1 # This file is part of NIT ( http://www.nitlanguage.org ).
3 # This file is free software, which comes along with NIT. This software is
4 # distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
5 # without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
6 # PARTICULAR PURPOSE. You can modify it is you want, provided this header
7 # is kept unaltered, and a notification of the changes is added.
8 # You are allowed to redistribute it and sell it, alone or is a part of
11 # Input and output streams of characters
24 # Any kind of error that could be produced by an operation on Streams
29 # Any kind of stream to read/write/both to or from a source
31 # Codec used to transform raw data to text
33 # Note: defaults to UTF-8
34 var codec
: Codec = utf8_codec
is protected writable(set_codec
)
36 # Lookahead buffer for codecs
38 # Since some codecs are multibyte, a lookahead may be required
39 # to store the next bytes and consume them only if a valid character
41 protected var lookahead
: CString is noinit
43 # Capacity of the lookahead
44 protected var lookahead_capacity
= 0
46 # Current occupation of the lookahead
47 protected var lookahead_length
= 0
49 # Buffer for writing data to a stream
50 protected var write_buffer
: CString is noinit
53 var lcap
= codec
.max_lookahead
54 lookahead
= new CString(lcap
)
55 write_buffer
= new CString(lcap
)
57 lookahead_capacity
= lcap
60 # Change the codec for this stream.
61 fun codec
=(c
: Codec) do
62 if c
.max_lookahead
> lookahead_capacity
then
63 var lcap
= codec
.max_lookahead
64 var lk
= new CString(lcap
)
65 var llen
= lookahead_length
67 lookahead
.copy_to
(lk
, llen
, 0, 0)
70 lookahead_capacity
= lcap
71 write_buffer
= new CString(lcap
)
76 # Error produced by the file stream
78 # var ifs = new FileReader.open("donotmakethisfile.binx")
81 # assert ifs.last_error != null
82 var last_error
: nullable IOError = null
89 # Used to inform `self` that operations will start.
90 # Specific streams can use this to prepare some resources.
92 # Is automatically invoked at the beginning of `with` structures.
94 # Do nothing by default.
99 # Used to inform `self` that the operations are over.
100 # Specific streams can use this to free some resources.
102 # Is automatically invoked at the end of `with` structures.
104 # call `close` by default.
108 # A `Stream` that can be read from
109 abstract class Reader
112 # Read a byte directly from the underlying stream, without
113 # considering any eventual buffer
114 protected fun raw_read_byte
: Int is abstract
116 # Read at most `max` bytes from the underlying stream into `buf`,
117 # without considering any eventual buffer
119 # Returns how many bytes were read
120 protected fun raw_read_bytes
(buf
: CString, max
: Int): Int do
122 for i
in [0 .. max
[ do
123 var b
= raw_read_byte
131 # Reads a character. Returns `null` on EOF or timeout
133 # Returns unicode replacement character '�' if an
134 # invalid byte sequence is read.
136 # `read_char` may block if:
138 # * No byte could be read from the current buffer
139 # * An incomplete char is partially read, and more bytes are
140 # required for full decoding.
