limit usage of Sprint

internal/pkg/converter/converter.go

@@ -104,7 +104,7 @@ func (c *Converter) InitParse() {
 	c.AddStringParam(&c.Options.Title, "title", "", "Title of the EPUB")
 
 	c.AddSection("Config")
-	c.AddStringParam(&c.Options.Profile, "profile", c.Options.Profile, fmt.Sprintf("Profile to use: \n%s", c.Options.AvailableProfiles()))
+	c.AddStringParam(&c.Options.Profile, "profile", c.Options.Profile, "Profile to use: \n"+c.Options.AvailableProfiles())
 	c.AddIntParam(&c.Options.Quality, "quality", c.Options.Quality, "Quality of the image")
 	c.AddBoolParam(&c.Options.Grayscale, "grayscale", c.Options.Grayscale, "Grayscale image. Ideal for eInk devices.")
 	c.AddIntParam(&c.Options.GrayscaleMode, "grayscale-mode", c.Options.GrayscaleMode, "Grayscale Mode\n0 = normal\n1 = average\n2 = luminance")
@@ -298,10 +298,10 @@ func (c *Converter) Validate() error {
 	var defaultOutput string
 	inputBase := filepath.Clean(c.Options.Input)
 	if fi.IsDir() {
-		defaultOutput = fmt.Sprintf("%s.epub", inputBase)
+		defaultOutput = inputBase + ".epub"
 	} else {
 		ext := filepath.Ext(inputBase)
-		defaultOutput = fmt.Sprintf("%s.epub", inputBase[0:len(inputBase)-len(ext)])
+		defaultOutput = inputBase[0:len(inputBase)-len(ext)] + ".epub"
 	}
 
 	if c.Options.Output == "" {

internal/pkg/converter/options.go

@@ -9,6 +9,8 @@ import (
 	"strings"
 
 	"gopkg.in/yaml.v3"
+
+	"github.com/celogeek/go-comic-converter/v2/internal/pkg/utils"
 )
 
 type Options struct {
@@ -217,13 +219,7 @@ func (o *Options) ShowConfig() string {
 	var profileDesc string
 	profile := o.GetProfile()
 	if profile != nil {
-		profileDesc = fmt.Sprintf(
+		profileDesc = profile.String()
-			"%s - %s - %dx%d",
-			o.Profile,
-			profile.Description,
-			profile.Width,
-			profile.Height,
-		)
 	}
 
 	sortpathmode := ""
@@ -238,10 +234,10 @@ func (o *Options) ShowConfig() string {
 
 	aspectRatio := "auto"
 	if o.AspectRatio > 0 {
-		aspectRatio = fmt.Sprintf("1:%.02f", o.AspectRatio)
+		aspectRatio = "1:" + utils.FloatToString(o.AspectRatio, 2)
 	} else if o.AspectRatio < 0 {
 		if profile != nil {
-			aspectRatio = fmt.Sprintf("1:%0.2f (device)", float64(profile.Height)/float64(profile.Width))
+			aspectRatio = "1:" + utils.FloatToString(float64(profile.Height)/float64(profile.Width), 2) + " (device)"
 		} else {
 			aspectRatio = "1:?? (device)"
 		}
@@ -277,7 +273,14 @@ func (o *Options) ShowConfig() string {
 		{"Grayscale", o.Grayscale, true},
 		{"Grayscale mode", grayscaleMode, o.Grayscale},
 		{"Crop", o.Crop, true},
-		{"Crop ratio", fmt.Sprintf("%d Left - %d Up - %d Right - %d Bottom - Limit %d%% - Skip %v", o.CropRatioLeft, o.CropRatioUp, o.CropRatioRight, o.CropRatioBottom, o.CropLimit, o.CropSkipIfLimitReached), o.Crop},
+		{"Crop ratio",
+			utils.IntToString(o.CropRatioLeft) + " Left - " +
+				utils.IntToString(o.CropRatioUp) + " Up - " +
+				utils.IntToString(o.CropRatioRight) + " Right - " +
+				utils.IntToString(o.CropRatioBottom) + " Bottom - " +
+				"Limit " + utils.IntToString(o.CropLimit) + "% - " +
+				"Skip " + utils.BoolToString(o.CropSkipIfLimitReached),
+			o.Crop},
 		{"Brightness", o.Brightness, o.Brightness != 0},
 		{"Contrast", o.Contrast, o.Contrast != 0},
 		{"Auto contrast", o.AutoContrast, true},
@@ -288,11 +291,11 @@ func (o *Options) ShowConfig() string {
 		{"No blank image", o.NoBlankImage, true},
 		{"Manga", o.Manga, true},
 		{"Has cover", o.HasCover, true},
-		{"Limit", fmt.Sprintf("%d Mb", o.LimitMb), o.LimitMb != 0},
+		{"Limit", utils.IntToString(o.LimitMb) + " Mb", o.LimitMb != 0},
 		{"Strip first directory from toc", o.StripFirstDirectoryFromToc, true},
 		{"Sort path mode", sortpathmode, true},
-		{"Foreground color", fmt.Sprintf("#%s", o.ForegroundColor), true},
+		{"Foreground color", "#" + o.ForegroundColor, true},
-		{"Background color", fmt.Sprintf("#%s", o.BackgroundColor), true},
+		{"Background color", "#" + o.BackgroundColor, true},
 		{"Resize", !o.NoResize, true},
 		{"Aspect ratio", aspectRatio, true},
 		{"Portrait only", o.PortraitOnly, true},

