将二进制文件读入C中的bool数组(Reading binary file into bool arrays in C)

将二进制文件读入C中的bool数组(Reading binary file into bool arrays in C)

我正在实施DES（与EBC）作为学校工作的一部分。 我正在使用来自<stdbool.h>布尔数组bool[64]作为块。 该阵列每个位使用1个字节（当我尝试使用memcpy for 64bits = 8个字节而不是64个字节时，我学到了很多东西）。 无论如何，如何进入位阵列？ 现在，我正在阅读一个未签名的长并转换它。 如下所示：

unsigned long buf; bool I[64], O[64]; int ctr = 0; while((ctr = fread(&buf, 1, 8, fin))>0) { dectobin(buf, I); encrypt(I, O); buf=bintodec(O); fwrite(&buf, 8, 1, fout); buf = 0; }

功能是：

void dectobin(unsigned long dec, bool bin[64]) { int i; for(i = 0; i< 64; i++) bin[i] = (dec>>(63-i)) & 1; } unsigned long bintodec(bool bin[64]) { unsigned long dec = 0; int i; for(i = 0; i < 64; i++) { dec <<= 1; dec |= (int)(bin[i]); } return dec; }

有一个更好的方法吗？

I am implementing DES (with EBC) as part of school work. I am using boolean arrays bool[64] from <stdbool.h> for the blocks. The array uses 1 byte for each bit (I learned this the hard way when I tried memcpy for 64bits=8 bytes instead of 64 bytes). Anyway, how to fread into the bit array? Right now, I'm reading into an unsigned long and converting it. Like below:

unsigned long buf; bool I[64], O[64]; int ctr = 0; while((ctr = fread(&buf, 1, 8, fin))>0) { dectobin(buf, I); encrypt(I, O); buf=bintodec(O); fwrite(&buf, 8, 1, fout); buf = 0; }

The functions are:

void dectobin(unsigned long dec, bool bin[64]) { int i; for(i = 0; i< 64; i++) bin[i] = (dec>>(63-i)) & 1; } unsigned long bintodec(bool bin[64]) { unsigned long dec = 0; int i; for(i = 0; i < 64; i++) { dec <<= 1; dec |= (int)(bin[i]); } return dec; }

Is there a better way to do this?

最满意答案

你不能直接在bool数组中找到位 （您必须读取字节并手动分配每个字节的每个8位）。

另一种解决方案，它也消耗更少的内存： 一组8个字符。 可以直接进行fread-ed，并通过二进制或/和＆|来访问这些位 如果你有一个char c和0到7之间的位数n： 将c中的位n设置为1：

c |= 1<<n;

将c中的位n设置为0：

c &= ~(1<<n);

检查c中的位n是否为1：

if(c & (1<<n))

You can´t directly fread bits in a bool array (you would have to read bytes and assign each 8 bits of each byte manually).

Another solution, which consumes less memory too: An array of 8 chars. Can be fread-ed directly, and the bits are accessed by binary Or/And & | If you have a char c and a bit number n between 0 and 7: Set bit n in c to 1:

c |= 1<<n;

Set bit n in c to 0:

c &= ~(1<<n);

Check if bit n in c is 1:

if(c & (1<<n))