super-graph/jsn/stack.go

52 lines
774 B
Go

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