package decompress
Implementation of Zlib in OCaml
Install
Dune Dependency
Authors
Maintainers
Sources
decompress-v0.9.0.tbz
sha256=70dd782b258a51a37c3971b9bd96c656b161876d781e168a626e9bb437833e3b
sha512=34033405c8dca30f67c39cad8f50875e255644d0e0b88019091d59932aaf90d87445070228291b1d3d1c07a98ce97aeca11554daf1a8f3b04d043b4f6c1ab83c
doc/src/decompress.impl/decompress_inflate.ml.html
Source file decompress_inflate.ml
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module Stdlib_buffer = Buffer module Buffer = Decompress_buffer module Window = Decompress_window module Safe = Decompress_safe module Tables = Decompress_tables module OS = Decompress_os module Tree = Decompress_tree module Option = Decompress_option let pf = Format.fprintf let invalid_arg ppf = Format.ksprintf (fun s -> invalid_arg s) ppf (** non-blocking and functionnal implementation of Inflate *) module type INFLATE = sig type error type crc type ('i, 'o) t val pp_error : Format.formatter -> error -> unit val pp : Format.formatter -> ('i, 'o) t -> unit val eval : 'a -> 'a -> ('a, 'a) t -> [ `Await of ('a, 'a) t | `Flush of ('a, 'a) t | `End of ('a, 'a) t | `Error of ('a, 'a) t * error ] val refill : int -> int -> ('i, 'o) t -> ('i, 'o) t val flush : int -> int -> ('i, 'o) t -> ('i, 'o) t val used_in : ('i, 'o) t -> int val used_out : ('i, 'o) t -> int val write : ('i, 'o) t -> int val default : ('o, crc) Window.t -> ('i, 'o) t val to_result : 'a -> 'a -> ('a -> int) -> ('a -> int -> int) -> ('a, 'a) t -> (('a, 'a) t, error) result val bytes : Bytes.t -> Bytes.t -> (Bytes.t -> int) -> (Bytes.t -> int -> int) -> (Bytes.t, Bytes.t) t -> ((Bytes.t, Bytes.t) t, error) result val bigstring : Buffer.Bigstring.t -> Buffer.Bigstring.t -> (Buffer.Bigstring.t -> int) -> (Buffer.Bigstring.t -> int -> int) -> (Buffer.Bigstring.t, Buffer.Bigstring.t) t -> ((Buffer.Bigstring.t, Buffer.Bigstring.t) t, error) result end module type S = sig type ('i, 'o) t type error val eval : 'a -> 'a -> ('a, 'a) t -> [ `Await of ('a, 'a) t | `Flush of ('a, 'a) t | `End of ('a, 'a) t | `Error of ('a, 'a) t * error ] val refill : int -> int -> ('i, 'o) t -> ('i, 'o) t val flush : int -> int -> ('i, 'o) t -> ('i, 'o) t val used_out : ('i, 'o) t -> int end module Convenience (X : S) = struct let to_result src dst refiller flusher t = let rec go t = match X.eval src dst t with | `Await t -> let n = refiller src in go (X.refill 0 n t) | `Flush t -> let n = X.used_out t in let n = flusher dst n in go (X.flush 0 n t) | `End t -> if X.used_out t = 0 then Ok t else let n = X.used_out t in let n = flusher dst n in Ok (X.flush 0 n t) | `Error (_, exn) -> Error exn in go t let bytes src dst refiller flusher t = to_result src dst refiller flusher t let bigstring src dst refiller flusher t = to_result src dst refiller flusher t end type error_rfc1951 = | Invalid_kind_of_block | Invalid_complement_of_length | Invalid_dictionary | Invalid_distance_code | Invalid_distance of {distance: int; max: int} module RFC1951 = struct (* functionnal implementation of Heap, bisoux @c-cube *) module Heap = struct type priority = int type 'a queue = None | Node of priority * 'a * 'a queue * 'a queue let rec push queue priority elt = match queue with | None -> Node (priority, elt, None, None) | Node (p, e, left, right) -> if priority <= p then Node (priority, elt, push right p e, left) else Node (p, e, push right priority elt, left) exception Empty let rec remove = function | None -> raise Empty | Node (_, _, left, None) -> left | Node (_, _, None, right) -> right | Node (_, _, (Node (lp, le, _, _) as left), (Node (rp, re, _, _) as right)) -> if lp <= rp then Node (lp, le, remove left, right) else Node (rp, re, left, remove right) let take = function | None -> raise Empty | Node (p, e, _, _) as queue -> (p, e, remove queue) end module Huffman = struct exception Invalid_huffman let prefix heap max = assert (max <= 15) ; (* lol *) let tbl = Array.make (1 lsl max) 0 in let rec backward huff incr = if huff land incr <> 0 then backward huff (incr lsr 1) else incr in let rec aux huff heap = match Heap.take heap with | _, (len, value), heap -> let rec loop decr fill = tbl.(huff + fill) <- (len lsl 15) lor value ; if fill <> 0 then loop decr (fill - decr) in let decr = 1 lsl len in loop decr ((1 lsl max) - decr) ; let incr = backward huff (1 lsl (len - 1)) in aux (if incr <> 0 then (huff land (incr - 1)) + incr else 0) heap | exception Heap.Empty -> () in aux 0 heap ; tbl let _MAX_BITS = 15 exception Break let make ?(kind = `CODES) table off codes _max_bits = let bl_count = Array.make (_MAX_BITS + 1) 0 in for sym = 0 to codes - 1 do let p = table.(off + sym) in bl_count.(p) <- bl_count.(p) + 1 done ; let max = ref _MAX_BITS in let () = try while !max >= 1 do if bl_count.(!max) <> 0 then raise Break ; decr max done with Break -> () in let code = ref 0 in let left = ref 1 in let next_code = Array.make (_MAX_BITS + 1) 0 in for i = 1 to _MAX_BITS do left := !left lsl 1 ; left := !left - bl_count.(i) ; if !left < 0 then raise Invalid_huffman ; code := (!code + bl_count.(i)) lsl 1 ; next_code.(i) <- !code done ; if !left > 0 && (kind = `CODES || !max <> 1) then raise Invalid_huffman ; let ordered = ref Heap.None in let max = ref 0 in for i = 0 to codes - 1 do let l = table.(off + i) in if l <> 0 then ( let n = next_code.(l - 1) in next_code.