bzr branch
/bzr/ld28
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2
by Josh C
basic delayed movement |
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-- deque from https://github.com/catwell/cw-lua/tree/master/deque
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-- under MIT license
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local push_right = function(self, x) |
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assert(x ~= nil) |
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self.tail = self.tail + 1 |
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self[self.tail] = x |
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end
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local push_left = function(self, x) |
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assert(x ~= nil) |
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self[self.head] = x |
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self.head = self.head - 1 |
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end
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local peek_right = function(self) |
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return self[self.tail] |
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end
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local peek_left = function(self) |
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return self[self.head+1] |
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end
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local pop_right = function(self) |
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if self:is_empty() then return nil end |
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local r = self[self.tail] |
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self[self.tail] = nil |
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self.tail = self.tail - 1 |
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return r |
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end
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local pop_left = function(self) |
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if self:is_empty() then return nil end |
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local r = self[self.head+1] |
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self.head = self.head + 1 |
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local r = self[self.head] |
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self[self.head] = nil |
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return r |
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end
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local rotate_right = function(self, n) |
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n = n or 1 |
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if self:is_empty() then return nil end |
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for i=1,n do self:push_left(self:pop_right()) end |
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end
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local rotate_left = function(self, n) |
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n = n or 1 |
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if self:is_empty() then return nil end |
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for i=1,n do self:push_right(self:pop_left()) end |
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end
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local _remove_at_internal = function(self, idx) |
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for i=idx, self.tail do self[i] = self[i+1] end |
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self.tail = self.tail - 1 |
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end
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local remove_right = function(self, x) |
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for i=self.tail,self.head+1,-1 do |
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if self[i] == x then |
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_remove_at_internal(self, i) |
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return true |
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end
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end
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return false |
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end
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local remove_left = function(self, x) |
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for i=self.head+1,self.tail do |
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if self[i] == x then |
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_remove_at_internal(self, i) |
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return true |
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end
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end
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return false |
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end
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local length = function(self) |
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return self.tail - self.head |
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end
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local is_empty = function(self) |
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return self:length() == 0 |
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end
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local contents = function(self) |
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local r = {} |
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for i=self.head+1,self.tail do |
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r[i-self.head] = self[i] |
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end
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return r |
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end
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local iter_right = function(self) |
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local i = self.tail+1 |
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return function() |
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if i > self.head+1 then |
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i = i-1 |
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return self[i] |
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end
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end
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end
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local iter_left = function(self) |
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local i = self.head |
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return function() |
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if i < self.tail then |
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i = i+1 |
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return self[i] |
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end
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end
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end
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local methods = { |
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push_right = push_right, |
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push_left = push_left, |
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peek_right = peek_right, |
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peek_left = peek_left, |
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pop_right = pop_right, |
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pop_left = pop_left, |
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rotate_right = rotate_right, |
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rotate_left = rotate_left, |
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remove_right = remove_right, |
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remove_left = remove_left, |
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iter_right = iter_right, |
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iter_left = iter_left, |
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length = length, |
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is_empty = is_empty, |
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contents = contents, |
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}
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local new = function() |
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local r = {head=0,tail=0} |
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return setmetatable(r, {__index=methods}) |
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end
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return { |
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new = new, |
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}
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