2021 Day 5

2021/aoc/aoc.go

@@ -2,6 +2,8 @@ package aoc
 
 import (
 	"bufio"
+	"io"
+	"io/fs"
 	"os"
 	"strconv"
 	"strings"
@@ -36,3 +38,49 @@ func MustInt(s string) int {
 	}
 	return i
 }
+
+type Inputs struct {
+	fs fs.FS
+}
+
+func (i Inputs) ReadLines(path string) (lines []string) {
+	f, err := i.fs.Open(path)
+	if err != nil {
+		panic(err)
+	}
+	defer f.Close()
+
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		lines = append(lines, scanner.Text())
+	}
+	return lines
+}
+
+func (i Inputs) ReadFile(path string) string {
+	f, err := i.fs.Open(path)
+	if err != nil {
+		panic(err)
+	}
+	defer f.Close()
+	b, err := io.ReadAll(f)
+	if err != nil {
+		panic(err)
+	}
+	return strings.TrimSpace(string(b))
+}
+
+func Input() Inputs {
+	if len(os.Args) > 1 {
+		return Inputs{os.DirFS(os.Args[1])}
+	}
+	return Inputs{os.DirFS("./input")}
+}
+
+// Cut will be added to strings in Go 1.18, so hack it in for now!
+func Cut(s, sep string) (before, after string) {
+	if i := strings.Index(s, sep); i >= 0 {
+		return s[:i], s[i+len(sep):]
+	}
+	panic("Separator was not found in string")
+}