(l - 1) <- n + 1 ; ordered := Heap.push !ordered n (l, i) ; max := if l > !max then l else !max ) done ; (prefix !ordered !max, !max) end let reverse_bits = let t = [| 0x00 ; 0x80 ; 0x40 ; 0xC0 ; 0x20 ; 0xA0 ; 0x60 ; 0xE0 ; 0x10 ; 0x90 ; 0x50 ; 0xD0 ; 0x30 ; 0xB0 ; 0x70 ; 0xF0 ; 0x08 ; 0x88 ; 0x48 ; 0xC8 ; 0x28 ; 0xA8 ; 0x68 ; 0xE8 ; 0x18 ; 0x98 ; 0x58 ; 0xD8 ; 0x38 ; 0xB8 ; 0x78 ; 0xF8 ; 0x04 ; 0x84 ; 0x44 ; 0xC4 ; 0x24 ; 0xA4 ; 0x64 ; 0xE4 ; 0x14 ; 0x94 ; 0x54 ; 0xD4 ; 0x34 ; 0xB4 ; 0x74 ; 0xF4 ; 0x0C ; 0x8C ; 0x4C ; 0xCC ; 0x2C ; 0xAC ; 0x6C ; 0xEC ; 0x1C ; 0x9C ; 0x5C ; 0xDC ; 0x3C ; 0xBC ; 0x7C ; 0xFC ; 0x02 ; 0x82 ; 0x42 ; 0xC2 ; 0x22 ; 0xA2 ; 0x62 ; 0xE2 ; 0x12 ; 0x92 ; 0x52 ; 0xD2 ; 0x32 ; 0xB2 ; 0x72 ; 0xF2 ; 0x0A ; 0x8A ; 0x4A ; 0xCA ; 0x2A ; 0xAA ; 0x6A ; 0xEA ; 0x1A ; 0x9A ; 0x5A ; 0xDA ; 0x3A ; 0xBA ; 0x7A ; 0xFA ; 0x06 ; 0x86 ; 0x46 ; 0xC6 ; 0x26 ; 0xA6 ; 0x66 ; 0xE6 ; 0x16 ; 0x96 ; 0x56 ; 0xD6 ; 0x36 ; 0xB6 ; 0x76 ; 0xF6 ; 0x0E ; 0x8E ; 0x4E ; 0xCE ; 0x2E ; 0xAE ; 0x6E ; 0xEE ; 0x1E ; 0x9E ; 0x5E ; 0xDE ; 0x3E ; 0xBE ; 0x7E ; 0xFE ; 0x01 ; 0x81 ; 0x41 ; 0xC1 ; 0x21 ; 0xA1 ; 0x61 ; 0xE1 ; 0x11 ; 0x91 ; 0x51 ; 0xD1 ; 0x31 ; 0xB1 ; 0x71 ; 0xF1 ; 0x09 ; 0x89 ; 0x49 ; 0xC9 ; 0x29 ; 0xA9 ; 0x69 ; 0xE9 ; 0x19 ; 0x99 ; 0x59 ; 0xD9 ; 0x39 ; 0xB9 ; 0x79 ; 0xF9 ; 0x05 ; 0x85 ; 0x45 ; 0xC5 ; 0x25 ; 0xA5 ; 0x65 ; 0xE5 ; 0x15 ; 0x95 ; 0x55 ; 0xD5 ; 0x35 ; 0xB5 ; 0x75 ; 0xF5 ; 0x0D ; 0x8D ; 0x4D ; 0xCD ; 0x2D ; 0xAD ; 0x6D ; 0xED ; 0x1D ; 0x9D ; 0x5D ; 0xDD ; 0x3D ; 0xBD ; 0x7D ; 0xFD ; 0x03 ; 0x83 ; 0x43 ; 0xC3 ; 0x23 ; 0xA3 ; 0x63 ; 0xE3 ; 0x13 ; 0x93 ; 0x53 ; 0xD3 ; 0x33 ; 0xB3 ; 0x73 ; 0xF3 ; 0x0B ; 0x8B ; 0x4B ; 0xCB ; 0x2B ; 0xAB ; 0x6B ; 0xEB ; 0x1B ; 0x9B ; 0x5B ; 0xDB ; 0x3B ; 0xBB ; 0x7B ; 0xFB ; 0x07 ; 0x87 ; 0x47 ; 0xC7 ; 0x27 ; 0xA7 ; 0x67 ; 0xE7 ; 0x17 ; 0x97 ; 0x57 ; 0xD7 ; 0x37 ; 0xB7 ; 0x77 ; 0xF7 ; 0x0F ; 0x8F ; 0x4F ; 0xCF ; 0x2F ; 0xAF ; 0x6F ; 0xEF ; 0x1F ; 0x9F ; 0x5F ; 0xDF ; 0x3F ; 0xBF ; 0x7F ; 0xFF |] in fun bits -> t.(bits) module Lookup = struct type t = {table: int array; max: int; mask: int} let max_mask = (1 lsl 15) - 1 let make table max = {table; max; mask= (1 lsl max) - 1} let fixed_chr = let tbl = Array.init 288 (fun n -> if n < 144 then 8 else if n < 256 then 9 else if n < 280 then 7 else 8 ) in let tbl, max = Huffman.make ~kind:`LENS tbl 0 288 9 in make tbl max let fixed_dst = let tbl = Array.make (1 lsl 5) 0 in Array.iteri (fun i _ -> tbl.(i) <- (5 lsl 15) lor reverse_bits (i lsl 3)) tbl ; make tbl 5 let get t idx = let shadow = t.table.(idx) in (shadow lsr 15, shadow land max_mask) end type ('i, 'o, 'crc) t = { last: bool ; hold: int ; bits: int ; o_off: int ; o_pos: int ; o_len: int ; i_off: int ; i_pos: int ; i_len: int ; write: int ; state: ('i, 'o, 'crc) state ; window: ('o, 'crc) Window.t ; wbits: int ; wi: 'i Buffer.t ; wo: 'o Buffer.t } and ('i, 'o, 'crc) k = (Safe.ro, 'i) Safe.t -> (Safe.wo, 'o) Safe.t -> ('i, 'o, 'crc) t -> ('i, 'o, 'crc) res and ('i, 'o, 'crc) state = | Last | Block | Flat of ('i, 'o, 'crc) k | Fixed | Dictionary of ('i, 'o, 'crc) k | Inffast of (Lookup.t * Lookup.t * code) | Inflate of ('i, 'o, 'crc) k | Switch | Finish of int | Exception of error and ('i, 'o, 'crc) res = | Cont of ('i, 'o, 'crc) t | Wait of ('i, 'o, 'crc) t | Flush of ('i, 'o, 'crc) t | Ok of ('i, 'o, 'crc) t | Error of ('i, 'o, 'crc) t * error and code = | Length | ExtLength of int | Dist of int | ExtDist of int * int | Write of int * int and error = error_rfc1951 let pp_error ppf = function | Invalid_kind_of_block -> pf ppf "Invalid_kind_of_block" | Invalid_complement_of_length -> pf ppf "Invalid_complement_of_length" | Invalid_dictionary -> pf ppf "Invalid_dictionary" | Invalid_distance_code -> pf ppf "Invalid_distance_code" | Invalid_distance {distance; max} -> pf ppf "(Invalid_distance { @[distance = %d;@ max = %d;@] })" distance max let pp_code ppf = function | Length -> pf ppf "Length" | ExtLength c -> pf ppf "(ExtLength %d)" c | Dist c -> pf ppf "(Dist %d)" c | ExtDist (a, b) -> pf ppf "(ExtDist (%d, %d))" a b | Write (a, b) -> pf ppf "(Write (%d, %d))" a b let pp_state ppf = function | Last -> pf ppf "Last" | Block -> pf ppf "Block" | Flat _ -> pf ppf "(Flat #fun)" | Fixed -> pf ppf "Fixed" | Dictionary _ -> pf ppf "(Dictionary #fun)" | Inffast (_, _, c) -> pf ppf "(Inffast %a)" pp_code c | Inflate _ -> pf ppf "(Inflate #fun)" | Switch -> pf ppf "Switch" | Finish n -> pf ppf "(Finish %d)" n | Exception e -> pf ppf "(Exception %a)" pp_error e let pp ppf { last ; hold ; bits ; o_off ; o_pos ; o_len ; i_off ; i_pos ; i_len ; write ; state ; wbits; _ } = pf ppf "{ @[<hov>last = %b;@ hold = %d;@ bits = %d;@ o_off = %d;@ o_pos = %d;@ \ o_len = %d;@ i_off = %d;@ i_pos = %d;@ i_len = %d;@ write = %d;@ state \ = %a;@ wbits = %d;@ window = #window;@] }" last hold bits o_off o_pos o_len i_off i_pos i_len write pp_state state wbits let error t exn = Error ({t with state= Exception exn}, exn) let ok t n = Ok {t with state= Finish n} (* Basics operations. *) let rec get_byte ~ctor k src dst t = if t.i_len - t.i_pos > 0 then let byte = Char.code (Safe.get t.wi src (t.i_off + t.i_pos)) in k byte src dst {t with i_pos= t.i_pos + 1} else Wait { t with state= ctor (fun src dst t -> (get_byte [@tailcall]) ~ctor k src dst t) } let rec put_byte ~ctor byte k src dst t = if t.o_len - t.o_pos > 0 then ( let chr = Char.unsafe_chr byte in let window = Window.write_char chr t.window in Safe.set t.wo dst (t.o_off + t.o_pos) chr ; k src dst {t with o_pos= t.o_pos + 1; write= t.write + 1; window} ) else Flush { t with state= ctor (fun src dst t -> (put_byte [@tailcall]) ~ctor byte k