initial commit

util/util.go

@@ -0,0 +1,115 @@
+package util
+
+import (
+	"bufio"
+	"crypto/sha256"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+
+	"net/url"
+	"path/filepath"
+
+	"golang.org/x/term"
+)
+
+func Assert(condition bool) {
+	if !condition {
+		panic("assertion failed!")
+	}
+}
+
+func Dirents(dir string) (entries []string, err error) {
+	d, err := os.Open(dir)
+	if err != nil {
+		return nil, errors.New(err.Error())
+	}
+
+	names, err := d.Readdirnames(0)
+	if err != nil {
+		return nil, errors.New(err.Error())
+	}
+
+	for _, e := range names {
+		entries = append(entries, e)
+	}
+
+	return
+}
+
+func DoChunks(f io.Reader, fun func (buf []byte)) (err error) {
+	err = nil
+	bytes, chunks := int64(0), int64(0)
+	r := bufio.NewReader(f)
+	buf := make([]byte, 0, 4*1024)
+
+	for {
+		var n int
+		n, err = r.Read(buf[:cap(buf)])
+		buf = buf[:n]
+		if n == 0 {
+			if err == nil {
+				continue
+			}
+			if err == io.EOF {
+				break
+			}
+			return
+		}
+		chunks++
+		bytes += int64(len(buf))
+
+		Assert(n == len(buf))
+		fun(buf)
+
+		if err != nil && err != io.EOF {
+			return
+		}
+	}
+
+	return
+}
+
+func EscapePath(path string) string {
+	return strings.ReplaceAll(url.QueryEscape(path), "%2F", "/")
+}
+
+func HashOf(s string) string {
+	h := sha256.New()
+	h.Write([]byte(s))
+	return fmt.Sprintf("%x", h.Sum(nil))
+}
+
+// print only if interactive
+func Iprint(format string, args ...any) {
+	if term.IsTerminal(int(os.Stderr.Fd())) {
+		fmt.Fprintf(os.Stderr, format, args...)
+	}
+}
+
+func MapToValues[Map ~map[K]V, K comparable, V any](m Map) (values []V) {
+	for _, v := range m {
+		values = append(values, v)
+	}
+
+	return
+}
+
+func OptionalString(cond bool, s string) string {
+	if cond {
+		return s
+	}
+	return ""
+}
+
+func Warn(format string, args ...any) {
+	fmt.Fprintf(os.Stderr, "%s: %s\n",
+		filepath.Base(os.Args[0]), fmt.Sprintf(format, args...))
+}
+
+func Die(format string, args ...any) {
+	Warn(format, args...)
+	os.Exit(1)
+}