C语言中的CRC32算法/实现，无查找表且具有公共许可证

我试图用C实现一个CRC32算法，它不使用查找表（我需要在没有足够内存的引导加载程序中使用它）。是否有一个具有公共许可证的可用解决方案？

快速搜索。我找不到这些代码片段的许可证

以下各项应能完成这项工作：

// ----------------------------- crc32b --------------------------------

/* This is the basic CRC-32 calculation with some optimization but no
table lookup. The the byte reversal is avoided by shifting the crc reg
right instead of left and by using a reversed 32-bit word to represent
the polynomial.
   When compiled to Cyclops with GCC, this function executes in 8 + 72n
instructions, where n is the number of bytes in the input message. It
should be doable in 4 + 61n instructions.
   If the inner loop is strung out (approx. 5*8 = 40 instructions),
it would take about 6 + 46n instructions. */

unsigned int crc32b(unsigned char *message) {
   int i, j;
   unsigned int byte, crc, mask;

   i = 0;
   crc = 0xFFFFFFFF;
   while (message[i] != 0) {
      byte = message[i];            // Get next byte.
      crc = crc ^ byte;
      for (j = 7; j >= 0; j--) {    // Do eight times.
         mask = -(crc & 1);
         crc = (crc >> 1) ^ (0xEDB88320 & mask);
      }
      i = i + 1;
   }
   return ~crc;
}

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准确地说，您是在寻找算法还是实现？对不起，您完全正确；我更喜欢一个实现，但是一个算法就可以了。