gomuks/lib/glob/glob.go

109 lines
2.0 KiB
Go

// Package glob provides objects for matching strings with globs
package glob
import "regexp"
// Glob is a wrapper of *regexp.Regexp.
// It should contain a glob expression compiled into a regular expression.
type Glob struct {
*regexp.Regexp
}
// Compile a takes a glob expression as a string and transforms it
// into a *Glob object (which is really just a regular expression)
// Compile also returns a possible error.
func Compile(pattern string) (*Glob, error) {
r, err := globToRegex(pattern)
return &Glob{r}, err
}
func globToRegex(glob string) (*regexp.Regexp, error) {
regex := ""
inGroup := 0
inClass := 0
firstIndexInClass := -1
arr := []byte(glob)
hasGlobCharacters := false
for i := 0; i < len(arr); i++ {
ch := arr[i]
switch ch {
case '\\':
i++
if i >= len(arr) {
regex += "\\"
} else {
next := arr[i]
switch next {
case ',':
// Nothing
case 'Q', 'E':
regex += "\\\\"
default:
regex += "\\"
}
regex += string(next)
}
case '*':
if inClass == 0 {
regex += ".*"
} else {
regex += "*"
}
hasGlobCharacters = true
case '?':
if inClass == 0 {
regex += "."
} else {
regex += "?"
}
hasGlobCharacters = true
case '[':
inClass++
firstIndexInClass = i + 1
regex += "["
hasGlobCharacters = true
case ']':
inClass--
regex += "]"
case '.', '(', ')', '+', '|', '^', '$', '@', '%':
if inClass == 0 || (firstIndexInClass == i && ch == '^') {
regex += "\\"
}
regex += string(ch)
hasGlobCharacters = true
case '!':
if firstIndexInClass == i {
regex += "^"
} else {
regex += "!"
}
hasGlobCharacters = true
case '{':
inGroup++
regex += "("
hasGlobCharacters = true
case '}':
inGroup--
regex += ")"
case ',':
if inGroup > 0 {
regex += "|"
hasGlobCharacters = true
} else {
regex += ","
}
default:
regex += string(ch)
}
}
if hasGlobCharacters {
return regexp.Compile("^" + regex + "$")
} else {
return regexp.Compile(regex)
}
}