635 lines
22 KiB
Standard ML
635 lines
22 KiB
Standard ML
structure PersistentVector =
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struct
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(* Clojure-style persistent vector, for building search list.
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* There is an "int table" too, which stores the last index
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* at the node with the same index.
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* We can use the size table for binary search.
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* *)
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datatype t =
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BRANCH of t vector * int vector
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| LEAF of {start: int, finish: int} vector * int vector
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val maxSize = 32
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val halfSize = 16
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fun isEmpty t =
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case t of
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LEAF (_, sizes) => Vector.length sizes = 0
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| _ => false
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val empty = LEAF (#[], #[])
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datatype append_result = APPEND of t | UPDATE of t
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fun isInRange (checkIdx, t) =
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case t of
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BRANCH (nodes, sizes) =>
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let
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val searchIdx = BinSearch.equalOrMore (checkIdx, sizes)
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in
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if searchIdx = ~1 then
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false
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else if searchIdx = 0 then
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isInRange (checkIdx, Vector.sub (nodes, searchIdx))
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else
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let val nextCheckIdx = checkIdx - Vector.sub (sizes, searchIdx - 1)
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in isInRange (nextCheckIdx, Vector.sub (nodes, searchIdx))
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end
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end
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| LEAF (values, sizes) =>
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let
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val searchIdx = BinSearch.equalOrMore (checkIdx, sizes)
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in
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if searchIdx = ~1 then
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false
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else
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let val {start, finish} = Vector.sub (values, searchIdx)
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in checkIdx >= start andalso checkIdx <= finish
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end
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end
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fun getFinishIdx t =
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case t of
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BRANCH (_, sizes) => Vector.sub (sizes, Vector.length sizes - 1)
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| LEAF (_, sizes) => Vector.sub (sizes, Vector.length sizes - 1)
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fun helpAppend (start, finish, tree) =
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case tree of
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BRANCH (nodes, sizes) =>
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let
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val lastNode = Vector.sub (nodes, Vector.length nodes - 1)
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val prevSize =
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if Vector.length sizes > 1 then
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Vector.sub (sizes, Vector.length sizes - 2)
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else
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0
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in
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case helpAppend (start - prevSize, finish - prevSize, lastNode) of
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UPDATE newLast =>
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let
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val lastPos = Vector.length nodes - 1
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val newNode = Vector.update (nodes, lastPos, newLast)
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val newSizes = Vector.update (sizes, lastPos, finish)
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val newNode = BRANCH (newNode, newSizes)
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in
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UPDATE newNode
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end
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| APPEND newVec =>
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if Vector.length nodes = maxSize then
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let
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(* adjust "finish" so that it does not consider
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* offset for "lower" vector *)
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val finish =
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finish - Vector.sub (sizes, Vector.length sizes - 1)
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val newNode = BRANCH
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(#[newVec], #[finish])
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in
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APPEND newNode
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end
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else
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let
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val newNodes = Vector.concat [nodes, #[newVec]]
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val newSizes = Vector.concat [sizes, #[finish]]
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val newNodes = BRANCH (newNodes, newSizes)
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in
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UPDATE newNodes
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end
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end
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| LEAF (values, sizes) =>
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if Vector.length values + 1 > maxSize then
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(* when we split a leaf into two vectors,
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* we want to adjust the start and finish parameters
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* so that they don't contain the offset relevant to the
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* "lower" vector, which was split from *)
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let
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val prevFinish = Vector.sub (sizes, Vector.length sizes - 1)
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val start = start - prevFinish
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val finish = finish - prevFinish
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val newNode = LEAF
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( #[{start = start, finish = finish}]
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, #[finish]
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)
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in
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APPEND newNode
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end
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else
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let
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val newNode = Vector.concat
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[values, #[{start = start, finish = finish}]]
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val newSizes = Vector.concat [sizes, #[finish]]
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val newNode = LEAF (newNode, newSizes)
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in
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UPDATE newNode
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end
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fun append (start, finish, tree) =
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case helpAppend (start, finish, tree) of
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UPDATE t => t
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| APPEND newNode =>
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let
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val maxSize = getFinishIdx tree
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in
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BRANCH