141 fun read_char
: nullable Char do
142 if eof
then return null
144 var codet_sz
= cod
.codet_size
146 var llen
= lookahead_length
147 if llen
< codet_sz
then
148 llen
+= raw_read_bytes
(lk
.fast_cstring
(llen
), codet_sz
- llen
)
150 if llen
< codet_sz
then
152 return 0xFFFD.code_point
154 var ret
= cod
.is_valid_char
(lk
, codet_sz
)
155 var max_llen
= cod
.max_lookahead
156 while ret
== 1 and llen
< max_llen
do
157 var rd
= raw_read_bytes
(lk
.fast_cstring
(llen
), codet_sz
)
158 if rd
< codet_sz
then
161 lookahead
.lshift
(codet_sz
, llen
, codet_sz
)
163 lookahead_length
= llen
.max
(0)
164 return 0xFFFD.code_point
167 ret
= cod
.is_valid_char
(lk
, llen
)
170 var c
= cod
.decode_char
(lk
)
171 var clen
= c
.u8char_len
174 lookahead
.lshift
(clen
, llen
, clen
)
176 lookahead_length
= llen
179 if ret
== 2 or ret
== 1 then
182 lookahead
.lshift
(codet_sz
, llen
, codet_sz
)
184 lookahead_length
= llen
185 return 0xFFFD.code_point
187 # Should not happen if the decoder works properly
188 var arr
= new Array[Object]
189 arr
.push
"Decoder error: could not decode nor recover from byte sequence ["
190 for i
in [0 .. llen
[ do
195 var err
= new IOError(arr
.plain_to_s
)
196 err
.cause
= last_error
198 return 0xFFFD.code_point
201 # Reads a byte. Returns a negative value on error
202 fun read_byte
: Int do
203 var llen
= lookahead_length
204 if llen
== 0 then return raw_read_byte
210 lk
.lshift
(1, llen
- 1, 1)
211 lookahead_length
-= 1
216 # Reads a String of at most `i` length
217 fun read
(i
: Int): String do
219 var cs
= new CString(i
)
220 var rd
= read_bytes_to_cstring
(cs
, i
)
221 if rd
< 0 then return ""
222 return codec
.decode_string
(cs
, rd
)
225 # Reads up to `max` bytes from source
226 fun read_bytes
(max
: Int): Bytes do
228 var cs
= new CString(max
)
229 var rd
= read_bytes_to_cstring
(cs
, max
)
230 return new Bytes(cs
, rd
, max
)
233 # Reads up to `max` bytes from source and stores them in `bytes`
234 fun read_bytes_to_cstring
(bytes
: CString, max
: Int): Int do
235 var llen
= lookahead_length
236 if llen
== 0 then return raw_read_bytes
(bytes
, max
)
237 var rd
= max
.min
(llen
)
239 lk
.copy_to
(bytes
, rd
, 0, 0)
241 lk
.lshift
(rd
, llen
- rd
, rd
)
242 lookahead_length
-= rd
246 return rd
+ raw_read_bytes
(bytes
, max
- rd
)
249 # Read a string until the end of the line.
251 # The line terminator '\n' and '\r\n', if any, is removed in each line.
254 # var txt = "Hello\n\nWorld\n"
255 # var i = new StringReader(txt)
256 # assert i.read_line == "Hello"
257 # assert i.read_line == ""
258 # assert i.read_line == "World"
262 # Only LINE FEED (`\n`), CARRIAGE RETURN & LINE FEED (`\r\n`), and
263 # the end or file (EOF) is considered to delimit the end of lines.
264 # CARRIAGE RETURN (`\r`) alone is not used for the end of line.
267 # var txt2 = "Hello\r\n\n\rWorld"
268 # var i2 = new StringReader(txt2)
269 # assert i2.read_line == "Hello"
270 # assert i2.read_line == ""
271 # assert i2.read_line == "\rWorld"
275 # NOTE: Use `append_line_to` if the line terminator needs to be preserved.
276 fun read_line
: String
278 if last_error
!= null then return ""
279 if eof
then return ""
280 var s
= new FlatBuffer
285 # Read all the lines until the eof.
287 # The line terminator '\n' and `\r\n` is removed in each line,
290 # var txt = "Hello\n\nWorld\n"
291 # var i = new StringReader(txt)
292 # assert i.read_lines == ["Hello", "", "World"]
295 # This method is more efficient that splitting
296 # the result of `read_all`.
298 # NOTE: SEE `read_line` for details.
299 fun read_lines
: Array[String]
301 var res
= new Array[String]
308 # Return an iterator that read each line.
310 # The line terminator '\n' and `\r\n` is removed in each line,
311 # The line are read with `read_line`. See this method for details.
314 # var txt = "Hello\n\nWorld\n"
315 # var i = new StringReader(txt)
316 # assert i.each_line.to_a == ["Hello", "", "World"]
319 # Unlike `read_lines` that read all lines at the call, `each_line` is lazy.
320 # Therefore, the stream should no be closed until the end of the stream.
323 # i = new StringReader(txt)
324 # var el = i.each_line
326 # assert el.item == "Hello"
328 # assert el.item == ""
333 # assert not el.is_ok
334 # # closed before "world" is read
336 fun each_line
: LineIterator do return new LineIterator(self)
338 # Read all the stream until the eof.
340 # The content of the file is returned as a String.
