Initial Commit

vercmp.go

@@ -0,0 +1,165 @@
+/*
+ * LURE - Linux User REpository
+ * Copyright (C) 2023 Arsen Musayelyan
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package vercmp
+
+import (
+	_ "embed"
+	"strconv"
+	"strings"
+
+	"golang.org/x/exp/slices"
+)
+
+// Compare compares two version strings.
+// It returns 1 if v1 is greater,
+// 0 if the versions are equal,
+// and -1 if v2 is greater
+func Compare(v1, v2 string) int {
+	if v1 == v2 {
+		return 0
+	}
+
+	return sepVerCmp(sepLabel(v1), sepLabel(v2))
+}
+
+func sepVerCmp(e1, e2 []string) int {
+	if slices.Equal(e1, e2) {
+		return 0
+	}
+
+	// proc stores the amount of elements processed
+	proc := 0
+
+	for i := 0; i < len(e1); i++ {
+		proc++
+
+		if i >= len(e2) {
+			return 1
+		}
+
+		elem1 := e1[i]
+		elem2 := e2[i]
+
+		if elem1 == elem2 {
+			continue
+		}
+
+		if isNumElem(elem1) && isNumElem(elem2) {
+			elem1v, err := strconv.ParseInt(elem1, 10, 64)
+			if err != nil {
+				// error should never happen due to isNumElem()
+				panic(err)
+			}
+
+			elem2v, err := strconv.ParseInt(elem2, 10, 64)
+			if err != nil {
+				// error should never happen due to isNumElem()
+				panic(err)
+			}
+
+			if elem1v > elem2v {
+				return 1
+			} else if elem1v < elem2v {
+				return -1
+			}
+		} else if isNumElem(elem1) && isAlphaElem(elem2) {
+			return 1
+		} else if isAlphaElem(elem1) && isNumElem(elem2) {
+			return -1
+		} else if isAlphaElem(elem1) && isAlphaElem(elem2) {
+			if elem1 > elem2 {
+				return 1
+			} else if elem1 < elem2 {
+				return -1
+			}
+		}
+	}
+
+	if proc < len(e2) {
+		return -1
+	}
+
+	return 0
+}
+
+func sepLabel(label string) []string {
+	const (
+		other = iota
+		alpha
+		num
+	)
+
+	var (
+		curType uint8
+		out     []string
+		sb      strings.Builder
+	)
+
+	for _, char := range label {
+		if isNum(char) {
+			if curType != num && curType != other {
+				out = append(out, sb.String())
+				sb.Reset()
+			}
+
+			sb.WriteRune(char)
+			curType = num
+		} else if isAlpha(char) {
+			if curType != alpha && curType != other {
+				out = append(out, sb.String())
+				sb.Reset()
+			}
+
+			sb.WriteRune(char)
+			curType = alpha
+		} else {
+			if curType != other {
+				out = append(out, sb.String())
+				sb.Reset()
+			}
+			curType = other
+		}
+	}
+
+	if sb.Len() != 0 {
+		out = append(out, sb.String())
+	}
+
+	return out
+}
+
+func isNumElem(s string) bool {
+	// Check only the first rune as all elements
+	// should consist of the same type of rune
+	return isNum([]rune(s[:1])[0])
+}
+
+func isNum(r rune) bool {
+	return r >= '0' && r <= '9'
+}
+
+func isAlphaElem(s string) bool {
+	// Check only the first rune as all elements
+	// should consist of the same type of rune
+	return isAlpha([]rune(s[:1])[0])
+}
+
+func isAlpha(r rune) bool {
+	return (r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z')
+}