src dst t ) } let rec fill_byte ~ctor byte length k src dst t = if t.o_len - t.o_pos > 0 then ( let chr = Char.unsafe_chr byte in let len = min length (t.o_len - t.o_pos) in let window = Window.fill_char chr len t.window in Safe.fill t.wo dst (t.o_off + t.o_pos) len chr ; if length - len > 0 then Flush { t with state= ctor (fun src dst t -> (fill_byte [@tailcall]) ~ctor byte (length - len) k src dst t ) ; o_pos= t.o_pos + len ; write= t.write + len ; window } else k src dst {t with o_pos= t.o_pos + len; write= t.write + len; window} ) else Flush { t with state= ctor (fun src dst t -> (fill_byte [@tailcall]) ~ctor byte length k src dst t ) } let peek_bits ~ctor n k src dst t = let get_byte = get_byte ~ctor in let rec go src dst t = if t.bits < n then get_byte (fun byte src dst t -> (go [@tailcall]) src dst {t with hold= t.hold lor (byte lsl t.bits); bits= t.bits + 8} ) src dst t else k src dst t in go src dst t let drop_bits ~ctor n k src dst t = let go src dst t = k src dst {t with hold= t.hold lsr n; bits= t.bits - n} in if t.bits < n then peek_bits ~ctor n go src dst t else go src dst t let get_bits ~ctor n k src dst t = let go src dst t = let v = t.hold land ((1 lsl n) - 1) in k v src dst {t with hold= t.hold lsr n; bits= t.bits - n} in if t.bits < n then peek_bits ~ctor n go src dst t else go src dst t let get_with_holding ~ctor k src dst t = (* XXX: [hold] contains one already read byte. *) if t.bits >= 8 then let byte = t.hold land 0xFF in k byte src dst {t with hold= t.hold lsr 8; bits= t.bits - 8} else get_byte ~ctor k src dst t let get_int16 ~ctor k src dst t = let get_byte = get_with_holding ~ctor in let k byte0 src dst t = let k byte1 src dst t = k (byte0 lor (byte1 lsl 8)) src dst t in get_byte k src dst t in get_byte k src dst t module KLast = struct let ctor _k = Last let peek_bits n k src dst t = peek_bits ~ctor n k src dst t end module KBlock = struct let ctor _k = Block let peek_bits n k src dst t = peek_bits ~ctor n k src dst t end module KDictionary = struct let ctor k = Dictionary k let peek_bits n k src dst t = peek_bits ~ctor n k src dst t let drop_bits n k src dst t = drop_bits ~ctor n k src dst t let get_bits n k src dst t = get_bits ~ctor n k src dst t end module KFlat = struct let ctor k = Flat k let get_int16 k src dst t = get_int16 ~ctor k src dst t let drop_bits n k src dst t = drop_bits ~ctor n k src dst t end module KInflate = struct let ctor k = Inflate k let peek_bits n k src dst t = peek_bits ~ctor n k src dst t let put_byte byte k src dst t = put_byte ~ctor byte k src dst t let fill_byte byte length k src dst t = fill_byte ~ctor byte length k src dst t let get lookup k src dst t0 = let safe src dst t1 = let len, v = Lookup.get lookup (t1.hold land lookup.Lookup.mask) in k v src dst {t1 with hold= t1.hold lsr len; bits= t1.bits - len} in peek_bits lookup.Lookup.max safe src dst t0 let rec put lookup_chr lookup_dst length distance k src dst t = match distance with | 1 -> let chr = Safe.get t.wo t.window.Window.buffer Window.((t.window.wpos - 1) % t.window) in let byte = Char.code chr in fill_byte byte length k src dst t | distance -> if distance > 1 lsl t.wbits then error t (Invalid_distance {distance; max= 1 lsl t.wbits}) else let len = min (t.o_len - t.o_pos) length in let off = Window.((t.window.wpos - distance) % t.window) in let sze = t.window.Window.size in let pre = sze - off in let ext = len - pre in let window = if ext > 0 then let window = Window.write t.window.Window.buffer off dst (t.o_off + t.o_pos) pre t.window in Window.write window.Window.buffer 0 dst (t.o_off + t.o_pos + pre) ext window else Window.write t.window.Window.buffer off dst (t.o_off + t.o_pos) len t.window in if length - len > 0 then Flush { t with o_pos= t.o_pos + len ; write= t.write + len ; state= Inflate (put lookup_chr lookup_dst (length - len) distance k) ; window } else Cont { t with o_pos= t.o_pos + len ; write= t.write + len ; state= Inffast (lookup_chr, lookup_dst, Length) ; window } let read_extra_dist distance k src dst t = match Tables._extra_dbits.(distance) with | len -> let safe src dst t = let extra = t.hold land ((1 lsl len) - 1) in k (Tables._base_dist.(distance) + 1 + extra) src dst {t with hold= t.hold lsr len; bits= t.bits - len} in peek_bits len safe src dst t | exception Invalid_argument _ -> error t Invalid_distance_code let read_extra_length length k src dst t = let len = Tables._extra_lbits.(length) in let safe src dst t = let extra = t.hold land ((1 lsl len) - 1) in k (Tables._base_length.(length) + 3 + extra) src dst {t with hold= t.hold lsr len; bits= t.bits - len} in peek_bits len safe src dst t end module Dictionary = struct type t = {idx: int; prv: int; max: int; dictionary: int array} let make max = {idx= 0; prv= 0; max; dictionary= Array.make max 0} let inflate (tbl, max_bits, max) k src dst t = let mask_bits = (1 lsl max_bits) - 1 in let get k src dst t = let k src dst t = (* safe-zone optimization: tbl is an integer array which integer is split in two parts. As we know about RFC1951, [v] should not be more than 32767. So, [len] is stored as [len << 15] and [v] is masked on [(1 << 15) - 1] - TODO it could not be necessary to mask 2 times to get [v]. *) let len, v = ( tbl.(t.hold land mask_bits) lsr 15 , tbl.(t.hold land mask_bits) land Lookup.max_mask ) in let k src dst t = k v src dst t in KDictionary.drop_bits len k src dst t in KDictionary.peek_bits max_bits k src dst t in let rec go state value src dst t = match value with | 16 -> let k state n src dst t = if state.idx + n + 3 > state.max then error t Invalid_dictionary else ( for j = 0 to n + 3 - 1 do state.dictionary.