Implement a formatter for mintage files

1 files changed, 175 insertions, 0 deletions

diff --git a/cmd/mfmt/main.go b/cmd/mfmt/main.go
new file mode 100644
index 0000000..c0d2b92
--- /dev/null
+++ b/cmd/mfmt/main.go
@@ -0,0 +1,175 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"unsafe"
+
+	"git.thomasvoss.com/euro-cash.eu/mintages"
+)
+
+const cols = unsafe.Sizeof(mintages.Row{}.Cols) /
+	unsafe.Sizeof(mintages.Row{}.Cols[0])
+
+var rv int
+
+func main() {
+	if len(os.Args) == 1 {
+		if err := mfmt("-", os.Stdin, os.Stdout); err != nil {
+			warn(err)
+		}
+	}
+	for _, arg := range os.Args[1:] {
+		f, err := os.OpenFile(arg, os.O_RDWR, 0)
+		if err != nil {
+			warn(err)
+			continue
+		}
+		defer f.Close()
+		if err := mfmt(arg, f, f); err != nil {
+			warn(err)
+		}
+	}
+	os.Exit(rv)
+}
+
+func mfmt(path string, in io.Reader, out io.Writer) error {
+	data, err := mintages.Parse(in, path)
+	if err != nil {
+		return err
+	}
+
+	f, outfile := out.(*os.File)
+	if outfile {
+		_, err := f.Seek(0, io.SeekStart)
+		if err != nil {
+			return err
+		}
+	}
+
+	fmt.Fprintf(out, `BEGIN %d`, data.StartYear)
+	if len(data.Circ) != 0 {
+		fmt.Fprintln(out, "\n\nBEGIN CIRC")
+		formatSection(out, data.Circ)
+	}
+	if len(data.BU) != 0 {
+		fmt.Fprintln(out, "\n\nBEGIN BU")
+		formatSection(out, data.BU)
+	}
+	if len(data.Proof) != 0 {
+		fmt.Fprintln(out, "\n\nBEGIN PROOF")
+		formatSection(out, data.Proof)
+	}
+
+	if outfile {
+		if off, err := f.Seek(0, io.SeekCurrent); err != nil {
+			return err
+		} else if err = f.Truncate(off); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func formatSection(out io.Writer, rows []mintages.Row) {
+	var (
+		year       string
+		longestMM  int
+		longestNum [cols]int
+	)
+
+	for _, row := range rows {
+		s, mm, ok := strings.Cut(row.Label, "\u00A0")
+		if ok {
+			n := len(mm)
+			if s != year {
+				n++
+			}
+			longestMM = max(longestMM, n)
+		}
+		year = s
+		for i, col := range row.Cols {
+			longestNum[i] = max(longestNum[i], intlen(col))
+		}
+	}
+
+	extraSpace := 0
+	if longestMM != 0 {
+		extraSpace = 2
+	}
+
+	year = ""
+
+	for i, row := range rows {
+		var label string
+
+		s, mm, ok := strings.Cut(row.Label, "\u00A0")
+		if ok {
+			if s != year {
+				label = mm + "*: "
+			} else {
+				label = mm + ": "
+			}
+		}
+		year = s
+
+		fmt.Fprintf(out, "%-*s", longestMM+extraSpace, label)
+		for j, n := range row.Cols {
+			if j != 0 {
+				fmt.Fprintf(out, " ")
+			}
+			fmt.Fprintf(out, "%*s", longestNum[j], formatInt(n))
+		}
+
+		if i != len(rows)-1 {
+			fmt.Fprintln(out, "")
+		}
+	}
+}
+
+func formatInt(n int) string {
+	if n < -1 {
+		panic("mintage count is negative and not -1")
+	} else if n == -1 {
+		return "?"
+	}
+
+	in := strconv.Itoa(n)
+	dots := (len(in) - 1) / 3
+	out := make([]byte, len(in)+dots)
+
+	for i, j, k := len(in)-1, len(out)-1, 0; ; i, j = i-1, j-1 {
+		out[j] = in[i]
+		if i == 0 {
+			return string(out)
+		}
+		if k++; k == 3 {
+			j, k = j-1, 0
+			out[j] = '.'
+		}
+	}
+}
+
+func intlen(v int) int {
+	switch {
+	case v < -1:
+		panic("mintage count is negative and not -1")
+	case v == 0, v == -1:
+		return 1
+	default:
+		n := 0
+		for x := v; x != 0; x /= 10 {
+			n++
+		}
+		return n + (n-1)/3 /* Thousands separators */
+	}
+}
+
+func warn(e error) {
+	fmt.Fprintf(os.Stderr, "%s: %+v\n", filepath.Base(os.Args[0]), e)
+	rv = 1
+}