1 files changed, 86 insertions, 0 deletions
diff --git a/pkg/field/set.go b/pkg/field/set.go
new file mode 100644
index 0000000..5044898
--- /dev/null
+++ b/pkg/field/set.go
@@ -0,0 +1,86 @@
+package field
+
+func (f *Field) Set(x, y, v int) {
+	if v == ' ' {
+		f.Blank(x, y)
+		return
+	}
+	if y >= f.y {
+		if y < f.y+f.ly {
+			l := &f.lines[y-f.y]
+			if l.l == 0 {
+				// an empty line is a special case
+				l.x = x
+				l.l = 1
+				l.columns = append(l.columns, v)
+			} else if x >= l.x {
+				if x < l.x+l.l {
+					// just set the value
+					l.columns[x-l.x] = v
+				} else {
+					// append columns
+					newL := x - l.x + 1
+					for i := l.l; i < newL-1; i++ {
+						l.columns = append(l.columns, ' ')
+					}
+					l.columns = append(l.columns, v)
+					l.l = newL
+					if f.lx-f.x < l.l-l.x {
+						f.lx = l.l - l.x
+					}
+				}
+			} else {
+				// prepend columns
+				newL := l.l + l.x - x
+				c := make([]int, newL)
+				c[0] = v
+				for i := 1; i < l.x-x; i++ {
+					c[i] = ' '
+				}
+				for i := l.x - x; i < newL; i++ {
+					c[i] = l.columns[i-l.x+x]
+				}
+				l.columns = c
+				l.x = x
+				l.l = newL
+				if f.x > x {
+					f.lx = f.lx + f.x - x
+					f.x = x
+				}
+			}
+		} else {
+			// append lines
+			newLy := y - f.y + 1
+			for i := f.ly; i < newLy-1; i++ {
+				f.lines = append(f.lines, Line{})
+			}
+			f.lines = append(f.lines, Line{x: x, l: 1, columns: []int{v}})
+			f.ly = newLy
+			if f.x > x {
+				f.lx = f.lx + f.x - x
+				f.x = x
+			}
+			if f.lx-f.x < x {
+				f.lx = x - f.x
+			}
+		}
+	} else {
+		// prepend lines
+		newLy := f.ly + f.y - y
+		lines := make([]Line, newLy)
+		lines[0] = Line{x: x, l: 1, columns: []int{v}}
+		for j := f.y - y; j < newLy; j++ {
+			lines[j] = f.lines[j-f.y+y]
+		}
+		f.lines = lines
+		f.y = y
+		f.ly = newLy
+		if f.x > x {
+			f.lx = f.lx + f.x - x
+			f.x = x
+		}
+		if f.lx-f.x < x {
+			f.lx = x - f.x + 1
+		}
+	}
+}