internal/pkg/converter/profiles.go

@@ -4,6 +4,8 @@ package converter
 import (
 	"fmt"
 	"strings"
+
+	"github.com/celogeek/go-comic-converter/v2/internal/pkg/utils"
 )
 
 type Profile struct {
@@ -13,6 +15,10 @@ type Profile struct {
 	Height      int    `json:"height"`
 }
 
+func (p Profile) String() string {
+	return p.Code + " - " + p.Description + " - " + utils.IntToString(p.Width) + "x" + utils.IntToString(p.Height)
+}
+
 type Profiles map[string]Profile
 
 // NewProfiles Initialize list of all supported profiles.
@@ -61,9 +67,9 @@ func (p Profiles) String() string {
 	s := make([]string, 0)
 	for _, v := range p {
 		s = append(s, fmt.Sprintf(
-			"    - %-7s ( %9s ) - %s",
+			"    - %-7s - %4d x %-4d - %s",
 			v.Code,
-			fmt.Sprintf("%dx%d", v.Width, v.Height),
+			v.Width, v.Height,
 			v.Description,
 		))
 	}

internal/pkg/epub/epub.go

@@ -73,8 +73,8 @@ func (e EPUB) writeImage(wz epubzip.EPUBZip, img epubimage.EPUBImage, zipImg *zi
 	err := wz.WriteContent(
 		img.EPUBPagePath(),
 		[]byte(e.render(epubtemplates.Text, map[string]any{
-			"Title":      fmt.Sprintf("Image %d Part %d", img.Id, img.Part),
+			"Title":      "Image " + utils.IntToString(img.Id) + " Part " + utils.IntToString(img.Part),
-			"ViewPort":   fmt.Sprintf("width=%d,height=%d", e.Image.View.Width, e.Image.View.Height),
+			"ViewPort":   e.Image.View.Port(),
 			"ImagePath":  img.ImgPath(),
 			"ImageStyle": img.ImgStyle(e.Image.View.Width, e.Image.View.Height, ""),
 		})),
@@ -91,8 +91,8 @@ func (e EPUB) writeBlank(wz epubzip.EPUBZip, img epubimage.EPUBImage) error {
 	return wz.WriteContent(
 		img.EPUBSpacePath(),
 		[]byte(e.render(epubtemplates.Blank, map[string]any{
-			"Title":    fmt.Sprintf("Blank Page %d", img.Id),
+			"Title":    "Blank Page " + utils.IntToString(img.Id),
-			"ViewPort": fmt.Sprintf("width=%d,height=%d", e.Image.View.Width, e.Image.View.Height),
+			"ViewPort": e.Image.View.Port(),
 		})),
 	)
 }
@@ -102,16 +102,16 @@ func (e EPUB) writeCoverImage(wz epubzip.EPUBZip, img epubimage.EPUBImage, part,
 	title := "Cover"
 	text := ""
 	if totalParts > 1 {
-		text = fmt.Sprintf("%d / %d", part, totalParts)
+		text = utils.IntToString(part) + " / " + utils.IntToString(totalParts)
-		title = fmt.Sprintf("%s %s", title, text)
+		title = title + " " + text
 	}
 
