gmp_testbit will be very useful for my (over 64-bit) bitmask checking.
In the meantime, I think these are the best replacements.
Mostly full:
<?php
(gmp_scan1($a, $index) == $index)
?>
Mostly empty:
<?php
(gmp_scan0($a, $index) != $index)
?>
Still worst-case O(N), though.
gmp_testbit
(PHP 5 >= 5.3.0)
gmp_testbit — Tests if a bit is set
參數
-
a -
可以是一個 GMP 數據 resouce，或一個可以轉換為數值的字串。
-
index -
The bit to test
回傳值
Returns TRUE if the bit is set in resource $a,
otherwise FALSE.
錯誤/例外
An E_WARNING level error is issued when
index is less than zero, and FALSE
is returned.
範例
Example #1 gmp_testbit() example
<?php
$n = gmp_init("1000000");
var_dump(gmp_testbit($n, 1));
gmp_setbit($n, 1);
var_dump(gmp_testbit($n, 1));
?>
上例將輸出：
bool(false) bool(true)
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User Contributed Notes 1 note
bluej100@gmail ¶
16 years ago
