libgo/go/golang.org/x/mod/semver/semver.go - gofrontend - Git at Google

 // Copyright 2018 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

 // Package semver implements comparison of semantic version strings.
 // In this package, semantic version strings must begin with a leading "v",
 // as in "v1.0.0".
 //
 // The general form of a semantic version string accepted by this package is
 //
 //	vMAJOR[.MINOR[.PATCH[-PRERELEASE][+BUILD]]]
 //
 // where square brackets indicate optional parts of the syntax;
 // MAJOR, MINOR, and PATCH are decimal integers without extra leading zeros;
 // PRERELEASE and BUILD are each a series of non-empty dot-separated identifiers
 // using only alphanumeric characters and hyphens; and
 // all-numeric PRERELEASE identifiers must not have leading zeros.
 //
 // This package follows Semantic Versioning 2.0.0 (see semver.org)
 // with two exceptions. First, it requires the "v" prefix. Second, it recognizes
 // vMAJOR and vMAJOR.MINOR (with no prerelease or build suffixes)
 // as shorthands for vMAJOR.0.0 and vMAJOR.MINOR.0.
 package semver

 // parsed returns the parsed form of a semantic version string.
 type parsed struct {
 	major      string
 	minor      string
 	patch      string
 	short      string
 	prerelease string
 	build      string
 	err        string
 }

 // IsValid reports whether v is a valid semantic version string.
 func IsValid(v string) bool {
 	_, ok := parse(v)
 	return ok
 }

 // Canonical returns the canonical formatting of the semantic version v.
 // It fills in any missing .MINOR or .PATCH and discards build metadata.
 // Two semantic versions compare equal only if their canonical formattings
 // are identical strings.
 // The canonical invalid semantic version is the empty string.
 func Canonical(v string) string {
 	p, ok := parse(v)
 	if !ok {
 		return ""
 	}
 	if p.build != "" {
 		return v[:len(v)-len(p.build)]
 	}
 	if p.short != "" {
 		return v + p.short
 	}
 	return v
 }

 // Major returns the major version prefix of the semantic version v.
 // For example, Major("v2.1.0") == "v2".
 // If v is an invalid semantic version string, Major returns the empty string.
 func Major(v string) string {
 	pv, ok := parse(v)
 	if !ok {
 		return ""
 	}
 	return v[:1+len(pv.major)]
 }

 // MajorMinor returns the major.minor version prefix of the semantic version v.
 // For example, MajorMinor("v2.1.0") == "v2.1".
 // If v is an invalid semantic version string, MajorMinor returns the empty string.
 func MajorMinor(v string) string {
 	pv, ok := parse(v)
 	if !ok {
 		return ""
 	}
 	i := 1 + len(pv.major)
 	if j := i + 1 + len(pv.minor); j <= len(v) && v[i] == '.' && v[i+1:j] == pv.minor {
 		return v[:j]
 	}
 	return v[:i] + "." + pv.minor
 }

 // Prerelease returns the prerelease suffix of the semantic version v.
 // For example, Prerelease("v2.1.0-pre+meta") == "-pre".
 // If v is an invalid semantic version string, Prerelease returns the empty string.
 func Prerelease(v string) string {
 	pv, ok := parse(v)
 	if !ok {
 		return ""
 	}
 	return pv.prerelease
 }

 // Build returns the build suffix of the semantic version v.
 // For example, Build("v2.1.0+meta") == "+meta".
 // If v is an invalid semantic version string, Build returns the empty string.
 func Build(v string) string {
 	pv, ok := parse(v)
 	if !ok {
 		return ""
 	}
 	return pv.build
 }

 // Compare returns an integer comparing two versions according to
 // semantic version precedence.
 // The result will be 0 if v == w, -1 if v < w, or +1 if v > w.
 //
 // An invalid semantic version string is considered less than a valid one.
 // All invalid semantic version strings compare equal to each other.
 func Compare(v, w string) int {
 	pv, ok1 := parse(v)
 	pw, ok2 := parse(w)
 	if !ok1 && !ok2 {
 		return 0
 	}
 	if !ok1 {
 		return -1
 	}
 	if !ok2 {
 		return +1
 	}
 	if c := compareInt(pv.major, pw.major); c != 0 {
 		return c
 	}
 	if c := compareInt(pv.minor, pw.minor); c != 0 {
 		return c
 	}
 	if c := compareInt(pv.patch, pw.patch); c != 0 {
 		return c
 	}
 	return comparePrerelease(pv.prerelease, pw.prerelease)
 }

