Question

我有两个C结构需要保存到DataFlash（AT45）的内存块中。我可以通过以下方式轻松保存一个这样的结构：

For One Struct

struct_name a;
struct_name * data;
data = &a;
struct_name read_buffer;

flash_write( &write_address, (uint8_t *)data, sizeof(a) ); //pack
flash_read( &read_address, (uint8_t *)read_buffer, sizeof(a) ); //unpack

包装和拆包（无填充）对于一个结构来说很容易。如果要two structs打包，我该怎么办？

For Two Struct

struct_name1 a;
struct_name2 b;
/** Pack them into one and pass reference to flash_write method */
/**    Also how do I unpack                                     */

我试图获得struct和struct_name1的{{1}}。但对如何做到这一点很困惑。

Answer 1

如果两个结构都可以是数组的成员，那么它将是微不足道的：

struct_name both[2];  // both[0] is a and both[1] is b
// store data in both[0] and both[1]
...

struct_name read_buffer[2];
flash_write( &write_address, (uint8_t *)both, sizeof(both) ); //pack
flash_read( &read_address, (uint8_t *)read_buffer, sizeof(read_buffer) ); //unpack

如果它们最初不是同一个数组的成员，则可以复制它们：

struct_name both[2];
both[0] = a;
both[1] = b;

struct_name read_buffer[2];
flash_write( &write_address, (uint8_t *)both, sizeof(both) ); //pack
flash_read( &read_address, (uint8_t *)read_buffer, sizeof(read_buffer) ); //unpack

如果它们是不同的结构，只需使用结构作为聚合，如notan的答案所示。

Answer 2

将两个结构打包到一个结构中并使用：

struct_name1 a;
struct_name2 b;

struct struct_for_both
{
    struct_name1 a;
    struct_name2 b;
} both = {a,b}; // initialize by copying Contents of a and b

struct_for_both read_buffer;

flash_write( &write_address, (uint8_t *)&both, sizeof(both) ); //pack
flash_read( &read_address, (uint8_t *)read_buffer, sizeof(read_buffer) ); //unpack

将两个C结构打包到uint8_t指针中以写入DataFlash

2 个答案: