Add harness

.github/workflows/mayhem.yml

@@ -59,7 +59,8 @@ jobs:
       fail-fast: false
       matrix:
         mayhemfile:
-          - mayhem/Mayhemfile
+          - mayhem/Mayhemfile_floor_log2i
+          - mayhem/Mayhemfile_basisu
 
     steps:
       - uses: actions/checkout@v3

mayhem/Dockerfile

@@ -1,13 +1,15 @@
 FROM --platform=linux/amd64 ubuntu:22.04 as builder
 
 RUN apt-get update
-RUN DEBIAN_FRONTEND=noninteractive apt-get install -y build-essential cmake
+RUN DEBIAN_FRONTEND=noninteractive apt-get install -y build-essential cmake clang
 
 COPY . /repo
 WORKDIR /repo/build
 RUN cmake .. -DCMAKE_INSTALL_PREFIX=/install
 RUN make -j8
 RUN make install
+RUN clang++ /repo/mayhem/fuzz_floor_log2i.cpp -fsanitize=fuzzer,address -I /repo/transcoder/ -o /fuzz
 
 FROM ubuntu:22.04 as package
 COPY --from=builder /install /install
+COPY --from=builder /fuzz /fuzz_floor_log2i

mayhem/Mayhemfile

@@ -1,7 +1,6 @@
 project: basis-universal
-target: basisu
+target: floor-log2i
 
 cmds:
-  - cmd: /install/bin/basisu @@ -validate
-    env:
-      DISABLE_SMOKETEST: '1'
+  - cmd: /fuzz_floor_log2i
+    libfuzzer: true

mayhem/Mayhemfile_basisu

@@ -0,0 +1,7 @@
+project: basis-universal
+target: basisu
+
+cmds:
+  - cmd: /install/bin/basisu @@ -validate
+    env:
+      DISABLE_SMOKETEST: '1'

mayhem/fuzz_floor_log2i.cpp

@@ -0,0 +1,15 @@
+#include <stdint.h>
+#include <stdio.h>
+#include <climits>
+
+#include <fuzzer/FuzzedDataProvider.h>
+#include "basisu_containers.h"
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
+{
+    FuzzedDataProvider provider(data, size);
+
+    uint32_t v = provider.ConsumeIntegral<uint32_t>();
+    basisu::helpers::floor_log2i(v);
+    return 0;
+}