/date_time_pattern_generator_fuzzer.cpp b/icu4c/source/test/fuzzer/date_time_pattern_generator_fuzzer.cpp
new file mode 100644
index 000000000000..a26037f98c2b
--- /dev/null
+++ b/icu4c/source/test/fuzzer/date_time_pattern_generator_fuzzer.cpp
@@ -0,0 +1,56 @@
+// © 2019 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
+
+#include <cstring>
+
+#include "fuzzer_utils.h"
+#include "unicode/dtptngen.h"
+#include "unicode/localpointer.h"
+#include "unicode/locid.h"
+
+IcuEnvironment* env = new IcuEnvironment();
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  UErrorCode status = U_ZERO_ERROR;
+
+  uint16_t rnd16;
+
+  if (size < 2 + sizeof(rnd16))
+    return 0;
+
+  std::memcpy(&rnd16, data, sizeof(rnd16));
+  size -= sizeof(rnd16);
+  data += sizeof(rnd16);
+  const icu::Locale& locale = GetRandomLocale(rnd16);
+
+  std::unique_ptr<char16_t[]> fuzzbuff(new char16_t[size/2]);
+  std::memcpy(fuzzbuff.get(), data, (size/2)*2);
+  icu::UnicodeString fuzzstr(false, fuzzbuff.get(), size/2);
+
+  icu::LocalPointer<icu::DateTimePatternGenerator > gen(
+      icu::DateTimePatternGenerator::createInstance(locale, status), status);
+  if (U_FAILURE(status))
+    return 0;
+
+  status = U_ZERO_ERROR;
+  gen->getSkeleton(fuzzstr, status);
+
+  status = U_ZERO_ERROR;
+  gen->getBaseSkeleton(fuzzstr, status);
+
+  status = U_ZERO_ERROR;
+  gen->getBaseSkeleton(fuzzstr, status);
+
+  status = U_ZERO_ERROR;
+  gen->getPatternForSkeleton(fuzzstr);
+
+  status = U_ZERO_ERROR;
+  gen->getBestPattern(fuzzstr, status);
+
+  status = U_ZERO_ERROR;
+  icu::DateTimePatternGenerator::staticGetSkeleton(fuzzstr, status);
+
+  status = U_ZERO_ERROR;
+  icu::DateTimePatternGenerator::staticGetBaseSkeleton (fuzzstr, status);
+  return 0;
+}