(state.idx + j) <- state.prv done ; if state.idx + n + 3 < state.max then let k v src dst t = (go [@tailcall]) {state with idx= state.idx + n + 3} v src dst t in get k src dst t else k state.dictionary src dst t ) in (* XXX(dinosaure): see invalid bit length repeat error on [zlib]. *) if state.idx = 0 then error t Invalid_dictionary else KDictionary.get_bits 2 (k state) src dst t | 17 -> let k state n src dst t = if state.idx + n + 3 > state.max then error t Invalid_dictionary else if state.idx + n + 3 < state.max then let k v src dst t = (go [@tailcall]) {state with idx= state.idx + n + 3} v src dst t in get k src dst t else k state.dictionary src dst t in KDictionary.get_bits 3 (k state) src dst t | 18 -> let k state n src dst t = if state.idx + n + 11 > state.max then error t Invalid_dictionary else if state.idx + n + 11 < state.max then let k v src dst t = (go [@tailcall]) {state with idx= state.idx + n + 11} v src dst t in get k src dst t else k state.dictionary src dst t in KDictionary.get_bits 7 (k state) src dst t | n -> if n <= 15 then ( state.dictionary.(state.idx) <- n ; if state.idx + 1 < state.max then let k v src dst t = (go [@tailcall]) {state with idx= state.idx + 1; prv= n} v src dst t in get k src dst t else k state.dictionary src dst t ) else error t Invalid_dictionary in let state = make max in let k v src dst t = go state v src dst t in get k src dst t end let fixed _src _dst t = Cont {t with state= Inffast (Lookup.fixed_chr, Lookup.fixed_dst, Length)} let dictionary src dst t = let make_table hlit hdist _hclen buf src dst t = match Huffman.make ~kind:`CODES buf 0 19 7 with | tbl, max -> let k dict _src _dst t = match ( Huffman.make ~kind:`LENS dict 0 hlit 15 , Huffman.make ~kind:`DIST dict hlit hdist 15 ) with | (tbl_chr, max_chr), (tbl_dst, max_dst) -> if max_chr > 0 (* && max_dst > 0 ? *) then Cont { t with state= Inffast ( Lookup.make tbl_chr max_chr , Lookup.make tbl_dst max_dst , Length ) } else error t Invalid_dictionary | exception Huffman.Invalid_huffman -> error t Invalid_dictionary in Dictionary.inflate (tbl, max, hlit + hdist) k src dst t | exception Huffman.Invalid_huffman -> error t Invalid_dictionary in let read_table hlit hdist hclen src dst t = let buf = Array.make 19 0 in let rec go idx code src dst t = buf.(Tables._hclen_order.(idx)) <- code ; if idx + 1 = hclen then ( for i = hclen to 18 do Array.unsafe_set buf (Array.unsafe_get Tables._hclen_order i) 0 done ; make_table hlit hdist hclen buf src dst t ) else let k src dst t = (go [@tailcall]) (idx + 1) src dst t in KDictionary.get_bits 3 k src dst t in let k code src dst t = go 0 code src dst t in KDictionary.get_bits 3 k src dst t in let read_hclen hlit hdist src dst t = let k hclen src dst t = read_table hlit hdist (hclen + 4) src dst t in KDictionary.get_bits 4 k src dst t in let read_hdist hlit src dst t = let k hdist src dst t = if hlit > 286 || hdist > 30 then error t Invalid_dictionary else read_hclen hlit (hdist + 1) src dst t in KDictionary.get_bits 5 k src dst t in let read_hlit src dst t = let k hlit src dst t = read_hdist (hlit + 257) src dst t in KDictionary.get_bits 5 k src dst t in read_hlit src dst t let switch _src _dst t = if t.last then ok t t.bits else Cont {t with state= Last} let flat src dst t = let rec go length src dst t = let n = min length (min (t.i_len - t.i_pos) (t.o_len - t.o_pos)) in let window = Window.write src (t.i_off + t.i_pos) dst (t.o_off + t.o_pos) n t.window in if length - n = 0 then Cont { t with i_pos= t.i_pos + n ; o_pos= t.o_pos + n ; write= t.write + n ; state= Switch ; window } else match (t.i_len - (t.i_pos + n), t.o_len - (t.o_pos + n)) with | 0, _ -> Wait { t with i_pos= t.i_pos + n ; o_pos= t.o_pos + n ; write= t.write + n ; state= Flat (go (length - n)) ; window } | _, 0 -> Flush { t with i_pos= t.i_pos + n ; o_pos= t.o_pos + n ; write= t.write + n ; state= Flat (go (length - n)) ; window } | _, _ -> Cont { t with i_pos= t.i_pos + n ; o_pos= t.o_pos + n ; write= t.write + n ; state= Flat (go (length - n)) ; window } in let header len nlen _src _dst t = if nlen <> 0xFFFF - len then error t Invalid_complement_of_length else Cont {t with hold= 0; bits= 0; state= Flat (go len)} in (* XXX: not sure about that, may be a part of [int16] is in [hold]. *) ( KFlat.drop_bits (t.bits mod 8) @@ KFlat.get_int16 @@ fun len -> KFlat.get_int16 @@ fun nlen -> header len nlen ) src dst t let inflate lookup_chr lookup_dst src dst t = let rec go length src dst t0 = (* XXX: recursion. *) let k length _src _dst t7 = Cont { t7 with state= Inflate (fun src dst t8 -> (go [@tailcall]) length src dst t8) } in let k src dst t6 = KInflate.get lookup_chr k src dst t6 in match length with | 256 -> Cont {t0 with state= Switch} | length -> if length < 256 then KInflate.put_byte length k src dst t0 else let k length distance src dst t5 = KInflate.put lookup_chr lookup_dst length distance k src dst t5 in let k length distance src dst t3 = KInflate.read_extra_dist distance (fun dist src dst t4 -> k length dist src dst t4) src dst t3 in let k length src dst t1 = KInflate.get lookup_dst (fun dist src dst t2 -> k length dist src dst t2) src dst t1 in KInflate.read_extra_length (length - 257) k src dst t0 in KInflate.get lookup_chr go src dst t exception End (* this is the end, beautiful friend. *) exception