How Does the GET_UINT32 Macro Convert Input into Hexadecimal Format?

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SUMMARY

The GET_UINT32 macro is a C preprocessor directive that converts a byte array into a 32-bit unsigned integer by shifting and combining four consecutive bytes. Specifically, it takes four bytes from the input array, shifts them to their respective positions, and combines them using bitwise OR operations. For example, when the macro is applied to the byte array containing the hexadecimal value 0xcccccccc, it outputs the integer 1315927840, which corresponds to the hexadecimal value 0x4E6F7726. This macro is essential for handling byte-level data in cryptographic applications.

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cutesteph
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Homework Statement


this is in my function
GET_UINT32( X, input, 0 );

this is a macro
#define GET_UINT32(n,b,i) \
{ \
(n) = ( (uint32) (b)[(i) ] << 24 ) \
| ( (uint32) (b)[(i) + 1] << 16 ) \
| ( (uint32) (b)[(i) + 2] << 8 ) \
| ( (uint32) (b)[(i) + 3] ); \
}

3435973836=0xcccccccc
when inputted into the macro, it out puts
0x4E6F7726 =1315927840.Oxcc, Oxcc, Oxcc, Oxcc, Oxcc, Oxcc, Oxcc, Oxcc
into
0x4E, 0x6F, 0x77, 0x20, 0x69, 0x73, 0x20, 0x74

The Attempt at a Solution


I am not sure how to begin. I am taking a cryptography class [/B]for fun as a statistics major. I tried understanding it but it just confused me. I want to see how (uint32) (b)[(i) + 1] << 16 ) changes the input
 
Last edited:
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cutesteph said:

Homework Statement


this is in my function
GET_UINT32( X, input, 0 );

this is a macro
#define GET_UINT32(n,b,i) \
{ \
(n) = ( (uint32) (b)[(i) ] << 24 ) \
| ( (uint32) (b)[(i) + 1] << 16 ) \
| ( (uint32) (b)[(i) + 2] << 8 ) \
| ( (uint32) (b)[(i) + 3] ); \
}

3435973836=0xcccccccc
when inputted into the macro, it out puts
0x4E6F7726 =1315927840.Oxcc, Oxcc, Oxcc, Oxcc, Oxcc, Oxcc, Oxcc, Oxcc
into
0x4E, 0x6F, 0x77, 0x20, 0x69, 0x73, 0x20, 0x74

The Attempt at a Solution


I am not sure how to begin. I am taking a cryptography class [/B]for fun as a statistics major. I tried understanding it but it just confused me. I want to see how (uint32) (b)[(i) + 1] << 16 ) changes the input
Please show us all of your code.
 
and use the code tags when you do it.
 

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