Mmap I/O for Golang

A portable I/O implement base on mmap for golang.

Overview

Use it like bufio in golang.

• NewReader(filePath string) returns a reader that uses mmap io to read file
• Read(p []byte) (n int, err error) read the file data into the slice
• ReadAll()(b []byte, err error) read whole file and format to string
• ReadLine() (b []byte, err error) returns one row of the file data
• LineNumber() int get current line number
• Close() error unmap file and release resources

Usage

Basic Usage

Create a reader from a filepath

reader, err := NewReader(testFile)
if err != nil{
	return
}
defer reader.Close()

Read data into slice

b := make([]byte, 20)

if n, err := reader.Read(b); err == nil {
	fmt.Printf("read " + strconv.Itoa(n) + " bytes data from file" + " : " + string(b))
}

The output of the above code is as follows

Welcome to mmap io !

Read the whole file at once

You can use ReadAll() to read it at once

if reader, err := NewReader(testFile); err == nil {
	defer reader.Close()
	if b, err := reader.ReadAll(); err == nil {
		fmt.Printf(string(b))	
	}
}

The output of the above code is as follows

Welcome to mmap io ! by Yuchao Huang @misterchaos
 _          _ _                                         _
| |__   ___| | | ___    _ __ ___  _ __ ___   __ _ _ __ (_) ___
| '_ \ / _ \ | |/ _ \  | '_ ` _ \| '_ ` _ \ / _` | '_ \| |/ _ \
| | | |  __/ | | (_) | | | | | | | | | | | | (_| | |_) | | (_) |
|_| |_|\___|_|_|\___/  |_| |_| |_|_| |_| |_|\__,_| .__/|_|\___/
                                                 |_|

ToDo

• Add file writing and locking support
• Implements io.Reader interface to be compatible with bufio
• Implements a mapping of the specified region

License

The code is open source using GPL3 protocol. If you need to use the code, please follow the relevant provisions of CPL3 protocol.

Authors

• Yuchao Huang @misterchaos - Original Author