Exn_invalid_distance of (int * int) let inffast src dst t lookup_chr lookup_dst goto = let hold = ref t.hold in let bits = ref t.bits in let goto = ref goto in let i_pos = ref t.i_pos in let o_pos = ref t.o_pos in let write = ref t.write in let window = ref t.window in try while t.i_len - !i_pos > 1 && t.o_len - !o_pos > 0 do match !goto with | Length -> if !bits < lookup_chr.Lookup.max then ( hold := !hold lor (Char.code (Safe.get t.wi src (t.i_off + !i_pos)) lsl !bits) ; bits := !bits + 8 ; incr i_pos ; hold := !hold lor (Char.code (Safe.get t.wi src (t.i_off + !i_pos)) lsl !bits) ; bits := !bits + 8 ; incr i_pos ) ; let len, value = Lookup.get lookup_chr (!hold land lookup_chr.Lookup.mask) in hold := !hold lsr len ; bits := !bits - len ; if value < 256 then ( Safe.set t.wo dst (t.o_off + !o_pos) (Char.chr value) ; window := Window.write_char (Char.chr value) !window ; incr o_pos ; incr write ; goto := Length ) else if value = 256 then raise End else goto := ExtLength (value - 257) | ExtLength length -> let len = Tables._extra_lbits.(length) in if !bits < len then ( hold := !hold lor (Char.code (Safe.get t.wi src (t.i_off + !i_pos)) lsl !bits) ; bits := !bits + 8 ; incr i_pos ) ; let extra = !hold land ((1 lsl len) - 1) in hold := !hold lsr len ; bits := !bits - len ; goto := Dist (Tables._base_length.(length) + 3 + extra) | Dist length -> if !bits < lookup_dst.Lookup.max then ( hold := !hold lor (Char.code (Safe.get t.wi src (t.i_off + !i_pos)) lsl !bits) ; bits := !bits + 8 ; incr i_pos ; hold := !hold lor (Char.code (Safe.get t.wi src (t.i_off + !i_pos)) lsl !bits) ; bits := !bits + 8 ; incr i_pos ) ; let len, value = Lookup.get lookup_dst (!hold land lookup_dst.Lookup.mask) in hold := !hold lsr len ; bits := !bits - len ; goto := ExtDist (length, value) | ExtDist (length, dist) -> let len = Tables._extra_dbits.(dist) in if !bits < len then ( hold := !hold lor (Char.code (Safe.get t.wi src (t.i_off + !i_pos)) lsl !bits) ; bits := !bits + 8 ; incr i_pos ; hold := !hold lor (Char.code (Safe.get t.wi src (t.i_off + !i_pos)) lsl !bits) ; bits := !bits + 8 ; incr i_pos ) ; let extra = !hold land ((1 lsl len) - 1) in hold := !hold lsr len ; bits := !bits - len ; goto := Write (length, Tables._base_dist.(dist) + 1 + extra) | Write (length, 1) -> let chr = Safe.get t.wo !window.Window.buffer Window.((!window.wpos - 1) % !window) in let n = min length (t.o_len - !o_pos) in window := Window.fill_char chr n !window ; Safe.fill t.wo dst (t.o_off + !o_pos) n chr ; o_pos := !o_pos + n ; write := !write + n ; goto := if length - n = 0 then Length else Write (length - n, 1) | Write (length, dist) -> if dist > 1 lsl t.wbits then raise (Exn_invalid_distance (dist, 1 lsl t.wbits)) ; let n = min length (t.o_len - !o_pos) in let off = Window.((!window.wpos - dist) % !window) in let len = !window.Window.size in let pre = len - off in let ext = n - pre in window := if ext > 0 then let window = Window.write !window.Window.buffer off dst (t.o_off + !o_pos) pre !window in Window.write window.Window.buffer 0 dst (t.o_off + !o_pos + pre) ext window else Window.write !window.Window.buffer off dst (t.o_off + !o_pos) n !window ; o_pos := !o_pos + n ; write := !write + n ; goto := if length - n = 0 then Length else Write (length - n, dist) done ; let k0 src dst t = inflate lookup_chr lookup_dst src dst t in let k1 length distance src dst t = KInflate.put lookup_chr lookup_dst length distance k0 src dst t in let k2 length distance src dst t = KInflate.read_extra_dist distance (k1 length) src dst t in let k3 length src dst t = KInflate.get lookup_dst (k2 length) src dst t in let k4 length src dst t = KInflate.read_extra_length length k3 src dst t in let state = match !goto with | Length -> Inflate (inflate lookup_chr lookup_dst) | ExtLength length -> Inflate (k4 length) | Dist length -> Inflate (k3 length) | ExtDist (length, distance) -> Inflate (k2 length distance) | Write (length, distance) -> Inflate (k1 length distance) in Cont { t with hold= !hold ; bits= !bits ; i_pos= !i_pos ; o_pos= !o_pos ; write= !write ; state ; window= !window } with End -> Cont { t with hold= !hold ; bits= !bits ; i_pos= !i_pos ; o_pos= !o_pos ; write= !write ; state= Switch ; window= !window } let block src dst t = let safe _src _dst t = let state = match t.hold land 0x3 with | 0 -> Flat flat | 1 -> Fixed | 2 -> Dictionary dictionary | _ -> Exception Invalid_kind_of_block in Cont {t with hold= t.hold lsr 2; bits= t.bits - 2; state} in KBlock.peek_bits 2 safe src dst t let last src dst t = let safe _src _dst t = let last = t.hold land 1 = 1 in Cont {t with last; hold= t.hold lsr 1; bits= t.bits - 1; state= Block} in KLast.peek_bits 1 safe src dst t let eval0 safe_src safe_dst t = match t.state with | Last -> last safe_src safe_dst t | Block -> block safe_src safe_dst t | Flat k -> k safe_src safe_dst t | Fixed -> fixed safe_src safe_dst t | Dictionary k -> k safe_src safe_dst t | Inffast (lookup_chr, lookup_dst, code) -> ( try inffast safe_src safe_dst t lookup_chr lookup_dst code with Exn_invalid_distance (distance, max) -> error t (Invalid_distance {distance; max}) ) | Inflate k -> k safe_src safe_dst t | Switch -> switch safe_src safe_dst t | Finish n -> ok t n | Exception exn -> error t exn let eval src dst t = let safe_src = Safe.ro t.wi src in let safe_dst = Safe.wo t.wo dst in let rec loop t = match eval0 safe_src safe_dst t with | Cont t -> loop t | Wait t -> `Await t | Flush t -> `Flush t | Ok t -> `End t | Error (t, exn) -> `Error (t, exn) in loop t let default ~witness ?