oss-fuzz: Add fuzzing headers

These includes header files were taken from:

    https://github.com/guidovranken/fuzzing-headers.git

with some minor changes required to make them compile cleanly
with the extra compiler warning flags used by the FLAC build
system.

oss-fuzz/fuzzing/datasource/datasource.hpp

@@ -0,0 +1,167 @@
+#pragma once
+
+#include <fuzzing/exception.hpp>
+#include <fuzzing/types.hpp>
+#include <cstddef>
+#include <cstdint>
+#include <cstdlib>
+#include <cstring>
+#include <string>
+#include <vector>
+
+namespace fuzzing {
+namespace datasource  {
+
+class Base
+{
+    protected:
+        virtual std::vector<uint8_t> get(const size_t min, const size_t max, const uint64_t id = 0) = 0;
+    public:
+        Base(void) = default;
+        virtual ~Base(void) = default;
+
+        template<class T> T Get(const uint64_t id = 0);
+        uint16_t GetChoice(const uint64_t id = 0);
+        std::vector<uint8_t> GetData(const uint64_t id, const size_t min = 0, const size_t max = 0);
+        template <class T> std::vector<T> GetVector(const uint64_t id = 0);
+
+        class OutOfData : public fuzzing::exception::FlowException {
+            public:
+                OutOfData() = default;
+        };
+
+        class DeserializationFailure : public fuzzing::exception::FlowException {
+            public:
+                DeserializationFailure() = default;
+        };
+};
+
+#ifndef FUZZING_HEADERS_NO_IMPL
+template<class T> T Base::Get(const uint64_t id)
+{
+    T ret;
+    const auto v = get(sizeof(ret), sizeof(ret), id);
+    memcpy(&ret, v.data(), sizeof(ret));
+    return ret;
+}
+
+template <> bool Base::Get<bool>(const uint64_t id)
+{
+    uint8_t ret;
+    const auto v = get(sizeof(ret), sizeof(ret), id);
+    memcpy(&ret, v.data(), sizeof(ret));
+    return (ret % 2) ? true : false;
+}
+
+template <> std::string Base::Get<std::string>(const uint64_t id)
+{
+    auto data = GetData(id);
+    return std::string(data.data(), data.data() + data.size());
+}
+
+template <> std::vector<std::string> Base::Get<std::vector<std::string>>(const uint64_t id)
+{
+    std::vector<std::string> ret;
+    while ( true ) {
+        auto data = GetData(id);
+        ret.push_back( std::string(data.data(), data.data() + data.size()) );
+        if ( Get<bool>(id) == false ) {
+            break;
+        }
+    }
+    return ret;
+}
+
+uint16_t Base::GetChoice(const uint64_t id)
+{
+    return Get<uint16_t>(id);
+}
+
+std::vector<uint8_t> Base::GetData(const uint64_t id, const size_t min, const size_t max)
+{
+    return get(min, max, id);
+}
+
+
+template <> types::String<> Base::Get<types::String<>>(const uint64_t id) {
+    const auto data = GetData(id);
+    types::String<> ret(data.data(), data.size());
+    return ret;
+}
+
+template <> types::Data<> Base::Get<types::Data<>>(const uint64_t id) {
+    const auto data = GetData(id);
+    types::Data<> ret(data.data(), data.size());
+    return ret;
+}
+
+template <class T>
+std::vector<T> Base::GetVector(const uint64_t id) {
+    std::vector<T> ret;
+
+    while ( Get<bool>(id) == true ) {
+        ret.push_back( Get<T>(id) );
+    }
+
+    return ret;
+}
+#endif
+
+class Datasource : public Base
+{
+    private:
+        const uint8_t* data;
+        const size_t size;
+        size_t idx;
+        size_t left;
+        std::vector<uint8_t> get(const size_t min, const size_t max, const uint64_t id = 0) override;
+
+		// Make copy constructor and assignment opertator private.
+        Datasource(const Datasource &) : data(0), size(0), idx(0), left(0) {}
+        Datasource& operator=(const Datasource &) { return *this; }
+    public:
+        Datasource(const uint8_t* _data, const size_t _size);
+};
+
+#ifndef FUZZING_HEADERS_NO_IMPL
+Datasource::Datasource(const uint8_t* _data, const size_t _size) :
+    Base(), data(_data), size(_size), idx(0), left(size)
+{
+}
+
+std::vector<uint8_t> Datasource::get(const size_t min, const size_t max, const uint64_t id) {
+    (void)id;
+
+    uint32_t getSize;
+    if ( left < sizeof(getSize) ) {
+        throw OutOfData();
+    }
+    memcpy(&getSize, data + idx, sizeof(getSize));
+    idx += sizeof(getSize);
+    left -= sizeof(getSize);
+
+    if ( getSize < min ) {
+        getSize = min;
+    }
+    if ( max && getSize > max ) {
+        getSize = max;
+    }
+
+    if ( left < getSize ) {
+        throw OutOfData();
+    }
+
+    std::vector<uint8_t> ret(getSize);
+
+    if ( getSize > 0 ) {
+        memcpy(ret.data(), data + idx, getSize);
+    }
+    idx += getSize;
+    left -= getSize;
+
+    return ret;
+}
+#endif
+
+} /* namespace datasource */
+} /* namespace fuzzing */

oss-fuzz/fuzzing/datasource/id.hpp

@@ -0,0 +1,52 @@
+#pragma once
+
+#include <stdio.h>
+#include <stdint.h>
+#include <utility>
+#include <map>
+
+namespace fuzzing {
+namespace datasource  {
+
+/* From: https://gist.github.com/underscorediscovery/81308642d0325fd386237cfa3b44785c */
+inline uint64_t hash_64_fnv1a(const void* key, const uint64_t len) {
+
+    const char* data = (char*)key;
+    uint64_t hash = 0xcbf29ce484222325;
+    uint64_t prime = 0x100000001b3;
+
+    for(uint64_t i = 0; i < len; ++i) {
+        uint8_t value = data[i];
+        hash = hash ^ value;
+        hash *= prime;
+    }
+
+    return hash;
+
+} //hash_64_fnv1a
+
+// FNV1a c++11 constexpr compile time hash functions, 32 and 64 bit
+// str should be a null terminated string literal, value should be left out 
+// e.g hash_32_fnv1a_const("example")
+// code license: public domain or equivalent
+// post: https://notes.underscorediscovery.com/constexpr-fnv1a/
+
+constexpr uint32_t val_32_const = 0x811c9dc5;
+constexpr uint32_t prime_32_const = 0x1000193;
+constexpr uint64_t val_64_const = 0xcbf29ce484222325;
+constexpr uint64_t prime_64_const = 0x100000001b3;
+
+
+inline constexpr uint64_t ID(const char* const str, const uint64_t value = val_64_const) noexcept {
+    auto ret = (str[0] == '\0') ? value : ID(&str[1], (value ^ uint64_t(str[0])) * prime_64_const);
+    return ret;
+}
+
+inline constexpr std::pair<const char*, uint64_t> IDPair(const char* const str, const uint64_t value = val_64_const) noexcept {
+    return {str, ID(str, value)};
+}
+
+using IDMap = std::map<const char*, uint64_t>;
+
+} /* namespace datasource */
+} /* namespace fuzzing */