【转】 http://www.syyong.com/Go/Go-implementation-version-comparison-VersionCompare-function.html
VersionCompare — 用于对比两个的版本数字字符串大小。
此函数首先在版本字符串里用一个点 . 替换 _、- 和 +，也会在任意非数字前后插入一个点 .，这样，类似 '4.3.2RC1' 将会变成 '4.3.2.RC.1'。 接下来它会分割结果，然后它会从左往右对比各个部分。如果某部分包含了特定的版本字符串，将会用以下顺序处理：列表中未找到的任意字符串 < dev < alpha = a < beta = b < RC = rc < # < pl = p。 这种方式不仅能够对比类似 '4.1' 和 '4.1.2' 那种不同的版本级别，同时也可以指定对比任何包含开发状态的版本。
VersionCompare
// version_compare()
// The possible operators are: <, lt, <=, le, >, gt, >=, ge, ==, =, eq, !=, <>, ne respectively.
// special version strings these are handled in the following order,
// (any string not found) < dev < alpha = a < beta = b < RC = rc < # < pl = p
// Usage:
// VersionCompare("1.2.3-alpha", "1.2.3RC7", '>=')
// VersionCompare("1.2.3-beta", "1.2.3pl", 'lt')
// VersionCompare("1.1_dev", "1.2any", 'eq')
func VersionCompare(version1, version2, operator string) bool {
var vcompare func(string, string) int
var canonicalize func(string) string
var special func(string, string) int // version compare
vcompare = func(origV1, origV2 string) int {
if origV1 == "" || origV2 == "" {
if origV1 == "" && origV2 == "" {
return
} else {
if origV1 == "" {
return -
} else {
return
}
}
} ver1, ver2, compare := "", "",
if origV1[] == '#' {
ver1 = origV1
} else {
ver1 = canonicalize(origV1)
}
if origV2[] == '#' {
ver2 = origV2
} else {
ver2 = canonicalize(origV2)
}
n1, n2 := ,
for {
p1, p2 := "", ""
n1 = strings.IndexByte(ver1, '.')
if n1 == - {
p1, ver1 = ver1, ""
} else {
p1, ver1 = ver1[:n1], ver1[n1+:]
}
n2 = strings.IndexByte(ver2, '.')
if n2 == - {
p2, ver2 = ver2, ""
} else {
p2, ver2 = ver2[:n2], ver2[n2+:]
}
if (p1[] >= '' && p1[] <= '') && (p2[] >= '' && p2[] <= '') { // all isdigit
l1, _ := strconv.Atoi(p1)
l2, _ := strconv.Atoi(p2)
if l1 > l2 {
compare =
} else if l1 == l2 {
compare =
} else {
compare = -
}
} else if !(p1[] >= '' && p1[] <= '') && !(p2[] >= '' && p2[] <= '') { // all isndigit
compare = special(p1, p2)
} else { // part isdigit
if p1[] >= '' && p1[] <= '' { // isdigit
compare = special("#N#", p2)
} else {
compare = special(p1, "#N#")
}
}
if compare != || n1 == - || n2 == - {
break
}
} if compare == {
if ver1 != "" {
if ver1[] >= '' && ver1[] <= '' {
compare =
} else {
compare = vcompare(ver1, "#N#")
}
} else if ver2 != "" {
if ver2[] >= '' && ver2[] <= '' {
compare = -
} else {
compare = vcompare("#N#", ver2)
}
}
} return compare
} // canonicalize
canonicalize = func(version string) string {
ver := []byte(version)
l := len(ver)
if l == {
return ""
}
var buf = make([]byte, l*)
j :=
for i, v := range ver {
next := uint8()
if i+ < l { // Have the next one
next = ver[i+]
}
if v == '-' || v == '_' || v == '+' { // repalce "-","_","+" to "."
if j > && buf[j-] != '.' {
buf[j] = '.'
j++
}
} else if (next > ) &&
(!(next >= '' && next <= '') && (v >= '' && v <= '')) ||
(!(v >= '' && v <= '') && (next >= '' && next <= '')) { // Insert '.' before and after a non-digit
buf[j] = v
j++
if v != '.' && next != '.' {
buf[j] = '.'
j++
}
continue
} else if !((v >= '' && v <= '') ||
(v >= 'a' && v <= 'z') || (v >= 'A' && v <= 'Z')) { // Non-letters and numbers
if j > && buf[j-] != '.' {
buf[j] = '.'
j++
}
} else {
buf[j] = v
j++
}
} return string(buf[:j])
} //compare special version forms
special = func(form1, form2 string) int {
found1, found2, len1, len2 := -, -, len(form1), len(form2)
// (Any string not found) < dev < alpha = a < beta = b < RC = rc < # < pl = p
forms := map[string]int{
"dev": ,
"alpha": ,
"a": ,
"beta": ,
"b": ,
"RC": ,
"rc": ,
"#": ,
"pl": ,
"p": ,
} for name, order := range forms {
if len1 < len(name) {
continue
}
if strings.Compare(form1[:len(name)], name) == {
found1 = order
break
}
}
for name, order := range forms {
if len2 < len(name) {
continue
}
if strings.Compare(form2[:len(name)], name) == {
found2 = order
break
}
} if found1 == found2 {
return
} else if found1 > found2 {
return
} else {
return -
}
} compare := vcompare(version1, version2) switch operator {
case "<", "lt":
return compare == -
case "<=", "le":
return compare !=
case ">", "gt":
return compare ==
case ">=", "ge":
return compare != -
case "==", "=", "eq":
return compare ==
case "!=", "<>", "ne":
return compare !=
default:
panic("operator: invalid")
}
}