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What is the best algorithm for overriding GetHashCode?
... quite how important that is.)
This is better than the common practice of XORing hashcodes for two main reasons. Suppose we have a type with two int fields:
XorHash(x, x) == XorHash(y, y) == 0 for all x, y
XorHash(x, y) == XorHash(y, x) for all x, y
By the way, the earlier algorithm is the one c...
How to check SQL Server version
...ROM sys.databases WHERE database_id=DB_ID() AND [compatibility_level] < 110)
RAISERROR('Database compatibility level must be SQL2008R2 or later (110)!', 16, 1)
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How do you set, clear, and toggle a single bit?
... string with the bitwise NOT operator (~), then AND it.
Toggling a bit
The XOR operator (^) can be used to toggle a bit.
number ^= 1UL << n;
That will toggle the nth bit of number.
Checking a bit
You didn't ask for this, but I might as well add it.
To check a bit, shift the number n to the ri...
Why is printing to stdout so slow? Can it be sped up?
...
print : 0.261 s
write to file (+fsync) : 0.110 s
print with stdout = /dev/null : 0.050 s
0.26s is MUCH better than 12s! I don't know whether wterm is more intelligent about how it renders to screen along the lines of how I was suggesting (render the 'visible' tail ...
What is getattr() exactly and how do I use it?
...alues:
>>> dir(1000)
['__abs__', '__add__', ..., '__trunc__', '__xor__', 'bit_length', 'conjugate', 'denominator', 'from_bytes', 'imag', 'numerator', 'real', 'to_bytes']
>>> obj = 1000
>>> for attr_name in dir(obj):
... attr_value = getattr(obj, attr_name)
... pr...
What's the (hidden) cost of Scala's lazy val?
...) and initializes the target field in a synchronized block if the relevant xor of the bitmap indicates it is necessary.
Using:
class Something {
lazy val foo = getFoo
def getFoo = "foo!"
}
produces sample bytecode:
0 aload_0 [this]
1 getfield blevins.example.Something.bitmap$0 : int [15...
What are the differences between Rust's `String` and `str`?
...ally, what used to be ~str is now Box<str>
– jv110
Apr 18 '18 at 17:41
4
@jv110: no, becaus...
Possible reason for NGINX 499 error codes
... happening in my case is that nginx would error.log an upstream timed out (110: Connection timed out) while reading upstream and then nginx retries "the next proxy server in the backend server group you configured." That's if you have more than one.
Then it tries the next and next till (by default)...
`testl` eax against eax?
...rom the same bag of tricks that holds the idea of clearing a register with XOR EAX,EAX (which i saw on someone's license plate in Colorado!) rather than the obvious but maybe slower MOV EAX, #0 (i use an older notation).
In asm, like perl, TMTOWTDI.
...
Unicode与UTF-8互转(C语言实现) - C/C++ - 清泛网 - 专注C/C++及内核技术
...unicode是十六进制数4E25, 转换成二进制数足足有15位
(100111000100101), 也就是说这个符号的表示至少需要2个字节. 表示其他更大的符号,
可能需要3个字节或者4个字节, 甚至更多.
这里就有两个严重的问题, 第一个问题是, 如何才能...