(wbits = 15) window = if wbits < 8 || wbits > 15 then invalid_arg "Invalid wbits value (8 >= wbits <= 15)" ; { last= false ; hold= 0 ; bits= 0 ; i_off= 0 ; i_pos= 0 ; i_len= 0 ; o_off= 0 ; o_pos= 0 ; o_len= 0 ; write= 0 ; state= Last ; wbits ; window ; wi= witness ; wo= witness } let refill off len t = if t.i_pos = t.i_len then {t with i_off= off; i_len= len; i_pos= 0} else match t.state with | Finish _ -> (* XXX(dinosaure): when inflation computation is done, we don care if we lost something. *) {t with i_off= off; i_len= len; i_pos= 0} | _ -> invalid_arg "refill: you lost something (pos: %d, len: %d)" t.i_pos t.i_len let flush off len t = {t with o_off= off; o_len= len; o_pos= 0} let used_in t = t.i_pos let used_out t = t.o_pos let write t = t.write let bits_remaining t = match t.state with | Finish n -> n | _ -> invalid_arg "bits_remaining: bad state" include Convenience (struct type nonrec ('i, 'o) t = ('i, 'o, Window.none) t type nonrec error = error let eval = eval let refill = refill let flush = flush let used_out = used_out end) end type error_z = | RFC1951 of RFC1951.error | Invalid_header | Invalid_checksum of {have: Optint.t; expect: Optint.t} module Zlib = struct type ('i, 'o) t = {d: ('i, 'o, crc) RFC1951.t; z: ('i, 'o) state; expected_wbits: int option} and ('i, 'o) k = (Safe.ro, 'i) Safe.t -> (Safe.wo, 'o) Safe.t -> ('i, 'o) t -> ('i, 'o) res and ('i, 'o) state = | Header of ('i, 'o) k | Inflate | Adler32 of ('i, 'o) k | Finish | Exception of error and ('i, 'o) res = | Cont of ('i, 'o) t | Wait of ('i, 'o) t | Flush of ('i, 'o) t | Ok of ('i, 'o) t | Error of ('i, 'o) t * error and error = error_z and crc = Window.adler32 let pp_error ppf = function | RFC1951 err -> pf ppf "(RFC1951 %a)" RFC1951.pp_error err | Invalid_header -> pf ppf "Invalid_header" | Invalid_checksum {have; expect} -> pf ppf "(Invalid_check (have:%a, expect:%a))" Optint.pp have Optint.pp expect let pp_state ppf = function | Header _ -> pf ppf "(Header #fun)" | Inflate -> pf ppf "Inflate" | Adler32 _ -> pf ppf "(Adler32 #fun)" | Finish -> pf ppf "Finish" | Exception e -> pf ppf "(Exception %a)" pp_error e let pp ppf {d; z; _} = pf ppf "{@[<hov>d = @[<hov>%a@];@ z = %a;@]}" RFC1951.pp d pp_state z let error t exn = Error ({t with z= Exception exn}, exn) let ok t = Ok {t with z= Finish} let rec get_byte ~ctor k src dst t = if t.d.RFC1951.i_len - t.d.RFC1951.i_pos > 0 then let byte = Char.code (Safe.get t.d.RFC1951.wi src (t.d.RFC1951.i_off + t.d.RFC1951.i_pos)) in k byte src dst {t with d= {t.d with RFC1951.i_pos= t.d.RFC1951.i_pos + 1}} else Wait { t with z= ctor (fun src dst t -> (get_byte [@tailcall]) ~ctor k src dst t) } let get_with_holding ~ctor k src dst t = (* XXX: [hold] contains one already read byte. *) if t.d.RFC1951.bits >= 8 then let byte = t.d.RFC1951.hold land 0xFF in k byte src dst { t with d= { t.d with RFC1951.hold= t.d.RFC1951.hold lsr 8 ; RFC1951.bits= t.d.RFC1951.bits - 8 } } else get_byte ~ctor k src dst t let peek_bits ~ctor n k src dst t = let get_byte = get_byte ~ctor in let rec go src dst t = if t.d.RFC1951.bits < n then get_byte (fun byte src dst t -> (go [@tailcall]) src dst { t with d= { t.d with RFC1951.hold= t.d.RFC1951.hold lor (byte lsl t.d.RFC1951.bits) ; RFC1951.bits= t.d.RFC1951.bits + 8 } } ) src dst t else k src dst t in go src dst t let drop_bits ~ctor n k src dst t = let go src dst t = k src dst { t with d= { t.d with RFC1951.hold= t.d.RFC1951.hold lsr n ; RFC1951.bits= t.d.RFC1951.bits - n } } in if t.d.RFC1951.bits < n then peek_bits ~ctor n go src dst t else go src dst t module KHeader = struct let ctor k = Header k let get_byte k src dst zlib = get_byte ~ctor k src dst zlib end module KCrc = struct let ctor k = Adler32 k let get_with_holding k src dst t = get_with_holding ~ctor k src dst t let drop_bits n k src dst t = drop_bits ~ctor n k src dst t end let adler32 src dst t = let have = Window.crc t.d.RFC1951.window in ( KCrc.drop_bits (t.d.RFC1951.bits mod 8) @@ KCrc.get_with_holding @@ fun a1 -> KCrc.get_with_holding @@ fun a2 -> KCrc.get_with_holding @@ fun b1 -> KCrc.get_with_holding @@ fun b2 _src _dst t -> let a1 = Optint.of_int a1 in let a2 = Optint.of_int a2 in let b1 = Optint.of_int b1 in let b2 = Optint.of_int b2 in let expect = Optint.Infix.(a1 << 24 || a2 << 16 || b1 << 8 || b2) in if Optint.equal have expect then ok t else error t (Invalid_checksum {have; expect}) ) src dst t let inflate src dst t = match RFC1951.eval0 src dst t.d with | RFC1951.Cont d -> Cont {t with d} | RFC1951.Wait d -> Wait {t with d} | RFC1951.Flush d -> Flush {t with d} | RFC1951.Ok d -> Cont {t with z= Adler32 adler32; d} | RFC1951.Error (d, exn) -> error {t with d} (RFC1951 exn) let header src dst t = ( KHeader.get_byte @@ fun byte0 -> KHeader.get_byte @@ fun byte1 _src _dst t -> let hold = byte0 in let hold = hold + (byte1 lsl 8) in let bits ?