whatcanGOwrong

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

@@ -0,0 +1,108 @@
+//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 (
+	"bufio"
+	"os"
+)
+
+const lineSize = 60
+
+var complement = [256]uint8{
+	'A': 'T', 'a': 'T',
+	'C': 'G', 'c': 'G',
+	'G': 'C', 'g': 'C',
+	'T': 'A', 't': 'A',
+	'U': 'A', 'u': 'A',
+	'M': 'K', 'm': 'K',
+	'R': 'Y', 'r': 'Y',
+	'W': 'W', 'w': 'W',
+	'S': 'S', 's': 'S',
+	'Y': 'R', 'y': 'R',
+	'K': 'M', 'k': 'M',
+	'V': 'B', 'v': 'B',
+	'H': 'D', 'h': 'D',
+	'D': 'H', 'd': 'H',
+	'B': 'V', 'b': 'V',
+	'N': 'N', 'n': 'N',
+}
+
+func main() {
+	in := bufio.NewReader(os.Stdin)
+	buf := make([]byte, 1024*1024)
+	line, err := in.ReadSlice('\n')
+	for err == nil {
+		os.Stdout.Write(line)
+
+		// Accumulate reversed complement in buf[w:]
+		nchar := 0
+		w := len(buf)
+		for {
+			line, err = in.ReadSlice('\n')
+			if err != nil || line[0] == '>' {
+				break
+			}
+			line = line[0 : len(line)-1]
+			nchar += len(line)
+			if len(line)+nchar/60+128 >= w {
+				nbuf := make([]byte, len(buf)*5)
+				copy(nbuf[len(nbuf)-len(buf):], buf)
+				w += len(nbuf) - len(buf)
+				buf = nbuf
+			}
+
+			// This loop is the bottleneck.
+			for _, c := range line {
+				w--
+				buf[w] = complement[c]
+			}
+		}
+
+		// Copy down to beginning of buffer, inserting newlines.
+		// The loop left room for the newlines and 128 bytes of padding.
+		i := 0
+		for j := w; j < len(buf); j += 60 {
+			n := copy(buf[i:i+60], buf[j:])
+			buf[i+n] = '\n'
+			i += n + 1
+		}
+		os.Stdout.Write(buf[0:i])
+	}
+}