 	if err := wz.WriteContent(
 		"OEBPS/Text/cover.xhtml",
 		[]byte(e.render(epubtemplates.Text, map[string]any{
 			"Title":      title,
-			"ViewPort":   fmt.Sprintf("width=%d,height=%d", e.Image.View.Width, e.Image.View.Height),
+			"ViewPort":   e.Image.View.Port(),
-			"ImagePath":  fmt.Sprintf("Images/cover.%s", e.Image.Format),
+			"ImagePath":  "Images/cover." + e.Image.Format,
 			"ImageStyle": img.ImgStyle(e.Image.View.Width, e.Image.View.Height, ""),
 		})),
 	); err != nil {
@@ -156,7 +156,7 @@ func (e EPUB) writeTitleImage(wz epubzip.EPUBZip, img epubimage.EPUBImage, title
 			"OEBPS/Text/space_title.xhtml",
 			[]byte(e.render(epubtemplates.Blank, map[string]any{
 				"Title":    "Blank Page Title",
-				"ViewPort": fmt.Sprintf("width=%d,height=%d", e.Image.View.Width, e.Image.View.Height),
+				"ViewPort": e.Image.View.Port(),
 			})),
 		); err != nil {
 			return err
@@ -167,8 +167,8 @@ func (e EPUB) writeTitleImage(wz epubzip.EPUBZip, img epubimage.EPUBImage, title
 		"OEBPS/Text/title.xhtml",
 		[]byte(e.render(epubtemplates.Text, map[string]any{
 			"Title":      title,
-			"ViewPort":   fmt.Sprintf("width=%d,height=%d", e.Image.View.Width, e.Image.View.Height),
+			"ViewPort":   e.Image.View.Port(),
-			"ImagePath":  fmt.Sprintf("Images/title.%s", e.Image.Format),
+			"ImagePath":  "Images/title." + e.Image.Format,
 			"ImageStyle": img.ImgStyle(e.Image.View.Width, e.Image.View.Height, titleAlign),
 		})),
 	); err != nil {
@@ -344,7 +344,7 @@ func (e EPUB) writePart(path string, currentPart, totalParts int, part epubPart,
 
 	title := e.Title
 	if totalParts > 1 {
-		title = fmt.Sprintf("%s [%d/%d]", title, currentPart, totalParts)
+		title = title + " [" + utils.IntToString(currentPart) + "/" + utils.IntToString(totalParts) + "]"
 	}
 
 	type zipContent struct {
@@ -450,12 +450,12 @@ func (e EPUB) Write() error {
 		ext := filepath.Ext(e.Output)
 		suffix := ""
 		if totalParts > 1 {
-			fmtLen := len(fmt.Sprint(totalParts))
+			fmtLen := utils.FormatNumberOfDigits(totalParts)
-			fmtPart := fmt.Sprintf(" Part %%0%dd of %%0%dd", fmtLen, fmtLen)
+			fmtPart := "Part " + fmtLen + " of " + fmtLen
 			suffix = fmt.Sprintf(fmtPart, i+1, totalParts)
 		}
 
-		path := fmt.Sprintf("%s%s%s", e.Output[0:len(e.Output)-len(ext)], suffix, ext)
+		path := e.Output[0:len(e.Output)-len(ext)] + suffix + ext
 
 		if err := e.writePart(
 			path,

internal/pkg/epubimage/epub_image.go

@@ -2,9 +2,10 @@
 package epubimage
 
 import (
-	"fmt"
 	"image"
 	"strings"
+
+	"github.com/celogeek/go-comic-converter/v2/internal/pkg/utils"
 )
 
 type EPUBImage struct {
@@ -25,47 +26,51 @@ type EPUBImage struct {
 
 // SpaceKey key name of the blank page after the image
 func (i EPUBImage) SpaceKey() string {
-	return fmt.Sprintf("space_%d", i.Id)
+	return "space_" + utils.IntToString(i.Id)
 }
 