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(#[tree, newNode], #[maxSize, finish])
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end
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fun getStart tree =
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case tree of
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LEAF (values, _) => Vector.sub (values, 0)
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| BRANCH (nodes, _) => getStart (Vector.sub (nodes, 0))
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fun helpNextMatch (cursorIdx, tree, acc) =
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case tree of
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LEAF (values, sizes) =>
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let
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val idx = BinSearch.equalOrMore (cursorIdx, sizes)
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in
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if idx = ~1 then
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{start = ~1, finish = ~1}
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else
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let val {start, finish} = Vector.sub (values, idx)
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in {start = start + acc, finish = finish + acc}
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end
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end
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| BRANCH (nodes, sizes) =>
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let
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val idx = BinSearch.equalOrMore (cursorIdx, sizes)
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in
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if idx = ~1 then
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{start = ~1, finish = ~1}
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else
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let
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val prevSize = if idx = 0 then 0 else Vector.sub (sizes, idx - 1)
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val acc = acc + prevSize
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val cursorIdx = cursorIdx - prevSize
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in
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helpNextMatch (cursorIdx, Vector.sub (nodes, idx), acc)
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end
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end
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fun startNextMatch (cursorIdx, tree) =
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case tree of
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LEAF (values, sizes) =>
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if Vector.length sizes = 0 then
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{start = ~1, finish = ~1}
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else
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let
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val idx = BinSearch.equalOrMore (cursorIdx, sizes)
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val idx = if idx = ~1 then 0 else idx
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in
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Vector.sub (values, idx)
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end
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| BRANCH (nodes, sizes) =>
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let
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val idx = BinSearch.equalOrMore (cursorIdx, sizes)
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in
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if idx = ~1 then
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{start = ~1, finish = ~1}
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else
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let
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val prevSize = if idx = 0 then 0 else Vector.sub (sizes, idx - 1)
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val cursorIdx = cursorIdx - prevSize
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in
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helpNextMatch (cursorIdx, Vector.sub (nodes, idx), prevSize)
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end
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end
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fun loopNextMatch (prevStart, prevFinish, tree, count) =
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if count = 0 then
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prevStart
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else
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let
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val {start, finish} = startNextMatch (prevFinish + 1, tree)
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in
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if start = ~1 then
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let val {start, finish} = getStart tree
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in loopNextMatch (start, finish, tree, count - 1)
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end
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else
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loopNextMatch (start, finish, tree, count - 1)
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end
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fun nextMatch (cursorIdx, tree, count) =
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if isEmpty tree then
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~1
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else
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let
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val {start, finish} = startNextMatch (cursorIdx, tree)
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in
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if start = ~1 then
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let val {start, finish} = getStart tree
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in loopNextMatch (start, finish, tree, count - 1)
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end
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else
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let in
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if cursorIdx >= start andalso cursorIdx <= finish then
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loopNextMatch (start, finish, tree, count)
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else
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loopNextMatch (start, finish, tree, count - 1)
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end
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end
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fun getLast (tree, acc) =
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case tree of
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LEAF (values, _) =>
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let val {start, finish} = Vector.sub (values, Vector.length values - 1)
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in {start = start + acc, finish = finish + acc}
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end
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| BRANCH (nodes, sizes) =>
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let
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val acc =
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if Vector.length sizes > 1 then
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acc + Vector.sub (sizes, Vector.length sizes - 1)
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else
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acc
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in
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getLast (Vector.sub (nodes, Vector.length nodes - 1), acc)
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end
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(* slightly tricky.
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* The `sizes` vector contains the last/finish position of the item
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* at the corresponding index in the `nodes` or `values` vector
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* However, what we when searching for the previous match
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* is different: we want the node that has a start prior
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* to the cursorIdx.
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* This information cannot be retrieved with 100% accuracy
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* using the `sizes` vector.
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* To get what we want, we recurse downwards using the `sizes` vector.
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* If we found the node we want, we return it.
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* Otherwise, we return a state meaning "no node at this position"
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* and we use the call stack to descend down the node at the previous index.
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* There might not be a previous index because the current index is 0.
