while(XH >= 7 || (XF >=5 && i >= 0 ) || (XD1 >=30) || (XF <= -8) ) { adc_value[4] = adc_get(ADC0, ADC_CH_15); adc_value[1] = adc_get(ADC0, ADC_CH_11); adc_value[3] = adc_get(ADC0, ADC_CH_13); XH =( ( adc_value[3]/100 ) - ( adc_value[1]/100 ) ); XD = (adc_value[4]/100); XD1 = (adc_value[3]/100); i = ( ( adc_value[4]/100 ) - ( adc_value[3]/100 ) ); if( (XD >= 12 ) || (i >= 3) || XD1 >=30 ) { adc_value[4] = adc_get(ADC0, ADC_CH_15); adc_value[1] = adc_get(ADC0, ADC_CH_11); adc_value[3] = adc_get(ADC0, ADC_CH_13); XH =( ( adc_value[3]/100 ) - ( adc_value[1]/100 ) ); XD = (adc_value[4]/100); XD1 = (adc_value[3]/100); i = ( ( adc_value[4]/100 ) - ( adc_value[3]/100 ) ); car_forward(); } if(XH < 0 || XF <= -8) { adc_value[4] = adc_get(ADC0, ADC_CH_15); adc_value[1] = adc_get(ADC0, ADC_CH_11); adc_value[3] = adc_get(ADC0, ADC_CH_13); XH =( ( adc_value[3]/100 ) - ( adc_value[1]/100 ) ); XD = (adc_value[4]/100); XD1 = (adc_value[3]/100); i = ( ( adc_value[4]/100 ) - ( adc_value[3]/100 ) ); PID1(); } }

以下是可能的优化建议：

1. 尽量避免在循环内部重复读取传感器数据，尤其是当这些数据在循环内部不会发生变化时。可以将读取传感器数据的代码移到循环外部或者只在必要的情况下进行读取。

2. 可以将重复的代码抽象为函数，以减少代码重复和提高代码可读性。

3. 考虑使用更高效的控制语句，例如 switch 语句，来替换多个 if 语句。

4. 如果有可能，可以使用硬件加速来提高代码执行效率，例如使用 DMA 或者定时器来采集传感器数据。

5. 尽量减少循环内部的计算和运算，可以考虑将一些计算移到循环外部或者使用更高效的算法。

6. 如果需要更高的运算速度，可以考虑使用更快的处理器或者使用并行处理技术。

相关问题

基于Feistel结构用C语言编写一个分组密码代码。要求： 1、分组长度 = 128 bit 2、主密钥长度 >= 128 bit 3、轮数 >= 8 轮函数的设计要用到LFSR

好的，我可以给你提供一个基于Feistel结构的分组密码的C语言实现代码。以下是代码实现：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#define BLOCK_SIZE 16 // 分组长度为128 bit，即16字节
#define KEY_SIZE 16 // 主密钥长度为128 bit，即16字节
#define ROUNDS 8 // 轮数为8轮
#define LFSR_TAPS 0x168 // LFSR多项式为x^8 + x^6 + x^5 + x^4 + 1

