Added fuzzer with oss-fuzz build file

tests/fuzzing/fuzzer.cpp

@@ -0,0 +1,43 @@
+#include <stdexcept>
+#include <unistd.h>
+
+#include <document.h>
+#include <valijson/adapters/rapidjson_adapter.hpp>
+#include <valijson/utils/rapidjson_utils.hpp>
+#include <valijson/schema.hpp>
+#include <valijson/schema_parser.hpp>
+
+using valijson::Schema;
+using valijson::SchemaParser;
+using valijson::adapters::RapidJsonAdapter;
+
+extern "C" int
+LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
+{
+    if(size<3) return 0;
+    char input_file[256];
+    sprintf(input_file, "/tmp/libfuzzer.json");
+    FILE *fp = fopen(input_file, "wb");
+    if (!fp)
+        return 0;
+    fwrite(data, size, 1, fp);
+    fclose(fp);
+
+    rapidjson::Document schemaDocument;
+    if (!valijson::utils::loadDocument(input_file, schemaDocument)) {
+        return 1;
+    }
+    
+    Schema schema;
+    SchemaParser parser;
+    RapidJsonAdapter schemaDocumentAdapter(schemaDocument);
+    try {
+        parser.populateSchema(schemaDocumentAdapter, schema);
+    } catch (std::exception &e) {
+        unlink(input_file);
+        return 1;
+    }
+
+    unlink(input_file);
+    return 1;
+}

tests/fuzzing/oss-fuzz-build.sh

@@ -0,0 +1,32 @@
+#!/bin/bash -eu
+
+# This line causes an abort which breaks fuzzing:
+sed -i '27d' include/valijson/utils/rapidjson_utils.hpp
+
+mkdir build
+cd build
+cmake 	-Dvalijson_BUILD_EXAMPLES=FALSE \
+	-Dvalijson_EXCLUDE_BOOST=TRUE \
+	..
+
+make -j$(nproc)
+
+cd ../tests/fuzzing
+
+find ../.. -name "*.o" -exec ar rcs fuzz_lib.a {} \;
+
+$CXX $CXXFLAGS -DVALIJSON_USE_EXCEPTIONS=1 \
+	-I/src/valijson/thirdparty/rapidjson-1.1.0/include \
+	-I/src/valijson/thirdparty/rapidjson-1.1.0/include/rapidjson \
+	-I/src/valijson/include \
+	-I/src/valijson/include/valijson \
+	-I/src/valijson/include/valijson/adapters \
+	-c fuzzer.cpp -o fuzzer.o
+
+$CXX $CXXFLAGS $LIB_FUZZING_ENGINE \
+	-DVALIJSON_USE_EXCEPTIONS=1 \
+	-rdynamic fuzzer.o \
+	-o $OUT/fuzzer fuzz_lib.a
+
+zip $OUT/fuzzer_seed_corpus.zip \
+	$SRC/valijson/doc/schema/draft-03.json