343 # var txt = "Hello\n\nWorld\n"
344 # var i = new StringReader(txt)
345 # assert i.read_all == txt
347 fun read_all
: String do
348 var s
= read_all_bytes
350 if slen
== 0 then return ""
351 return codec
.decode_string
(s
.items
, s
.length
)
354 # Read all the stream until the eof.
356 # The content of the file is returned verbatim.
357 fun read_all_bytes
: Bytes
359 if last_error
!= null then return new Bytes.empty
360 var s
= new Bytes.empty
361 var buf
= new CString(4096)
363 var rd
= read_bytes_to_cstring
(buf
, 4096)
369 # Read a string until the end of the line and append it to `s`.
371 # Unlike `read_line` and other related methods,
372 # the line terminator '\n', if any, is preserved in each line.
373 # Use the method `Text::chomp` to safely remove it.
376 # var txt = "Hello\n\nWorld\n"
377 # var i = new StringReader(txt)
378 # var b = new FlatBuffer
379 # i.append_line_to(b)
380 # assert b == "Hello\n"
381 # i.append_line_to(b)
382 # assert b == "Hello\n\n"
383 # i.append_line_to(b)
388 # If `\n` is not present at the end of the result, it means that
389 # a non-eol terminated last line was returned.
392 # var i2 = new StringReader("hello")
394 # var b2 = new FlatBuffer
395 # i2.append_line_to(b2)
396 # assert b2 == "hello"
400 # NOTE: The single character LINE FEED (`\n`) delimits the end of lines.
401 # Therefore CARRIAGE RETURN & LINE FEED (`\r\n`) is also recognized.
402 fun append_line_to
(s
: Buffer)
404 if last_error
!= null then return
411 if x
== '\n' then return
416 # Is there something to read.
417 # This function returns 'false' if there is something to read.
418 fun eof
: Bool is abstract
420 # Read the next sequence of non whitespace characters.
422 # Leading whitespace characters are skipped.
423 # The first whitespace character that follows the result is consumed.
425 # An empty string is returned if the end of the file or an error is encounter.
428 # var w = new StringReader(" Hello, \n\t World!")
429 # assert w.read_word == "Hello,"
430 # assert w.read_char == '\n'
431 # assert w.read_word == "World!"
432 # assert w.read_word == ""
435 # `Char::is_whitespace` determines what is a whitespace.
436 fun read_word
: String
438 var buf
= new FlatBuffer
439 var c
= read_nonwhitespace
444 if c
== null then break
445 if c
.is_whitespace
then break
453 # Skip whitespace characters (if any) then return the following non-whitespace character.
455 # Returns the code point of the character.
456 # Returns `null` on end of file or error.
458 # In fact, this method works like `read_char` except it skips whitespace.
461 # var w = new StringReader(" \nab\tc")
462 # assert w.read_nonwhitespace == 'a'
463 # assert w.read_nonwhitespace == 'b'
464 # assert w.read_nonwhitespace == 'c'
465 # assert w.read_nonwhitespace == null
468 # `Char::is_whitespace` determines what is a whitespace.
469 fun read_nonwhitespace
: nullable Char
471 var c
: nullable Char = null
474 if c
== null or not c
.is_whitespace
then break
480 # Iterator returned by `Reader::each_line`.
481 # See the aforementioned method for details.
483 super Iterator[String]
485 # The original stream
490 var res
= not stream
.eof
491 if not res
and close_on_finish
then stream
.close
499 line
= stream
.read_line
505 # The last line read (cache)
506 private var line
: nullable String = null
511 if line
== null then item
516 # Close the stream when the stream is at the EOF.
519 var close_on_finish
= false is writable
523 if close_on_finish
then stream
.close
527 # `Reader` capable of declaring if readable without blocking
528 abstract class PollableReader
531 # Is there something to read? (without blocking)
532 fun poll_in
: Bool is abstract
536 # A `Stream` that can be written to
537 abstract class Writer
540 # Write bytes from `s`
541 fun write_bytes
(s
: Bytes) do write_bytes_from_cstring
(s
.items
, s
.length
)
543 # Write `len` bytes from `ns`
544 fun write_bytes_from_cstring
(ns
: CString, len
: Int) is abstract
547 fun write
(s
: Text) is abstract
549 # Write a single byte
550 fun write_byte
(value
: Byte) is abstract
552 # Write a single char
553 fun write_char
(c
: Char) do
554 var ln
= codec
.add_char_to
(c
, write_buffer
)
555 write_bytes_from_cstring
(write_buffer
, ln
)
558 # Can the stream be used to write
559 fun is_writable
: Bool is abstract
562 # Things that can be efficienlty written to a `Writer`
564 # The point of this interface is to allow the instance to be efficiently
565 # written into a `Writer`.