(hold = hold) n = hold land ((1 lsl n) - 1) in let drop n = hold lsr n in let option_is v e = match v with Some e' -> e = e' | None -> true in if ((bits 8 lsl 8) + (hold lsr 8)) mod 31 = 0 && bits 4 = 8 && bits ~hold:(drop 4) 4 + 8 <= 15 && option_is t.expected_wbits (bits ~hold:(drop 4) 4 + 8) then Cont { t with z= Inflate; d= {t.d with RFC1951.wbits= bits ~hold:(drop 4) 4 + 8} } else error t Invalid_header ) src dst t let eval src dst t = let safe_src = Safe.ro t.d.RFC1951.wi src in let safe_dst = Safe.wo t.d.RFC1951.wo dst in let eval0 t = match t.z with | Header k -> k safe_src safe_dst t | Inflate -> inflate safe_src safe_dst t | Adler32 k -> k safe_src safe_dst t | Finish -> ok t | Exception exn -> error t exn in let rec loop t = match eval0 t with | Cont t -> loop t | Wait t -> `Await t | Flush t -> `Flush t | Ok t -> `End t | Error (t, exn) -> `Error (t, exn) in loop t let default ~witness ?wbits window = { d= RFC1951.default ~witness ?wbits window ; z= Header header ; expected_wbits= wbits } let refill off len t = {t with d= RFC1951.refill off len t.d} let flush off len t = {t with d= RFC1951.flush off len t.d} let used_in t = RFC1951.used_in t.d let used_out t = RFC1951.used_out t.d let write t = RFC1951.write t.d include Convenience (struct type nonrec ('i, 'o) t = ('i, 'o) t type nonrec error = error let eval = eval let refill = refill let flush = flush let used_out = used_out end) end type error_g = | RFC1951 of RFC1951.error | Invalid_header | Invalid_header_checksum of {have: Optint.t; expect: Optint.t} | Invalid_checksum of {have: Optint.t; expect: Optint.t} | Invalid_size of {have: Optint.t; expect: Optint.t} module Gzip = struct type ('i, 'o) t = { d: ('i, 'o, crc) RFC1951.t ; z: ('i, 'o) state ; mtime: Optint.t ; xfl: int ; os: OS.t ; extra_l: int option ; extra: string option ; name: string option ; comment: string option ; crc16: Optint.t ; hcrc16: int option } and ('i, 'o) k = (Safe.ro, 'i) Safe.t -> (Safe.wo, 'o) Safe.t -> ('i, 'o) t -> ('i, 'o) res and ('i, 'o) state = | Header of ('i, 'o) k | Inflate | Crc32 of ('i, 'o) k | Size of ('i, 'o) k | Finish | Exception of error and ('i, 'o) res = | Cont of ('i, 'o) t | Wait of ('i, 'o) t | Flush of ('i, 'o) t | Ok of ('i, 'o) t | Error of ('i, 'o) t * error and error = error_g and crc = Window.crc32 let pp_error ppf = function | RFC1951 err -> pf ppf "(RFC1951 %a)" RFC1951.pp_error err | Invalid_header -> pf ppf "Invalid_header" | Invalid_header_checksum {have; expect} -> pf ppf "(Invalid_header_checksum (have:%x, expect:%x))" (Optint.to_int have) (Optint.to_int expect) | Invalid_checksum {have; expect} -> pf ppf "(Invalid_checksum (have:%x, expect:%x))" (Optint.to_int have) (Optint.to_int expect) | Invalid_size {have; expect} -> pf ppf "(Invalid_size (have:%a, expect:%a))" Optint.pp have Optint.pp expect let pp_state ppf = function | Header _ -> pf ppf "(Header #fun)" | Inflate -> pf ppf "Inflate" | Crc32 _ -> pf ppf "(Crc32 #fun)" | Size _ -> pf ppf "(Size #fun)" | Finish -> pf ppf "Finish" | Exception e -> pf ppf "(Exception %a)" pp_error e let pp ppf {d; z; _} = pf ppf "{@[<hov>d = @[<hov>%a@];@ z = %a;@]}" RFC1951.pp d pp_state z let error t exn = Error ({t with z= Exception exn}, exn) let ok t = Ok {t with z= Finish} let rec get_byte ~ctor k src dst t = if t.d.RFC1951.i_len - t.d.RFC1951.i_pos > 0 then let byte = Char.code (Safe.get t.d.RFC1951.wi src (t.d.RFC1951.i_off + t.d.RFC1951.i_pos)) in k byte src dst {t with d= {t.d with RFC1951.i_pos= t.d.RFC1951.i_pos + 1}} else Wait { t with z= ctor (fun src dst t -> (get_byte [@tailcall]) ~ctor k src dst t) } let get_with_holding ~ctor k src dst t = (* XXX: [hold] contains one already read byte. *) if t.d.RFC1951.bits >= 8 then let byte = t.d.RFC1951.hold land 0xFF in k byte src dst { t with d= { t.d with RFC1951.hold= t.d.RFC1951.hold lsr 8 ; RFC1951.bits= t.d.RFC1951.bits - 8 } } else get_byte ~ctor k src dst t let peek_bits ~ctor n k src dst t = let get_byte = get_byte ~ctor in let rec go src dst t = if t.d.RFC1951.bits < n then get_byte (fun byte src dst t -> (go [@tailcall]) src dst { t with d= { t.d with RFC1951.hold= t.d.RFC1951.hold lor (byte lsl t.d.RFC1951.bits) ; RFC1951.bits= t.d.RFC1951.bits + 8 } } ) src dst t else k src dst t in go src dst t let drop_bits ~ctor n k src dst t = let go src dst t = k src dst { t with d= { t.d with RFC1951.hold= t.d.RFC1951.hold lsr n ; RFC1951.bits= t.d.RFC1951.bits - n } } in if t.d.RFC1951.bits < n then peek_bits ~ctor n go src dst t else go src dst t let get_int16 ~ctor k src dst t = let get_byte = get_with_holding ~ctor in let k byte0 src dst t = let k byte1 src dst t = k (byte0 lor (byte1 lsl 8)) src dst t in get_byte k src dst t in get_byte k src dst t let get_string ~ctor n k src dst t = let get_byte = get_byte ~ctor in let bytes = Bytes.create n in let rec go i src dst t = if i < n then get_byte (fun byte src dst t -> Bytes.set bytes i (Char.chr byte) ; (go [@tailcall]) (i + 1) src dst t ) src dst t else k (Bytes.unsafe_to_string bytes) src dst t in go 0 src dst t let get_zero_term_string ~ctor k src dst t = let get_byte = get_byte ~ctor in let buf = Stdlib_buffer.create 256 in let rec go src dst t = get_byte (fun byte src dst t -> match byte with | 0 -> k (Stdlib_buffer.contents buf) src dst t | b -> Stdlib_buffer.add_char buf (Char.chr b) ; go src dst t ) src dst t in go src dst t let digest_crc16_byte k byte src dst t = let crc16 = Checkseum.Crc32.digest_string (String.make 1 (char_of_int byte)) 0 1 t.crc16 in k byte src dst {t with crc16} let digest_crc16_int16 k short src dst t = let crc16 = Checkseum.Crc32.digest_string (String.make 1 (char_of_int (short land 0xFF))) 0 1 t.crc16 in let crc16 = Checkseum.Crc32.digest_string (String.make 1 (char_of_int ((short lsr 8) land 0xFF))) 0 1 crc16 in k short src dst {t with crc16} let digest_crc16_z_string k str src dst t = let crc16 = Checkseum.Crc32.digest_string str 0 (String.length str) t.crc16 in let crc16 = Checkseum.Crc32.digest_string "\x00" 0 1 crc16 in k str src dst {t