main: refactor a bit to get logic out of main and into ./cmd/

Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>

cmd/openssl.go

@@ -0,0 +1,68 @@
+package cmd
+
+import (
+	"bufio"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+
+	"github.com/kyokomi/emoji"
+)
+
+/*
+ParseOpenSSL expects some input like:
+```shell
+$> openssl sha256 tmp.efLuko
+SHA256(tmp.efLuko)= f18bd8b680e834ab8097a66deb0255821195d9624e39da6b65903ff6a09a01bb
+```
+*/
+func ParseOpenSSL(line string) (hash, filename string, sum []byte, err error) {
+	if !strings.Contains(line, "(") {
+		return "", "", nil, ErrNotOpenSSLLine
+	}
+	chunks := strings.SplitN(strings.TrimRight(line, "\n"), ")= ", 2)
+	if len(chunks) != 2 {
+		return "", "", nil, ErrNotOpenSSLLine
+	}
+	chunksprime := strings.SplitN(chunks[0], "(", 2)
+	if len(chunks) != 2 {
+		return "", "", nil, ErrNotOpenSSLLine
+	}
+	sum, err = hex.DecodeString(chunks[1])
+	if err != nil {
+		return "", "", nil, err
+	}
+	return chunksprime[0], chunksprime[1], sum, nil
+}
+
+// ErrNotOpenSSLLine when the line to parse is not formated like an OpenSSL checksum line
+var ErrNotOpenSSLLine = errors.New("not an openssl checksum line")
+
+// PrintOpenSSL reads in the content like from `openssl sha25 ...` and returns
+// in likeness but with emojisum instead.
+// TODO(vb) return a buffer that the caller can choose to print out themselves
+func PrintOpenSSL(rdr io.Reader) error {
+	buf := bufio.NewReader(rdr)
+	for {
+		line, err := buf.ReadString('\n')
+		if err != nil && err == io.EOF {
+			break
+		} else if err != nil {
+			return err
+		}
+		hash, name, sum, err := ParseOpenSSL(line)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "%s: %q\n", err, line)
+			continue
+		}
+		str := EmojiFromBytes(sum)
+		fmt.Printf("%s(%s)= %x\n", hash, name, sum)
+		fmt.Printf("%s(%s)= %s\n", hash, name, str)
+		fmt.Printf("%s(%s)= ", hash, name)
+		emoji.Println(str)
+	}
+	return nil
+}