belt_Array.ml

(***********************************************************************)
(*                                                                     *)
(*                           OCaml                                     *)
(*                                                                     *)
(*            Xavier Leroy, projet Cristal, INRIA Rocquencourt         *)
(*                                                                     *)
(*  Copyright 1996 Institut National de Recherche en Informatique et   *)
(*  en Automatique.  All rights reserved.  This file is distributed    *)
(*  under the terms of the GNU Library General Public License, with    *)
(*  the special exception on linking described in file ../LICENSE.     *)
(*                                                                     *)
(***********************************************************************)

(* Array operations *)

external length: 'a array -> int = "%array_length"
external size: 'a array -> int = "%array_length"  
external getUnsafe: 'a array -> int -> 'a = "%array_unsafe_get"
external setUnsafe: 'a array -> int -> 'a -> unit = "%array_unsafe_set"
external getUndefined: 'a array -> int -> 'a Js.undefined = "%array_unsafe_get"
external get: 'a array -> int -> 'a = "%array_safe_get"
let get arr i =
  if i >= 0 && i < length arr then Some (getUnsafe arr i) else None
let getExn arr i =
    [%assert i >= 0 && i < length arr] ;
    getUnsafe arr i
let set arr i v =
  if i >= 0 && i < length arr then (setUnsafe arr i v; true) else false

let setExn arr i v = 
  [%assert i >= 0 && i < length arr];  
  setUnsafe arr i v 


external truncateToLengthUnsafe : 'a array -> int ->  unit = "length" [@@bs.set]  
external makeUninitialized : int -> 'a Js.undefined array = "Array" [@@bs.new]
external makeUninitializedUnsafe : int -> 'a  array = "Array" [@@bs.new]


external copy : 'a array -> (_ [@bs.as 0]) -> 'a array = 
  "slice"  [@@bs.send]


let swapUnsafe xs i j =    
  let tmp = getUnsafe xs i in 
  setUnsafe xs i (getUnsafe xs j) ;
  setUnsafe xs j tmp

let shuffleInPlace xs =     
  let len = length xs in 
  for i = 0 to len - 1 do
    swapUnsafe xs i (Js_math.random_int i len) (* [i,len)*)
  done 

let shuffle xs =
  let result = copy xs in
  shuffleInPlace result; (* TODO: improve*)
  result

let reverseAux xs ofs len =
  for i = 0 to len/2 - 1 do
    swapUnsafe xs (ofs + i) (ofs + len - i - 1)
  done

let reverseInPlace xs =
  let len = length xs in
  reverseAux xs 0 len

let reverse xs =
  let len = length xs in
  let result = makeUninitializedUnsafe len in 
  for i = 0 to len - 1 do
    setUnsafe result i (getUnsafe xs (len - 1 - i))
  done;
  result
  
let make l f =
  if l <= 0 then [||]
  else 
    let res = makeUninitializedUnsafe l in 
    for i = 0 to  l - 1 do
      setUnsafe res i f
    done;
    res


(* See #6575. We could also check for maximum array size, but this depends
     on whether we create a float array or a regular one... *)
let makeByU l f =
  if l <= 0 then [||]
  else 
    let res = makeUninitializedUnsafe l in 
    for i = 0 to  l - 1 do
      setUnsafe res i (f i [@bs])
    done;
    res

let makeBy l f = makeByU l (fun[@bs] a -> f a) 

let makeByAndShuffleU l f =
  let u  = makeByU l f in
  shuffleInPlace u ;
  u

let makeByAndShuffle l f = makeByAndShuffleU l (fun[@bs] a -> f a)

let range start finish =
  let cut = finish - start in 
  if cut < 0  then [||]
  else
    let arr = makeUninitializedUnsafe (cut + 1 ) in
    for i = 0 to cut do
      setUnsafe arr i (start + i)
    done;
    arr

let rangeBy start finish ~step =
  let cut = finish - start in
  if cut < 0 || step <=0 then
    [||]
  else
    let nb = cut/step + 1 in
    let arr = makeUninitializedUnsafe  nb in
    let cur = ref start in 
    for i = 0 to nb - 1 do
      setUnsafe arr i !cur;
      cur := !cur + step ; 
    done;
    arr 

let zip xs ys = 
  let lenx, leny = length xs, length ys in 
  let len = Pervasives.min lenx leny  in 
  let s = makeUninitializedUnsafe len in 
  for i = 0 to len - 1 do 
    setUnsafe s i (getUnsafe xs i, getUnsafe ys i)
  done ; 
  s 

let zipByU xs ys f = 
  let lenx, leny = length xs, length ys in 
  let len = Pervasives.min lenx leny  in 
  let s = makeUninitializedUnsafe len in 
  for i = 0 to len - 1 do 
    setUnsafe s i (f (getUnsafe xs i) (getUnsafe ys i) [@bs])
  done ; 
  s 

let zipBy xs ys f = zipByU xs ys (fun [@bs] a b -> f a b)