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* In this case, either the call stack will handle it,
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* or the caller to `helpPrevMatch` will. *)
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fun helpPrevMatch (cursorIdx, tree, acc) =
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case tree of
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LEAF (values, sizes) =>
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let
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val idx = BinSearch.equalOrMore (cursorIdx, sizes)
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in
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if idx < 0 then
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{start = ~1, finish = ~1}
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else if idx = 0 then
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let
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val result = Vector.sub (values, 0)
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in
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if #start result < cursorIdx then
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{start = #start result + acc, finish = #finish result + acc}
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else
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{start = ~1, finish = ~1}
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end
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else
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let
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val current = Vector.sub (values, idx)
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val {start, finish} =
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if cursorIdx > #start current then current
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else Vector.sub (values, idx - 1)
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in
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{start = start + acc, finish = finish + acc}
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end
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end
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| BRANCH (nodes, sizes) =>
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let
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val idx = BinSearch.equalOrMore (cursorIdx, sizes)
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in
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if idx < 0 then
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{start = ~1, finish = ~1}
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else if idx = 0 then
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helpPrevMatch (cursorIdx, Vector.sub (nodes, idx), acc)
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else
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let
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val node = Vector.sub (nodes, idx)
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val prevSize = Vector.sub (sizes, idx - 1)
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val result =
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helpPrevMatch (cursorIdx - prevSize, node, acc + prevSize)
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in
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if #start result = ~1 then
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let
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val prevPrevSize =
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if idx - 2 < 0 then 0 else Vector.sub (sizes, idx - 2)
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in
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getLast (Vector.sub (nodes, idx - 1), acc + prevPrevSize)
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end
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else
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result
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end
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end
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fun loopPrevMatch (prevStart, prevFinish, tree, count) =
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if count = 0 then
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prevStart
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else
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let
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val {start, finish} = helpPrevMatch (prevFinish - 1, tree, 0)
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in
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if start = ~1 then
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let val {start, finish} = getLast (tree, ~1)
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in loopPrevMatch (start, finish, tree, count - 1)
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end
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else
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loopPrevMatch (start, finish, tree, count - 1)
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end
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fun prevMatch (cursorIdx, tree, count) =
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if isEmpty tree then
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~1
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else
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let
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val {start, finish} = helpPrevMatch (cursorIdx, tree, 0)
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in
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if start = ~1 then
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let val {start, finish} = getLast (tree, ~1)
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in loopPrevMatch (start, finish, tree, count - 1)
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end
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else if cursorIdx >= start andalso cursorIdx <= finish then
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loopPrevMatch (start, finish, tree, count)
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else
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loopPrevMatch (start, finish, tree, count - 1)
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end
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(* todo: modify below functions so that they also
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* use rope-like metadata *)
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datatype insert_result =
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INSERT_UPDATE of t
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| INSERT_SPLIT of t * t
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fun getMaxSize tree =
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case tree of
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LEAF (_, sizes) => Vector.sub (sizes, Vector.length sizes - 1)
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| BRANCH (_, sizes) => Vector.sub (sizes, Vector.length sizes - 1)
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fun helpInsert (start, finish, tree) =
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case tree of
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BRANCH (nodes, sizes) =>
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if finish >= Vector.sub (sizes, Vector.length sizes - 1) then
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(* if we want to append *)
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case
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helpAppend (start, finish, Vector.sub
