lru-cache | :dizzy: A feature complete LRU cache implementation in C++ | Caching library

 by   goldsborough C++ Version: Current License: MIT

kandi X-RAY | lru-cache Summary

kandi X-RAY | lru-cache Summary

lru-cache is a C++ library typically used in Server, Caching applications. lru-cache has no bugs, it has no vulnerabilities, it has a Permissive License and it has low support. You can download it from GitHub.

A least recently used (LRU) cache is a fixed size cache that behaves just like a regular lookup table, but remembers the order in which elements are accessed. Once its (user-defined) capacity is reached, it uses this information to replace the least recently used element with a newly inserted one. This is ideal for caching function return values, where fast lookup of complex computations is favorable, but a memory blowup from caching all (input, output) pairs is to be avoided. We provide two implementations of an LRU cache: one has only the basic functionality described above, and another can be additionally supplied with a time to live. This is useful, for example, when caching resources on a server, where cache entries should be invalidated automatically after a certain amount of time, because they are no longer "fresh". Additionally, all our caches can be connected to statistics objects, that keep track of cache hits and misses for all keys and, upon request, individual keys (similar to functools.lru_cache in Python). You can also register arbitrary callbacks for hits, misses or accesses in general.
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            kandi-support Support

              lru-cache has a low active ecosystem.
              It has 211 star(s) with 25 fork(s). There are 19 watchers for this library.
              OutlinedDot
              It had no major release in the last 6 months.
              There are 2 open issues and 11 have been closed. On average issues are closed in 189 days. There are no pull requests.
              It has a neutral sentiment in the developer community.
              The latest version of lru-cache is current.

            kandi-Quality Quality

              lru-cache has 0 bugs and 0 code smells.

            kandi-Security Security

              lru-cache has no vulnerabilities reported, and its dependent libraries have no vulnerabilities reported.
              lru-cache code analysis shows 0 unresolved vulnerabilities.
              There are 0 security hotspots that need review.

            kandi-License License

              lru-cache is licensed under the MIT License. This license is Permissive.
              Permissive licenses have the least restrictions, and you can use them in most projects.

            kandi-Reuse Reuse

              lru-cache releases are not available. You will need to build from source code and install.
              Installation instructions are not available. Examples and code snippets are available.

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            Currently covering the most popular Java, JavaScript and Python libraries. See a Sample of lru-cache
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            lru-cache Key Features

            No Key Features are available at this moment for lru-cache.

            lru-cache Examples and Code Snippets

            Create a decorator to cache a function .
            pythondot img1Lines of Code : 28dot img1License : Permissive (MIT License)
            copy iconCopy
            def decorator(
                    cls, size: int = 128
                ) -> Callable[[Callable[[T], U]], Callable[..., U]]:
                    """
                    Decorator version of LRU Cache
            
                    Decorated function must be function of T -> U
                    """
            
                    def cache_decora  
            Print out the LRU cache .
            javadot img2Lines of Code : 12dot img2no licencesLicense : No License
            copy iconCopy
            public static void main(String[] args) {
                    LRUCache lRUCache = new LRUCache(2);
                    lRUCache.put(1, 1); // cache is {1=1}
                    lRUCache.put(2, 2); // cache is {1=1, 2=2}
                    System.out.println(lRUCache.get(1));    // return 1
                     

            Community Discussions

            QUESTION

            unable to fix project build React
            Asked 2022-Apr-07 at 14:17

            error lru-cache@7.7.3: The engine "node" is incompatible with this module. Expected version ">=12". Got "10.15.1" error Found incompatible module

            enter image description here

            ...

            ANSWER

            Answered 2022-Apr-07 at 14:17

            Have you tried updating the node? U need to update to a higher version of node (v12) probably.

            You can download the latest stable node from here - https://nodejs.org/en/download/ Or can use NVM (node version manager)

            Source https://stackoverflow.com/questions/71780372

            QUESTION

            zsh: command not found python after running "brew upgrade"
            Asked 2022-Mar-23 at 18:30

            I am not able to install any npm packages as I get the following error on my M1 Mac mini

            ...

            ANSWER

            Answered 2022-Mar-23 at 18:30

            import sys; print "%s.%s.%s"

            That's some good old Python 2 notation if I ever saw some :)

            As @ElapsedSoul mentioned. macOS 12.3 removed the Python 2 that came by default for all these years. Therefore, I would personally recommend for others not to upgrade to 12.3 if you need Python 2 until you find an alternative solution.

            Some possible alternatives include the following:

            Option 0: Reinstall Python 2 via Homebrew

            Homebrew unfortunately got rid of Python 2 a long time ago. There are however some workarounds to try and get it to work: How to reinstall python@2 from Homebrew?.

