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(***********************************************************************)
(* *)
(* Objective Caml *)
(* *)
(* 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. *)
(* *)
(***********************************************************************)
(* $Id$ *)
(* The run-time library for lexers generated by camllex *)
type lexbuf =
{ refill_buff : lexbuf -> unit;
mutable lex_buffer : string;
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 }
type lex_tables =
{ lex_base: string;
lex_backtrk: string;
lex_default: string;
lex_trans: string;
lex_check: string }
external engine: lex_tables -> int -> lexbuf -> int = "lex_engine"
let lex_refill read_fun aux_buffer lexbuf =
let read =
read_fun aux_buffer (String.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 String.length buffer
*)
if lexbuf.lex_buffer_len + n > String.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
<= String.length lexbuf.lex_buffer
then begin
(* But there is enough space if we reclaim the junk at the beginning
of the buffer *)
String.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 =
min (2 * String.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 = String.create newlen in
(* Copy the valid data to the beginning of the new buffer *)
String.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
end;
(* There is now enough space at the end of the buffer *)
String.blit aux_buffer 0
lexbuf.lex_buffer lexbuf.lex_buffer_len
n;
lexbuf.lex_buffer_len <- lexbuf.lex_buffer_len + n
let from_function f =
{ refill_buff = lex_refill f (String.create 512);
lex_buffer = String.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_eof_reached = false }
let from_channel ic =
from_function (fun buf n -> input ic buf 0 n)
let from_string s =
{ refill_buff = (fun lexbuf -> lexbuf.lex_eof_reached <- true);
lex_buffer = s ^ "";
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_eof_reached = true }
let lexeme lexbuf =
let len = lexbuf.lex_curr_pos - lexbuf.lex_start_pos in
let s = String.create len in
String.unsafe_blit lexbuf.lex_buffer lexbuf.lex_start_pos s 0 len;
s
let lexeme_char lexbuf i =
String.get lexbuf.lex_buffer (lexbuf.lex_start_pos + i)
let lexeme_start lexbuf =
lexbuf.lex_abs_pos + lexbuf.lex_start_pos
and lexeme_end lexbuf =
lexbuf.lex_abs_pos + lexbuf.lex_curr_pos
|
