regarding bitwise shift in "eventloop.h"

[Harry Tanama]

Hi Experts,

I don't really understand the purpose of using bitwise left-shift in
constant value of PurpleInputCondition enum.

typedef enum
{
    PURPLE_INPUT_READ  = 1 << 0,  /**< A read condition.  */
    PURPLE_INPUT_WRITE = 1 << 1   /**< A write condition. */

} PurpleInputCondition;

Could we just use these method instead?

typedef enum
{
    PURPLE_INPUT_READ  = 1,  /**< A read condition.  */
    PURPLE_INPUT_WRITE = 2   /**< A write condition. */

} PurpleInputCondition;


When I google for bitwise shift, they said that bitwise shifts are more
efficient than the normal arithmetic operations.

Example: 4 << 2.

4 is 100 in binary. Adding 2 zeros to the end gives 10000, which is 16, i.e.

4*22 = 4*4 = 16.
I don't quiet understand why we're doing arithmetic binary in the
    PURPLE_INPUT_READ  = 1 << 0,  and PURPLE_INPUT_WRITE = 1 << 1



Thank you for the explaination.

Kindes Regard,
pr0gm3r
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