这个是什么搜索算法

只看该作者 · 2019-7-20 10:40

void searchfile(const char *filename, int fd, const unsigned char *value, const unsigned char *mask, int len)
{
off_t offset = 0;
unsigned char buf[1024];

len--;

while (1)
{
      int r;

      memmove(buf, buf + sizeof(buf) - len, len);
      r = read(fd, buf + len, sizeof(buf) - len);

      if (r < 0)
      {
         perror("read");
         return;
      } else if (!r)
         return;

      int o, i;
      for (o = offset ? 0 : len; o < r; ++o)
      {
         for (i = 0; i <= len; ++i)
            if ((buf[o + i] & mask[i]) != value[i])
                  break;
         if (i > len)
         {
            unsigned long long pos = (unsigned long long)(offset + o - len);
            printf("%s: %08llx\n", filename, pos);
            if (bytes_before || bytes_after)
                  dump_context(fd, pos);
         }
      }

      offset += r;

}
}