with crc16} let digest_crc16_n_string k n str src dst t = let crc16 = Checkseum.Crc32.digest_string str 0 n t.crc16 in k str src dst {t with crc16} module KHeader = struct let ctor k = Header k let get_byte k src dst t = get_byte ~ctor (digest_crc16_byte k) src dst t let get_int16 k src dst gzip = get_int16 ~ctor (digest_crc16_int16 k) src dst gzip let get_string n k src dst gzip = get_string ~ctor n (digest_crc16_n_string k n) src dst gzip let get_zero_term_string k src dst gzip = get_zero_term_string ~ctor (digest_crc16_z_string k) src dst gzip end module KCrc = struct let ctor k = Crc32 k let get_with_holding k src dst t = get_with_holding ~ctor k src dst t let drop_bits n k src dst t = drop_bits ~ctor n k src dst t end module KSize = struct let ctor k = Size k let get_byte k src dst gzip = get_byte ~ctor k src dst gzip end let size src dst t = let have = Optint.of_int (RFC1951.write t.d) in ( KSize.get_byte @@ fun size0 -> KSize.get_byte @@ fun size1 -> KSize.get_byte @@ fun size2 -> KSize.get_byte @@ fun size3 _src _dst t -> let size0 = Optint.of_int size0 in let size1 = Optint.of_int size1 in let size2 = Optint.of_int size2 in let size3 = Optint.of_int size3 in let expect = Optint.Infix.(size3 << 24 || size2 << 16 || size1 << 8 || size0) in if Optint.equal have expect then ok t else error t (Invalid_size {have; expect}) ) src dst t let crc32 src dst t = let have = Window.crc t.d.RFC1951.window in ( KCrc.drop_bits (t.d.RFC1951.bits mod 8) @@ KCrc.get_with_holding @@ fun crc1 -> KCrc.get_with_holding @@ fun crc2 -> KCrc.get_with_holding @@ fun crc3 -> KCrc.get_with_holding @@ fun crc4 _src _dst t -> let crc1 = Optint.of_int crc1 in let crc2 = Optint.of_int crc2 in let crc3 = Optint.of_int crc3 in let crc4 = Optint.of_int crc4 in let expect = Optint.Infix.(crc4 << 24 || crc3 << 16 || crc2 << 8 || crc1) in if Optint.equal have expect then Cont {t with z= Size size} else error t (Invalid_checksum {have; expect}) ) src dst t let inflate src dst t = match RFC1951.eval0 src dst t.d with | RFC1951.Cont d -> Cont {t with d} | RFC1951.Wait d -> Wait {t with d} | RFC1951.Flush d -> Flush {t with d} | RFC1951.Ok d -> Cont {t with z= Crc32 crc32; d} | RFC1951.Error (d, exn) -> error {t with d} (RFC1951 exn) let nop k src dst t = k src dst t let fextra k src dst t = ( KHeader.get_int16 @@ fun extra_l -> KHeader.get_string extra_l @@ fun extra src dst t -> k src dst {t with extra_l= Some extra_l; extra= Some extra} ) src dst t let fname k src dst t = ( KHeader.get_zero_term_string @@ fun name src dst t -> k src dst {t with name= Some name} ) src dst t let fcomment k src dst t = ( KHeader.get_zero_term_string @@ fun comment src dst t -> k src dst {t with comment= Some comment} ) src dst t let fcrc16 k src dst t = let have = Optint.logand t.crc16 (Optint.of_int32 0xFFFFl) in ( KHeader.get_int16 @@ fun crc16 src dst t -> let expect = Optint.of_int crc16 in if Optint.equal have expect then k src dst {t with hcrc16= Some crc16} else error t (Invalid_header_checksum {have; expect}) ) src dst t let header src dst t = ( KHeader.get_byte @@ fun id1 -> KHeader.get_byte @@ fun id2 -> KHeader.get_byte @@ fun cm -> KHeader.get_byte @@ fun flg -> KHeader.get_byte @@ fun mt0 -> KHeader.get_byte @@ fun mt1 -> KHeader.get_byte @@ fun mt2 -> KHeader.get_byte @@ fun mt3 -> KHeader.get_byte @@ fun xfl -> KHeader.get_byte @@ fun os _src _dst t -> let mt0 = Optint.of_int mt0 in let mt1 = Optint.of_int mt1 in let mt2 = Optint.of_int mt2 in let mt3 = Optint.of_int mt3 in let mtime = Optint.Infix.(mt3 << 24 || mt2 << 16 || mt1 << 8 || mt0) in let os = Option.get ~def:OS.default (OS.of_int os) in if id1 = 31 && id2 = 139 && cm = 8 then let fcrc16 = if flg land 0b10 <> 0 then fcrc16 else nop in let fextra = if flg land 0b100 <> 0 then fextra else nop in let fname = if flg land 0b1000 <> 0 then fname else nop in let fcomment = if flg land 0b10000 <> 0 then fcomment else nop in let final _src _dst t = Cont {t with z= Inflate} in let options = fextra @@ fname @@ fcomment @@ fcrc16 @@ final in options src dst {t with d= {t.d with RFC1951.wbits= 15}; mtime; xfl; os} else error t Invalid_header ) src dst t let eval src dst t = let safe_src = Safe.ro t.d.RFC1951.wi src in let safe_dst = Safe.wo t.d.RFC1951.wo dst in let eval0 t = match t.z with | Header k -> k safe_src safe_dst t | Inflate -> inflate safe_src safe_dst t | Crc32 k -> k safe_src safe_dst t | Size k -> k safe_src safe_dst t | Finish -> ok t | Exception exn -> error t exn in let rec loop t = match eval0 t with | Cont t -> loop t | Wait t -> `Await t | Flush t -> `Flush t | Ok t -> `End t | Error (t, exn) -> `Error (t, exn) in loop t let default ~witness ?wbits window = { d= RFC1951.default ~witness ?wbits window ; z= Header header ; mtime= Optint.zero ; xfl= 0 ; os= OS.default ; extra_l= None ; extra= None ; name= None ; comment= None ; crc16= Optint.zero ; hcrc16= None } let refill off len t = {t with d= RFC1951.refill off len t.d} let flush off len t = {t with d= RFC1951.flush off len t.d} let used_in t = RFC1951.used_in t.d let used_out t = RFC1951.used_out t.d let write t = RFC1951.write t.d let xfl t = t.xfl let os t = t.os let mtime t = t.mtime let extra t = t.extra let name t = t.name let comment t = t.comment include Convenience (struct type nonrec ('i, 'o) t = ('i, 'o) t type nonrec error = error let eval = eval let refill = refill let flush = flush let used_out = used_out end) end
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