whatcanGOwrong

go/pkg/mod/golang.org/x/exp@v0.0.0-20230224173230-c95f2b4c22f2/shootout/regex-dna.go

@@ -0,0 +1,109 @@
+//go:build ignore
+// +build ignore
+
+/*
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in the
+    documentation and/or other materials provided with the distribution.
+
+    * Neither the name of "The Computer Language Benchmarks Game" nor the
+    name of "The Computer Language Shootout Benchmarks" nor the names of
+    its contributors may be used to endorse or promote products derived
+    from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/* The Computer Language Benchmarks Game
+ * http://shootout.alioth.debian.org/
+ *
+ * contributed by The Go Authors.
+ */
+
+package main
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"regexp"
+)
+
+var variants = []string{
+	"agggtaaa|tttaccct",
+	"[cgt]gggtaaa|tttaccc[acg]",
+	"a[act]ggtaaa|tttacc[agt]t",
+	"ag[act]gtaaa|tttac[agt]ct",
+	"agg[act]taaa|ttta[agt]cct",
+	"aggg[acg]aaa|ttt[cgt]ccct",
+	"agggt[cgt]aa|tt[acg]accct",
+	"agggta[cgt]a|t[acg]taccct",
+	"agggtaa[cgt]|[acg]ttaccct",
+}
+
+type Subst struct {
+	pat, repl string
+}
+
+var substs = []Subst{
+	Subst{"B", "(c|g|t)"},
+	Subst{"D", "(a|g|t)"},
+	Subst{"H", "(a|c|t)"},
+	Subst{"K", "(g|t)"},
+	Subst{"M", "(a|c)"},
+	Subst{"N", "(a|c|g|t)"},
+	Subst{"R", "(a|g)"},
+	Subst{"S", "(c|g)"},
+	Subst{"V", "(a|c|g)"},
+	Subst{"W", "(a|t)"},
+	Subst{"Y", "(c|t)"},
+}
+
+func countMatches(pat string, bytes []byte) int {
+	re := regexp.MustCompile(pat)
+	n := 0
+	for {
+		e := re.FindIndex(bytes)
+		if len(e) == 0 {
+			break
+		}
+		n++
+		bytes = bytes[e[1]:]
+	}
+	return n
+}
+
+func main() {
+	bytes, err := io.ReadAll(os.Stdin)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "can't read input: %s\n", err)
+		os.Exit(2)
+	}
+	ilen := len(bytes)
+	// Delete the comment lines and newlines
+	bytes = regexp.MustCompile("(>[^\n]+)?\n").ReplaceAll(bytes, []byte{})
+	clen := len(bytes)
+	for _, s := range variants {
+		fmt.Printf("%s %d\n", s, countMatches(s, bytes))
+	}
+	for _, sub := range substs {
+		bytes = regexp.MustCompile(sub.pat).ReplaceAll(bytes, []byte(sub.repl))
+	}
+	fmt.Printf("\n%d\n%d\n%d\n", ilen, clen, len(bytes))
+}