Release catalyst

caql/wildcard.go

@@ -0,0 +1,155 @@
+// Adapted from https://github.com/golang/go
+// Original License:
+//
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the https://go.dev/LICENSE file.
+
+package caql
+
+import (
+	"errors"
+	"strings"
+	"unicode/utf8"
+)
+
+// ErrBadPattern indicates a pattern was malformed.
+var ErrBadPattern = errors.New("syntax error in pattern")
+
+// match reports whether name matches the shell pattern.
+// The pattern syntax is:
+//
+//	pattern:
+//		{ term }
+//	term:
+//		'%'         matches any sequence of non-/ characters
+//		'_'         matches any single non-/ character
+//		c           matches character c (c != '%', '_', '\\')
+//		'\\' c      matches character c
+//
+// match requires pattern to match all of name, not just a substring.
+// The only possible returned error is ErrBadPattern, when pattern
+// is malformed.
+//
+func match(pattern, name string) (matched bool, err error) {
+Pattern:
+	for len(pattern) > 0 {
+		var star bool
+		var chunk string
+		star, chunk, pattern = scanChunk(pattern)
+		if star && chunk == "" {
+			// Trailing * matches rest of string unless it has a /.
+			return !strings.ContainsRune(name, '/'), nil
+		}
+		// Look for match at current position.
+		t, ok, err := matchChunk(chunk, name)
+		// if we're the last chunk, make sure we've exhausted the name
+		// otherwise we'll give a false result even if we could still match
+		// using the star
+		if ok && (len(t) == 0 || len(pattern) > 0) {
+			name = t
+			continue
+		}
+		if err != nil {
+			return false, err
+		}
+		if star {
+			// Look for match skipping i+1 bytes.
+			// Cannot skip /.
+			for i := 0; i < len(name) && name[i] != '/'; i++ {
+				t, ok, err := matchChunk(chunk, name[i+1:])
+				if ok {
+					// if we're the last chunk, make sure we exhausted the name
+					if len(pattern) == 0 && len(t) > 0 {
+						continue
+					}
+					name = t
+					continue Pattern
+				}
+				if err != nil {
+					return false, err
+				}
+			}
+		}
+		// Before returning false with no error,
+		// check that the remainder of the pattern is syntactically valid.
+		for len(pattern) > 0 {
+			_, chunk, pattern = scanChunk(pattern)
+			if _, _, err := matchChunk(chunk, ""); err != nil {
+				return false, err
+			}
+		}
+		return false, nil
+	}
+	return len(name) == 0, nil
+}
+
+// scanChunk gets the next segment of pattern, which is a non-star string
+// possibly preceded by a star.
+func scanChunk(pattern string) (star bool, chunk, rest string) {
+	for len(pattern) > 0 && pattern[0] == '%' {
+		pattern = pattern[1:]
+		star = true
+	}
+	var i int
+Scan:
+	for i = 0; i < len(pattern); i++ {
+		switch pattern[i] {
+		case '\\':
+			// error check handled in matchChunk: bad pattern.
+			if i+1 < len(pattern) {
+				i++
+			}
+		case '%':
+			break Scan
+		}
+	}
+	return star, pattern[0:i], pattern[i:]
+}
+
+// matchChunk checks whether chunk matches the beginning of s.
+// If so, it returns the remainder of s (after the match).
+// Chunk is all single-character operators: literals, char classes, and ?.
+func matchChunk(chunk, s string) (rest string, ok bool, err error) {
+	// failed records whether the match has failed.
+	// After the match fails, the loop continues on processing chunk,
+	// checking that the pattern is well-formed but no longer reading s.
+	failed := false
+	for len(chunk) > 0 {
+		if !failed && len(s) == 0 {
+			failed = true
+		}
+		switch chunk[0] {
+
+		case '_':
+			if !failed {
+				if s[0] == '/' {
+					failed = true
+				}
+				_, n := utf8.DecodeRuneInString(s)
+				s = s[n:]
+			}
+			chunk = chunk[1:]
+
+		case '\\':
+			chunk = chunk[1:]
+			if len(chunk) == 0 {
+				return "", false, ErrBadPattern
+			}
+			fallthrough
+
+		default:
+			if !failed {
+				if chunk[0] != s[0] {
+					failed = true
+				}
+				s = s[1:]
+			}
+			chunk = chunk[1:]
+		}
+	}
+	if failed {
+		return "", false, nil
+	}
+	return s, true, nil
+}