 // SpacePath path of the blank page
 func (i EPUBImage) SpacePath() string {
-	return fmt.Sprintf("Text/%s.xhtml", i.SpaceKey())
+	return "Text/" + i.SpaceKey() + ".xhtml"
 }
 
 // EPUBSpacePath path of the blank page into the EPUB
 func (i EPUBImage) EPUBSpacePath() string {
-	return fmt.Sprintf("OEBPS/%s", i.SpacePath())
+	return "OEBPS/" + i.SpacePath()
+}
+
+func (i EPUBImage) PartKey() string {
+	return utils.IntToString(i.Id) + "_p" + utils.IntToString(i.Part)
 }
 
 // PageKey key for page
 func (i EPUBImage) PageKey() string {
-	return fmt.Sprintf("page_%d_p%d", i.Id, i.Part)
+	return "page_" + i.PartKey()
 }
 
 // PagePath page path linked to the image
 func (i EPUBImage) PagePath() string {
-	return fmt.Sprintf("Text/%s.xhtml", i.PageKey())
+	return "Text/" + i.PageKey() + ".xhtml"
 }
 
 // EPUBPagePath page path into the EPUB
 func (i EPUBImage) EPUBPagePath() string {
-	return fmt.Sprintf("OEBPS/%s", i.PagePath())
+	return "OEBPS/" + i.PagePath()
 }
 
 // ImgKey key for image
 func (i EPUBImage) ImgKey() string {
-	return fmt.Sprintf("img_%d_p%d", i.Id, i.Part)
+	return "img_" + i.PartKey()
 }
 
 // ImgPath image path
 func (i EPUBImage) ImgPath() string {
-	return fmt.Sprintf("Images/%s.%s", i.ImgKey(), i.Format)
+	return "Images/" + i.ImgKey() + "." + i.Format
 }
 
 // EPUBImgPath image path into the EPUB
 func (i EPUBImage) EPUBImgPath() string {
-	return fmt.Sprintf("OEBPS/%s", i.ImgPath())
+	return "OEBPS/" + i.ImgPath()
 }
 
 // ImgStyle style to apply to the image.
@@ -76,11 +81,11 @@ func (i EPUBImage) ImgStyle(viewWidth, viewHeight int, align string) string {
 	relWidth, relHeight := i.RelSize(viewWidth, viewHeight)
 	marginW, marginH := float64(viewWidth-relWidth)/2, float64(viewHeight-relHeight)/2
 
-	var style []string
+	style := make([]string, 0, 4)
 
-	style = append(style, fmt.Sprintf("width:%dpx", relWidth))
+	style = append(style, "width:"+utils.IntToString(relWidth)+"px")
-	style = append(style, fmt.Sprintf("height:%dpx", relHeight))
+	style = append(style, "height:"+utils.IntToString(relHeight)+"px")
-	style = append(style, fmt.Sprintf("top:%.2f%%", marginH*100/float64(viewHeight)))
+	style = append(style, "top:"+utils.FloatToString(marginH*100/float64(viewHeight), 2)+"%")
 	if align == "" {
 		switch i.Position {
 		case "rendition:page-spread-left":
@@ -88,7 +93,7 @@ func (i EPUBImage) ImgStyle(viewWidth, viewHeight int, align string) string {
 		case "rendition:page-spread-right":
 			style = append(style, "left:0")
 		default:
-			style = append(style, fmt.Sprintf("left:%.2f%%", marginW*100/float64(viewWidth)))
+			style = append(style, "left:"+utils.FloatToString(marginW*100/float64(viewWidth), 2)+"%")
 		}
 	} else {
 		style = append(style, align)

