util: add a text wrapping function

1 files changed, 100 insertions, 0 deletions

diff --git a/util/text.go b/util/text.go
new file mode 100644
index 00000000..83a101d3
--- /dev/null
+++ b/util/text.go
@@ -0,0 +1,100 @@
+package util
+
+import (
+	"bytes"
+	"strings"
+)
+
+func WordWrap(text string, lineWidth int) (string, int) {
+	words := strings.Fields(strings.TrimSpace(text))
+	if len(words) == 0 {
+		return "", 1
+	}
+	lines := 1
+	wrapped := words[0]
+	spaceLeft := lineWidth - len(wrapped)
+	for _, word := range words[1:] {
+		if len(word)+1 > spaceLeft {
+			wrapped += "\n" + word
+			spaceLeft = lineWidth - len(word)
+			lines++
+		} else {
+			wrapped += " " + word
+			spaceLeft -= 1 + len(word)
+		}
+	}
+
+	return wrapped, lines
+}
+
+func TextWrap(text string, lineWidth int) (string, int) {
+	var textBuffer bytes.Buffer
+	var lineBuffer bytes.Buffer
+	nbLine := 1
+	firstLine := true
+
+	// tabs are formatted as 4 spaces
+	text = strings.Replace(text, "\t", "    ", 4)
+
+	for _, line := range strings.Split(text, "\n") {
+		spaceLeft := lineWidth
+
+		if !firstLine {
+			textBuffer.WriteString("\n")
+			nbLine++
+		}
+
+		firstWord := true
+
+		for _, word := range strings.Split(line, " ") {
+			if spaceLeft > len(word) {
+				if !firstWord {
+					lineBuffer.WriteString(" ")
+					spaceLeft -= 1
+				}
+				lineBuffer.WriteString(word)
+				spaceLeft -= len(word)
+				firstWord = false
+			} else {
+				if len(word) > lineWidth {
+					for len(word) > 0 {
+						l := minInt(spaceLeft, len(word))
+						part := word[:l]
+						word = word[l:]
+
+						lineBuffer.WriteString(part)
+						textBuffer.Write(lineBuffer.Bytes())
+						lineBuffer.Reset()
+
+						if len(word) > 0 {
+							textBuffer.WriteString("\n")
+							nbLine++
+						}
+
+						spaceLeft = lineWidth
+					}
+				} else {
+					textBuffer.WriteString(strings.TrimRight(lineBuffer.String(), " "))
+					textBuffer.WriteString("\n")
+					lineBuffer.Reset()
+					lineBuffer.WriteString(word)
+					firstWord = false
+					spaceLeft = lineWidth - len(word)
+					nbLine++
+				}
+			}
+		}
+		textBuffer.WriteString(strings.TrimRight(lineBuffer.String(), " "))
+		lineBuffer.Reset()
+		firstLine = false
+	}
+
+	return textBuffer.String(), nbLine
+}
+
+func minInt(a, b int) int {
+	if a > b {
+		return b
+	}
+	return a
+}