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(nodes, Vector.length sizes - 1))
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of
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UPDATE newLast =>
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let
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val sizes = Vector.update
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(sizes, Vector.length sizes - 1, finish)
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val nodes = Vector.update
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(nodes, Vector.length nodes - 1, newLast)
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in
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INSERT_UPDATE (BRANCH (nodes, sizes))
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end
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| APPEND newLast =>
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if Vector.length nodes = maxSize then
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(* have to split *)
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let
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val leftLen = SOME halfSize
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val rightLen = SOME (Vector.length nodes - halfSize)
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val leftNodeSlice = VectorSlice.slice (nodes, 0, leftLen)
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val rightNodeSlice =
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VectorSlice.slice (nodes, halfSize, rightLen)
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val leftSizeSlice = VectorSlice.slice (sizes, 0, leftLen)
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val rightSizeSlice =
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VectorSlice.slice (sizes, halfSize, rightLen)
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val leftNodes = VectorSlice.vector leftNodeSlice
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val leftSizes = VectorSlice.vector leftSizeSlice
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val newLast = VectorSlice.full (#[newLast])
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val finish = VectorSlice.full (#[finish])
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val rightNodes = VectorSlice.concat [rightNodeSlice, newLast]
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val rightSizes = VectorSlice.concat [rightSizeSlice, finish]
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val left = BRANCH (leftNodes, leftSizes)
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val right = BRANCH (rightNodes, rightSizes)
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in
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INSERT_SPLIT (left, right)
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end
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else
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(* append newLast to current node *)
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let
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val newLast = #[newLast]
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val finish = #[finish]
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val nodes = Vector.concat [nodes, newLast]
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val sizes = Vector.concat [sizes, finish]
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in
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INSERT_UPDATE (BRANCH (nodes, sizes))
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end
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else
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let
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val idx = BinSearch.equalOrMore (finish, sizes)
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val idx = if idx = ~1 then 0 else idx
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in
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case helpInsert (start, finish, tree) of
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INSERT_UPDATE newNode =>
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let
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val sizes =
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if finish > Vector.sub (sizes, idx) then
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Vector.update (sizes, idx, finish)
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else
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sizes
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val nodes = Vector.update (nodes, idx, newNode)
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in
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INSERT_UPDATE (BRANCH (nodes, sizes))
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end
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| INSERT_SPLIT (left, right) =>
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if Vector.length nodes = maxSize then
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(* have to split this node too *)
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let
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(* slice sizes *)
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val leftSize =
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VectorSlice.full #[getMaxSize left]
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val rightSize =
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VectorSlice.full #[getMaxSize right]
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val leftLen = SOME idx
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val rightLen = SOME (Vector.length nodes - idx - 1)
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val leftSizeSlice = VectorSlice.slice (sizes, 0, leftLen)
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val rightSizeSlice =
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VectorSlice.slice (sizes, idx + 1, rightLen)
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val leftSizes = VectorSlice.concat [leftSizeSlice, leftSize]
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val rightSizes =
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VectorSlice.concat [rightSizeSlice, rightSize]
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(* slice nodes *)
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val left = VectorSlice.full #[left]
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val right = VectorSlice.full #[right]
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val leftNodesSlice = VectorSlice.slice (nodes, 0, leftLen)
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val rightNodesSlice =
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VectorSlice.slice (nodes, idx + 1, rightLen)
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val leftNodes = VectorSlice.concat [leftNodesSlice, left]
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val rightNodes = VectorSlice.concat [right, rightNodesSlice]
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(* join sizes and nodes *)
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val left = BRANCH (leftNodes, leftSizes)
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val right = BRANCH (rightNodes, rightSizes)
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in
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INSERT_SPLIT (left, right)
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end
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else
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(* can join children into parent *)
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let
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val midSizes =
