Source file lexing.ml

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
(**************************************************************************)
(*                                                                        *)
(*                                 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 Lesser General Public License version 2.1, with the          *)
(*   special exception on linking described in the file LICENSE.          *)
(*                                                                        *)
(**************************************************************************)

(* The run-time library for lexers generated by camllex *)

type position = {
  pos_fname : string;
  pos_lnum : int;
  pos_bol : int;
  pos_cnum : int;
}

let dummy_pos = {
  pos_fname = "";
  pos_lnum = 0;
  pos_bol = 0;
  pos_cnum = -1;
}

type lexbuf =
  { refill_buff : lexbuf -> unit;
    mutable lex_buffer : bytes;
    mutable lex_buffer_len : int;
    mutable lex_abs_pos : int;
    mutable lex_start_pos : int;
    mutable lex_curr_pos : int;
    mutable lex_last_pos : int;
    mutable lex_last_action : int;
    mutable lex_eof_reached : bool;
    mutable lex_mem : int array;
    mutable lex_start_p : position;
    mutable lex_curr_p : position;
  }

type lex_tables =
  { lex_base: string;
    lex_backtrk: string;
    lex_default: string;
    lex_trans: string;
    lex_check: string;
    lex_base_code : string;
    lex_backtrk_code : string;
    lex_default_code : string;
    lex_trans_code : string;
    lex_check_code : string;
    lex_code: string;}

external c_engine : lex_tables -> int -> lexbuf -> int = "caml_lex_engine"
external c_new_engine : lex_tables -> int -> lexbuf -> int
                      = "caml_new_lex_engine"

let engine tbl state buf =
  let result = c_engine tbl state buf in
  if result >= 0 && buf.lex_curr_p != dummy_pos then begin
    buf.lex_start_p <- buf.lex_curr_p;
    buf.lex_curr_p <- {buf.lex_curr_p
                       with pos_cnum = buf.lex_abs_pos + buf.lex_curr_pos};
  end;
  result


let new_engine tbl state buf =
  let result = c_new_engine tbl state buf in
  if result >= 0 && buf.lex_curr_p != dummy_pos then begin
    buf.lex_start_p <- buf.lex_curr_p;
    buf.lex_curr_p <- {buf.lex_curr_p
                       with pos_cnum = buf.lex_abs_pos + buf.lex_curr_pos};
  end;
  result

let lex_refill read_fun aux_buffer lexbuf =
  let read =
    read_fun aux_buffer (Bytes.length aux_buffer) in
  let n =
    if read > 0
    then read
    else (lexbuf.lex_eof_reached <- true; 0) in
  (* Current state of the buffer:
        <-------|---------------------|----------->
        |  junk |      valid data     |   junk    |
        ^       ^                     ^           ^
        0    start_pos             buffer_end    Bytes.length buffer
  *)
  if lexbuf.lex_buffer_len + n > Bytes.length lexbuf.lex_buffer then begin
    (* There is not enough space at the end of the buffer *)
    if lexbuf.lex_buffer_len - lexbuf.lex_start_pos + n
       <= Bytes.length lexbuf.lex_buffer
    then begin
      (* But there is enough space if we reclaim the junk at the beginning
         of the buffer *)
      Bytes.blit lexbuf.lex_buffer lexbuf.lex_start_pos
                  lexbuf.lex_buffer 0
                  (lexbuf.lex_buffer_len - lexbuf.lex_start_pos)
    end else begin
      (* We must grow the buffer.  Doubling its size will provide enough
         space since n <= String.length aux_buffer <= String.length buffer.
         Watch out for string length overflow, though. *)
      let newlen =
        Int.min (2 * Bytes.length lexbuf.lex_buffer) Sys.max_string_length in
      if lexbuf.lex_buffer_len - lexbuf.lex_start_pos + n > newlen
      then failwith "Lexing.lex_refill: cannot grow buffer";
      let newbuf = Bytes.create newlen in
      (* Copy the valid data to the beginning of the new buffer *)
      Bytes.blit lexbuf.lex_buffer lexbuf.lex_start_pos
                  newbuf 0
                  (lexbuf.lex_buffer_len - lexbuf.lex_start_pos);
      lexbuf.lex_buffer <- newbuf
    end;
    (* Reallocation or not, we have shifted the data left by
       start_pos characters; update the positions *)
    let s = lexbuf.lex_start_pos in
    lexbuf.lex_abs_pos <- lexbuf.lex_abs_pos + s;
    lexbuf.lex_curr_pos <- lexbuf.lex_curr_pos - s;
    lexbuf.lex_start_pos <- 0;
    lexbuf.lex_last_pos <- lexbuf.lex_last_pos - s;
    lexbuf.lex_buffer_len <- lexbuf.lex_buffer_len - s ;
    let t = lexbuf.lex_mem in
    for i = 0 to Array.length t-1 do
      let v = t.(i) in
      if v >= 0 then
        t.(i) <- v-s
    done
  end;
  (* There is now enough space at the end of the buffer *)
  Bytes.blit aux_buffer 0 lexbuf.lex_buffer lexbuf.lex_buffer_len n;
  lexbuf.lex_buffer_len <- lexbuf.lex_buffer_len + n

