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/*
* Copyright (c) SAS Institute, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package rpmutils
import (
"regexp"
"strings"
)
var (
R_NONALNUMTILDE = regexp.MustCompile(`^([^a-zA-Z0-9~]*)(.*)$`)
R_NUM = regexp.MustCompile(`^([\d]+)(.*)$`)
R_ALPHA = regexp.MustCompile(`^([a-zA-Z]+)(.*)$`)
)
// VersionSlice provides the Sort interface for sorting version strings.
type VersionSlice []string
// Len is the number of elements in the collection.
func (vs VersionSlice) Len() int {
return len(vs)
}
// Less reports wheather the element with index i should sort before the
// element with index j.
func (vs VersionSlice) Less(i, j int) bool {
return Vercmp(vs[i], vs[j]) == -1
}
// Swap swaps the elements with indexes i and j.
func (vs VersionSlice) Swap(i, j int) {
s1 := vs[i]
vs[i] = vs[j]
vs[j] = s1
}
// Vercmp compares two version strings using the same algorithm as rpm uses.
// Returns -1 if first < second, 1 if first > second, and 0 if first == second.
func Vercmp(first, second string) int {
var m1Head, m2Head string
for first != "" || second != "" {
m1 := R_NONALNUMTILDE.FindStringSubmatch(first)
m2 := R_NONALNUMTILDE.FindStringSubmatch(second)
// This probably needs to return something different.
if m1 == nil || m2 == nil {
return 0
}
m1Head, first = m1[1], m1[2]
m2Head, second = m2[1], m2[2]
// Ignore junk at begining of version.
if m1Head != "" || m2Head != "" {
continue
}
// Hnalde the tolde seporator, it sorts before everything else.
if strings.HasPrefix(first, "~") {
if !strings.HasPrefix(second, "~") {
return -1
}
first, second = first[1:], second[1:]
continue
}
if strings.HasPrefix(second, "~") {
return 1
}
// If we ran to the end of either, we are finished with the loop.
if first == "" || second == "" {
break
}
// Grab the first completely alpha or completely numeric segment.
isnum := false
m1 = R_NUM.FindStringSubmatch(first)
m2 = R_NUM.FindStringSubmatch(second)
if R_NUM.MatchString(first) {
if !R_NUM.MatchString(second) {
// numeric segments are always newer than alpha segments.
return 1
}
isnum = true
} else {
m1 = R_ALPHA.FindStringSubmatch(first)
m2 = R_ALPHA.FindStringSubmatch(second)
}
if len(m1) == 0 {
// This condition should not be reached since we previously
// tested to make sure that the first string has a non-nill
// segment.
return -1
}
if len(m2) == 0 {
if isnum {
return 1
}
return -1
}
m1Head, first = m1[1], m1[2]
m2Head, second = m2[1], m2[2]
if isnum {
// Throw away any leading zeros.
m1Head = strings.TrimLeft(m1Head, "0")
m2Head = strings.TrimLeft(m2Head, "0")
// Whichever number has more digits wins
m1Hlen := len(m1Head)
m2Hlen := len(m2Head)
if m1Hlen < m2Hlen {
return -1
}
if m1Hlen > m2Hlen {
return 1
}
}
// Same number of chars
if m1Head < m2Head {
return -1
} else if m1Head > m2Head {
return 1
}
// Both segments equal
continue
}
m1Hlen := len(first)
m2Hlen := len(second)
if m1Hlen == 0 && m2Hlen == 0 {
return 0
}
if m1Hlen != 0 {
return 1
}
return -1
}
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