feat: initial commit

vendor/github.com/charmbracelet/x/ansi/width.go

@@ -0,0 +1,113 @@
+package ansi
+
+import (
+	"bytes"
+
+	"github.com/charmbracelet/x/ansi/parser"
+	"github.com/mattn/go-runewidth"
+	"github.com/rivo/uniseg"
+)
+
+// Strip removes ANSI escape codes from a string.
+func Strip(s string) string {
+	var (
+		buf    bytes.Buffer         // buffer for collecting printable characters
+		ri     int                  // rune index
+		rw     int                  // rune width
+		pstate = parser.GroundState // initial state
+	)
+
+	// This implements a subset of the Parser to only collect runes and
+	// printable characters.
+	for i := range len(s) {
+		if pstate == parser.Utf8State {
+			// During this state, collect rw bytes to form a valid rune in the
+			// buffer. After getting all the rune bytes into the buffer,
+			// transition to GroundState and reset the counters.
+			buf.WriteByte(s[i])
+			ri++
+			if ri < rw {
+				continue
+			}
+			pstate = parser.GroundState
+			ri = 0
+			rw = 0
+			continue
+		}
+
+		state, action := parser.Table.Transition(pstate, s[i])
+		switch action {
+		case parser.CollectAction:
+			if state == parser.Utf8State {
+				// This action happens when we transition to the Utf8State.
+				rw = utf8ByteLen(s[i])
+				buf.WriteByte(s[i])
+				ri++
+			}
+		case parser.PrintAction, parser.ExecuteAction:
+			// collects printable ASCII and non-printable characters
+			buf.WriteByte(s[i])
+		}
+
+		// Transition to the next state.
+		// The Utf8State is managed separately above.
+		if pstate != parser.Utf8State {
+			pstate = state
+		}
+	}
+
+	return buf.String()
+}
+
+// StringWidth returns the width of a string in cells. This is the number of
+// cells that the string will occupy when printed in a terminal. ANSI escape
+// codes are ignored and wide characters (such as East Asians and emojis) are
+// accounted for.
+// This treats the text as a sequence of grapheme clusters.
+func StringWidth(s string) int {
+	return stringWidth(GraphemeWidth, s)
+}
+
+// StringWidthWc returns the width of a string in cells. This is the number of
+// cells that the string will occupy when printed in a terminal. ANSI escape
+// codes are ignored and wide characters (such as East Asians and emojis) are
+// accounted for.
+// This treats the text as a sequence of wide characters and runes.
+func StringWidthWc(s string) int {
+	return stringWidth(WcWidth, s)
+}
+
+func stringWidth(m Method, s string) int {
+	if s == "" {
+		return 0
+	}
+
+	var (
+		pstate  = parser.GroundState // initial state
+		cluster string
+		width   int
+	)
+
+	for i := 0; i < len(s); i++ {
+		state, action := parser.Table.Transition(pstate, s[i])
+		if state == parser.Utf8State {
+			var w int
+			cluster, _, w, _ = uniseg.FirstGraphemeClusterInString(s[i:], -1)
+			if m == WcWidth {
+				w = runewidth.StringWidth(cluster)
+			}
+			width += w
+			i += len(cluster) - 1
+			pstate = parser.GroundState
+			continue
+		}
+
+		if action == parser.PrintAction {
+			width++
+		}
+
+		pstate = state
+	}
+
+	return width
+}