unpack

问题 #!/usr/bin/env perl use warnings; use 5.012; my $var = 1 << 31; say unpack( "B*", pack( "N", $var ) ); # 10000000000000000000000000000000 How can I get with pack/unpack from my $var = 1 << 63; an output like this? # 1000000000000000000000000000000000000000000000000000000000000000 回答1: say unpack("B*", pack( "Q>", $var )); The > forces big-endian byte-order on the Q (unsigned 64-bit "quad") type. 来源： https://stackoverflow.com/questions/4672213/pack-unpack-litle-endian-64bit-question

问题 I am relatively new to Lua, and am experimenting with embedding it in a library. I can execute the script just fine from the command line, but I hit the following error when calling a function in my script when embedded PANIC: unprotected error in call to Lua API ([string "-- #! /usr/local/bin/lua..."]:72: attempt to call global 'unpack' (a nil value)) Where did unpack go? 回答1: You're probably embedding Lua as source, not as a pre-built library. In this case, you have probably not enabled

问题 So, long story short, I am trying to 'unpack' some data myself, but I am not able to do so. Fortunately I have the solution, but I cannot figure out the method. Basically, I have this array of data here, [16 130 164 65 103 136 209 64 19 36 185 190 83] , and I am told that when 'unpacked' via 'fffB' , I get: [ 20.56350708,   6.54790068,  -0.36160335,  83] I know for a fact that this solution is correct, but I am not sure how we attained it. The context here is that the input array was

问题 I am building a repository of clean, non-hard coded (= not using the data frame column names inside) function templates that enable creating 4 types of functions: 1 new column from 1 existing, many new columns from 1 existing, 1 new column from many and finally many-to-many. The first 3 look like this and work: In [97]: data={'level1':[20,19,20,21,25,29,30,31,30,29,31], 'level2': [10,10,20,20,20,10,10,20,20,10,10]} index= pd.date_range('12/1/2014', periods=11) frame=DataFrame(data, index

问题 Kind of a noob with tomcat 7, how do you implement this setting found here: http://tomcat.apache.org/tomcat-7.0-doc/config/host.html#Common_Attributes Trying to set unpackWARs to true so i dont have to manually unpack a war to deploy it, but have no idea where to do this. 回答1: This setting can be found in server.xml under your Tomcat 7 configuration directory. For example, on Ubuntu, this is /etc/tomcat7/server.xml , and the setting is part of the <Host> element: <Host name="localhost"

问题 I'm reading this code and I'm a tad confused as to what is going on. This code is using Ruby's OpenSSL library. encrypted_message = cipher.update(address_string) + cipher.final encrypted_message => "G\xCB\xE10prs\x1D\xA7\xD0\xB0\xCEmX\xDC@k\xDD\x8B\x8BB\xE1#!v\xF1\xDC\x19\xDD\xD0\xCA\xC9\x8B?B\xD4\xED\xA1\x83\x10\x1F\b\xF0A\xFEMBs'\xF3\xC7\xBC\x87\x9D_n\\z\xB7\xC1\xA5\xDA\xF4s \x99\\\xFD^\x85\x89s\e" [3] pry(Encoder)> encrypted_message.unpack('H*') => [

问题 I have a struct wich contains: struct mystruct{ int id[10]; char text[40]; unsigned short int len; }; And I'm trying to unpack it in a single line, something like this: my(@ids,$text,$length) = unpack("N10C40n",$buff) ; But everything is going to the first array(@ids), i've tried templates as " N10 C40 n " and " (N10)(C40)(n) " So, either this can't be done or I'm not using the proper template string. Note: I'm using big endian data. Any hints? 回答1: In list assignment the first array or hash

问题 I need to convert integer to a 4 byte (32 bit) hex for sending it as ACK to a device i am currently trying to integrate. For example 3 = 00000003 15 = 0000000F Check http://www.mathsisfun.com/binary-decimal-hexadecimal-converter.html 1. Select signed 32 bit from the dropdown 2. Enter the value in decomal text box 3. Check value in hex field. I am using php pack function with this parameter but based on the response from the device, it does not seem to be the correct approach. $reply = pack(L*

问题 For unpacking complex binary strings with mixed doubles and integers using Ruby's String.unpack I need to determine offsets within the binary string. Commonly, doubles are 8 bytes and integers are 4 bytes, but in order to make my code machine-independent, I would like to query these sizes from within my Ruby code. What is the easiest way to determine the size of integers and doubles from within Ruby, i.e., request the response of a request to C's sizeof( type ) method? 回答1: I have found a

问题 I'm working with serial communication, and I receive 32bit integers in a QByteArray , packed in 4 separate bytes (little-endian). I attempt to unpack the value from the 4 bytes using QByteArray::toLong() but it fails the conversion and returns the wrong number: quint8 packed_bytes[] { 0x12, 0x34, 0x56, 0x78 }; QByteArray packed_array { QByteArray(reinterpret_cast<char*>(packed_bytes), sizeof(packed_bytes)) }; bool isConversionOK; qint64 unpacked_value { packed_array.toLong(&isConversionOK) };