Set Previous Block Allocation Status

Task

Implement the function set_prev_status

• Given a pointer to a block_header and a status value (0 or 1), and update the “previous block busy” bit
• The second least significant bit (bit 1) indicates previous block status
  • 1 → allocated
  • 0 → free
• Preserve all other bits in size_status (size and current block status)
• Don’t modify the struct definition at the top of the file

Function Signature

// Given a pointer to a block_header and status (0 or 1), set the previous block's allocation status bit while preserving all other bits.
void set_prev_status(struct block_header* block, int status);

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Testing

Compiling

Use gcc to compile the program and use ./ to run the program

$ gcc set_prev_status.c -o set_prev_status
$ ./set_prev_status

Example

Test Case 1

Input: size_status = 0x0000000000000041, status = 1
Expected: size_status becomes 0x0000000000000043

Test Case 2

Input: size_status = 0x0000000000000043, status = 0
Expected: size_status becomes 0x0000000000000041

NOTE

• To set bit 1 to 1: block->size_status |= 0x2
• To set bit 1 to 0: block->size_status &= ~0x2
• Use conditional logic based on the status parameter

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Code

#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
 
struct block_header
{
    size_t size_status;
};
 
void set_prev_status(struct block_header *block, int status)
{
    if(status == 1){
            block->size_status |= 0x2;
    } else {
            block->size_status &= ~0x2;
    }
}