// S盒
const unsigned char s_box[256] = {
    0x63, 0x7C, 0x77, 0x7B, 0xF2, 0x6B, 0x6F, 0xC5, 0x30, 0x01, 0x67, 0x2B, 0xFE, 0xD7, 0xAB, 0x76,
    0xCA, 0x82, 0xC9, 0x7D, 0xFA, 0x59, 0x47, 0xF0, 0xAD, 0xD4, 0xA2, 0xAF, 0x9C, 0xA4, 0x72, 0xC0,
    0xB7, 0xFD, 0x93, 0x26, 0x36, 0x3F, 0xF7, 0xCC, 0x34, 0xA5, 0xE5, 0xF1, 0x71, 0xD8, 0x31, 0x15,
    0x04, 0xC7, 0x23, 0xC3, 0x18, 0x96, 0x05, 0x9A, 0x07, 0x12, 0x80, 0xE2, 0xEB, 0x27, 0xB2, 0x75,
    0x09, 0x83, 0x2C, 0x1A, 0x1B, 0x6E, 0x5A, 0xA0, 0x52, 0x3B, 0xD6, 0xB3, 0x29, 0xE3, 0x2F, 0x84,
    0x53, 0xD1, 0x00, 0xED, 0x20, 0xFC, 0xB1, 0x5B, 0x6A, 0xCB, 0xBE, 0x39, 0x4A, 0x4C, 0x58, 0xCF,
    0xD0, 0xEF, 0xAA, 0xFB, 0x43, 0x4D, 0x33, 0x85, 0x45, 0xF9, 0x02, 0x7F, 0x50, 0x3C, 0x9F, 0xA8,
    0x51, 0xA3, 0x40, 0x8F, 0x92, 0x9D, 0x38, 0xF5, 0xBC, 0xB6, 0xDA, 0x21, 0x10, 0xFF, 0xF3, 0xD2,
    0xCD, 0x0C, 0x13, 0xEC, 0x5F, 0x97, 0x44, 0x17, 0xC4, 0xA7, 0x7E, 0x3D, 0x64, 0x5D, 0x19, 0x73,
    0x60, 0x81, 0x4F, 0xDC, 0x22, 0x2A, 0x90, 0x88, 0x46, 0xEE, 0xB8, 0x14, 0xDE, 0x5E, 0x0B, 0xDB,
    0xE0, 0x32, 0x3A, 0x0A, 0x49, 0x06, 0x24, 0x5C, 0xC2, 0xD3, 0xAC, 0x62, 0x91, 0x95, 0xE4, 0x79,
    0xE7, 0xC8, 0x37, 0x6D, 0x8D, 0xD5, 0x4E, 0xA9, 0x6C, 0x56, 0xF4, 0xEA, 0x65, 0x7A, 0xAE, 0x08,
    0xBA, 0x78, 0x25, 0x2E, 0x1C, 0xA6, 0xB4, 0xC6, 0xE8, 0xDD, 0x74, 0x1F, 0x4B, 0xBD, 0x8B, 0x8A,
    0x70, 0x3E, 0xB5, 0x66, 0x48, 0x03, 0xF6, 0x0E, 0x61, 0x35, 0x57, 0xB9, 0x86, 0xC1, 0x1D, 0x9E,
    0xE1, 0xF8, 0x98, 0x11, 0x69, 0xD9, 0x8E, 0x94, 0x9B, 0x1E, 0x87, 0xE9, 0xCE, 0x55, 0x28, 0xDF,
    0x8C, 0xA1, 0x89, 0x0D, 0xBF, 0xE6, 0x42, 0x68, 0x41, 0x99, 0x2D, 0x0F, 0xB0, 0x54, 0xBB, 0x16
};

// 加密函数
void encrypt(const unsigned char *in, const unsigned char *key, unsigned char *out)
{
    unsigned char left[BLOCK_SIZE/2], right[BLOCK_SIZE/2], temp[BLOCK_SIZE/2];
    unsigned int lfsr = 0xACE1; // LFSR初始值
    unsigned char round_key[BLOCK_SIZE/2], lfsr_key[BLOCK_SIZE/2];

    // 将明文分成两半
    memcpy(left, in, BLOCK_SIZE/2);
    memcpy(right, in + BLOCK_SIZE/2, BLOCK_SIZE/2);

    // 主密钥扩展
    memcpy(round_key, key, BLOCK_SIZE/2);
    memcpy(lfsr_key, key + BLOCK_SIZE/2, BLOCK_SIZE/2);

    // 迭代加密
    for (int i = 0; i < ROUNDS; i++) {
        // 生成轮密钥
        for (int j = 0; j < BLOCK_SIZE/2; j++) {
            round_key[j] ^= lfsr_key[j];
        }

        // 线性变换
        for (int j = 0; j < BLOCK_SIZE/2; j++) {
            lfsr = (lfsr >> 1) ^ (-(lfsr & 1u) & LFSR_TAPS); // LFSR生成伪随机数
            temp[j] = right[j] ^ (lfsr >> 8); // 取高8位与right异或
        }

        // 非线性变换
        for (int j = 0; j < BLOCK_SIZE/2; j++) {
            right[j] = s_box[temp[j]];
        }

        // 异或操作
        for (int j = 0; j < BLOCK_SIZE/2; j++) {
            temp[j] = left[j] ^ right[j];
        }

        // 交换左右两半
        memcpy(left, right, BLOCK_SIZE/2);
        memcpy(right, temp, BLOCK_SIZE/2);

        // 更新LFSR密钥
        memcpy(lfsr_key, round_key, BLOCK_SIZE/2);
        memcpy(round_key, key + (i+2)*BLOCK_SIZE/2, BLOCK_SIZE/2);
    }

    // 将左右两半交换
    memcpy(out, right, BLOCK_SIZE/2);
    memcpy(out + BLOCK_SIZE/2, left, BLOCK_SIZE/2);
}

// 解密函数
void decrypt(const unsigned char *in, const unsigned char *key, unsigned char *out)
{
    unsigned char left[BLOCK_SIZE/2], right[BLOCK_SIZE/2], temp[BLOCK_SIZE/2];
    unsigned int lfsr = 0xACE1;
    unsigned char round_key[BLOCK_SIZE/2], lfsr_key[BLOCK_SIZE/2];

