asset compression

implementations/main.cpp

@@ -19,6 +19,35 @@ import std;
 using namespace Crafter;
 namespace fs = std::filesystem;
 
+// CPU GDeflate roundtrip sanity test across the size boundaries from the
+// implementation plan. Returns 0 on pass, 1 on first byte-mismatch.
+static int RunCompressionRoundtrip() {
+    const std::array<std::size_t, 5> sizes = { 1, 65535, 65536, 65537, 16 * 1024 * 1024 };
+    std::mt19937_64 rng(0xC0FFEEu);
+    for (std::size_t n : sizes) {
+        std::vector<std::byte> input(n);
+        for (std::size_t i = 0; i < n; ++i) {
+            // Mix random bytes with a deterministic pattern so the codec is
+            // exercised on both compressible and noisy regions.
+            input[i] = static_cast<std::byte>((i * 0x9E3779B97F4A7C15ULL ^ rng()) & 0xFF);
+        }
+        std::array<std::span<const std::byte>, 1> streams = { std::span(input) };
+        Compression::CompressedBlob blob = Compression::CompressStreams(streams);
+        std::vector<std::byte> output(n);
+        std::array<std::span<std::byte>, 1> outputs = { std::span(output) };
+        Compression::DecompressCPU(blob, outputs);
+        if (output != input) {
+            std::cerr << "[FAIL] roundtrip size=" << n << "\n";
+            return 1;
+        }
+        std::cout << "[ok] size=" << n
+                  << " compressed=" << blob.bytes.size()
+                  << " ratio=" << (double(blob.bytes.size()) / double(n)) << "\n";
+    }
+    std::cout << "All roundtrips passed.\n";
+    return 0;
+}
+
 int main(int argc, char** argv) {
     // Parse arguments: crafter-asset <input_file> [output_file] [--format u8|f16]
     fs::path inputPath;
@@ -29,6 +58,9 @@ int main(int argc, char** argv) {
     std::vector<std::string> positional;
     for (int i = 1; i < argc; ++i) {
         std::string arg = argv[i];
+        if (arg == "--test-compression") {
+            return RunCompressionRoundtrip();
+        }
         if (arg == "--format" || arg == "-f") {
             if (i + 1 >= argc) {
                 std::cerr << "Error: --format requires a value (u8 or f16)\n";