Shamelessly copy Josiah

source/lib/json/tests/thirdparty/Fuzzer/test/SwapCmpTest.cpp

@@ -0,0 +1,34 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// The fuzzer must find several constants with swapped bytes.
+#include <cstdint>
+#include <cstdlib>
+#include <cstring>
+#include <cstdio>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Size < 14) return 0;
+  uint64_t x = 0;
+  uint32_t y = 0;
+  uint16_t z = 0;
+  memcpy(&x, Data, sizeof(x));
+  memcpy(&y, Data + Size / 2, sizeof(y));
+  memcpy(&z, Data + Size - sizeof(z), sizeof(z));
+
+  x = __builtin_bswap64(x);
+  y = __builtin_bswap32(y);
+  z = __builtin_bswap16(z);
+
+  if (x == 0x46555A5A5A5A5546ULL &&
+      z == 0x4F4B &&
+      y == 0x66757A7A &&
+      true
+      ) {
+    if (Data[Size - 3] == 'z') {
+      fprintf(stderr, "BINGO; Found the target\n");
+      exit(1);
+    }
+  }
+  return 0;
+}