 // Max canonicalizes its arguments and then returns the version string
 // that compares greater.
 func Max(v, w string) string {
 	v = Canonical(v)
 	w = Canonical(w)
 	if Compare(v, w) > 0 {
 		return v
 	}
 	return w
 }

 func parse(v string) (p parsed, ok bool) {
 	if v == "" || v[0] != 'v' {
 		p.err = "missing v prefix"
 		return
 	}
 	p.major, v, ok = parseInt(v[1:])
 	if !ok {
 		p.err = "bad major version"
 		return
 	}
 	if v == "" {
 		p.minor = "0"
 		p.patch = "0"
 		p.short = ".0.0"
 		return
 	}
 	if v[0] != '.' {
 		p.err = "bad minor prefix"
 		ok = false
 		return
 	}
 	p.minor, v, ok = parseInt(v[1:])
 	if !ok {
 		p.err = "bad minor version"
 		return
 	}
 	if v == "" {
 		p.patch = "0"
 		p.short = ".0"
 		return
 	}
 	if v[0] != '.' {
 		p.err = "bad patch prefix"
 		ok = false
 		return
 	}
 	p.patch, v, ok = parseInt(v[1:])
 	if !ok {
 		p.err = "bad patch version"
 		return
 	}
 	if len(v) > 0 && v[0] == '-' {
 		p.prerelease, v, ok = parsePrerelease(v)
 		if !ok {
 			p.err = "bad prerelease"
 			return
 		}
 	}
 	if len(v) > 0 && v[0] == '+' {
 		p.build, v, ok = parseBuild(v)
 		if !ok {
 			p.err = "bad build"
 			return
 		}
 	}
 	if v != "" {
 		p.err = "junk on end"
 		ok = false
 		return
 	}
 	ok = true
 	return
 }

 func parseInt(v string) (t, rest string, ok bool) {
 	if v == "" {
 		return
 	}
 	if v[0] < '0' || '9' < v[0] {
 		return
 	}
 	i := 1
 	for i < len(v) && '0' <= v[i] && v[i] <= '9' {
 		i++
 	}
 	if v[0] == '0' && i != 1 {
 		return
 	}
 	return v[:i], v[i:], true
 }

 func parsePrerelease(v string) (t, rest string, ok bool) {
 	// "A pre-release version MAY be denoted by appending a hyphen and
 	// a series of dot separated identifiers immediately following the patch version.
 	// Identifiers MUST comprise only ASCII alphanumerics and hyphen [0-9A-Za-z-].
 	// Identifiers MUST NOT be empty. Numeric identifiers MUST NOT include leading zeroes."
 	if v == "" || v[0] != '-' {
 		return
 	}
 	i := 1
 	start := 1
 	for i < len(v) && v[i] != '+' {
 		if !isIdentChar(v[i]) && v[i] != '.' {
 			return
 		}
 		if v[i] == '.' {
 			if start == i || isBadNum(v[start:i]) {
 				return
 			}
 			start = i + 1
 		}
 		i++
 	}
 	if start == i || isBadNum(v[start:i]) {
 		return
 	}
 	return v[:i], v[i:], true
 }

 func parseBuild(v string) (t, rest string, ok bool) {
 	if v == "" || v[0] != '+' {
 		return
 	}
 	i := 1
 	start := 1
 	for i < len(v) {
 		if !isIdentChar(v[i]) && v[i] != '.' {
 			return
 		}
 		if v[i] == '.' {
 			if start == i {
 				return
 			}
 			start = i + 1
 		}
 		i++
 	}
 	if start == i {
 		return
 	}
 	return v[:i], v[i:], true
 }

 func isIdentChar(c byte) bool {
 	return 'A' <= c && c <= 'Z' || 'a' <= c && c <= 'z' || '0' <= c && c <= '9' || c == '-'
 }

 func isBadNum(v string) bool {
 	i := 0
 	for i < len(v) && '0' <= v[i] && v[i] <= '9' {
 		i++
 	}
 	return i == len(v) && i > 1 && v[0] == '0'
 }