let concat a1 a2 =
  let l1 = length a1 in
  let l2 = length a2 in 
  let a1a2 = makeUninitializedUnsafe (l1 + l2) in
  for i = 0 to l1 - 1 do
    setUnsafe a1a2 i (getUnsafe a1 i)
  done ;
  for i = 0 to l2 - 1 do
    setUnsafe a1a2 (l1 + i) (getUnsafe a2 i)
  done ;
  a1a2

let concatMany arrs =
  let lenArrs = length arrs in
  let totalLen = ref 0 in 
  for i = 0 to lenArrs - 1 do
    totalLen := !totalLen + length (getUnsafe arrs i)
  done;
  let result = makeUninitializedUnsafe !totalLen in
  totalLen := 0 ; 
  for j = 0 to lenArrs - 1 do
    let cur = getUnsafe arrs j in 
    for k = 0 to length cur - 1 do
      setUnsafe result !totalLen (getUnsafe cur k);
      incr totalLen
    done 
  done ;
  result
  
let slice a ~offset ~len =
  if len <= 0  then  [||]
  else
    let lena = length a in
    let ofs =
      if offset < 0 then
        max (lena + offset) 0
      else offset in
    let hasLen = lena - ofs in  
    let copyLength = min hasLen len in
    if copyLength <= 0 then [||]
    else
      let result = makeUninitializedUnsafe copyLength  in
      for i = 0 to copyLength - 1 do
        setUnsafe result i (getUnsafe a (ofs + i))
      done ;
      result

let sliceToEnd a offset =
  let lena = length a in
  let ofs = if offset < 0 then max (lena + offset) 0 else offset in
  let len = lena - ofs in
  let result = makeUninitializedUnsafe len in
  for i = 0 to len - 1 do
    setUnsafe result i (getUnsafe a (ofs + i))
  done;
  result

let fill a ~offset ~len v =
  if len > 0 then 
    let lena = length a in
    let ofs =
      if offset < 0 then
        max (lena + offset ) 0
      else offset in
    let hasLen = lena - ofs in      
    let fillLength = min hasLen len in
    if fillLength > 0 then
      for i = ofs to  ofs + fillLength - 1 do
        setUnsafe a i v 
      done 
        

let blitUnsafe ~src:a1  ~srcOffset:srcofs1 ~dst:a2 ~dstOffset:srcofs2 ~len:blitLength =
  if srcofs2 <= srcofs1 then
    for j = 0 to blitLength - 1 do
      setUnsafe a2 (j + srcofs2) (getUnsafe a1 (j + srcofs1))
    done
  else
    for j = blitLength - 1 downto 0 do
      setUnsafe a2 (j + srcofs2) (getUnsafe a1 (j + srcofs1))
    done 

(* We don't need check [blitLength] since when [blitLength < 0] the 
   for loop will be nop
*)    
let blit ~src:a1 ~srcOffset:ofs1 ~dst:a2 ~dstOffset:ofs2 ~len =  
    let lena1 = length a1 in
    let lena2 = length a2 in 
    let srcofs1 = if ofs1 < 0 then max (lena1 + ofs1) 0 else ofs1 in
    let srcofs2 = if ofs2 < 0 then max (lena2 + ofs2) 0 else ofs2 in
    let blitLength =
      min len (min (lena1 - srcofs1) (lena2 - srcofs2)) in 
    (* blitUnsafe a1 srcofs1 a2 srcofs2 blitLength *)
    (if srcofs2 <= srcofs1 then
      for j = 0 to blitLength - 1 do
        setUnsafe a2 (j + srcofs2) (getUnsafe a1 (j + srcofs1))
      done
    else
      for j = blitLength - 1 downto 0 do
        setUnsafe a2 (j + srcofs2) (getUnsafe a1 (j + srcofs1))
      done)

let forEachU a f =
  for i = 0 to length a - 1 do f(getUnsafe a i) [@bs] done

let forEach a f = forEachU a (fun[@bs] a -> f a)
  
let mapU a f =
  let l = length a in
  let r = makeUninitializedUnsafe l in 
  for i = 0 to l - 1 do
    setUnsafe r i (f(getUnsafe a i) [@bs])
  done;
  r

let map a f = mapU a (fun[@bs] a -> f a)
  
let keepU a f =
  let l = length a in
  let r = makeUninitializedUnsafe l in
  let j = ref 0 in 
  for i = 0 to l - 1 do
    let v = (getUnsafe a i) in 
    if f v [@bs] then
      begin 
        setUnsafe r !j v;
        incr j 
      end
  done;
  truncateToLengthUnsafe r !j;
  r 

let keep a f = keepU a (fun [@bs] a -> f a)
    
