Adds helper functions for strings and hashes. Closes #29

helpers/hash.go

@@ -0,0 +1,54 @@
+package helpers
+
+import (
+	"bytes"
+	"crypto/md5"
+	"encoding/hex"
+	"hash/fnv"
+	"io"
+	"os"
+)
+
+// FileMD5Hash streams a file into a MD5 hasher and returns the resultant MD5 hash bytes
+// This DOES NOT read the whole file into memory
+func FileMD5Hash(filePath string) ([]byte, error) {
+	file, err := os.Open(filePath)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	hasher := md5.New()
+	if _, err := io.Copy(hasher, file); err != nil {
+		return nil, err
+	}
+	return hasher.Sum(nil), nil
+}
+
+// FileHash streams a file into a MD5 hasher and returns the resultant MD5 hash
+// as a HEX encoded string. Uses FileMD5Hash under-the-hood
+func FileHash(filePath string) (string, error) {
+	hash, err := FileMD5Hash(filePath)
+	if err != nil {
+		return "", err
+	}
+	return hex.EncodeToString(hash), nil
+}
+
+// StringFnvHash returns a FNV1 hash of the given string.
+// returns 0 if there's an error
+func StringFnvHash(s string) uint32 {
+	b := bytes.NewBufferString(s)
+	h := fnv.New32a()
+	if _, err := io.Copy(h, b); err != nil {
+		return 0
+	}
+	return h.Sum32()
+}
+
+// GetMD5Hash returns the MD5 hash of the given string
+func GetMD5Hash(text string) string {
+	hash := md5.Sum([]byte(text))
+	h := hex.EncodeToString(hash[:])
+	return h
+}

helpers/string.go

@@ -1,6 +1,8 @@
 package helpers
 
 import (
+	"bytes"
+	"encoding/csv"
 	"fmt"
 	"strings"
 	"unicode"
@@ -83,3 +85,51 @@ func Clean(str string) string {
 		return -1
 	}, str)
 }
+
+// SplitByRune uses the CSV decoder to parse out the tokens - even if they are quoted and/or escaped
+func SplitByRune(str string, r rune) []string {
+	csvDecoder := csv.NewReader(strings.NewReader(str))
+	csvDecoder.Comma = r
+	csvDecoder.LazyQuotes = true
+	csvDecoder.TrimLeadingSpace = true
+	split, _ := csvDecoder.Read()
+	return split
+}
+
+// SplitByWhitespace splits by the ' ' rune
+func SplitByWhitespace(str string) []string {
+	return SplitByRune(str, ' ')
+}
+
+// Resize resizes the string with the given length. It ellipses with '…' when the string's length exceeds
+// the desired length or pads spaces to the right of the string when length is smaller than desired
+func Resize(s string, length uint) string {
+	n := int(length)
+	if len(s) == n {
+		return s
+	}
+	// Pads only when length of the string smaller than len needed
+	s = PadRight(s, n, ' ')
+	if len(s) > n {
+		b := []byte(s)
+		var buf bytes.Buffer
+		for i := 0; i < n-1; i++ {
+			buf.WriteByte(b[i])
+		}
+		buf.WriteString("…")
+		s = buf.String()
+	}
+	return s
+}
+
+// PadRight returns a new string of a specified length in which the end of the current string is padded with spaces or with a specified Unicode character.
+func PadRight(str string, length int, pad byte) string {
+	if len(str) >= length {
+		return str
+	}
+	buf := bytes.NewBufferString(str)
+	for i := 0; i < length-len(str); i++ {
+		buf.WriteByte(pad)
+	}
+	return buf.String()
+}