https://github.com/jdonnerstag/vlang-mmap

Provide memory mapping functionality to v-lang
https://github.com/jdonnerstag/vlang-mmap

Last synced: 3 months ago
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Provide memory mapping functionality to v-lang

• Host: GitHub
• URL: https://github.com/jdonnerstag/vlang-mmap
• Owner: jdonnerstag
• License: mit
• Created: 2021-05-17T16:33:17.000Z (over 3 years ago)
• Default Branch: main
• Last Pushed: 2021-06-21T06:45:53.000Z (over 3 years ago)
• Last Synced: 2024-04-23T16:38:36.304Z (7 months ago)
• Language: V
• Size: 13.7 KB
• Stars: 6
• Watchers: 1
• Forks: 2
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • License: LICENSE

Awesome Lists containing this project

• awesome-v - mmap - Provide native V-lang support for memory-mapping on Linux and Windows. (Libraries / Operating system)

README

        
# Memory Mapping support for [V-lang](https://vlang.io)

Inspired by [mman-win32](https://github.com/alitrack/mman-win32), this module

provides [V-lang](https://vlang.io) with easy to use memory mapping support. 

## Key Features

- Supports Linux and Windows

- Consistent public API for Linux and Windows

- V-lang like error handling

## API

```v

	pub fn mmap(args MmapOptions) ?voidptr

	pub fn munmap(addr voidptr, len u64) ?

	pub fn mprotect(addr voidptr, len u64, prot int) ?

	pub fn msync(addr voidptr, len u64, flags int) ?

	pub fn mlock(addr voidptr, len u64) ?

	pub fn munlock(addr voidptr, len u64) ? 

```

Additionally

```v

	// Cast the memory mapped region to a byte array

	pub fn to_byte_array(addr voidptr, len u64) []byte {

```

and

```v

	// Open a file (binary, read-only) and map its content into memory 

	pub fn mmap_file(file string) ?MmapInfo {

	// Release the memory mapped region and close the file

	pub fn (mut this MmapInfo) close() {

```

## Example

```v

import mmap

fn main() {

	big_file_path := '../../MY_BIG_FILE.20180119104659.A901'

	mut minfo := mmap.mmap_file(big_file_path)?

	defer { minfo.close() }

	b := minfo.bytes

	eprintln('src: $minfo.src')

	eprintln('b.len after: $b.len')

	eprintln('b starts with:')

	eprintln(b[0..64].hex())

	defer { eprintln('finished') }

}

/*

home: $ ./v run ./mmap_example.v

src: 0000000000B30000

b.len before: 0

b.len after: 2096582968

b starts with:

20202020203130303031324b64697077696d6c79676f716a6d712038205720202020202020202020202020202020202020202020202020202020202020202020

finished

*/

```