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#[getMaxSize left, getMaxSize right]
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val midSizes = VectorSlice.full midSizes
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val midNodes = #[left, right]
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val midNodes = VectorSlice.full midNodes
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val leftLen = SOME idx
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val rightLen = SOME (Vector.length sizes - idx)
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val leftSizes = VectorSlice.slice (sizes, 0, leftLen)
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val rightSizes = VectorSlice.slice (sizes, idx, rightLen)
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val leftNodes = VectorSlice.slice (nodes, 0, leftLen)
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val rightNodes = VectorSlice.slice (nodes, idx, rightLen)
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val sizes =
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VectorSlice.concat [leftSizes, midSizes, rightSizes]
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val nodes =
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VectorSlice.concat [leftNodes, midNodes, rightNodes]
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in
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INSERT_UPDATE (BRANCH (nodes, sizes))
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end
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end
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| LEAF (items, sizes) =>
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if Vector.length items = 0 then
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(* leaf is empty, so return leaf containing one item *)
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let
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val item = #[{start = start, finish = finish}]
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val size = #[finish]
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in
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INSERT_UPDATE (LEAF (item, size))
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end
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else if finish > Vector.sub (sizes, Vector.length sizes - 1) then
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if Vector.length sizes = maxSize then
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(* have to split *)
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let
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val startLen = SOME halfSize
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val midLen = SOME (Vector.length items - halfSize)
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val leftSizes = VectorSlice.slice (sizes, 0, startLen)
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val leftItems = VectorSlice.slice (items, 0, startLen)
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val midSizes = VectorSlice.slice (sizes, halfSize, midLen)
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val midItems = VectorSlice.slice (items, halfSize, midLen)
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val rightSizes = VectorSlice.full #[finish]
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val rightItems =
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VectorSlice.full #[{start = start, finish = finish}]
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val rightItems = VectorSlice.concat [midItems, rightItems]
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val leftItems = VectorSlice.vector leftItems
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val rightSizes = VectorSlice.concat [midSizes, rightSizes]
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val leftSizes = VectorSlice.vector leftSizes
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val left = LEAF (leftItems, leftSizes)
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val right = LEAF (rightItems, rightSizes)
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in
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INSERT_SPLIT (left, right)
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end
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else
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(* can just append *)
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let
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val sizes = Vector.concat [sizes, #[finish]]
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val item = #[{start = start, finish = finish}]
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val items = Vector.concat [items, item]
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in
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INSERT_UPDATE (LEAF (items, sizes))
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end
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else if finish < #start (Vector.sub (items, 0)) then
|
|
(* prepend *)
|
|
if Vector.length sizes = maxSize then
|
|
(* have to split *)
|
|
let
|
|
val leftSizes = VectorSlice.full #[finish]
|
|
val leftItems =
|
|
VectorSlice.full #[{start = start, finish = finish}]
|
|
|
|
val midLen = SOME halfSize
|
|
val rightLen = SOME (Vector.length items - halfSize)
|
|
|
|
val midSizes = VectorSlice.slice (sizes, 0, midLen)
|
|
val midItems = VectorSlice.slice (items, 0, midLen)
|
|
|
|
val rightSizes = VectorSlice.slice (sizes, halfSize, rightLen)
|
|
val rightItems = VectorSlice.slice (items, halfSize, rightLen)
|
|
|
|
val leftSizes = VectorSlice.concat [leftSizes, midSizes]
|
|
val rightSizes = VectorSlice.vector rightSizes
|
|
|
|
val leftItems = VectorSlice.concat [leftItems, midItems]
|
|
val rightItems = VectorSlice.vector rightItems
|
|
|
|
val left = LEAF (leftItems, leftSizes)
|
|
val right = LEAF (rightItems, rightSizes)
|
|
in
|
|
INSERT_SPLIT (left, right)
|
|
end
|
|
else
|
|
(* just prepend *)
|
|
let
|
|
val sizes = Vector.concat [#[finish], sizes]
|
|
val item = {start = start, finish = finish}
|
|
val items = Vector.concat [#[item], items]
|
|
in
|
|
INSERT_UPDATE (LEAF (items, sizes))
|
|
end
|
|
else
|
|
(* insert into middle *)
|
|
let
|
|
val idx = BinSearch.equalOrMore (finish, sizes)
|
|
val leftLen = SOME idx
|
|
val rightLen = SOME (Vector.length sizes - idx)
|
|
|
|
val leftSizes = VectorSlice.slice (sizes, 0, leftLen)
|
|
val rightSizes = VectorSlice.slice (sizes, idx, rightLen)
|
|
|
|
val leftItems = VectorSlice.slice (items, 0, leftLen)
|
|
val rightItems = VectorSlice.slice (items, idx, rightLen)
|
|
val midSize = VectorSlice.full #[finish]
|
|
val midItem =
|
|
VectorSlice.full #[{start = start, finish = finish}]
|
|
in
|
|
if Vector.length items = maxSize then
|
|
(* have to return split *)
|
|
let
|
|
val leftSizes = VectorSlice.concat [leftSizes, midSize]
|
|
val rightSizes = VectorSlice.vector rightSizes
|
|
|
|
val leftItems = VectorSlice.concat [leftItems, midItem]
|
|
val rightItems = VectorSlice.vector rightItems
|
|
|
|
val left = LEAF (leftItems, leftSizes)
|
|
val right = LEAF (rightItems, rightSizes)
|
|
in
|
|
INSERT_SPLIT (left, right)
|
|
end
|
|
else
|
|
(* have to return update *)
|
|
let
|
|
val sizes = VectorSlice.concat [leftSizes, midSize, rightSizes]
|
|
val items = VectorSlice.concat [leftItems, midItem, rightItems]
|
|
in
|
|
INSERT_UPDATE (LEAF (items, sizes))
|
|
end
|
|
end
|
|
|
|
fun insert (start, finish, tree) =
|
|
case helpInsert (start, finish, tree) of
|
|
INSERT_UPDATE tree => tree
|
|
| INSERT_SPLIT (left, right) =>
|
|
let
|
|
val sizes = #[getMaxSize left, getMaxSize right]
|
|
val nodes = #[left, right]
|
|
in
|
|
BRANCH (nodes, sizes)
|
|
end
|
|
end
|