ICU-22549 Add fuzzer for NumberFormatter

icu4c/source/test/fuzzer/Makefile.in

@@ -42,6 +42,7 @@ FUZZER_TARGETS = \
 		 list_format_fuzzer locale_fuzzer \
 		 locale_morph_fuzzer \
 		 number_format_fuzzer \
+		 number_formatter_fuzzer \
 		 relative_date_time_formatter_fuzzer \
 		 rule_based_break_iterator_fuzzer \
 		 ucasemap_fuzzer \

icu4c/source/test/fuzzer/number_formatter_fuzzer.cpp

@@ -0,0 +1,45 @@
+// © 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/localpointer.h"
+#include "unicode/numberformatter.h"
+
+IcuEnvironment* env = new IcuEnvironment();
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  UErrorCode status = U_ZERO_ERROR;
+
+  int16_t rnd;
+  int64_t value;
+  double doubleValue;
+  if (size < sizeof(rnd) + sizeof(value) + sizeof(doubleValue)) return 0;
+  icu::StringPiece fuzzData(reinterpret_cast<const char *>(data), size);
+
+  std::memcpy(&rnd, fuzzData.data(), sizeof(rnd));
+  icu::Locale locale = GetRandomLocale(rnd);
+  fuzzData.remove_prefix(sizeof(rnd));
+
+  std::memcpy(&value, fuzzData.data(), sizeof(value));
+  fuzzData.remove_prefix(sizeof(value));
+
+  std::memcpy(&doubleValue, fuzzData.data(), sizeof(doubleValue));
+  fuzzData.remove_prefix(sizeof(doubleValue));
+
+  size_t len = fuzzData.size() / sizeof(char16_t);
+  icu::UnicodeString fuzzstr(false, reinterpret_cast<const char16_t*>(fuzzData.data()), len);
+
+  icu::number::UnlocalizedNumberFormatter unf = icu::number::NumberFormatter::forSkeleton(
+      fuzzstr, status);
+
+  icu::number::LocalizedNumberFormatter nf = unf.locale(locale);
+
+  status = U_ZERO_ERROR;
+  nf.formatInt(value, status);
+
+  status = U_ZERO_ERROR;
+  nf.formatDouble(doubleValue, status);
+  return 0;
+}