super-graph/jsn/intstack.go

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package jsn
type intStack struct {
stA [20]int
st []int
top int
}
// Create a new intStack
func newIntStack() *intStack {
s := &intStack{top: -1}
s.st = s.stA[:0]
return s
}
// Return the number of items in the intStack
func (s *intStack) Len() int {
return (s.top + 1)
}
// View the top item on the intStack
func (s *intStack) Peek() int {
if s.top == -1 {
return -1
}
return s.st[s.top]
}
// Pop the top item of the intStack and return it
func (s *intStack) Pop() int {
if s.top == -1 {
return -1
}
s.top--
return s.st[(s.top + 1)]
}
// Push a value onto the top of the intStack
func (s *intStack) Push(value int) {
s.top++
if len(s.st) <= s.top {
s.st = append(s.st, value)
} else {
s.st[s.top] = value
}
}