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1 ------------------------------------------------------------------------------
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2 -- --
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3 -- GNAT COMPILER COMPONENTS --
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4 -- --
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5 -- W I D E C H A R --
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6 -- --
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7 -- S p e c --
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8 -- --
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9 -- Copyright (C) 1992-2017, Free Software Foundation, Inc. --
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10 -- --
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11 -- GNAT is free software; you can redistribute it and/or modify it under --
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12 -- terms of the GNU General Public License as published by the Free Soft- --
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13 -- ware Foundation; either version 3, or (at your option) any later ver- --
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14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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16 -- or FITNESS FOR A PARTICULAR PURPOSE. --
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17 -- --
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18 -- As a special exception under Section 7 of GPL version 3, you are granted --
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19 -- additional permissions described in the GCC Runtime Library Exception, --
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20 -- version 3.1, as published by the Free Software Foundation. --
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21 -- --
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22 -- You should have received a copy of the GNU General Public License and --
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23 -- a copy of the GCC Runtime Library Exception along with this program; --
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24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
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25 -- <http://www.gnu.org/licenses/>. --
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26 -- --
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27 -- GNAT was originally developed by the GNAT team at New York University. --
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28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
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29 -- --
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30 ------------------------------------------------------------------------------
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31
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32 -- Subprograms for manipulation of wide character sequences. Note that in
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33 -- this package, wide character and wide wide character are not distinguished
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34 -- since this package is basically concerned with syntactic notions, and it
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35 -- deals with Char_Code values, rather than values of actual Ada types.
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36
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37 with Types; use Types;
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38
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39 package Widechar is
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40
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41 Wide_Char_Byte_Count : Nat := 0;
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42 -- This value is incremented whenever Scan_Wide or Skip_Wide is called.
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43 -- The amount added is the length of the wide character sequence minus
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44 -- one. This means that the count that accumulates here represents the
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45 -- difference between the length in characters and the length in bytes.
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46 -- This is used for checking the line length in characters.
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47
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48 function Length_Wide return Nat;
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49 -- Returns the maximum length in characters for the escape sequence that
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50 -- is used to encode wide character literals outside the ASCII range. Used
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51 -- only in the implementation of the attribute Width for Wide_Character
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52 -- and Wide_Wide_Character.
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53
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54 procedure Scan_Wide
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55 (S : Source_Buffer_Ptr;
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56 P : in out Source_Ptr;
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57 C : out Char_Code;
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58 Err : out Boolean);
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59 -- On entry S (P) points to the first character in the source text for
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60 -- a wide character (i.e. to an ESC character, a left bracket, or an
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61 -- upper half character, depending on the representation method). A
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62 -- single wide character is scanned. If no error is found, the value
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63 -- stored in C is the code for this wide character, P is updated past
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64 -- the sequence and Err is set to False. If an error is found, then
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65 -- P points to the improper character, C is undefined, and Err is
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66 -- set to True.
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67
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68 procedure Set_Wide
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69 (C : Char_Code;
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70 S : in out String;
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71 P : in out Natural);
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72 -- The escape sequence (including any leading ESC character) for the
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73 -- given character code is stored starting at S (P + 1), and on return
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74 -- P points to the last stored character (i.e. P is the count of stored
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75 -- characters on entry and exit, and the escape sequence is appended to
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76 -- the end of the stored string). The character code C represents a code
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77 -- originally constructed by Scan_Wide, so it is known to be in a range
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78 -- that is appropriate for the encoding method in use.
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79
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80 procedure Skip_Wide (S : String; P : in out Natural);
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81 -- On entry, S (P) points to an ESC character for a wide character escape
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82 -- sequence or to an upper half character if the encoding method uses the
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83 -- upper bit, or to a left bracket if the brackets encoding method is in
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84 -- use. On exit, P is bumped past the wide character sequence. No error
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85 -- checking is done, since this is only used on escape sequences generated
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86 -- by Set_Wide, which are known to be correct.
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87
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88 procedure Skip_Wide (S : Source_Buffer_Ptr; P : in out Source_Ptr);
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89 -- Similar to the above procedure, but operates on a source buffer
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90 -- instead of a string, with P being a Source_Ptr referencing the
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91 -- contents of the source buffer.
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92
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93 function Is_Start_Of_Wide_Char
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94 (S : Source_Buffer_Ptr;
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95 P : Source_Ptr) return Boolean;
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96 -- Determines if S (P) is the start of a wide character sequence
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97
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98 private
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99 pragma Inline (Is_Start_Of_Wide_Char);
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100
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101 end Widechar;
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