utils.go

package dnnl

import (
	"os"
	"path/filepath"
	"strconv"
	"sync"
	"time"

	"github.com/Unknwon/com"
)

// Random number state.
// We generate random temporary file names so that there's a good
// chance the file doesn't exist yet - keeps the number of tries in
// TempFile to a minimum.
var rand uint32
var randmu sync.Mutex

func reseed() uint32 {
	return uint32(time.Now().UnixNano() + int64(os.Getpid()))
}

func nextSuffix() string {
	randmu.Lock()
	r := rand
	if r == 0 {
		r = reseed()
	}
	r = r*1664525 + 1013904223 // constants from Numerical Recipes
	rand = r
	randmu.Unlock()
	return strconv.Itoa(int(1e9 + r%1e9))[1:]
}

// tempFile creates a new temporary file in the directory dir
// If dir is the empty string, TempFile uses the default directory
// for temporary files (see os.TempDir).
// Multiple programs calling TempFile simultaneously
func tempFile(dir, prefix, suffix string) (name string, err error) {
	if dir == "" {
		dir = os.TempDir()
	}

	nconflict := 0
	for i := 0; i < 10000; i++ {
		name = filepath.Join(dir, prefix+nextSuffix()+suffix)
		if com.IsFile(name) {
			if nconflict++; nconflict > 10 {
				randmu.Lock()
				rand = reseed()
				randmu.Unlock()
			}
			continue
		}
		break
	}
	return
}

func uint32SliceToUint(data []uint32) []uint {
	sz := len(data)
	res := make([]uint, sz)
	for ii, val := range data {
		res[ii] = uint(val)
	}
	return res
}

func intSliceToUint32(data []int) []uint32 {
	sz := len(data)
	res := make([]uint32, sz)
	for ii, val := range data {
		res[ii] = uint32(val)
	}
	return res
}

func uintSliceToUint32(data []uint) []uint32 {
	sz := len(data)
	res := make([]uint32, sz)
	for ii, val := range data {
		res[ii] = uint32(val)
	}
	return res
}