JSMN
simdjson
JSMN | simdjson | |
---|---|---|
14 | 65 | |
3,553 | 18,386 | |
- | 0.5% | |
0.0 | 9.2 | |
about 2 months ago | 5 days ago | |
C | C++ | |
MIT License | Apache License 2.0 |
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Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
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JSMN
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Building a high performance JSON parser
Like how https://github.com/zserge/jsmn works. I thought it would be neat to have such as parser for https://github.com/vshymanskyy/muon
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Flattening ASTs (and Other Compiler Data Structures)
One more JSON implementation using this approach is https://github.com/zserge/jsmn.
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Show HN: WinGPT, AI Assistant for Windows 3.1
Yep! I'm using JSMN (https://github.com/zserge/jsmn), which is a streaming parser that visits each token sequentially, so there's only one copy of each JSON response in memory. I also avoid allocating new intermediate memory whenever possible; for example, to unescape backslashes in the JSON strings, I use a destructive loop that moves the non-backslash characters forward in memory, and truncates the string by moving the null terminator earlier in the string. Not something I'd imagine doing in most environments today, but as you said, it saves a bit of space at the expense of CPU time :)
void DestructivelyUnescapeStr(LPSTR lpInput) {
- A good C library to parse json data
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Lightweight data serialization/deserialization format
After reviewing several options, I’ve settled on plain old JSON. For parsing, I use https://github.com/zserge/jsmn. For serialization I use https://github.com/rdpoor/jems (disclaimer: I wrote the latter, but others use it as well).
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jemi: a compact JSON serializer for embedded systems
As mentioned here, it appears that tiny-json is a parser, not a serializer. If you're looking for parsers, I've been very happy with jsmn.
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What is the proper way to store a RFC3339 date string?
Very small, 4-5 fields but I'm still going to write in binary because I'm trying to reduce dependencies and https://github.com/zserge/jsmn looks like good fit but jsmn only does parsing which I need for parsing some Oauth json data and config.json file. I will be able to dump the state struct in a state.bin file and read it later for comparing it with system time. Not having to write in text fits well for this particular use case. Benefits: Reduced dependencies and almost cost less decoding of the state struct(which the user will never see).
- Jsmn: A minimalistic JSON parser in C
- CJSON – Ultralightweight JSON parser in ANSI C
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A tiny zero-allocation JSON serializer compatible with C89!
This is my very straight-forward implementation that came to be from the lack of JSON encoding in jsmn:
simdjson
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Tips on adding JSON output to your command line utility. (2021)
It's also supported by simdjson [0] (which has a lot of language bindings [1]):
> Multithreaded processing of gigantic Newline-Delimited JSON (ndjson) and related formats at 3.5 GB/s
[0] https://simdjson.org/
[0] https://github.com/simdjson/simdjson?tab=readme-ov-file#bind...
- 1BRC Merykitty's Magic SWAR: 8 Lines of Code Explained in 3k Words
- Training great LLMs from ground zero in the wilderness as a startup
- simdjson: Parsing Gigabytes of JSON per Second
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Use any web browser as GUI, with Zig in the back end and HTML5 in the front end
String parsing is negligible compared to the speed of the DOM which is glacially slow: https://news.ycombinator.com/item?id=38835920
Come on, people, make an effort to learn how insanely fast computers are, and how insanely inefficient our software is.
String parsing can be done at gigabytes per second: https://github.com/simdjson/simdjson If you think that is the slowest operation in the browser, please find some resources that talk about what is actually happening in the browser?
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Cray-1 performance vs. modern CPUs
Thanks for all the detailed information! That answers a bunch of my questions and the implementation of strlen is nice.
The instruction I was thinking of is pshufb. An example ‘weird’ use can be found for detecting white space in simdjson: https://github.com/simdjson/simdjson/blob/24b44309fb52c3e2c5...
This works as follows:
1. Observe that each ascii whitespace character ends with a different nibble.
2. Make some vector of 16 bytes which has the white space character whose final nibble is the index of the byte, or some other character with a different final nibble from the byte (eg first element is space =0x20, next could be eg 0xff but not 0xf1 as that ends in the same nibble as index)
3. For each block where you want to find white space, compute pcmpeqb(pshufb(whitespace, input), input). The rules of pshufb mean (a) non-ascii (ie bit 7 set) characters go to 0 so will compare false, (b) other characters are replaced with an element of whitespace according to their last nibble so will compare equal only if they are that whitespace character.
I’m not sure how easy it would be to do such tricks with vgather.vv. In particular, the length of the input doesn’t matter (could be longer) but the length of white space must be 16 bytes. I’m not sure how the whole vlen stuff interacts with tricks like this where you (a) require certain fixed lengths and (b) may have different lengths for tables and input vectors. (and indeed there might just be better ways, eg you could imagine an operation with a 256-bit register where you permute some vector of bytes by sign-extending the nth bit of the 256-bit register into the result where the input byte is n).
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Codebases to read
Additionally, if you like low level stuff, check out libfmt (https://github.com/fmtlib/fmt) - not a big project, not difficult to understand. Or something like simdjson (https://github.com/simdjson/simdjson).
- Simdjson: Parsing Gigabytes of JSON per Second
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Building a high performance JSON parser
Everything you said is totally reasonable. I'm a big fan of napkin math and theoretical upper bounds on performance.
simdjson (https://github.com/simdjson/simdjson) claims to fully parse JSON on the order of 3 GB/sec. Which is faster than OP's Go whitespace parsing! These tests are running on different hardware so it's not apples-to-apples.
The phrase "cannot go faster than this" is just begging for a "well ackshully". Which I hate to do. But the fact that there is an existence proof of Problem A running faster in C++ SIMD than OP's Probably B scalar Go is quite interesting and worth calling out imho. But I admit it doesn't change the rest of the post.
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New package : lspce - a simple LSP Client for Emacs
I have same question as /u/JDRiverRun : how do you deal with JSON, do you parse json on Rust side or on Emacs side. I see that you are requiring json.el in your lspce.el, but I haven't looked through entire file carefully. If you parse on Rust side, do you use simdjson (there are at least two Rust bindings to it)? If yes, what are your impressions, experiences compared to more "standard" json library?
What are some alternatives?
cJSON - Ultralightweight JSON parser in ANSI C
RapidJSON - A fast JSON parser/generator for C++ with both SAX/DOM style API
json-c - https://github.com/json-c/json-c is the official code repository for json-c. See the wiki for release tarballs for download. API docs at http://json-c.github.io/json-c/
jsoniter - jsoniter (json-iterator) is fast and flexible JSON parser available in Java and Go
Jansson - C library for encoding, decoding and manipulating JSON data
json - JSON for Modern C++
json-schema-validator - JSON schema validator for JSON for Modern C++
ArduinoJson - 📟 JSON library for Arduino and embedded C++. Simple and efficient.
JsonCpp - A C++ library for interacting with JSON.
json - A C++11 library for parsing and serializing JSON to and from a DOM container in memory.