            Option 1: Use pyenv

            I haven't tested this, so it might not work. But if it does, this is likely the best solution for your needs. From the following:

            Source https://stackoverflow.com/questions/71582261

            QUESTION

            Error 11903 when developing first gatsby project
            Asked 2022-Mar-21 at 06:34

            I am trying to set up my first Gatsby website. After running npm install -g gatsby-cli, I do gatsby new gatsby-starter-hello-world https://github.com/gatsbyjs/gatsby-starter-hello-world (just like the website https://www.gatsbyjs.com/starters/gatsbyjs/gatsby-starter-hello-world/ says) to download the hello world starter. When I run gatsby develop I see the following error

            ...

            ANSWER

            Answered 2022-Mar-21 at 06:34

            As has been commented in the comments section, the issue has been solved by moving the project folder outside the OneDrive directory.

            Because it's a synchronized cloud folder, as soon as you install/add/delete/update anything, it's being updated in the OneDrive cloud so the file/folder it's being used in the background and potentially unreachable. If at this time you try to develop the project (gatsby develop or gatsby build) and the file is being used, you won't be able to run it.

            I don't think it's a good practice to use a cloud folder because the amount of data synchronized (mainly because of the node_modules) it's something to care about (it's also ignored in the .gitignore for a reason) so moving it to any other folder outside the OneDrive directory should be enough to run your project because the rest of global dependencies, according to your logs, were successfully installed.

            Source https://stackoverflow.com/questions/71552122

            QUESTION

            Compling Rust on Mac M1 for target x86_64 linux
            Asked 2022-Jan-18 at 17:25

            I'm trying to compile my Rust code on my M1 Mac for a x86_64 target with linux. I use Docker to achieve that.

            My Dockerfile:

            ...

            ANSWER

            Answered 2022-Jan-18 at 17:25

            It looks like the executable is actually named x86_64-linux-gnu-gcc, see https://packages.debian.org/bullseye/arm64/gcc-x86-64-linux-gnu/filelist.

            Source https://stackoverflow.com/questions/70755856

            QUESTION

            Difference between functool's cache and lru_cache
            Asked 2021-Dec-10 at 08:10

            Recently I came across functools.cache and didn't know how it differs from functools.lru_cache.

            I found posts about the difference between functools.cached_property and lru_cache but nothing specifically for cache and lru_cache.

            ...

            ANSWER

            Answered 2021-Dec-10 at 08:10

            functools.cache was newly added in version 3.9.

            The documentation states:

            Simple lightweight unbounded function cache. Sometimes called “memoize”.

            Returns the same as lru_cache(maxsize=None), creating a thin wrapper around a dictionary lookup for the function arguments. Because it never needs to evict old values, this is smaller and faster than lru_cache() with a size limit.

            Example from the docs:

            Source https://stackoverflow.com/questions/70301475

            QUESTION

            TypeError: Cannot read property 'combine' of undefined in rollup bundle [monorepo] [yarn workspaces] [nodejs]
            Asked 2021-Nov-17 at 23:07

            I'm trying to create a bundle of a nodeJS app within a yarn monorepo.

            Compiling Typescript to JS works fine (through tsc), then rollup finishes too. However, when running the compiled bundle in node, I'm getting the following exception that points to that the external module cannot be found:

            ...

            ANSWER

            Answered 2021-Nov-17 at 23:07

            The issue was that tsconfig.json must use "module": "esnext". Otherwise the compiled code is not compatible.

            Source https://stackoverflow.com/questions/69993125

            QUESTION

            Can't install node-sodium on Windows
            Asked 2021-Oct-16 at 11:21

            I am trying to program a Discord Bot that plays music from Youtube. I chose Sodium as the encryption package, but I'm having difficulties when it comes to installing it.

            I tried setting my VS version to 2015 by installing the required build tools and setting the version from the npm config, with no avail:

            ...

            ANSWER

            Answered 2021-Aug-30 at 20:34
            76 error gyp ERR! find VS msvs_version was set from command line or npm config
            76 error gyp ERR! find VS - looking for Visual Studio version 2015
            76 error gyp ERR! find VS VCINSTALLDIR not set, not running in VS Command Prompt
            76 error gyp ERR! find VS checking VS2017 (15.9.28307.1622) found at:
            76 error gyp ERR! find VS "C:\Program Files (x86)\Microsoft Visual Studio\2017\BuildTools"
            76 error gyp ERR! find VS - found "Visual Studio C++ core features"
            76 error gyp ERR! find VS - found VC++ toolset: v141
            76 error gyp ERR! find VS - found Windows SDK: 10.0.17763.0
            76 error gyp ERR! find VS - msvs_version does not match this version
            76 error gyp ERR! find VS could not find a version of Visual Studio 2017 or newer to use
            76 error gyp ERR! find VS looking for Visual Studio 2015
            76 error gyp ERR! find VS - not found
            76 error gyp ERR! find VS not looking for VS2013 as it is only supported up to Node.js 8
            76 error gyp ERR! find VS
            76 error gyp ERR! find VS valid versions for msvs_version:
            76 error gyp ERR! find VS - "2017"
            

            Source https://stackoverflow.com/questions/68989910

            QUESTION

            Why is moving data between two CPU registers so slow that it costs 30% of total time?
            Asked 2021-Oct-06 at 19:17

            In an attempt to profile & optimize a caching algorithm, I got stuck at something I don't understand.

