whatcanGOwrong

go/pkg/mod/github.com/go-delve/liner@v1.2.3-0.20231231155935-4726ab1d7f62/width.go

@@ -0,0 +1,90 @@
+package liner
+
+import (
+	"unicode"
+
+	"github.com/mattn/go-runewidth"
+)
+
+// These character classes are mostly zero width (when combined).
+// A few might not be, depending on the user's font. Fixing this
+// is non-trivial, given that some terminals don't support
+// ANSI DSR/CPR
+var zeroWidth = []*unicode.RangeTable{
+	unicode.Mn,
+	unicode.Me,
+	unicode.Cc,
+	unicode.Cf,
+}
+
+// countGlyphs considers zero-width characters to be zero glyphs wide,
+// and members of Chinese, Japanese, and Korean scripts to be 2 glyphs wide.
+func countGlyphs(s []rune) int {
+	n := 0
+	for _, r := range s {
+		// speed up the common case
+		if r < 127 {
+			n++
+			continue
+		}
+
+		n += runewidth.RuneWidth(r)
+	}
+	return n
+}
+
+func countMultiLineGlyphs(s []rune, columns int, start int) int {
+	n := start
+	for _, r := range s {
+		if r < 127 {
+			n++
+			continue
+		}
+		switch runewidth.RuneWidth(r) {
+		case 0:
+		case 1:
+			n++
+		case 2:
+			n += 2
+			// no room for a 2-glyphs-wide char in the ending
+			// so skip a column and display it at the beginning
+			if n%columns == 1 {
+				n++
+			}
+		}
+	}
+	return n
+}
+
+func getPrefixGlyphs(s []rune, num int) []rune {
+	p := 0
+	for n := 0; n < num && p < len(s); p++ {
+		// speed up the common case
+		if s[p] < 127 {
+			n++
+			continue
+		}
+		if !unicode.IsOneOf(zeroWidth, s[p]) {
+			n++
+		}
+	}
+	for p < len(s) && unicode.IsOneOf(zeroWidth, s[p]) {
+		p++
+	}
+	return s[:p]
+}
+
+func getSuffixGlyphs(s []rune, num int) []rune {
+	p := len(s)
+	for n := 0; n < num && p > 0; p-- {
+		// speed up the common case
+		if s[p-1] < 127 {
+			n++
+			continue
+		}
+		if !unicode.IsOneOf(zeroWidth, s[p-1]) {
+			n++
+		}
+	}
+	return s[p:]
+}