 func isNum(v string) bool {
 	i := 0
 	for i < len(v) && '0' <= v[i] && v[i] <= '9' {
 		i++
 	}
 	return i == len(v)
 }

 func compareInt(x, y string) int {
 	if x == y {
 		return 0
 	}
 	if len(x) < len(y) {
 		return -1
 	}
 	if len(x) > len(y) {
 		return +1
 	}
 	if x < y {
 		return -1
 	} else {
 		return +1
 	}
 }

 func comparePrerelease(x, y string) int {
 	// "When major, minor, and patch are equal, a pre-release version has
 	// lower precedence than a normal version.
 	// Example: 1.0.0-alpha < 1.0.0.
 	// Precedence for two pre-release versions with the same major, minor,
 	// and patch version MUST be determined by comparing each dot separated
 	// identifier from left to right until a difference is found as follows:
 	// identifiers consisting of only digits are compared numerically and
 	// identifiers with letters or hyphens are compared lexically in ASCII
 	// sort order. Numeric identifiers always have lower precedence than
 	// non-numeric identifiers. A larger set of pre-release fields has a
 	// higher precedence than a smaller set, if all of the preceding
 	// identifiers are equal.
 	// Example: 1.0.0-alpha < 1.0.0-alpha.1 < 1.0.0-alpha.beta <
 	// 1.0.0-beta < 1.0.0-beta.2 < 1.0.0-beta.11 < 1.0.0-rc.1 < 1.0.0."
 	if x == y {
 		return 0
 	}
 	if x == "" {
 		return +1
 	}
 	if y == "" {
 		return -1
 	}
 	for x != "" && y != "" {
 		x = x[1:] // skip - or .
 		y = y[1:] // skip - or .
 		var dx, dy string
 		dx, x = nextIdent(x)
 		dy, y = nextIdent(y)
 		if dx != dy {
 			ix := isNum(dx)
 			iy := isNum(dy)
 			if ix != iy {
 				if ix {
 					return -1
 				} else {
 					return +1
 				}
 			}
 			if ix {
 				if len(dx) < len(dy) {
 					return -1
 				}
 				if len(dx) > len(dy) {
 					return +1
 				}
 			}
 			if dx < dy {
 				return -1
 			} else {
 				return +1
 			}
 		}
 	}
 	if x == "" {
 		return -1
 	} else {
 		return +1
 	}
 }

 func nextIdent(x string) (dx, rest string) {
 	i := 0
 	for i < len(x) && x[i] != '.' {
 		i++
 	}
 	return x[:i], x[i:]
 }
	// Copyright 2018 The Go Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.

	// Package semver implements comparison of semantic version strings.
	// In this package, semantic version strings must begin with a leading "v",
	// as in "v1.0.0".
	//
	// The general form of a semantic version string accepted by this package is
	//
	// vMAJOR[.MINOR[.PATCH[-PRERELEASE][+BUILD]]]
	//
	// where square brackets indicate optional parts of the syntax;
	// MAJOR, MINOR, and PATCH are decimal integers without extra leading zeros;
	// PRERELEASE and BUILD are each a series of non-empty dot-separated identifiers
	// using only alphanumeric characters and hyphens; and
	// all-numeric PRERELEASE identifiers must not have leading zeros.
	//
	// This package follows Semantic Versioning 2.0.0 (see semver.org)
	// with two exceptions. First, it requires the "v" prefix. Second, it recognizes
	// vMAJOR and vMAJOR.MINOR (with no prerelease or build suffixes)
	// as shorthands for vMAJOR.0.0 and vMAJOR.MINOR.0.
	package semver

	// parsed returns the parsed form of a semantic version string.
	type parsed struct {
	major string
	minor string
	patch string
	short string
	prerelease string
	build string
	err string
	}

	// IsValid reports whether v is a valid semantic version string.
	func IsValid(v string) bool {
	_, ok := parse(v)
	return ok
	}

	// Canonical returns the canonical formatting of the semantic version v.
	// It fills in any missing .MINOR or .PATCH and discards build metadata.
	// Two semantic versions compare equal only if their canonical formattings
	// are identical strings.
	// The canonical invalid semantic version is the empty string.
	func Canonical(v string) string {
	p, ok := parse(v)
	if !ok {
	return ""
	}
	if p.build != "" {
	return v[:len(v)-len(p.build)]
	}
	if p.short != "" {
	return v + p.short
	}
	return v
	}

