chore: vendor

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

@@ -0,0 +1,112 @@
+package ansi
+
+import (
+	"bytes"
+
+	"github.com/charmbracelet/x/ansi/parser"
+	"github.com/rivo/uniseg"
+)
+
+// Truncate truncates a string to a given length, adding a tail to the
+// end if the string is longer than the given length.
+// This function is aware of ANSI escape codes and will not break them, and
+// accounts for wide-characters (such as East Asians and emojis).
+func Truncate(s string, length int, tail string) string {
+	if sw := StringWidth(s); sw <= length {
+		return s
+	}
+
+	tw := StringWidth(tail)
+	length -= tw
+	if length < 0 {
+		return ""
+	}
+
+	var cluster []byte
+	var buf bytes.Buffer
+	curWidth := 0
+	ignoring := false
+	gstate := -1
+	pstate := parser.GroundState // initial state
+	b := []byte(s)
+	i := 0
+
+	// Here we iterate over the bytes of the string and collect printable
+	// characters and runes. We also keep track of the width of the string
+	// in cells.
+	// Once we reach the given length, we start ignoring characters and only
+	// collect ANSI escape codes until we reach the end of string.
+	for i < len(b) {
+		state, action := parser.Table.Transition(pstate, b[i])
+
+		switch action {
+		case parser.PrintAction:
+			if utf8ByteLen(b[i]) > 1 {
+				// This action happens when we transition to the Utf8State.
+				var width int
+				cluster, _, width, gstate = uniseg.FirstGraphemeCluster(b[i:], gstate)
+
+				// increment the index by the length of the cluster
+				i += len(cluster)
+
+				// Are we ignoring? Skip to the next byte
+				if ignoring {
+					continue
+				}
+
+				// Is this gonna be too wide?
+				// If so write the tail and stop collecting.
+				if curWidth+width > length && !ignoring {
+					ignoring = true
+					buf.WriteString(tail)
+				}
+
+				if curWidth+width > length {
+					continue
+				}
+
+				curWidth += width
+				for _, r := range cluster {
+					buf.WriteByte(r)
+				}
+
+				gstate = -1 // reset grapheme state otherwise, width calculation might be off
+				// Done collecting, now we're back in the ground state.
+				pstate = parser.GroundState
+				continue
+			}
+
+			// Is this gonna be too wide?
+			// If so write the tail and stop collecting.
+			if curWidth >= length && !ignoring {
+				ignoring = true
+				buf.WriteString(tail)
+			}
+
+			// Skip to the next byte if we're ignoring
+			if ignoring {
+				i++
+				continue
+			}
+
+			// collects printable ASCII
+			curWidth++
+			fallthrough
+		default:
+			buf.WriteByte(b[i])
+			i++
+		}
+
+		// Transition to the next state.
+		pstate = state
+
+		// Once we reach the given length, we start ignoring runes and write
+		// the tail to the buffer.
+		if curWidth > length && !ignoring {
+			ignoring = true
+			buf.WriteString(tail)
+		}
+	}
+
+	return buf.String()
+}