            Here is the hot-spot of the perf's report (in Ubuntu 18.04 LTS and g++ 7.5):

            How does just a "mov" operatiaon between rax and rdx registers cause ~30% of total run-time of program? It's not a register-heavy program (an LRU-cache approximation algorithm that is doing ~50million lookups per second at max and this is around 400MB/s throughput(and certainly not faster than RAM for bigger key-value pairs) which should not be related to register bandwidth at all)

            Test system's CPU is FX8150 and has 1 channel memory attached with 9GB/s bandwidth which is way higher than this single-thread cache can achieve for just "int" key + "int" value pairs. So I guess it should be safe to leave RAM out of this problem. Also the mov instruction looks like a part of std::unordered_map's lookup operations. I know this CPU is old but not really ancient-old so perhaps compiler is not using the right instruction here due to some "support for old CPU" issue?

            Source code to reproduce the hot-spot:

            ...

            ANSWER

            Answered 2021-Oct-06 at 19:17

            That's not moving between rax and rdx.

            That's indexing into an array pointed to by rax by rdx and putting the result in rax. Probable L1 cache miss.

            Source https://stackoverflow.com/questions/69471340

            QUESTION

            Redis performance comparison: using TTL vs allkeys-lru policy
            Asked 2021-Aug-19 at 12:27

            In Redis, using allkeys-lru deletes the key no matter if it's an expire-set key or not.

            Using TTL, setting an expiration for the key, uses memory.

            Quoting from Redis.io:

            It is also worth noting that setting an expire to a key costs memory, so using a policy like allkeys-lru is more memory efficient since there is no need to set an expire for the key to be evicted under memory pressure.

            1. Is it really more efficient overall to NOT put a TTL on the key and let allkeys-lru policy handle it?
            2. Isn't there any tradeoffs in this situation? For example, does the allkeys-lru block the write action until it completes the expiration? That would make me use the TTL if this expiration is going to take long durations.

            I would love to discuss about this. Thanks for everybody's input!

            ...

            ANSWER

            Answered 2021-Aug-19 at 12:27

            allkeys-lru is triggered by Redis allocated memory limit. It's a safety feature to avoid crashing Redis entirely. If you rely on only allkeys-lru to cleanup your data then your Redis will run slower because any operation would have to be applied to a bigger DB. And your Redis DB will always be at max size.

            Also it makes it harder to monitor your resources during your business growth.

            Using TTL on your values is more a technical decision based on your use case. It gives you more control over which events you don't need anymore. TTL uses more memory because it has to store the TTL value for each record, makes sense.

            For Redis-Streams, you can use the MAXLEN property to not grow your streams too much, specially when you don't need older data. This property is per stream so it will not increase Redis memory that much. Redis-streams are expired by stream(by key), not by record. So it's not possible to expire old records from Streams based on a TTL/record if you continuously receive new data.

            Main conclusion: Use TTL and MAXLEN where possible to cleanup unnecessary data sooner so Redis will not need to do it all at once and you will have more control over your data and resources.

            Source https://stackoverflow.com/questions/68775278

            QUESTION

            AttributeError: could not import keras and segmentation models
            Asked 2021-Jul-02 at 05:33

            I am trying to import segmentation models and keras and i am getting an attribute error, i am using tensor flow version 2.5.0

            ...

            ANSWER

            Answered 2021-Jul-02 at 05:33

            I have solved my issue by adding tf.compat.v1.enable_eager_execution() to import and it works fine

            Source https://stackoverflow.com/questions/68209795

            Community Discussions, Code Snippets contain sources that include Stack Exchange Network

            Vulnerabilities

            No vulnerabilities reported

            Install lru-cache

            You can download it from GitHub.

            Support

            We have 100% public and private documentation coverage with a decent effort behind it. As such we ask you to RTFM to see the full interface we provide (it is a superset of std::unordered_map, minus the new node interface). Documentation can be generated with Doxygen by running the doxygen command inside the docs/ folder.
            Find more information at:

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            gh repo clone goldsborough/lru-cache

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            git@github.com:goldsborough/lru-cache.git

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