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40 lines
955 B
Go
40 lines
955 B
Go
package genstack
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// stack is a wrapper around an array implementing a stack.
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//
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// We cannot use slice to represent the stack because append might change the
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// pointer value of the slice. That would be an issue in GenStack
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// implementation.
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type stack[T any] struct {
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arr []T
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}
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// push pushes a new element at the top of a stack.
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func (s *stack[T]) push(vs ...T) { s.arr = append(s.arr, vs...) }
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// pop pops the stack top-most element.
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//
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// If stack length is zero, this method panics.
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func (s *stack[T]) pop() T {
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idx := s.len() - 1
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val := s.arr[idx]
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// Avoid memory leak
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var zero T
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s.arr[idx] = zero
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s.arr = s.arr[:idx]
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return val
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}
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// takeAll returns all elements in the stack in order as they are stored - i.e.
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// the top-most stack element is the last one.
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func (s *stack[T]) takeAll() []T {
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arr := s.arr
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s.arr = nil
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return arr
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}
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// len returns number of elements in the stack.
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func (s *stack[T]) len() int { return len(s.arr) }
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