include crc32.hpp

src/dusk/randomizer/generator/utility/crc32.hpp

@@ -0,0 +1,34 @@
+#pragma once
+
+#include <array>
+
+namespace randomizer::utility {
+
+// Generates standard lookup table
+constexpr std::array<uint32_t, 256> generate_crc32_table() {
+    std::array<uint32_t, 256> table{};
+    for (uint32_t i = 0; i < 256; ++i) {
+        uint32_t ch = i;
+        for (size_t j = 0; j < 8; ++j) {
+            ch = (ch & 1) ? (0xEDB88320 ^ (ch >> 1)) : (ch >> 1);
+        }
+        table[i] = ch;
+    }
+    return table;
+}
+
+inline constexpr std::array<uint32_t, 256> crc32_table = generate_crc32_table();
+
+inline uint32_t crc32(const void* data, size_t length, uint32_t previous_crc = 0) {
+    const auto* bytes = static_cast<const uint8_t*>(data);
+    uint32_t crc = ~previous_crc;
+
+    for (size_t i = 0; i < length; ++i) {
+        auto index = static_cast<uint8_t>(crc ^ bytes[i]);
+        crc = (crc >> 8) ^ crc32_table[index];
+    }
+
+    return ~crc;
+}
+
+}