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.

1 files changed, 52 insertions, 0 deletions

diff --git a/oss-fuzz/fuzzing/datasource/id.hpp b/oss-fuzz/fuzzing/datasource/id.hpp
new file mode 100644
index 00000000..3ba38d71
--- /dev/null
+++ b/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 */