55 lines
2.5 KiB
Markdown
55 lines
2.5 KiB
Markdown
# pcre
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[](https://pkg.go.dev/go.elara.ws/pcre)
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[](https://ci.elara.ws/49)
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This package provides a CGo-free port of the PCRE2 regular expression library. The [lib](lib) directory contains source code automatically translated from PCRE2's C source. This package wraps that code and provides an interface as close as possible to Go's stdlib [regexp](https://pkg.go.dev/regexp) package
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---
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## IMPORTANT NOTE!
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Due to the use of PCRE2, this library contains extra features such as lookaheads/lookbehinds. The stdlib regex engine, RE2, left these features out for a reason. It's easy to create regular expressions with this library that have exponential runtime. This creates the possibility of a denial of service attack. Only use this library if the extra features are needed and the user providing the regex is trusted (such as if it's in a config file). Otherwise, use the standard library regexp package.
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---
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## Supported GOOS/GOARCH:
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- linux/amd64
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- linux/386
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- linux/arm64
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- linux/arm
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- linux/riscv64
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- darwin/amd64
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- darwin/arm64
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More OS support is planned.
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---
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## How to transpile pcre2
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In order to transpile pcre2, a Go and C compiler (preferably GCC) will be needed.
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- First, install [ccgo](https://pkg.go.dev/modernc.org/ccgo/v3)
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- Then, download the pcre source code. It can be found here: https://github.com/PCRE2Project/pcre2.
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- Once downloaded, `cd` into the source directory
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- Run `./configure`. If cross-compiling, provide the path to the cross-compiler in the `CC` variable, and set `--target` to the target architecture.
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- When it completes, there should be a `Makefile` in the directory.
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- Run `ccgo -compiledb pcre.json make`. Do not add `-j` arguments to the make command.
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- Run the following command (replace items in triangle brackets):
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```shell
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CC=/usr/bin/gcc ccgo -o pcre2_<os>_<arch>.go -pkgname lib -trace-translation-units -export-externs X -export-defines D -export-fields F -export-structs S -export-typedefs T pcre.json .libs/libpcre2-8.a
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```
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- If cross-compiling, set the `CCGO_CC` variable to to path of the cross-compiler, and the `CCGO_AR` variable to the path of the cross-compiler's `ar` binary. Also, set `TARGET_GOARCH` to the GOARCH you're targeting and `TARGET_GOOS` to the OS you're targeting.
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- Once the command completes, two go files will be created. One will start with `pcre2`, the other with `capi`. Copy both of these to the `lib` directory in this repo.
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