	// Major returns the major version prefix of the semantic version v.
	// For example, Major("v2.1.0") == "v2".
	// If v is an invalid semantic version string, Major returns the empty string.
	func Major(v string) string {
	pv, ok := parse(v)
	if !ok {
	return ""
	}
	return v[:1+len(pv.major)]
	}

	// MajorMinor returns the major.minor version prefix of the semantic version v.
	// For example, MajorMinor("v2.1.0") == "v2.1".
	// If v is an invalid semantic version string, MajorMinor returns the empty string.
	func MajorMinor(v string) string {
	pv, ok := parse(v)
	if !ok {
	return ""
	}
	i := 1 + len(pv.major)
	if j := i + 1 + len(pv.minor); j <= len(v) && v[i] == '.' && v[i+1:j] == pv.minor {
	return v[:j]
	}
	return v[:i] + "." + pv.minor
	}

	// Prerelease returns the prerelease suffix of the semantic version v.
	// For example, Prerelease("v2.1.0-pre+meta") == "-pre".
	// If v is an invalid semantic version string, Prerelease returns the empty string.
	func Prerelease(v string) string {
	pv, ok := parse(v)
	if !ok {
	return ""
	}
	return pv.prerelease
	}

	// Build returns the build suffix of the semantic version v.
	// For example, Build("v2.1.0+meta") == "+meta".
	// If v is an invalid semantic version string, Build returns the empty string.
	func Build(v string) string {
	pv, ok := parse(v)
	if !ok {
	return ""
	}
	return pv.build
	}

	// Compare returns an integer comparing two versions according to
	// semantic version precedence.
	// The result will be 0 if v == w, -1 if v < w, or +1 if v > w.
	//
	// An invalid semantic version string is considered less than a valid one.
	// All invalid semantic version strings compare equal to each other.
	func Compare(v, w string) int {
	pv, ok1 := parse(v)
	pw, ok2 := parse(w)
	if !ok1 && !ok2 {
	return 0
	}
	if !ok1 {
	return -1
	}
	if !ok2 {
	return +1
	}
	if c := compareInt(pv.major, pw.major); c != 0 {
	return c
	}
	if c := compareInt(pv.minor, pw.minor); c != 0 {
	return c
	}
	if c := compareInt(pv.patch, pw.patch); c != 0 {
	return c
	}
	return comparePrerelease(pv.prerelease, pw.prerelease)
	}

	// Max canonicalizes its arguments and then returns the version string
	// that compares greater.
	func Max(v, w string) string {
	v = Canonical(v)
	w = Canonical(w)
	if Compare(v, w) > 0 {
	return v
	}
	return w
	}

	func parse(v string) (p parsed, ok bool) {
	if v == "" \|\| v[0] != 'v' {
	p.err = "missing v prefix"
	return
	}
	p.major, v, ok = parseInt(v[1:])
	if !ok {
	p.err = "bad major version"
	return
	}
	if v == "" {
	p.minor = "0"
	p.patch = "0"
	p.short = ".0.0"
	return
	}
	if v[0] != '.' {
	p.err = "bad minor prefix"
	ok = false
	return
	}
	p.minor, v, ok = parseInt(v[1:])
	if !ok {
	p.err = "bad minor version"
	return
	}
	if v == "" {
	p.patch = "0"
	p.short = ".0"
	return
	}
	if v[0] != '.' {
	p.err = "bad patch prefix"
	ok = false
	return
	}
	p.patch, v, ok = parseInt(v[1:])
	if !ok {
	p.err = "bad patch version"
	return
	}
	if len(v) > 0 && v[0] == '-' {
	p.prerelease, v, ok = parsePrerelease(v)
	if !ok {
	p.err = "bad prerelease"
	return
	}
	}
	if len(v) > 0 && v[0] == '+' {
	p.build, v, ok = parseBuild(v)
	if !ok {
	p.err = "bad build"
	return
	}
	}
	if v != "" {
	p.err = "junk on end"
	ok = false
	return
	}
	ok = true
	return
	}

	func parseInt(v string) (t, rest string, ok bool) {
	if v == "" {
	return
	}
	if v[0] < '0' \|\| '9' < v[0] {
	return
	}
	i := 1
	for i < len(v) && '0' <= v[i] && v[i] <= '9' {
	i++
	}
	if v[0] == '0' && i != 1 {
	return
	}
	return v[:i], v[i:], true
	}

