ginger/gim/terminal/mat.go

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package terminal
import (
"container/list"
)
type matEl struct {
x int
v interface{}
}
type matRow struct {
y int
l *list.List
}
// a 2-d sparse matrix
type mat struct {
rows *list.List
currY int
currRowEl *list.Element
currEl *list.Element
}
func newMat() *mat {
return &mat{
rows: list.New(),
}
}
func (m *mat) getRow(y int) *list.List {
m.currY = y // this will end up being true no matter what
if m.currRowEl == nil { // first call
l := list.New()
m.currRowEl = m.rows.PushFront(matRow{y: y, l: l})
return l
} else if m.currRowEl.Value.(matRow).y > y {
m.currRowEl = m.rows.Front()
}
for {
currRow := m.currRowEl.Value.(matRow)
switch {
case currRow.y == y:
return currRow.l
case currRow.y < y:
if m.currRowEl = m.currRowEl.Next(); m.currRowEl == nil {
l := list.New()
m.currRowEl = m.rows.PushBack(matRow{y: y, l: l})
return l
}
default: // currRow.y > y
l := list.New()
m.currRowEl = m.rows.InsertBefore(matRow{y: y, l: l}, m.currRowEl)
return l
}
}
}
func (m *mat) getEl(x, y int) *matEl {
var rowL *list.List
if m.currRowEl == nil || m.currY != y {
rowL = m.getRow(y)
m.currEl = rowL.Front()
} else {
rowL = m.currRowEl.Value.(matRow).l
}
if m.currEl == nil || m.currEl.Value.(*matEl).x > x {
if m.currEl = rowL.Front(); m.currEl == nil {
// row is empty
mel := &matEl{x: x}
m.currEl = rowL.PushFront(mel)
return mel
}
}
for {
currEl := m.currEl.Value.(*matEl)
switch {
case currEl.x == x:
return currEl
case currEl.x < x:
if m.currEl = m.currEl.Next(); m.currEl == nil {
mel := &matEl{x: x}
m.currEl = rowL.PushBack(mel)
return mel
}
default: // currEl.x > x
mel := &matEl{x: x}
m.currEl = rowL.InsertBefore(mel, m.currEl)
return mel
}
}
}
func (m *mat) get(x, y int) interface{} {
return m.getEl(x, y).v
}
func (m *mat) set(x, y int, v interface{}) {
m.getEl(x, y).v = v
}
func (m *mat) iter(f func(x, y int, v interface{}) bool) {
for rowEl := m.rows.Front(); rowEl != nil; rowEl = rowEl.Next() {
row := rowEl.Value.(matRow)
for el := row.l.Front(); el != nil; el = el.Next() {
mel := el.Value.(*matEl)
if !f(mel.x, row.y, mel.v) {
return
}
}
}
}