567 # Ready-to-save documents usually provide this interface.
569 # Write itself to a `stream`
570 # The specific logic it let to the concrete subclasses
571 fun write_to
(stream
: Writer) is abstract
573 # Like `write_to` but return a new String (may be quite large)
575 # This funtionality is anectodical, since the point
576 # of streamable object to to be efficienlty written to a
577 # stream without having to allocate and concatenate strings
578 fun write_to_string
: String
580 var stream
= new StringWriter
588 redef fun write_to
(s
) do s
.write_bytes
(self)
590 redef fun write_to_string
do return to_s
595 redef fun write_to
(stream
) do stream
.write
(self)
598 # Input streams with a buffered input for efficiency purposes
599 abstract class BufferedReader
602 redef fun raw_read_byte
604 if last_error
!= null then return -1
606 last_error
= new IOError("Stream has reached eof")
609 var c
= _buffer
[_buffer_pos
]
614 # Resets the internal buffer
620 # Peeks up to `n` bytes in the buffer
622 # The operation does not consume the buffer
625 # var x = new FileReader.open("File.txt")
626 # assert x.peek(5) == x.read(5)
628 fun peek
(i
: Int): Bytes do
629 if eof
then return new Bytes.empty
630 var remsp
= _buffer_length
- _buffer_pos
632 var bf
= new Bytes.with_capacity
(i
)
633 bf
.append_ns_from
(_buffer
, i
, _buffer_pos
)
636 var bf
= new Bytes.with_capacity
(i
)
637 bf
.append_ns_from
(_buffer
, remsp
, _buffer_pos
)
638 _buffer_pos
= _buffer_length
639 read_intern
(i
- bf
.length
, bf
)
640 remsp
= _buffer_length
- _buffer_pos
641 var full_len
= bf
.length
+ remsp
642 if full_len
> _buffer_capacity
then
643 var c
= _buffer_capacity
644 while c
< full_len
do c
= c
* 2 + 2
647 var nns
= new CString(_buffer_capacity
)
648 bf
.items
.copy_to
(nns
, bf
.length
, 0, 0)
649 _buffer
.copy_to
(nns
, remsp
, _buffer_pos
, bf
.length
)
652 _buffer_length
= full_len
656 redef fun read_bytes_to_cstring
(buf
, i
)
658 if last_error
!= null then return 0
659 var bbf
= new Bytes(buf
, 0, i
)
660 return read_intern
(i
, bbf
)
663 # Fills `buf` with at most `i` bytes read from `self`
664 private fun read_intern
(i
: Int, buf
: Bytes): Int do
667 var bufsp
= _buffer_length
- p
670 buf
.append_ns_from
(_buffer
, i
, p
)
673 _buffer_pos
= _buffer_length
674 var readln
= _buffer_length
- p
675 buf
.append_ns_from
(_buffer
, readln
, p
)
676 var rd
= read_intern
(i
- readln
, buf
)
680 redef fun read_all_bytes
682 if last_error
!= null then return new Bytes.empty
683 var s
= new Bytes.with_capacity
(10)
687 var k
= _buffer_length
689 s
.append_ns_from
(b
, rd_sz
, j
)
696 redef fun append_line_to
(s
)
698 var lb
= new Bytes.with_capacity
(10)
700 # First phase: look for a '\n'
702 while i
< _buffer_length
and _buffer
[i
] != 0xAu
8 do
707 if i
< _buffer_length
then
708 assert _buffer
[i
] == 0xAu
8
715 # if there is something to append
716 if i
> _buffer_pos
then
717 # Copy from the buffer to the string
747 if _buffer_pos
< _buffer_length
then return false
748 if end_reached
then return true
750 return _buffer_pos
>= _buffer_length
and end_reached
754 private var buffer
: CString = new CString(0)
756 # The current position in the buffer
757 private var buffer_pos
= 0
759 # Length of the current buffer (i.e. nuber of bytes in the buffer)
760 private var buffer_length
= 0
762 # Capacity of the buffer
763 private var buffer_capacity
= 0
766 protected fun fill_buffer
is abstract
768 # Has the last fill_buffer reached the end
769 protected fun end_reached
: Bool is abstract
771 # Allocate a `_buffer` for a given `capacity`.