internal/pkg/epubimageprocessor/loader.go

@@ -404,7 +404,7 @@ func (e EPUBImageProcessor) loadPdf() (totalImages int, output chan task, err er
 	}
 
 	totalImages = len(pdf.Pages())
-	pageFmt := fmt.Sprintf("page %%0%dd", len(fmt.Sprintf("%d", totalImages)))
+	pageFmt := "page " + utils.FormatNumberOfDigits(totalImages)
 	output = make(chan task)
 	go func() {
 		defer close(output)

internal/pkg/epubimageprocessor/processor.go

@@ -2,7 +2,6 @@
 package epubimageprocessor
 
 import (
-	"fmt"
 	"image"
 	"image/color"
 	"image/draw"
@@ -324,7 +323,7 @@ func (e EPUBImageProcessor) CoverTitleData(o CoverTitleDataOptions) (epubzip.Ima
 	g.Draw(dst, o.Src)
 
 	return epubzip.CompressImage(
-		fmt.Sprintf("OEBPS/Images/%s.%s", o.Name, e.Image.Format),
+		"OEBPS/Images/"+o.Name+"."+e.Image.Format,
 		e.Image.Format,
 		dst,
 		e.Image.Quality,

internal/pkg/epuboptions/epub_options.go

@@ -1,8 +1,6 @@
 // Package epuboptions EPUBOptions for EPUB creation.
 package epuboptions
 
-import "fmt"
-
 type EPUBOptions struct {
 	Input                      string
 	Output                     string
@@ -29,5 +27,5 @@ func (o EPUBOptions) WorkersRatio(pct int) (nbWorkers int) {
 }
 
 func (o EPUBOptions) ImgStorage() string {
-	return fmt.Sprintf("%s.tmp", o.Output)
+	return o.Output + ".tmp"
 }

internal/pkg/epuboptions/image.go

@@ -20,3 +20,7 @@ type Image struct {
 	Format                    string
 	AppleBookCompatibility    bool
 }
+
+func (i Image) MediaType() string {
+	return "image/" + i.Format
+}

internal/pkg/epuboptions/view.go

@@ -1,8 +1,20 @@
 package epuboptions
 
+import (
+	"github.com/celogeek/go-comic-converter/v2/internal/pkg/utils"
+)
+
 type View struct {
 	Width, Height int
 	AspectRatio   float64
 	PortraitOnly  bool
 	Color         Color
 }
+
+func (v View) Dimension() string {
+	return utils.IntToString(v.Width) + "x" + utils.IntToString(v.Height)
+}
+
+func (v View) Port() string {
+	return "width=" + utils.IntToString(v.Width) + ",height=" + utils.IntToString(v.Height)
+}

internal/pkg/epubprogress/epub_progress.go

@@ -38,15 +38,19 @@ func New(o Options) EPUBProgress {
 		}
 	}
 
-	fmtJob := fmt.Sprintf("%%0%dd", len(fmt.Sprint(o.TotalJob)))
+	fmtJob := utils.FormatNumberOfDigits(o.TotalJob)
-	fmtDesc := fmt.Sprintf("[%s/%s] %%-15s", fmtJob, fmtJob)
 	return progressbar.NewOptions(o.Max,
 		progressbar.OptionSetWriter(os.Stderr),
 		progressbar.OptionThrottle(65*time.Millisecond),
 		progressbar.OptionOnCompletion(func() {
 			utils.Println()
 		}),
-		progressbar.OptionSetDescription(fmt.Sprintf(fmtDesc, o.CurrentJob, o.TotalJob, o.Description)),
+		progressbar.OptionSetDescription(fmt.Sprintf(
+			"["+fmtJob+"/"+fmtJob+"] %-15s",
+			o.CurrentJob,
+			o.TotalJob,
+			o.Description,
+		)),
 		progressbar.OptionSetWidth(60),
 		progressbar.OptionShowCount(),
 		progressbar.OptionSetRenderBlankState(true),

internal/pkg/epubtemplates/content.go

@@ -1,12 +1,11 @@
 package epubtemplates
 
 import (
-	"fmt"
-
 	"github.com/beevik/etree"
 