    // 将密文分成两半
    memcpy(right, in, BLOCK_SIZE/2);
    memcpy(left, in + BLOCK_SIZE/2, BLOCK_SIZE/2);

    // 主密钥扩展
    memcpy(round_key, key + (ROUNDS+1)*BLOCK_SIZE/2, BLOCK_SIZE/2);
    memcpy(lfsr_key, key + ROUNDS*BLOCK_SIZE/2, BLOCK_SIZE/2);

    // 迭代解密
    for (int i = ROUNDS-1; i >= 0; i--) {
        // 生成轮密钥
        for (int j = 0; j < BLOCK_SIZE/2; j++) {
            round_key[j] ^= lfsr_key[j];
        }

        // 线性变换
        for (int j = 0; j < BLOCK_SIZE/2; j++) {
            lfsr = (lfsr >> 1) ^ (-(lfsr & 1u) & LFSR_TAPS);
            temp[j] = right[j] ^ (lfsr >> 8);
        }

        // 非线性变换
        for (int j = 0; j < BLOCK_SIZE/2; j++) {
            right[j] = s_box[temp[j]];
        }

        // 异或操作
        for (int j = 0; j < BLOCK_SIZE/2; j++) {
            temp[j] = left[j] ^ right[j];
        }

        // 交换左右两半
        memcpy(left, right, BLOCK_SIZE/2);
        memcpy(right, temp, BLOCK_SIZE/2);

        // 更新LFSR密钥
        memcpy(lfsr_key, round_key, BLOCK_SIZE/2);
        memcpy(round_key, key + (i+1)*BLOCK_SIZE/2, BLOCK_SIZE/2);
    }

    // 将左右两半交换
    memcpy(out, right, BLOCK_SIZE/2);
    memcpy(out + BLOCK_SIZE/2, left, BLOCK_SIZE/2);
}

int main()
{
    unsigned char in[BLOCK_SIZE] = {0x12, 0x34, 0x56, 0x78, 0x9A, 0xBC, 0xDE, 0xF0, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88}; // 明文
    unsigned char key[2*KEY_SIZE] = {0}; // 主密钥和LFSR密钥
    unsigned char out[BLOCK_SIZE] = {0}; // 密文

    // 生成主密钥和LFSR密钥
    srand((unsigned int)time(NULL));
    for (int i = 0; i < 2*KEY_SIZE; i++) {
        key[i] = rand() % 256;
    }

    // 输出主密钥和明文
    printf("Key: ");
    for (int i = 0; i < 2*KEY_SIZE; i++) {
        printf("%02x", key[i]);
    }
    printf("\n");
    printf("Plaintext: ");
    for (int i = 0; i < BLOCK_SIZE; i++) {
        printf("%02x", in[i]);
    }
    printf("\n");

    // 加密
    encrypt(in, key, out);
    printf("Ciphertext: ");
    for (int i = 0; i < BLOCK_SIZE; i++) {
        printf("%02x", out[i]);
    }
    printf("\n");

    // 解密
    decrypt(out, key, in);
    printf("Decrypted text: ");
    for (int i = 0; i < BLOCK_SIZE; i++) {
        printf("%02x", in[i]);
    }
    printf("\n");

    return 0;
}

在这个代码中，我使用了一个LFSR来生成伪随机数，进行线性变换。由于C语言中没有位运算符的布尔版本，我使用了“-”符号来进行逻辑运算。具体来说，-x的值为1，当x为0时，否则为0。

在主函数中，我生成了一个随机的主密钥和LFSR密钥，然后对明文进行加密和解密操作，并输出结果。需要注意的是，由于Feistel结构是一种迭代加密算法，所以加密和解密的过程是类似的，只是轮密钥的使用顺序有所不同。

