Struct Casting

Hi All

I'm trying to get uint32_t data into a 4 * uint8_t struct, I dont want to pass in byte by byte so i am trying to achieve soemthing like the following:

Code:

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uint32_t test = 0xFFFFFFFF;

typedef struct word32To4xByte
{
uint8_t byte1;
uint8_t byte2;
uint8_t byte3;
uint8_t byte4;
}wordtobyte;

struct word32To4xByte expectedResp;

ecpectedResp= (wordtobyte) test;

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You could do something like this.

Code:

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uint32_t test = 0xFFFFFFFF;

typedef struct {
uint8_t byte1;
uint8_t byte2;
uint8_t byte3;
uint8_t byte4;
} wordtobyte;

wordtobyte expectedResp;

expectedResp = *((wordtobyte*)(&test));

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Or use memcpy(). :)

Load in bytes, read dword... load in dword, read bytes...

Code:

---

typedef union t_dwordtobyte
{
  uint32_t dword;
  struct bytes
    {
      uint8_t b1;
      uint8_t b2;
      uint8_t b3;
      uint8_t b4;
    }
}dwordtobyte;


// use as...
dwordtobyte wb;

wb.dword = utf32_value;

byte1 = wb.bytes.b1;

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Note... this will expose you to Endian issues, so the order of bytes in the example may not be correct for all cases.