whitelisted x86_32 from boot logo detections

Author: Requiem

auxiliary/boot_logo_hasher.cpp

@@ -28,33 +28,50 @@
 
 static inline uint32_t crc32c_bmp(const char* filename) {
     std::ifstream in{ filename, std::ios::binary | std::ios::ate };
+    if (!in) return 0;
     auto size = in.tellg();
-    in.seekg(0);
-    std::vector<uint8_t> buf(size);
+    in.seekg(0, std::ios::beg);
+
+    std::vector<uint8_t> buf(static_cast<size_t>(size));
     in.read(reinterpret_cast<char*>(buf.data()), size);
 
-    // BMP offset at bytes 10–13
+    // offset in BMP header (bytes 10–13)
     uint32_t offset = *reinterpret_cast<uint32_t*>(buf.data() + 10);
     uint8_t* bmp = buf.data() + offset;
-    size_t len = buf.size() - offset;
+    size_t  len = buf.size() - offset;
 
-    uint64_t crcReg = 0xFFFFFFFFull;
-    size_t qwords = len / 8;
-    auto ptr = reinterpret_cast<uint64_t*>(bmp);
-    for (size_t i = 0; i < qwords; ++i)
-        crcReg = _mm_crc32_u64(crcReg, ptr[i]);
+#if defined(_M_X64) || defined(__x86_64__)
+    uint64_t crc64 = 0xFFFFFFFFull;
+    auto     q64 = len / 8;
+    auto const* p64 = reinterpret_cast<uint64_t const*>(bmp);
+    for (size_t i = 0; i < q64; ++i)
+        crc64 = _mm_crc32_u64(crc64, p64[i]);
 
-    uint32_t crc = static_cast<uint32_t>(crcReg);
-    auto tail = reinterpret_cast<uint8_t*>(ptr + qwords);
+    uint32_t crc = static_cast<uint32_t>(crc64);
+    auto const* tail = reinterpret_cast<uint8_t const*>(p64 + q64);
     for (size_t i = 0, r = len & 7; i < r; ++i)
         crc = _mm_crc32_u8(crc, tail[i]);
+#else
+    uint32_t crc = 0xFFFFFFFFu;
+    auto     q32 = len / 4;
+    auto const* p32 = reinterpret_cast<uint32_t const*>(bmp);
+    for (size_t i = 0; i < q32; ++i)
+        crc = _mm_crc32_u32(crc, p32[i]);
+
+    auto const* tail = reinterpret_cast<uint8_t const*>(p32 + q32);
+    for (size_t i = 0, r = len & 3; i < r; ++i)
+        crc = _mm_crc32_u8(crc, tail[i]);
+#endif
 
     return crc ^ 0xFFFFFFFFu;
 }
 
 int main(int argc, char** argv) {
     for (int i = 1; i < argc; ++i) {
         uint32_t h = crc32c_bmp(argv[i]);
-        std::cout << argv[i] << ": 0x" << std::hex << std::uppercase << h << "\n";
+        std::cout << argv[i]
+            << ": 0x" << std::hex << std::uppercase << h
+            << std::dec << "\n";
     }
+    return 0;
 }