	func parsePrerelease(v string) (t, rest string, ok bool) {
	// "A pre-release version MAY be denoted by appending a hyphen and
	// a series of dot separated identifiers immediately following the patch version.
	// Identifiers MUST comprise only ASCII alphanumerics and hyphen [0-9A-Za-z-].
	// Identifiers MUST NOT be empty. Numeric identifiers MUST NOT include leading zeroes."
	if v == "" \|\| v[0] != '-' {
	return
	}
	i := 1
	start := 1
	for i < len(v) && v[i] != '+' {
	if !isIdentChar(v[i]) && v[i] != '.' {
	return
	}
	if v[i] == '.' {
	if start == i \|\| isBadNum(v[start:i]) {
	return
	}
	start = i + 1
	}
	i++
	}
	if start == i \|\| isBadNum(v[start:i]) {
	return
	}
	return v[:i], v[i:], true
	}

	func parseBuild(v string) (t, rest string, ok bool) {
	if v == "" \|\| v[0] != '+' {
	return
	}
	i := 1
	start := 1
	for i < len(v) {
	if !isIdentChar(v[i]) && v[i] != '.' {
	return
	}
	if v[i] == '.' {
	if start == i {
	return
	}
	start = i + 1
	}
	i++
	}
	if start == i {
	return
	}
	return v[:i], v[i:], true
	}

	func isIdentChar(c byte) bool {
	return 'A' <= c && c <= 'Z' \|\| 'a' <= c && c <= 'z' \|\| '0' <= c && c <= '9' \|\| c == '-'
	}

	func isBadNum(v string) bool {
	i := 0
	for i < len(v) && '0' <= v[i] && v[i] <= '9' {
	i++
	}
	return i == len(v) && i > 1 && v[0] == '0'
	}

	func isNum(v string) bool {
	i := 0
	for i < len(v) && '0' <= v[i] && v[i] <= '9' {
	i++
	}
	return i == len(v)
	}

	func compareInt(x, y string) int {
	if x == y {
	return 0
	}
	if len(x) < len(y) {
	return -1
	}
	if len(x) > len(y) {
	return +1
	}
	if x < y {
	return -1
	} else {
	return +1
	}
	}

	func comparePrerelease(x, y string) int {
	// "When major, minor, and patch are equal, a pre-release version has
	// lower precedence than a normal version.
	// Example: 1.0.0-alpha < 1.0.0.
	// Precedence for two pre-release versions with the same major, minor,
	// and patch version MUST be determined by comparing each dot separated
	// identifier from left to right until a difference is found as follows:
	// identifiers consisting of only digits are compared numerically and
	// identifiers with letters or hyphens are compared lexically in ASCII
	// sort order. Numeric identifiers always have lower precedence than
	// non-numeric identifiers. A larger set of pre-release fields has a
	// higher precedence than a smaller set, if all of the preceding
	// identifiers are equal.
	// Example: 1.0.0-alpha < 1.0.0-alpha.1 < 1.0.0-alpha.beta <
	// 1.0.0-beta < 1.0.0-beta.2 < 1.0.0-beta.11 < 1.0.0-rc.1 < 1.0.0."
	if x == y {
	return 0
	}
	if x == "" {
	return +1
	}
	if y == "" {
	return -1
	}
	for x != "" && y != "" {
	x = x[1:] // skip - or .
	y = y[1:] // skip - or .
	var dx, dy string
	dx, x = nextIdent(x)
	dy, y = nextIdent(y)
	if dx != dy {
	ix := isNum(dx)
	iy := isNum(dy)
	if ix != iy {
	if ix {
	return -1
	} else {
	return +1
	}
	}
	if ix {
	if len(dx) < len(dy) {
	return -1
	}
	if len(dx) > len(dy) {
	return +1
	}
	}
	if dx < dy {
	return -1
	} else {
	return +1
	}
	}
	}
	if x == "" {
	return -1
	} else {
	return +1
	}
	}

	func nextIdent(x string) (dx, rest string) {
	i := 0
	for i < len(x) && x[i] != '.' {
	i++
	}
	return x[:i], x[i:]
	}