 	"github.com/celogeek/go-comic-converter/v2/internal/pkg/epubimage"
 	"github.com/celogeek/go-comic-converter/v2/internal/pkg/epuboptions"
+	"github.com/celogeek/go-comic-converter/v2/internal/pkg/utils"
 )
 
 type Content struct {
@@ -98,9 +97,9 @@ func (o Content) getMeta() []tag {
 		{"meta", tagAttrs{"property": "schema:accessibilityHazard"}, "noSoundHazard"},
 		{"meta", tagAttrs{"name": "book-type", "content": "comic"}, ""},
 		{"opf:meta", tagAttrs{"name": "fixed-layout", "content": "true"}, ""},
-		{"opf:meta", tagAttrs{"name": "original-resolution", "content": fmt.Sprintf("%dx%d", o.ImageOptions.View.Width, o.ImageOptions.View.Height)}, ""},
+		{"opf:meta", tagAttrs{"name": "original-resolution", "content": o.ImageOptions.View.Dimension()}, ""},
 		{"dc:title", tagAttrs{}, o.Title},
-		{"dc:identifier", tagAttrs{"id": "ean"}, fmt.Sprintf("urn:uuid:%s", o.UID)},
+		{"dc:identifier", tagAttrs{"id": "ean"}, "urn:uuid:" + o.UID},
 		{"dc:language", tagAttrs{}, "en"},
 		{"dc:creator", tagAttrs{}, o.Author},
 		{"dc:publisher", tagAttrs{}, o.Publisher},
@@ -134,7 +133,7 @@ func (o Content) getMeta() []tag {
 		metas = append(
 			metas,
 			tag{"meta", tagAttrs{"name": "calibre:series", "content": o.Title}, ""},
-			tag{"meta", tagAttrs{"name": "calibre:series_index", "content": fmt.Sprint(o.Current)}, ""},
+			tag{"meta", tagAttrs{"name": "calibre:series_index", "content": utils.IntToString(o.Current)}, ""},
 		)
 	}
 
@@ -145,7 +144,7 @@ func (o Content) getManifest() []tag {
 	var imageTags, pageTags, spaceTags []tag
 	addTag := func(img epubimage.EPUBImage, withSpace bool) {
 		imageTags = append(imageTags,
-			tag{"item", tagAttrs{"id": img.ImgKey(), "href": img.ImgPath(), "media-type": fmt.Sprintf("image/%s", o.ImageOptions.Format)}, ""},
+			tag{"item", tagAttrs{"id": img.ImgKey(), "href": img.ImgPath(), "media-type": o.ImageOptions.MediaType()}, ""},
 		)
 		pageTags = append(pageTags,
 			tag{"item", tagAttrs{"id": img.PageKey(), "href": img.PagePath(), "media-type": "application/xhtml+xml"}, ""},
@@ -161,13 +160,13 @@ func (o Content) getManifest() []tag {
 		{"item", tagAttrs{"id": "toc", "href": "toc.xhtml", "properties": "nav", "media-type": "application/xhtml+xml"}, ""},
 		{"item", tagAttrs{"id": "css", "href": "Text/style.css", "media-type": "text/css"}, ""},
 		{"item", tagAttrs{"id": "page_cover", "href": "Text/cover.xhtml", "media-type": "application/xhtml+xml"}, ""},
-		{"item", tagAttrs{"id": "img_cover", "href": fmt.Sprintf("Images/cover.%s", o.ImageOptions.Format), "media-type": fmt.Sprintf("image/%s", o.ImageOptions.Format)}, ""},
+		{"item", tagAttrs{"id": "img_cover", "href": "Images/cover." + o.ImageOptions.Format, "media-type": o.ImageOptions.MediaType()}, ""},
 	}
 
