Bug in function check_char corrected: instead of only accepting \r\n as a new
line, it accepted any amount of \r followed by \n. Float scanning code revisited, commenting the code and avoiding side effect in function application. Type file_name now used to define in_channel_name, hence its definition goes before in_channel_name. open/close_in --> Pervasives.open/close_in when necessary. Indentation revisited. git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@16421 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02master
Pierre Weis
parent
24b8bf59f9
commit
1cd50636fa
122
stdlib/scanf.ml
122
stdlib/scanf.ml
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@ -38,7 +38,7 @@ module type SCANNING = sig
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val stdin : in_channel;;
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(* The scanning buffer reading from [Pervasives.stdin].
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[stdib] is equivalent to [Scanning.from_channel Pervasives.stdin]. *)
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[stdib] is equivalent to [Scanning.from_channel Pervasives.stdin]. *)
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val stdib : in_channel;;
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(* An alias for [Scanf.stdin], the scanning buffer reading from
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@ -46,32 +46,32 @@ module type SCANNING = sig
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val next_char : scanbuf -> char;;
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(* [Scanning.next_char ib] advance the scanning buffer for
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one character.
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If no more character can be read, sets a end of file condition and
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returns '\000'. *)
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one character.
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If no more character can be read, sets a end of file condition and
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returns '\000'. *)
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val invalidate_current_char : scanbuf -> unit;;
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(* [Scanning.invalidate_current_char ib] mark the current_char as already
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scanned. *)
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scanned. *)
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val peek_char : scanbuf -> char;;
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(* [Scanning.peek_char ib] returns the current char available in
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the buffer or reads one if necessary (when the current character is
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already scanned).
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If no character can be read, sets an end of file condition and
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returns '\000'. *)
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the buffer or reads one if necessary (when the current character is
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already scanned).
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If no character can be read, sets an end of file condition and
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returns '\000'. *)
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val checked_peek_char : scanbuf -> char;;
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(* Same as above but always returns a valid char or fails:
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instead of returning a null char when the reading method of the
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input buffer has reached an end of file, the function raises exception
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[End_of_file]. *)
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(* Same as [Scanning.peek_char] above but always returns a valid char or
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fails: instead of returning a null char when the reading method of the
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input buffer has reached an end of file, the function raises exception
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[End_of_file]. *)
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val store_char : int -> scanbuf -> char -> int;;
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(* [Scanning.store_char lim ib c] adds [c] to the token buffer
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of the scanning buffer. It also advances the scanning buffer for one
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character and returns [lim - 1], indicating the new limit
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for the length of the current token. *)
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of the scanning buffer [ib]. It also advances the scanning buffer for
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one character and returns [lim - 1], indicating the new limit for the
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length of the current token. *)
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val skip_char : int -> scanbuf -> int;;
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(* [Scanning.skip_char lim ib] ignores the current character. *)
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@ -82,41 +82,41 @@ module type SCANNING = sig
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val token : scanbuf -> string;;
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(* [Scanning.token ib] returns the string stored into the token
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buffer of the scanning buffer: it returns the token matched by the
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format. *)
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buffer of the scanning buffer: it returns the token matched by the
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format. *)
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val reset_token : scanbuf -> unit;;
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(* [Scanning.reset_token ib] resets the token buffer of
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the given scanning buffer. *)
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the given scanning buffer. *)
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val char_count : scanbuf -> int;;
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(* [Scanning.char_count ib] returns the number of characters
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read so far from the given buffer. *)
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read so far from the given buffer. *)
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val line_count : scanbuf -> int;;
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(* [Scanning.line_count ib] returns the number of new line
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characters read so far from the given buffer. *)
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characters read so far from the given buffer. *)
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val token_count : scanbuf -> int;;
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(* [Scanning.token_count ib] returns the number of tokens read
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so far from [ib]. *)
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so far from [ib]. *)
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val eof : scanbuf -> bool;;
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(* [Scanning.eof ib] returns the end of input condition
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of the given buffer. *)
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of the given buffer. *)
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val end_of_input : scanbuf -> bool;;
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(* [Scanning.end_of_input ib] tests the end of input condition
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of the given buffer (if no char has ever been read, an attempt to
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read one is performed). *)
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of the given buffer (if no char has ever been read, an attempt to
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read one is performed). *)
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val beginning_of_input : scanbuf -> bool;;
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(* [Scanning.beginning_of_input ib] tests the beginning of input
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condition of the given buffer. *)
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condition of the given buffer. *)
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val name_of_input : scanbuf -> string;;
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(* [Scanning.name_of_input ib] returns the name of the character
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source for input buffer [ib]. *)
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source for input buffer [ib]. *)
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val open_in : file_name -> in_channel;;
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val open_in_bin : file_name -> in_channel;;
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@ -134,8 +134,11 @@ end
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module Scanning : SCANNING = struct
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(* The run-time library for scanf. *)
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type file_name = string;;
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type in_channel_name =
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| From_file of string * Pervasives.in_channel
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| From_file of file_name * Pervasives.in_channel
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| From_string
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| From_function
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| From_channel of Pervasives.in_channel
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@ -156,13 +159,11 @@ module Scanning : SCANNING = struct
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type scanbuf = in_channel;;
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type file_name = string;;
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let null_char = '\000';;
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(* Reads a new character from input buffer. Next_char never fails,
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even in case of end of input: it then simply sets the end of file
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condition. *)
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(* Reads a new character from input buffer.
