iofiles.go

package dxsvalue

import (
	"io"
	"os"
)


func ReadFile(name string) ([]byte, error) {
	f, err := os.Open(name)
	if err != nil {
		return nil, err
	}
	defer f.Close()

	var size int
	if info, err := f.Stat(); err == nil {
		size64 := info.Size()
		if int64(int(size64)) == size64 {
			size = int(size64)
		}
	}
	size++ // one byte for final read at EOF

	// If a file claims a small size, read at least 512 bytes.
	// In particular, files in Linux's /proc claim size 0 but
	// then do not work right if read in small pieces,
	// so an initial read of 1 byte would not work correctly.
	if size < 512 {
		size = 512
	}

	data := make([]byte, 0, size)
	for {
		if len(data) >= cap(data) {
			d := append(data[:cap(data)], 0)
			data = d[:len(data)]
		}
		n, err := f.Read(data[len(data):cap(data)])
		data = data[:len(data)+n]
		if err != nil {
			if err == io.EOF {
				err = nil
			}
			return data, err
		}
	}
}