github.com/google/martian/v3@v3.3.3/martianurl/host.go (about) 1 // Copyright 2016 Google Inc. All rights reserved. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 package martianurl 16 17 // MatchHost matches two URL hosts with support for wildcards. 18 func MatchHost(host, match string) bool { 19 // Short circuit if host is empty. 20 if host == "" { 21 return false 22 } 23 24 // Exact match, no need to loop. 25 if host == match { 26 return true 27 } 28 29 // Walk backward over the host. 30 hi := len(host) - 1 31 for mi := len(match) - 1; mi >= 0; mi-- { 32 // Found wildcard, skip to next period. 33 if match[mi] == '*' { 34 for hi > 0 && host[hi] != '.' { 35 hi-- 36 } 37 38 // Wildcard was the leftmost part and we have walked the entire host, 39 // success. 40 if mi == 0 && hi == 0 { 41 return true 42 } 43 44 continue 45 } 46 47 if host[hi] != match[mi] { 48 return false 49 } 50 51 // We have walked the entire host, if we have not walked the entire matcher 52 // (mi != 0) that means the matcher has remaining characters to match and 53 // thus the host cannot match. 54 if hi == 0 { 55 return mi == 0 56 } 57 58 hi-- 59 } 60 61 // We have walked the entire length of the matcher, but haven't finished 62 // walking the host thus they cannot match. 63 return false 64 }