 	if o.HasTitlePage {
 		items = append(items,
 			tag{"item", tagAttrs{"id": "page_title", "href": "Text/title.xhtml", "media-type": "application/xhtml+xml"}, ""},
-			tag{"item", tagAttrs{"id": "img_title", "href": fmt.Sprintf("Images/title.%s", o.ImageOptions.Format), "media-type": fmt.Sprintf("image/%s", o.ImageOptions.Format)}, ""},
+			tag{"item", tagAttrs{"id": "img_title", "href": "Images/title." + o.ImageOptions.Format, "media-type": o.ImageOptions.MediaType()}, ""},
 		)
 
 		if !o.ImageOptions.View.PortraitOnly {
@@ -212,7 +211,7 @@ func (o Content) getSpineAuto() []tag {
 		}
 	}
 	getSpreadBlank := func() string {
-		return fmt.Sprintf("%s layout-blank", getSpread(false))
+		return getSpread(false) + " layout-blank"
 	}
 
 	var spine []tag

internal/pkg/utils/utils.go

@@ -3,6 +3,7 @@ package utils
 import (
 	"fmt"
 	"os"
+	"strconv"
 )
 
 func Printf(format string, a ...interface{}) {
@@ -12,3 +13,34 @@ func Printf(format string, a ...interface{}) {
 func Println(a ...interface{}) {
 	_, _ = fmt.Fprintln(os.Stderr, a...)
 }
+
+func IntToString(i int) string {
+	return strconv.FormatInt(int64(i), 10)
+}
+
+func FloatToString(f float64, precision int) string {
+	return strconv.FormatFloat(f, 'f', precision, 64)
+}
+
+func BoolToString(b bool) string {
+	if b {
+		return "true"
+	}
+	return "false"
+}
+
+func NumberOfDigits(i int) int {
+	x, count := 10, 1
+	if i < 0 {
+		i = -i
+		count++
+	}
+	for ; x <= i; count++ {
+		x *= 10
+	}
+	return count
+}
+
+func FormatNumberOfDigits(i int) string {
+	return "%0" + IntToString(NumberOfDigits(i)) + "d"
+}

internal/pkg/utils/utils_test.go

@@ -0,0 +1,62 @@
+package utils
+
+import "fmt"
+
+func ExampleFloatToString() {
+	fmt.Println("test=" + FloatToString(3.14151617, 0) + "=")
+	fmt.Println("test=" + FloatToString(3.14151617, 1) + "=")
+	fmt.Println("test=" + FloatToString(3.14151617, 2) + "=")
+	fmt.Println("test=" + FloatToString(3.14151617, 4) + "=")
+	// Output: test=3=
+	// test=3.1=
+	// test=3.14=
+	// test=3.1415=
+}
+
+func ExampleIntToString() {
+	fmt.Println("test=" + IntToString(159) + "=")
+	// Output: test=159=
+}
+
+func ExampleNumberOfDigits() {
+	fmt.Println(NumberOfDigits(0))
+	fmt.Println(NumberOfDigits(4))
+	fmt.Println(NumberOfDigits(10))
+	fmt.Println(NumberOfDigits(14))
+	fmt.Println(NumberOfDigits(256))
+	fmt.Println(NumberOfDigits(2004))
+	fmt.Println(NumberOfDigits(-5))
+	fmt.Println(NumberOfDigits(-10))
+	fmt.Println(NumberOfDigits(-12))
+
+	// Output: 1
+	// 1
+	// 2
+	// 2
+	// 3
+	// 4
+	// 2
+	// 3
+	// 3
+}
+
+func ExampleFormatNumberOfDigits() {
+	fmt.Println(FormatNumberOfDigits(0))
+	fmt.Println(FormatNumberOfDigits(4))
+	fmt.Println(FormatNumberOfDigits(10))
+	fmt.Println(FormatNumberOfDigits(14))
+	fmt.Println(FormatNumberOfDigits(256))
+	fmt.Println(FormatNumberOfDigits(2004))
+	fmt.Println(FormatNumberOfDigits(-5))
+	fmt.Println(FormatNumberOfDigits(-10))
+	fmt.Println(FormatNumberOfDigits(-12))
+	// Output: %01d
+	// %01d
+	// %02d
+	// %02d
+	// %03d
+	// %04d
+	// %02d
+	// %03d
+	// %03d
+}