772 protected fun prepare_buffer
(capacity
: Int)
774 _buffer
= new CString(capacity
)
775 _buffer_pos
= 0 # need to read
777 _buffer_capacity
= capacity
781 # A `Stream` that can be written to and read from
782 abstract class Duplex
787 # Write to `bytes` in memory
790 # var writer = new BytesWriter
792 # writer.write "Strings "
793 # writer.write_char '&'
794 # writer.write_byte 0x20u8
795 # writer.write_bytes "bytes".to_bytes
797 # assert writer.to_s == "\\x53\\x74\\x72\\x69\\x6E\\x67\\x73\\x20\\x26\\x20\\x62\\x79\\x74\\x65\\x73"
798 # assert writer.bytes.to_s == "Strings & bytes"
801 # As with any binary data, UTF-8 code points encoded on two bytes or more
802 # can be constructed byte by byte.
805 # writer = new BytesWriter
807 # # Write just the character first half
808 # writer.write_byte 0xC2u8
809 # assert writer.to_s == "\\xC2"
810 # assert writer.bytes.to_s == "�"
812 # # Complete the character
813 # writer.write_byte 0xA2u8
814 # assert writer.to_s == "\\xC2\\xA2"
815 # assert writer.bytes.to_s == "¢"
821 var bytes
= new Bytes.empty
823 redef fun to_s
do return bytes
.chexdigest
827 if closed
then return
828 str
.append_to_bytes bytes
831 redef fun write_char
(c
)
833 if closed
then return
837 redef fun write_byte
(value
)
839 if closed
then return
843 redef fun write_bytes_from_cstring
(ns
, len
) do
844 if closed
then return
845 bytes
.append_ns
(ns
, len
)
848 # Is the stream closed?
849 protected var closed
= false
851 redef fun close
do closed
= true
852 redef fun is_writable
do return not closed
855 # `Stream` writing to a `String`
857 # This class has the same behavior as `BytesWriter`
858 # except for `to_s` which decodes `bytes` to a string.
861 # var writer = new StringWriter
863 # writer.write "Strings "
864 # writer.write_char '&'
865 # writer.write_byte 0x20u8
866 # writer.write_bytes "bytes".to_bytes
868 # assert writer.to_s == "Strings & bytes"
873 redef fun to_s
do return bytes
.to_s
876 # Read from `bytes` in memory
879 # var reader = new BytesReader(b"a…b")
880 # assert reader.read_char == 'a'
881 # assert reader.read_byte == 0xE2 # 1st byte of '…'
882 # assert reader.read_byte == 0x80 # 2nd byte of '…'
883 # assert reader.read_char == '�' # Reads the last byte as an invalid char
884 # assert reader.read_all_bytes == b"b"
889 # Source data to read
892 # The current position in `bytes`
893 private var cursor
= 0
895 redef fun raw_read_byte
897 if cursor
>= bytes
.length
then return -1
899 var c
= bytes
[cursor
]
904 redef fun close
do bytes
= new Bytes.empty
906 redef fun read_all_bytes
908 var res
= bytes
.slice_from
(cursor
)
909 cursor
= bytes
.length
913 redef fun raw_read_bytes
(ns
, max
) do
914 if cursor
>= bytes
.length
then return 0
916 var copy
= max
.min
(bytes
.length
- cursor
)
917 bytes
.items
.copy_to
(ns
, copy
, cursor
, 0)
922 redef fun eof
do return cursor
>= bytes
.length
925 # `Stream` reading from a `String` source
927 # This class has the same behavior as `BytesReader`
928 # except for its constructor accepting a `String`.
931 # var reader = new StringReader("a…b")
932 # assert reader.read_char == 'a'
933 # assert reader.read_byte == 0xE2 # 1st byte of '…'
934 # assert reader.read_byte == 0x80 # 2nd byte of '…'
935 # assert reader.read_char == '�' # Reads the last byte as an invalid char
936 # assert reader.read_all == "b"
943 # Source data to read
946 init do bytes
= source
.to_bytes