wehub-resource-sync
75 lines
1.9 KiB
Go
75 lines
1.9 KiB
Go
// Copyright 2023 Dolthub, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package utils
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// Stack is a generic stack.
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type Stack[T any] struct {
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values []T
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}
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// NewStack creates a new, empty stack.
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func NewStack[T any]() *Stack[T] {
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return &Stack[T]{}
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}
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// Len returns the size of the stack.
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func (s *Stack[T]) Len() int {
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return len(s.values)
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}
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// Peek returns the top value on the stack without removing it.
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func (s *Stack[T]) Peek() (value T) {
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if len(s.values) == 0 {
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return
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}
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return s.values[len(s.values)-1]
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}
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// PeekDepth returns the n-th value from the top. PeekDepth(0) is equivalent to the standard Peek().
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func (s *Stack[T]) PeekDepth(depth int) (value T) {
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if len(s.values) <= depth {
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return
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}
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return s.values[len(s.values)-(1+depth)]
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}
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// PeekReference returns a reference to the top value on the stack without removing it.
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func (s *Stack[T]) PeekReference() *T {
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if len(s.values) == 0 {
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return nil
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}
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return &s.values[len(s.values)-1]
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}
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// Pop returns the top value on the stack while also removing it from the stack.
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func (s *Stack[T]) Pop() (value T) {
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if len(s.values) == 0 {
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return
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}
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value = s.values[len(s.values)-1]
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s.values = s.values[:len(s.values)-1]
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return
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}
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// Push adds the given value to the stack.
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func (s *Stack[T]) Push(value T) {
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s.values = append(s.values, value)
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}
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// Empty returns whether the stack is empty.
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func (s *Stack[T]) Empty() bool {
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return len(s.values) == 0
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}
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