https://www.newbie.pics/index.php/archives/53/

前面了解了mkimage 64字节的数据组成，现在进行解析

数据格式如下：

#define IH_NMLEN    32    /* Image Name Length        */
typedef struct image_header {
    __be32        ih_magic;    /* Image Header Magic Number    */
    __be32        ih_hcrc;    /* Image Header CRC Checksum    */
    __be32        ih_time;    /* Image Creation Timestamp    */
    __be32        ih_size;    /* Image Data Size        */
    __be32        ih_load;    /* Data     Load  Address        */
    __be32        ih_ep;        /* Entry Point Address        */
    __be32        ih_dcrc;    /* Image Data CRC Checksum    */
    uint8_t        ih_os;        /* Operating System        */
    uint8_t        ih_arch;    /* CPU architecture        */
    uint8_t        ih_type;    /* Image Type            */
    uint8_t        ih_comp;    /* Compression Type        */
    uint8_t        ih_name[IH_NMLEN];    /* Image Name        */
} image_header_t;

我们使用的是STM32，在app中已经附加了这64字节的数据，但这里的数据是大端格式，我们要转换成小段格式处理

伪代码

/*大端字节序转小端字节序*/
uint32_t my_ntohl(uint32_t netlong) {
    return ((netlong & 0xFF000000) >> 24) |
           ((netlong & 0x00FF0000) >> 8) |
           ((netlong & 0x0000FF00) << 8) |
           ((netlong & 0x000000FF) << 24);
}



/*打印头部信息*/
void printf_app_head(image_header_t *pimage_header_t , char *name){
    
    if (strcmp(name, APP1_FILE_NAME) == 0) {
        printf("| app1 head information     \r\n");
    } else if (strcmp(name, APP2_FILE_NAME) == 0) {
        printf("| app2 head information     \r\n");
    }

    # if(0)   //用于调试
   printf("ih_magic in hexadecimal: 0x%x\r\n", my_ntohl(pimage_header_t->ih_magic));
     printf("ih_hcrc in hexadecimal: 0x%x\r\n", my_ntohl(pimage_header_t->ih_hcrc));
     printf("ih_time in hexadecimal: 0x%x\r\n", my_ntohl(pimage_header_t->ih_time));
     printf("ih_size in hexadecimal: 0x%x\r\n", my_ntohl(pimage_header_t->ih_size));
     printf("ih_load in hexadecimal: 0x%x\r\n", my_ntohl(pimage_header_t->ih_load));
     printf("ih_ep in hexadecimal: 0x%x\r\n", my_ntohl(pimage_header_t->ih_ep));
     printf("ih_dcrc in hexadecimal: 0x%x\r\n", my_ntohl(pimage_header_t->ih_dcrc));
    
     printf("ih_os in hexadecimal: 0x%x\r\n",   pimage_header_t->ih_os);
     printf("ih_arch in hexadecimal: 0x%x\r\n", pimage_header_t->ih_arch);
     printf("ih_type in hexadecimal: 0x%x\r\n", pimage_header_t->ih_type);
     printf("ih_comp in hexadecimal: 0x%x\r\n", pimage_header_t->ih_comp);
     printf("| ih_name is: ");
   for (int i = 0; i < IH_NMLEN; i++) 
     printf("%c", (unsigned char)pimage_header_t->ih_name[i]);  printf("\r\n");
    #else
     printf("| ih_name   |");
   for (int i = 0; i < IH_NMLEN; i++) 
     printf("%c", (unsigned char)pimage_header_t->ih_name[i]);  printf("\r\n");
    
     printf("| ih_size   |  %u Byte    \r\n", my_ntohl(pimage_header_t->ih_size));
     printf("| ih_load   |  0x%x       \r\n", my_ntohl(pimage_header_t->ih_load));
     printf("| ih_ep     |  0x%x       \r\n", my_ntohl(pimage_header_t->ih_ep));
     printf("| ih_hcrc   |  0x%x       \r\n", my_ntohl(pimage_header_t->ih_hcrc)); //头部crc
     printf("| ih_dcrc   |  0x%x       \r\n", my_ntohl(pimage_header_t->ih_dcrc)); //app crc32
     printf("\r\n");
    #endif
 
}
    


void get_app_head(image_header_t *app_image_header_t, char *app_name) {
    int bytesRead = 0;
    //读取头部64字节
    bytesRead = readFileContent(app_name, app_image_header_t, sizeof(image_header_t), 0);

    if (bytesRead = sizeof(image_header_t)) {
        //打印该头部结构体信息
         printf_app_head(app_image_header_t, app_name);
            
    }
}


//使用如下
image_header_t app1_image_header_t;
image_header_t app2_image_header_t;

get_app_head(&app1_image_header_t,APP1_FILE_NAME);
get_app_head(&app2_image_header_t,APP2_FILE_NAME);