bitset | 易学教程

How do I convert bitset to array of bytes/uint8?

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问题 I need to extact bytes from the bitset which may (not) contain a multiple of CHAR_BIT bits. I now how many of the bits in the bitset I need to put into an array. For example, the bits set is declared as std::bitset < 40> id; There is a separate variable nBits how many of the bits in id are usable. Now I want to extract those bits in multiples of CHAR_BIT. I also need to take care of cases where nBits % CHAR_BIT != 0 . I am okay to put this into an array of uint8 回答1: Unfortunately there's no

Bitwise memmove

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问题 What is the best way to implement a bitwise memmove ? The method should take an additional destination and source bit-offset and the count should be in bits too. I saw that ARM provides a non-standard _membitmove, which does exactly what I need, but I couldn't find its source. Bind's bitset includes isc_bitstring_copy, but it's not efficient I'm aware that the C standard library doesn't provide such a method, but I also couldn't find any third-party code providing a similar method. 回答1:

Define a large bitset in C++

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问题 In my program I need to check if I have already generated a value in a set of 2.5*10^9. I expect to generate about the half of the set and need to have a fast way to check and update it. The bitset seemed to me as a good idea as it takes not too much memory (1 bit per value) and is fast. The problem is that when I define my set in my class, I got a segmentation fault as the size is too big (it works with smaller sizes). private: std::bitset<2500000000UL> cover; // not working std::bitset

Concatenate boost::dynamic_bitset or std::bitset

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问题 what is the best way to concatenate 2 bitsets? For example i've got boost::dynamic_bitset<> test1( std::string("1111") ); boost::dynamic_bitset<> test2( std::string("00") ); they should be concatenated into a thrid Bitset test3 which then holds 111100 Solutions should use boost::dynamic_bitset. If the solution works with std::bitset, it would be nice too. There should be a focus on performance when concatenating the bits. UPDATE: I've compared both methods (stringmethod from me and Neil and

Concatenate boost::dynamic_bitset or std::bitset

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Java- Mapping multi-dimensional arrays to single

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问题 I am posting this in relation to another open question i have, however I thought that this deserved it's own question. Alternate question (for reference): Java Proxy Discovering Bot Basically, I need to store a very large amount of data and have it accessible very quickly. This would work ideally in an unlimited memory situation: boolean[][][][] sets = new boolean[256][256][256][256]; boolean get(byte[] a) { return sets[a[0]][a[1]][a[2]][a[3]]; } However, this uses around 16gb of ram which is

How to translate a string of zeros and ones into bitset?

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问题 So I have this code snippet to translate a string into bitset. String huffmancode = "0010110100"; char[] ch = huffmancode.toCharArray(); BitSet bs = new BitSet(); for (int i = 0; i < ch.length; i++) { if (ch[i] == '1') { bs.set(i); } } My question is how to determine the boundary / size / length of the bitset given that the first and the last indexes of huffman code were 0's ? 回答1: The following bitset contains [0,1] in order and the last line of the following code prints out 2 , the length

Calling constexpr function for bitset template parameter

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问题 I'm trying to type alias the std::bitset class where the template parameter N is calculated using a constexpr function. However, this approach seems to be running into a wall. The code currently looks like this: static constexpr std::size_t ComponentCount() noexcept { return 3U; } static constexpr std::size_t TagCount() noexcept { return 5U; } using Bitset = std::bitset<ComponentCount() + TagCount()>; And the error I'm receiving is as follows: 1>error C2975: '_Bits': invalid template argument

sleuth+zipkin自定义采样率

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【推荐】2019 Java 开发者跳槽指南.pdf(吐血整理) >>> 问题背景 zipkin原生提供的采样率设置，仅能针对全局进行设置，无法做到精细化设置，比如，有些接口我们觉得比较重要，所以想采样率高一点，有些接口很简单，我们希望不采集或者采集率设置低一点，原生是没办法做到的，需要完成这个功能，需要我们重写他的采样率计算器。配置重写下面的是他原生的配置，由于它是使用了@ConditionalOnMissingBean注解的，也就是容器中不存在这个Bean的时候，才初始化他自己默认的配置，因此我们可以重写他的配置。 @Bean @ConditionalOnMissingBean public Sampler defaultTraceSampler(SamplerProperties config) { return new PercentageBasedSampler(config); } 重写配置如下 @Bean Sampler percentageLocalSampler(SamplerLocalProperties samplerLocalProperties){ return new PercentageLocalSampler(samplerLocalProperties); } 1 2 3 4 5 在Config类上面添加

How to calculate total number of bits in BitSet object?

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问题 I want to calculate the total number of bits in a BitSet object. The method length returns the "logical size" of the BitSet : the index of the highest set bit in the BitSet plus one, while method cardinality will give the total number of bits set to 1 in the object. I want to calculate the total number of bits including both 0s and 1s. How do I do that? 回答1: How about BitSet.size()?..... 回答2: The getObjectSize(Object o) method in the Instrumentation library is your guy: http://docs.oracle.com