let zero_pos = {
  pos_fname = "";
  pos_lnum = 1;
  pos_bol = 0;
  pos_cnum = 0;
}

let from_function ?(with_positions = true) f =
  { refill_buff = lex_refill f (Bytes.create 512);
    lex_buffer = Bytes.create 1024;
    lex_buffer_len = 0;
    lex_abs_pos = 0;
    lex_start_pos = 0;
    lex_curr_pos = 0;
    lex_last_pos = 0;
    lex_last_action = 0;
    lex_mem = [||];
    lex_eof_reached = false;
    lex_start_p = if with_positions then zero_pos else dummy_pos;
    lex_curr_p = if with_positions then zero_pos else dummy_pos;
  }

let from_channel ?with_positions ic =
  from_function ?with_positions (fun buf n -> input ic buf 0 n)

let from_string ?(with_positions = true) s =
  { refill_buff = (fun lexbuf -> lexbuf.lex_eof_reached <- true);
    lex_buffer = Bytes.of_string s; (* have to make a copy for compatibility
                                       with unsafe-string mode *)
    lex_buffer_len = String.length s;
    lex_abs_pos = 0;
    lex_start_pos = 0;
    lex_curr_pos = 0;
    lex_last_pos = 0;
    lex_last_action = 0;
    lex_mem = [||];
    lex_eof_reached = true;
    lex_start_p = if with_positions then zero_pos else dummy_pos;
    lex_curr_p = if with_positions then zero_pos else dummy_pos;
  }

let set_position lexbuf position =
  lexbuf.lex_curr_p  <- {position with pos_fname = lexbuf.lex_curr_p.pos_fname};
  lexbuf.lex_abs_pos <- position.pos_cnum

let set_filename lexbuf fname =
  lexbuf.lex_curr_p <- {lexbuf.lex_curr_p with pos_fname = fname}

let with_positions lexbuf = lexbuf.lex_curr_p != dummy_pos

let lexeme lexbuf =
  let len = lexbuf.lex_curr_pos - lexbuf.lex_start_pos in
  Bytes.sub_string lexbuf.lex_buffer lexbuf.lex_start_pos len

let sub_lexeme lexbuf i1 i2 =
  let len = i2-i1 in
  Bytes.sub_string lexbuf.lex_buffer i1 len

let sub_lexeme_opt lexbuf i1 i2 =
  if i1 >= 0 then begin
    let len = i2-i1 in
    Some (Bytes.sub_string lexbuf.lex_buffer i1 len)
  end else begin
    None
  end

let sub_lexeme_char lexbuf i = Bytes.get lexbuf.lex_buffer i

let sub_lexeme_char_opt lexbuf i =
  if i >= 0 then
    Some (Bytes.get lexbuf.lex_buffer i)
  else
    None


let lexeme_char lexbuf i =
  Bytes.get lexbuf.lex_buffer (lexbuf.lex_start_pos + i)

let lexeme_start lexbuf = lexbuf.lex_start_p.pos_cnum
let lexeme_end lexbuf = lexbuf.lex_curr_p.pos_cnum

let lexeme_start_p lexbuf = lexbuf.lex_start_p
let lexeme_end_p lexbuf = lexbuf.lex_curr_p

let new_line lexbuf =
  let lcp = lexbuf.lex_curr_p in
  if lcp != dummy_pos then
    lexbuf.lex_curr_p <-
      { lcp with
        pos_lnum = lcp.pos_lnum + 1;
        pos_bol = lcp.pos_cnum;
      }



(* Discard data left in lexer buffer. *)

let flush_input lb =
  lb.lex_curr_pos <- 0;
  lb.lex_abs_pos <- 0;
  let lcp = lb.lex_curr_p in
  if lcp != dummy_pos then
    lb.lex_curr_p <- {zero_pos with pos_fname = lcp.pos_fname};
  lb.lex_buffer_len <- 0;