希望这个代码可以对你有所帮助！

将这个crc校验加到Android studio中3Crc16Ccitt校验 unsigned short Crc16Ccitt(u8 *q, unsigned int len) { static unsigned short ccitt_table[256] = { 0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5, 0x60C6, 0x70E7, 0x8108, 0x9129, 0xA14A, 0xB16B, 0xC18C, 0xD1AD, 0xE1CE, 0xF1EF, 0x1231, 0x0210, 0x3273, 0x2252, 0x52B5, 0x4294, 0x72F7, 0x62D6, 0x9339, 0x8318, 0xB37B, 0xA35A, 0xD3BD, 0xC39C, 0xF3FF, 0xE3DE, 0x2462, 0x3443, 0x0420, 0x1401, 0x64E6, 0x74C7, 0x44A4, 0x5485, 0xA56A, 0xB54B, 0x8528, 0x9509, 0xE5EE, 0xF5CF, 0xC5AC, 0xD58D, 0x3653, 0x2672, 0x1611, 0x0630, 0x76D7, 0x66F6, 0x5695, 0x46B4, 0xB75B, 0xA77A, 0x9719, 0x8738, 0xF7DF, 0xE7FE, 0xD79D, 0xC7BC, 0x48C4, 0x58E5, 0x6886, 0x78A7, 0x0840, 0x1861, 0x2802, 0x3823, 0xC9CC, 0xD9ED, 0xE98E, 0xF9AF, 0x8948, 0x9969, 0xA90A, 0xB92B, 0x5AF5, 0x4AD4, 0x7AB7, 0x6A96, 0x1A71, 0x0A50, 0x3A33, 0x2A12, 0xDBFD, 0xCBDC, 0xFBBF, 0xEB9E, 0x9B79, 0x8B58, 0xBB3B, 0xAB1A,0x6CA6, 0x7C87, 0x4CE4, 0x5CC5, 0x2C22, 0x3C03, 0x0C60, 0x1C41,0xEDAE, 0xFD8F, 0xCDEC, 0xDDCD, 0xAD2A, 0xBD0B, 0x8D68, 0x9D49,0x7E97, 0x6EB6, 0x5ED5, 0x4EF4, 0x3E13, 0x2E32, 0x1E51, 0x0E70,0xFF9F, 0xEFBE, 0xDFDD, 0xCFFC, 0xBF1B, 0xAF3A, 0x9F59, 0x8F78,0x9188, 0x81A9, 0xB1CA, 0xA1EB, 0xD10C, 0xC12D, 0xF14E, 0xE16F,0x1080, 0x00A1, 0x30C2, 0x20E3, 0x5004, 0x4025, 0x7046, 0x6067,0x83B9, 0x9398, 0xA3FB, 0xB3DA, 0xC33D, 0xD31C, 0xE37F, 0xF35E,0x02B1, 0x1290, 0x22F3, 0x32D2, 0x4235, 0x5214, 0x6277, 0x7256,0xB5EA, 0xA5CB, 0x95A8, 0x8589, 0xF56E, 0xE54F, 0xD52C, 0xC50D,0x34E2, 0x24C3, 0x14A0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,0xA7DB, 0xB7FA, 0x8799, 0x97B8, 0xE75F, 0xF77E, 0xC71D, 0xD73C,0x26D3, 0x36F2, 0x0691, 0x16B0, 0x6657, 0x7676, 0x4615, 0x5634,0xD94C, 0xC96D, 0xF90E, 0xE92F, 0x99C8, 0x89E9, 0xB98A, 0xA9AB,0x5844, 0x4865, 0x7806, 0x6827, 0x18C0, 0x08E1, 0x3882, 0x28A3,0xCB7D, 0xDB5C, 0xEB3F, 0xFB1E, 0x8BF9, 0x9BD8, 0xABBB, 0xBB9A,0x4A75, 0x5A54, 0x6A37, 0x7A16, 0x0AF1, 0x1AD0, 0x2AB3, 0x3A92,0xFD2E, 0xED0F, 0xDD6C, 0xCD4D, 0xBDAA, 0xAD8B, 0x9DE8, 0x8DC9,0x7C26, 0x6C07, 0x5C64, 0x4C45, 0x3CA2, 0x2C83, 0x1CE0, 0x0CC1,0xEF1F, 0xFF3E, 0xCF5D, 0xDF7C, 0xAF9B, 0xBFBA, 0x8FD9, 0x9FF8,0x6E17, 0x7E36, 0x4E55, 0x5E74, 0x2E93, 0x3EB2, 0x0ED1, 0x1EF0 }; unsigned short crc = 0; while (len-- > 0) crc = ccitt_table[(crc >> 8 ^ *q++) & 0xff] ^ (crc << 8); return crc; }

您可以将这段代码添加到您的 Android Studio 项目中，具体步骤如下：

1. 在您的项目中创建一个 Java 类，例如命名为 `CrcUtils`。

2. 将上述 `Crc16Ccitt` 函数的代码复制到 `CrcUtils` 类中。

3. 在您的代码中使用 `CrcUtils.Crc16Ccitt` 函数来计算 CRC 校验值。例如：

byte[] data = new byte[] {0x12, 0x34, 0x56};
int crc = CrcUtils.Crc16Ccitt(data, data.length);

其中，`data` 是待计算 CRC 校验值的数据，`crc` 是计算得到的 CRC 校验值。

请注意，如果您的项目中已经存在一个名为 `CrcUtils` 的 Java 类，则需要在命名时使用其他名称，以避免名称冲突。