complexstr.sa


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partial class COMPLEX_STR{T} < $TEXT, $FLT_FMT

partial class COMPLEX_STR{T} < $TEXT, $FLT_FMT is -- This partial class provides numeric real number conversion routines, -- to and from character strings. -- The character representation of a complex number consists of two -- floating point values separated by a space-surrounded sign and followed -- by an imaginary component indicator as in "1.23 + 4.56j". -- Version 1.1 Mar 99. Copyright K Hopper, U of Waikato -- Development History -- ------------------- -- Date Who By Detail -- ---- ------ ------ -- 2 Oct 98 kh Original from RAT_STR/FLOAT_STR -- 29 Mar 99 kh Revised for V8 of text classes private const Imaginary_Component_Indicator : UNICODE := UNICODE::LATIN_SMALL_LETTER_J ; private scan( cursor : STR_CURSOR ) : SAME pre ~void(cursor) post true -- should involve 'void' is -- This routine is the complex number 'scanner' to obtain the value -- expected to be next in the indicated string - or returning with the string -- unchanged, returning void if there is a format error or NaN if there is -- a range error. start_index : CARD := cursor.index ; loc_lib : LIBCHARS := cursor.buffer.index_lib ; loc_start : CARD ; loc_re : T := T::build(cursor) ; if cursor.index = start_index then return void else loc_start := cursor.index ; cursor.skip_space ; if cursor.item = loc_lib.Plus_Sign.char or cursor.item = loc_lib.Minus_Sign.char then cursor.skip_space else cursor.set_index(start_index) ; return void end ; loc_start := cursor.index end ; loc_im : T := T::build(cursor) ; loc_ICI : CHAR := CHAR_CODE::create(Imaginary_Component_Indicator.card,loc_lib).char ; if cursor.index = loc_start then cursor.set_index(start_index) ; return void elsif cursor.item = loc_ICI then return re(loc_re).im(loc_im) else cursor.set_index(start_index) ; return void end end ; is_complex( str : STR_CURSOR ) : CONVERSION_RESULTS pre true post (result = CONVERSION_RESULTS::All_Right) or (result = CONVERSION_RESULTS::Out_of_Range) or (result = CONVERSION_RESULTS::Bad_Format) or (result = CONVERSION_RESULTS::Empty) is -- This routine checks that the format of of the leading characters of -- the given string using the given repertoire and encoding corresponds to -- that required for a complex number, returning the relevant result state. if str.remaining = 0 then return CONVERSION_RESULTS::Empty end ; start_index : CARD := 0 ; loc_cursor : STR_CURSOR := str ; loc_res : SAME := scan(loc_cursor) ; if loc_cursor.index = start_index then return CONVERSION_RESULTS::Bad_Format else loc_cursor.set_index(start_index) ; return CONVERSION_RESULTS::All_Right end end ; build( loc_cursor : STR_CURSOR ) : SAME pre ~void(loc_cursor) and (((loc_cursor.remaining >= 3) -- as in x.y and ((loc_cursor.item /= loc_cursor.buffer.index_lib.Plus_Sign.char) and (loc_cursor.item /= loc_cursor.buffer.index_lib.Minus_Sign.char))) or (loc_cursor.remaining >= 4)) and ~loc_cursor.is_done post true -- should involve 'void' is -- This routine creates the complex number corresponding to the textual -- representation contained in str which must have a digit both before and -- after a mandatory decimal mark! If the string indicated does not -- contain a real number as the next non-blank item in the string then zero is -- returned or if out of range then quiet_NaN is returned -- and the cursor -- has not been moved! return scan(loc_cursor) end ; create( str : STR ) : SAME pre ~void(str.index_lib) and (is_complex(str.cursor) = CONVERSION_RESULTS::All_Right) post true is -- This routine creates the real number corresponding to the textual -- representation contained in str. return build(str.cursor) end ; num_chars : CARD is -- This routine returns the number of digits in the result, excluding -- any exponent. loc_val : T := im.abs ; return re.num_chars + loc_val.num_chars + 3 end ; str( lib : LIBCHARS ) : STR pre ~void(lib) -- and (re /= T::quiet_NaN(0.int)) -- and (im /= T::quiet_NaN(0.int)) post (result.size > 0) is -- This routine returns a string representation of self using the given -- repertoire and encoding. The format will be either fixed point or -- floating point dependent upon the value of self. res : STR := re.str(lib) + lib.Space.char ; loc_im : T := im ; if loc_im < T::zero then res := res + lib.Minus_Sign.char ; loc_im := -loc_im else res := res + lib.Plus_Sign.char end ; return res + lib.Space.char + loc_im.str(lib) + CHAR_CODE::create(Imaginary_Component_Indicator.card,lib).char end ; str : STR pre true -- (re /= T::quiet_NaN(0.int)) -- and (im /= T::quiet_NaN(0.int)) post (result.size > 0) is -- This routine returns a string representation of self using the given -- repertoire and encoding. The format will be either fixed point or -- floating point dependent upon which of the two is the shorter string. return str(LIBCHARS::default) end ; fmt( format : FLT_DESCR, lib : LIBCHARS ) : STR pre ~void(format) and ~void(lib) post result.size > 0 is -- This routine returns a formatted representation of self in the given -- repertoire and encoding as dictated by the given format description. -- -- NOTE This pair of routines produces a string in which the teo components -- are formatted individually as indicated. Further layout may be done -- by using the last formatting routine. res : STR := re.fmt(format,lib) + lib.Space.char ; loc_im : T := im ; if loc_im < T::zero then res := res + lib.Minus_Sign.char ; loc_im := -loc_im else res := res + lib.Plus_Sign.char end ; return res + lib.Space.char + loc_im.fmt(format,lib) + CHAR_CODE::create(Imaginary_Component_Indicator.card,lib).char end ; fmt( format : FLT_DESCR ) : STR pre ~void(format) post result.size > 0 is -- This routine returns a formatted representation of self in the default -- repertoire and encoding as dictated by the given format description. return fmt(format,LIBCHARS::default) end ; fmt( format : FLT_DESCR, final_fmt : ANCHORED_DESCR, -- anchored about central sign lib : LIBCHARS ) : STR pre ~void(format) and ~void(lib) post result.size > 0 is -- This routine returns a formatted representation of self in the given -- repertoire and encoding as dictated by the given format description. -- -- NOTE This pair of routines produces a string in which the teo components -- are formatted individually as indicated. Further layout may be done -- by using the following pair of routines instead. res : STR ; tail : STR ; res := re.fmt(format,lib) + lib.Space.char ; if final_fmt.leading > res.size then -- needs some leading fillers res := STR::create(final_fmt.filler.card,lib).repeat( final_fmt.leading - res.size) + res end ; loc_im : T := im ; if loc_im < T::zero then res := res + lib.Minus_Sign.char ; loc_im := -loc_im else res := res + lib.Plus_Sign.char end ; tail := STR::create + lib.Space.char + loc_im.fmt(format,lib) + Imaginary_Component_Indicator.code.char ; if final_fmt.trailing > tail.size then tail := tail + STR::create(final_fmt.filler.card,lib).repeat( final_fmt.trailing - tail.size) end ; return res + tail end ; end ; -- COMPLEX_STR