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Next_char never fails, even in case of end of input:
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it then simply sets the end of file condition. *)
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let next_char ib =
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try
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let c = ib.get_next_char () in
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@ -180,7 +181,8 @@ module Scanning : SCANNING = struct
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;;
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let peek_char ib =
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if ib.current_char_is_valid then ib.current_char else next_char ib;;
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if ib.current_char_is_valid then ib.current_char else next_char ib
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;;
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(* Returns a valid current char for the input buffer. In particular
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no irrelevant null character (as set by [next_char] in case of end
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@ -201,6 +203,7 @@ module Scanning : SCANNING = struct
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let eof ib = ib.eof;;
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let beginning_of_input ib = ib.char_count = 0;;
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let name_of_input ib =
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match ib.input_name with
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| From_file (fname, _ic) -> fname
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@ -212,8 +215,11 @@ module Scanning : SCANNING = struct
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let char_count ib =
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if ib.current_char_is_valid then ib.char_count - 1 else ib.char_count
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;;
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let line_count ib = ib.line_count;;
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let reset_token ib = Buffer.reset ib.tokbuf;;
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let invalidate_current_char ib = ib.current_char_is_valid <- false;;
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let token ib =
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@ -324,7 +330,7 @@ module Scanning : SCANNING = struct
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let file_buffer_size = ref 1024;;
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(* The scanner closes the input channel at end of input. *)
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let scan_close_at_end ic = close_in ic; raise End_of_file;;
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let scan_close_at_end ic = Pervasives.close_in ic; raise End_of_file;;
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(* The scanner does not close the input channel at end of input:
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it just raises [End_of_file]. *)
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@ -375,7 +381,7 @@ module Scanning : SCANNING = struct
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match fname with
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| "-" -> stdin
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| fname ->
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let ic = open_in fname in
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let ic = Pervasives.open_in fname in
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from_ic_close_at_end (From_file (fname, ic)) ic
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;;
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@ -383,7 +389,7 @@ module Scanning : SCANNING = struct
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match fname with
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| "-" -> stdin
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| fname ->
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let ic = open_in_bin fname in
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let ic = Pervasives.open_in_bin fname in
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from_ic_close_at_end (From_file (fname, ic)) ic
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;;
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@ -431,14 +437,16 @@ let bad_token_length message =
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bad_input
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(Printf.sprintf
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"scanning of %s failed: \
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the specified length was too short for token" message)
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the specified length was too short for token"
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message)
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;;
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let bad_end_of_input message =
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bad_input
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(Printf.sprintf
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"scanning of %s failed: \
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premature end of file occurred before end of token" message)
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premature end of file occurred before end of token"
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message)
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;;
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let bad_float () =
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@ -478,13 +486,22 @@ let rec skip_whites ib =
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We are also careful to treat "\r\n" in the input as an end of line marker:
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it always matches a '\n' specification in the input format string. *)
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let rec check_char ib c =
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if c = ' ' then skip_whites ib else
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let ci = Scanning.checked_peek_char ib in
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if ci = c then Scanning.invalidate_current_char ib else
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match ci with
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| '\r' when c = '\n' ->
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Scanning.invalidate_current_char ib; check_char ib '\n'
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| _ -> character_mismatch c ci
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match c with
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| ' ' -> skip_whites ib
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| '\n' -> check_newline ib
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| c -> check_this_char ib c
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and check_this_char ib c =
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let ci = Scanning.checked_peek_char ib in
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if ci = c then Scanning.invalidate_current_char ib else
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character_mismatch c ci
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and check_newline ib =
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let ci = Scanning.checked_peek_char ib in
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match ci with
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| '\n' -> Scanning.invalidate_current_char ib
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| '\r' -> Scanning.invalidate_current_char ib; check_this_char ib '\n'
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| _ -> character_mismatch '\n' ci
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;;
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(* Extracting tokens from the output token buffer. *)
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@ -682,6 +699,7 @@ let scan_int_conv conv width ib =
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;;
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(* Scanning floating point numbers. *)
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(* Fractional part is optional and can be reduced to 0 digits. *)
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let scan_frac_part width ib =
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if width = 0 then width else
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@ -768,12 +786,22 @@ let scan_caml_float width precision ib =
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match c with
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| '.' ->
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let width = Scanning.store_char width ib c in
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(* The effective width available for scanning the fractional part is
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the minimum of declared precision and width left. *)
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let precision = min width precision in
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let width = width - (precision - scan_frac_part precision ib) in
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(* After scanning the fractional part with [precision] provisional width,
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[width_precision] is left. *)
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let width_precision = scan_frac_part precision ib in
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(* Hence, scanning the fractional part took exactly
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[precision - width_precision] chars. *)
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let frac_width = precision - width_precision in
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(* And new provisional width is [width - width_precision. *)
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let width = width - frac_width in
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scan_exp_part width ib
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| 'e' | 'E' ->
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scan_exp_part width ib
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| _ -> bad_float ()
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;;
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(* Scan a regular string:
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stops when encountering a space, if no scanning indication has been given;
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