let keepMapU a f =
  let l = length a in
  let r = makeUninitializedUnsafe l in
  let j = ref 0 in 
  for i = 0 to l - 1 do
    let v = getUnsafe a i in 
    match f v [@bs] with
    | None -> ()
    | Some v -> 
      begin 
        setUnsafe r !j v;
        incr j 
      end
  done;
  truncateToLengthUnsafe r !j;
  r 

let keepMap a f = keepMapU a (fun[@bs] a -> f a)
    
let forEachWithIndexU a f=
  for i = 0 to length a - 1 do f i (getUnsafe a i) [@bs] done

let forEachWithIndex a f = forEachWithIndexU a (fun[@bs] a b -> f a b)
    
let mapWithIndexU  a f =
  let l = length a in
  let r = makeUninitializedUnsafe l in 
  for i = 0 to l - 1 do
    setUnsafe r i (f i (getUnsafe a i) [@bs])
  done;
  r

let mapWithIndex a f = mapWithIndexU a (fun[@bs] a b -> f a b)
  
let reduceU a x f =
  let r = ref x in
  for i = 0 to length a - 1 do
    r := f !r (getUnsafe a i) [@bs]
  done;
  !r

let reduce a x f = reduceU a x (fun[@bs] a b -> f a b)
    
let reduceReverseU a x f =
  let r = ref x in
  for i = length a - 1 downto 0 do
    r := f  !r (getUnsafe a i) [@bs]
  done;
  !r

let reduceReverse a x f = reduceReverseU a x (fun[@bs] a b -> f a b)

let reduceReverse2U a b x f =
  let r = ref x in
  let len = min (length a) (length b) in
  for i = len - 1 downto  0 do
    r := f !r (getUnsafe a i) (getUnsafe b i) [@bs]
  done;
  !r 

let reduceReverse2 a b x f =
  reduceReverse2U a b x (fun [@bs] a b c -> f a b c)

let rec everyAux arr i b len =   
  if i = len then true 
  else if b (getUnsafe arr i) [@bs] then 
    everyAux arr (i + 1) b len
  else false    

let rec someAux arr i b len =
  if i = len then false
  else
  if b (getUnsafe arr i) [@bs] then true
  else someAux arr (i + 1) b len
      
let everyU arr b =   
  let len = length arr in 
  everyAux arr 0 b len 

let every arr f = everyU arr (fun[@bs] b -> f b)

let someU arr b =
  let len = length arr in
  someAux arr 0 b len
let some arr f = someU arr (fun [@bs] b -> f b)
    
let rec everyAux2 arr1 arr2 i b len =   
  if i = len then true 
  else if b (getUnsafe arr1 i) (getUnsafe arr2 i) [@bs] then 
    everyAux2 arr1 arr2 (i + 1) b len
  else false      

let rec someAux2 arr1 arr2 i b len =   
  if i = len then false
  else if b (getUnsafe arr1 i) (getUnsafe arr2 i) [@bs] then
    true
  else someAux2 arr1 arr2 (i + 1) b len


let every2U  a b p =   
  everyAux2  a b 0 p (min (length a) (length b))

let every2 a b p = every2U  a b (fun[@bs] a b -> p a b)

let some2U a b p =
  someAux2 a b 0 p (min (length a) (length b))

let some2 a b p = some2U a b (fun [@bs] a b -> p a b)
    
let eqU a b p =
  let lena = length a in
  let lenb = length b in
  if lena = lenb then 
    everyAux2 a b 0 p lena
  else false

let eq a b p = eqU a b (fun [@bs] a b -> p a b )

let rec everyCmpAux2 arr1 arr2 i b len =   
  if i = len then 0
  else
    let c = b (getUnsafe arr1 i) (getUnsafe arr2 i) [@bs]  in 
    if c = 0 then 
      everyCmpAux2 arr1 arr2 (i + 1) b len
    else c

let cmpU a b p =
  let lena = length a in  
  let lenb = length b in
  if lena > lenb then 1
  else if lena < lenb then -1
  else everyCmpAux2 a b 0 p lena

let cmp a b p = cmpU a b (fun[@bs] a b -> p a b)

let partitionU a f =
  let l = length a in
  let i = ref 0 in
  let j = ref 0 in
  let a1 = makeUninitializedUnsafe l in
  let a2 = makeUninitializedUnsafe l in
  for ii = 0 to l - 1 do
    let v = getUnsafe a ii in
    if f v [@bs] then (
      setUnsafe a1 !i v;
      incr i
    )
    else (
      setUnsafe a2 !j v;
      incr j
    )
  done;
  truncateToLengthUnsafe a1 !i;
  truncateToLengthUnsafe a2 !j;
  (a1, a2)

let partition a f = partitionU a (fun [@bs] x -> f x)

let unzip a =
  let l = length a in
  let a1 = makeUninitializedUnsafe l in
  let a2 = makeUninitializedUnsafe l in
  for i = 0 to l - 1 do
    let (v1, v2) = getUnsafe a i in
    setUnsafe a1 i v1;
    setUnsafe a2 i v2
  done;
  (a1, a2)