vendor HEAD main

1 files changed, 237 insertions, 0 deletions

diff --git a/vendor/github.com/tidwall/match/match.go b/vendor/github.com/tidwall/match/match.go
new file mode 100644
index 0000000..11da28f
--- /dev/null
+++ b/vendor/github.com/tidwall/match/match.go
@@ -0,0 +1,237 @@
+// Package match provides a simple pattern matcher with unicode support.
+package match
+
+import (
+	"unicode/utf8"
+)
+
+// Match returns true if str matches pattern. This is a very
+// simple wildcard match where '*' matches on any number characters
+// and '?' matches on any one character.
+//
+// pattern:
+// 	{ term }
+// term:
+// 	'*'         matches any sequence of non-Separator characters
+// 	'?'         matches any single non-Separator character
+// 	c           matches character c (c != '*', '?', '\\')
+// 	'\\' c      matches character c
+//
+func Match(str, pattern string) bool {
+	if pattern == "*" {
+		return true
+	}
+	return match(str, pattern, 0, nil, -1) == rMatch
+}
+
+// MatchLimit is the same as Match but will limit the complexity of the match
+// operation. This is to avoid long running matches, specifically to avoid ReDos
+// attacks from arbritary inputs.
+//
+// How it works:
+// The underlying match routine is recursive and may call itself when it
+// encounters a sandwiched wildcard pattern, such as: `user:*:name`.
+// Everytime it calls itself a counter is incremented.
+// The operation is stopped when counter > maxcomp*len(str).
+func MatchLimit(str, pattern string, maxcomp int) (matched, stopped bool) {
+	if pattern == "*" {
+		return true, false
+	}
+	counter := 0
+	r := match(str, pattern, len(str), &counter, maxcomp)
+	if r == rStop {
+		return false, true
+	}
+	return r == rMatch, false
+}
+
+type result int
+
+const (
+	rNoMatch result = iota
+	rMatch
+	rStop
+)
+
+func match(str, pat string, slen int, counter *int, maxcomp int) result {
+	// check complexity limit
+	if maxcomp > -1 {
+		if *counter > slen*maxcomp {
+			return rStop
+		}
+		*counter++
+	}
+
+	for len(pat) > 0 {
+		var wild bool
+		pc, ps := rune(pat[0]), 1
+		if pc > 0x7f {
+			pc, ps = utf8.DecodeRuneInString(pat)
+		}
+		var sc rune
+		var ss int
+		if len(str) > 0 {
+			sc, ss = rune(str[0]), 1
+			if sc > 0x7f {
+				sc, ss = utf8.DecodeRuneInString(str)
+			}
+		}
+		switch pc {
+		case '?':
+			if ss == 0 {
+				return rNoMatch
+			}
+		case '*':
+			// Ignore repeating stars.
+			for len(pat) > 1 && pat[1] == '*' {
+				pat = pat[1:]
+			}
+
+			// If this star is the last character then it must be a match.
+			if len(pat) == 1 {
+				return rMatch
+			}
+
+			// Match and trim any non-wildcard suffix characters.
+			var ok bool
+			str, pat, ok = matchTrimSuffix(str, pat)
+			if !ok {
+				return rNoMatch
+			}
+
+			// Check for single star again.
+			if len(pat) == 1 {
+				return rMatch
+			}
+
+			// Perform recursive wildcard search.
+			r := match(str, pat[1:], slen, counter, maxcomp)
+			if r != rNoMatch {
+				return r
+			}
+			if len(str) == 0 {
+				return rNoMatch
+			}
+			wild = true
+		default:
+			if ss == 0 {
+				return rNoMatch
+			}
+			if pc == '\\' {
+				pat = pat[ps:]
+				pc, ps = utf8.DecodeRuneInString(pat)
+				if ps == 0 {
+					return rNoMatch
+				}
+			}
+			if sc != pc {
+				return rNoMatch
+			}
+		}
+		str = str[ss:]
+		if !wild {
+			pat = pat[ps:]
+		}
+	}
+	if len(str) == 0 {
+		return rMatch
+	}
+	return rNoMatch
+}
+
+// matchTrimSuffix matches and trims any non-wildcard suffix characters.
+// Returns the trimed string and pattern.
+//
+// This is called because the pattern contains extra data after the wildcard
+// star. Here we compare any suffix characters in the pattern to the suffix of
+// the target string. Basically a reverse match that stops when a wildcard
+// character is reached. This is a little trickier than a forward match because
+// we need to evaluate an escaped character in reverse.
+//
+// Any matched characters will be trimmed from both the target
+// string and the pattern.
+func matchTrimSuffix(str, pat string) (string, string, bool) {
+	// It's expected that the pattern has at least two bytes and the first byte
+	// is a wildcard star '*'
+	match := true
+	for len(str) > 0 && len(pat) > 1 {
+		pc, ps := utf8.DecodeLastRuneInString(pat)
+		var esc bool
+		for i := 0; ; i++ {
+			if pat[len(pat)-ps-i-1] != '\\' {
+				if i&1 == 1 {
+					esc = true
+					ps++
+				}
+				break
+			}
+		}
+		if pc == '*' && !esc {
+			match = true
+			break
+		}
+		sc, ss := utf8.DecodeLastRuneInString(str)
+		if !((pc == '?' && !esc) || pc == sc) {
+			match = false
+			break
+		}
+		str = str[:len(str)-ss]
+		pat = pat[:len(pat)-ps]
+	}
+	return str, pat, match
+}
+
+var maxRuneBytes = [...]byte{244, 143, 191, 191}
+
+// Allowable parses the pattern and determines the minimum and maximum allowable
+// values that the pattern can represent.
+// When the max cannot be determined, 'true' will be returned
+// for infinite.
+func Allowable(pattern string) (min, max string) {
+	if pattern == "" || pattern[0] == '*' {
+		return "", ""
+	}
+
+	minb := make([]byte, 0, len(pattern))
+	maxb := make([]byte, 0, len(pattern))
+	var wild bool
+	for i := 0; i < len(pattern); i++ {
+		if pattern[i] == '*' {
+			wild = true
+			break
+		}
+		if pattern[i] == '?' {
+			minb = append(minb, 0)
+			maxb = append(maxb, maxRuneBytes[:]...)
+		} else {
+			minb = append(minb, pattern[i])
+			maxb = append(maxb, pattern[i])
+		}
+	}
+	if wild {
+		r, n := utf8.DecodeLastRune(maxb)
+		if r != utf8.RuneError {
+			if r < utf8.MaxRune {
+				r++
+				if r > 0x7f {
+					b := make([]byte, 4)
+					nn := utf8.EncodeRune(b, r)
+					maxb = append(maxb[:len(maxb)-n], b[:nn]...)
+				} else {
+					maxb = append(maxb[:len(maxb)-n], byte(r))
+				}
+			}
+		}
+	}
+	return string(minb), string(maxb)
+}
+
+// IsPattern returns true if the string is a pattern.
+func IsPattern(str string) bool {
+	for i := 0; i < len(str); i++ {
+		if str[i] == '*' || str[i] == '?' {
+			return true
+		}
+	}
+	return false
+}